Process for the production of a monolayer composite article, the monolayer composite article and a ballistic-resistant article

Abstract

Process for the production of a monolayer composite article comprising an unidirectional array of high performance polyolefin fibers, the process comprising the steps of positioning of the fibers in a coplanar, parallel fashion consolidation of the fibers to obtain the monolayer composite article, the process comprises after the step of position of the fibers and before or after the step of consolidation of the fibers, a step in which the fibers are stretched.

1 . Process for the production of a monolayer composite article comprising an unidirectional array of high performance polyolefin fibers, the process comprising the steps of positioning of the fibers in a coplanar, parallel fashion consolidation of the fibers to obtain the monolayer composite article, characterized in that, the process comprises after the step of position of the fibers and before or after the step of consolidation of the fibers, a step in which the fibers are stretched. 
   
   
       2 . Process for the production of a monolayer composite article according to  claim 1 , wherein a plastic matrix material is used for the consolidation. 
   
   
       3 . Process for the production of a monolayer composite article according to  claim 2 , wherein the fibers are consolidated by embedding the fibers partially or wholly in a plastic matrix material. 
   
   
       4 . Process for the production of a monolayer composite article according to  claim 1 , wherein the stretching of the fibers takes place by increasing the transport velocity of the fibers at a position in the process line for the production of the monolayer composite article. 
   
   
       5 . Process for the production of a monolayer composite article according to  claim 4 , wherein the increase in the transport velocity is accomplished by transporting the fibers over at least a first and at least a subsequent second transportation roll, the second transportation roll having a tangential velocity at its surface that is higher than the tangential velocity at its surface of the first roll. 
   
   
       6 . Process for the production of a monolayer composite article according to  claim 4 , wherein the increase in transport velocity is at most a factor of 3. 
   
   
       7 . Process for the production of a monolayer composite article according to  claim 4 , wherein the increase in transport velocity is at least a factor of 1.05. 
   
   
       8 . Process for the production of a monolayer composite article according to  claim 1 , wherein the step of stretching the fibers is after the consolidation of the fibers. 
   
   
       9 . Process for the production of a cross-layered composite article whereby at least one pair of monolayer composite articles according to  claim 1  is stacked whereby the fiber direction in each monolayer composite article is rotated with respect to the fiber direction in an adjacent monolayer. 
   
   
       10 . Monolayer composite article obtainable by the process according to  claim 1 . 
   
   
       11 . Article comprising a high performance polyolefin fiber having a stretch ratio at break of less than 1.4, measured at 150° C. and with a deformation rate of 0.2 min −1 . 
   
   
       12 . Article according to  claim 11 , which article comprises a high performance polyolefin fiber having a stretch ratio at break of less than 1.35, measured at 150° C. and with a deformation rate of 0.2 min −1 . 
   
   
       13 . A monolayer composite articles or a cross-layered composite article that show a V 50  of at least 380 m/s, if produced into flexible composite article, comprising a stack of the monolayer composite article or the cross-layered composite article, the flexible composite article having an aerial density between 1.95 and 2.05 kg/m 2  and shot by a 9 mm parabellum having a weight of 8 gram, according to STANAG 2920. 
   
   
       14 . A flexible ballistic resistant article, preferably a bullet resistant vest, having a SEA, if shot by a 9 mm parabellum having a weight of 8 gram, according to STANAG 2929, of at least 300 J.m 2 /kg. 
   
   
       15 . A rigid ballistic resistant article, preferably a bullet resistant vest, having a SEA, if shot by a 9 mm parabellum having a weight of 8 gram, according to STANAG 2929, of at least 300 J.m 2 /kg. 
   
   
       16 . Process according to  claim 1  or an article, wherein the high performance polyolefin fibers have a strength of at least 1.2 GPa and a modulus of at least 40 GPa. 
   
   
       17 . Process according to  claim 1  or an article, wherein the high performance polyolefin fibers are obtained by the gel spinning process. 
   
   
       18 . Process or article according to  claim 1 , wherein the high performance polyolefin fibers are fibers of high molecular weight linear polyethylene having a weight average molecular weight of at least 400,000 g/mol.