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AssigneeDsm IP Assets B.V.
InventorsJoseph Arnold Paul Maria Simmelink, Jacobus Johannes Mencke, Martinus Johannes Nicolaas Jacobs, Roeloef Marissen
Estimating the term…
Processes for making high-performance polyethylene multi-filament yarn are disclosed which include the steps of a) making a solution of ultra-high molar mass polyethylene in a solvent; b) spinning of the solution through a spinplate containing at least 5 spinholes into an air-gap to form fluid filaments, while applying a draw ratio DRfluid; c) cooling the fluid filaments to form solvent-containing gel filaments; d) removing at least partly the solvent from the filaments; and e) drawing the filaments in at least one step before, during and/or after said solvent removing, while applying a draw ratio DRsolid of at least 4, wherein in step b) each spinhole comprises a contraction zone of specific dimension and a downstream zone of diameter Dn and length Dn with Ln/Dn of from 0 to at most 25, to result in a draw ratio DRfluid=DRsp*DRag of at least 150, wherein DRsp is the draw ratio in the spinholes and DRag is the draw ratio in the air-gap, with DRsp being greater than 1 and DRag at least 1. High-performance polyethylene multifilament yarn, and semi-finished or end-use products containing said yarn, especially to ropes and ballistic-resistant composites, are also disclosed.
A preformed sheet comprising four mono-layers, each mono-layer comprising polyethylene filaments obtained from multifilament polyethylene yarn, the polyethylene having an IV of between 8 and 40 dl/g as measured on decalin solutions at 135° C., wherein the filaments in the mono-layers are spread unidirectionally, and wherein a direction of the filaments in each of the mono-layers is rotated with respect to a direction of the filaments in an adjacent layer, and wherein the preformed sheet exhibits a specific energy absorption of more than 265 and at most 479 J·kg/m2 against a 9*19 mm FMJ Parabellum FMJ bullet, as measured on panels assembled from a plurality of the preformed sheets having an areal density of 2.0 kg/m2.
Dependencies are inferred from the claim text.