Dsm IP Assets B.v.

Avient Protective Materials B.v.

Roeloef Marissen

Joseph Arnold Paul Maria Simmelink

Jacobus Johannes Mencke

Martinus Johannes Nicolaas Jacobs

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 DR; 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 DRof 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 DR=DR*DRof at least 150, wherein DRis the draw ratio in the spinholes and DRis the draw ratio in the air-gap, with DRbeing greater than 1 and DRat 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.

High-performance polyethylene multifilament yarn

Preformed sheet layers of multiple high-performance polyethylene (HPPE) multifilament yarn monolayers and ballistic-resistant assemblies comprising the same

Process for making high-performance polyethylene multifilament yarn

The invention relates to a process for making high-performance polyethylene multi-filament yarn comprising 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 Ln 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. The invention further relates to a high-performance polyethylene multifilament yarn, and to semi-finished or end-use products containing said yarn, especially to ropes and ballistic-resistant composites.

Ballistic-resistant assemblies include monolayers formed of high-performance polyethylene multi-filament yarns. The assemblies have an areal density of at least 1.5 kg/mand a specific energy absorption of at least 300 J&#xb7;m/kg as measured against a 9*19 mm FMJ Parabellum bullet according to a test procedure based on Stanag 2920.

Ballistic-resistant assemblies with monolayers of high-performance polyethylene multifilament yarns

The invention relates to a process for the manufacture of an object, curved in one or more directions, from a package of at least one stacked ply containing polymeric fibers by the deforming thereof at elevated temperature, the process comprising imposing on the fibres a tensile stress at a temperature lying between the melting point of the fibers at the imposed tensile stress and 20&#xb0; C. below the melting point, which tensile stress is high enough for the fibers to be drawn. This process allows objects, curved in one or more directions, to be produced from flat fiber plies without appreciable wrinkling using even fiber plies with low internal and/or mutual deformability and without material being drawn into the die in a controlled manner. The invention also relates to an object, curved in one or more directions, obtainable by the process according to the invention.

Process for the manufacture of curved objects

The invention relates to a process for making high-performance polyethylene multi-filament yarn comprising 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 DR; 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 DRof at least 4, wherein in step b) each spinhole comprises a contraction zone of specific dimension and a downstream zone of diameter Dand length Dwith L/Dof from 0 to at most 25, to result in a draw ratio DR=DR*DRof at least 150, wherein DRis the draw ratio in the spinholes and DRis the draw ratio in the air-gap, with DRbeing greater than 1 and DRat least 1. The invention further relates to a high-performance polyethylene multifilament yarn, and to semi-finished or end-use products containing said yarn, especially to ropes and ballistic-resistant composites.

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Born, Netherlands

Roeloef Marissen