Material sheet and process for its preparation

Patent metadata

Field	Value
Publication number	US-9541351-B2
Application number	US-74049008-A
Country	US
Kind code	B2
Filing date	Oct 29, 2008
Priority date	Nov 1, 2007
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

The invention relates to a material sheet comprising at least one monolayer, wherein at least one monolayer comprises a plurality of drawn unidirectional polymer fibers having a strength of greater than 1.2 GPa, characterized in that the at least one monolayer has a thickness of less than 100 μm and the material sheet comprises a bonding agent of less than 13 wt % relative to the total weight of the material sheet.

First claim

The invention claimed is:

1. An integral material sheet with interconnected fibers comprising at least two integral monolayers, wherein
at least one integral monolayer of the integral material sheet is free of bonding agent and has a thickness of less than 100 μm, and wherein
the at least one integral monolayer comprises a plurality of drawn unidirectional polymer fibers having a strength of greater than 1.2 GPa, and wherein
at least 80 wt. % of adjacent fibers within the at least one monolayer are mechanically fused together along at least 30% of fiber length through mechanical interlocking thereby forming an integral material sheet with interconnected fibers, and wherein
the fibers are monofilaments or filaments spread from a multifilament yarn, and wherein
the at least one monolayer has a maximum thickness of no more than 3 times a thickness of an individual fiber.

2. The material sheet of claim 1 , comprising at least two monolayers wherein the fiber direction in adjacent monolayers in the material sheet differs.

3. The material sheet of claim 1 , wherein the at least one monolayer has a thickness of no more than 2 times a thickness of the drawn unidirectional polymer fibers.

4. The material sheet of claim 1 , wherein a bonding agent is present in the material sheet, wherein the bonding agent further comprises melt recrystallised fibers at a level of less than 5 wt % relative to the total weight of the polymer fibers, as determined by DSC (10° C./min).

5. The material sheet of claim 1 , wherein a bonding agent is present in the material sheet, wherein the bonding agent is in a form of bonding strips or fibers to bond the fibers in a monolayer, wherein the bonding strips or fibers are orientated in a different direction then the drawn unidirectional polymer fibers within the at least one monolayer.

6. The material sheet of claim 5 , wherein the bonding strips or fibers are bonded to a surface area of the at least one monolayer, and wherein the bonding strips cover no more than 20% of the monolayer surface area.

7. The material sheet of claim 1 , wherein the drawn unidirectional polymer fibers are made from ultra-high molecular weight polyethylene with an intrinsic viscosity as determined on solutions in decalin at 135° C. of at least 4 dl/g.

8. The material sheet of claim 4 , wherein the bonding agent is at least one selected from the group of polyurethanes, polyvinyls, polyacrylics, polyolefins or thermoplastic elastomeric block copolymers such as polyisopropene-polyethylene-butylene-polystyrene and polystyrene-polyisoprene-polystyrene block copolymers.

9. A material sheet obtained from a process comprising:
(a) unidirectionally aligning a plurality of drawn polymer fibers having a strength of greater than 1.2 GPa thereby forming a monolayer having a thickness of less than 100 μm which is free of a bonding agent, wherein the drawn polymer fibers are aligned such that at least 80 wt. % of the fibers within the monolayer are in abutting contact along at least 30% of fiber length; and
(b) compressing the material sheet under at least 75 bar pressure, such that the abutting fibers of the monolayer are mechanically fused together through mechanical interlocking thereby forming an integral material sheet with interconnected fibers, and wherein
the fibers are monofilaments or filaments spread from a multifilament yarn, and wherein
the monolayer has a maximum thickness of no more than 3 times a thickness of an individual fiber.

10. A tape with a width of between 1 and 250 mm comprising:
a plurality of drawn unidirectional polymer fibers made from ultra-high molecular weight polyethylene with an intrinsic viscosity as determined on solutions in decalin at 135° C. of a least 4 dl/g, wherein
at least 80 wt. % of adjacent polymer fibers in the tape are mechanically fused along at least 30% of fiber length through mechanical interlocking, and wherein
the tape is free of a bonding agent, and wherein
the fibers are monofilaments or filaments spread from a multifilament yarn, and wherein
the tape has a maximum thickness of no more than 3 times a thickness of an individual fiber.

11. A ballistic resistant article comprising a tape according to claim 10 .

12. A woven ballistic resistant article comprising the tape according to claim 10 .

13. A ballistic resistant article comprising a material sheet according to claim 1 .

14. A woven ballistic resistant article comprising the material sheet according to claim 1 .

Assignees

• Marissen Roelof R
• Steeman Reinard Jozef Maria R J M
• Nielaba Leonard Josef Arnold L J A
• Dsm Ip Assets Bv

Inventors

• Marissen Roelof R
• Steeman Reinard Jozef Maria R J M
• Nielaba Leonard Josef Arnold L J A

Classifications

• B32B2307/558

  Impact strength, toughness · CPC title

• B32B2323/04

  Polyethylene · CPC title

• F41H5/0478 Primary

  Fibre- or fabric-reinforced layers in combination with plastics layers · CPC title

• F41H5/0485 Primary

  all the layers being only fibre- or fabric-reinforced layers · CPC title

• B32B2571/02

  defensive, e.g. armour plates or anti-ballistic clothing · CPC title