WO2009141276A1

WO2009141276A1 - Smart laminates

Info

Publication number: WO2009141276A1
Application number: PCT/EP2009/055913
Authority: WO
Inventors: Bart Clemens Kranz; Jan Adolph Dam Backer
Original assignee: Novameer B.V.
Priority date: 2008-05-23
Filing date: 2009-05-15
Publication date: 2009-11-26

Abstract

A laminate for anti ballistic purposes is proposed which comprises unidirectionally placed polymeric tapes with a E-modulus of an individual polymeric tape of at least 50 GPa and a square meter weight of the laminate above 150 grams.

Description

Smart Laminates

Description:

The invention pertains a laminate, stack, panel and formed part comprising at least one laminate of unidirectional arranged polymeric tape, in particular for anti ballistic applications.

Prior art

These unidirectional tapes are known and achieve good anti ballistic results e.g.: WO2007/122009, WO2007/122010, WO2007/122011 , EP0833742B1 , EP1627719A1

Prior art claims the best anti ballistic performance with unidirectional arranged tapes in laminates which contains ca 50 grams/m² and which are stacked alternating by 0 - 90 etc degrees on top of each other. Because of the low weight per square meter, the laminates are fragile, not easy to produce, not easy to handle and expensive because there are a lot of laminates needed in order to get a panel for an anti ballistic application. Therefore, making a panel is very time consuming.

This invention proposes a laminate for anti ballistic purposes which comprises unidirectional placed polymeric tapes with a E-modulus of an individual tape of at least 50 GPa and a square meter weight of the laminate above 150 grams.

Surprisingly, at least the same anti ballistic performance can be achieved by a thicker laminate with a higher square meter weight. Therefore more possibilities to decrease the adhesive, i.e. glue content in the laminate and to increase the tape content in the laminate are available. And with a thicker laminate, there are more possibilities to optimize different delaminating zones.

But there are also economical benefits. Because of the thickness, the laminate is more easy to produce, is less fragile and to handle during production. And with the same production velocity, a higher output due to the thicker laminates is achieved.

A panel from a certain thickness needs fewer layers and can therefore be faster produced.

Preferably the laminate according to the invention exhibits a square meter weight above 210 grams, more preferably above 300 grams.

The tapes for the laminate according to the invention may be connected to each other only by means of hot compaction or selective melting and no adhesive is used for the laminate. Preferably, the laminates according to the invention are connected by means of an adhesive. The adhesive content of the laminate may be at most 20% of the total weight of the laminate.

In a preferred embodiment of the laminate according to the invention the square meter weight of the tapes in the laminate is at least 150 grams, more preferably at least 180 grams, most preferably at least 210 grams.

As shown in the example, in most cases the anti ballistic performance is even better with thicker laminates.

When comparing, the final total panel weight of the panel constructed from thin laminates and from thick laminates was identical. The difference was the amount of laminates and the thickness of the laminates.

The laminate according to the invention comprises at least 2 unidirectional positioned drawn polymeric tapes, connect to each other by glue or thermo bonding. Under the term "stack" at least two laminates are to be understood, which laminates have directions deviating from each other in an angle from 0 to 90 °, i.e. the laminates are not parallel to each other.

Further to that, with the term "panel" or "plate" contains a combination of two or more stacks in a rigid manner is meant, which can be achieved e.g. by applying pressure and temperature to the stack(s).

With the term "tape" a highly drawn slitted film, an extruded mono-polymer, or bicomponent extruded drawn slitted films or co-extruded multilayer "monofilament", a so called SSE (solid state extruded) highly drawn film known as e.g. Tensylon, Pamaco and other equivalents is meant. Important is a tape strength between 50 cN /tex and 500cN/tex and a "thickness to width" ratio between 1 :2 and 1 : 100.000, preferably between 1 :10 and 1 : 10000. Examples of suitable tapes are disclosed in WO 2006/107197 and in applicant's unpublished applications No. PCT/EP2007/008495, PCT/EP2007/008500, PCT/EP2007/008499, and PCT/EP2007/008498.

For the tapes preferably polymers, such as PP, PE, HDPE, PET, PA, PPS, PBO, HDPP, UHMWPE, UHMWPP, HDPA, UHMWPA are used. The most common polymers for these tapes are polyethylene, polypropylene, PET (Polyethylene terephthalate), PEN (Polyethylene Naphthalate), Polyamide, PPS and/or mixtures thereof.

One aspect of the stack according to the invention is the relatively low adhesion between and/or within the various layers, caused by a low adhesive or resin content in the layers. Preferred are adhesive contents between 0 % and 30 %, more preferably between 2% and 30% and most preferably between 5% and 12 %, of the weight of the total stack, leaving - even under high pressures and heat, e.g. a pressure of 2 MPa or more and a temperature of 100 ⁰C or more during the manufacturing of the stack, laminate or panel - some or better most filaments "unbonded" within the stack.

Preferred adhesives or resins are e.g. lattices of Kraton, PU, Acrylics , but also dispersions of EAA, EMA, EVA ,OBC (Olefin Block Copolymer) (Infuse ® DOW) etc. or various solvent based/water based adhesives with chloroprene and alike. Further suitable adhesives may be selected from the group consisting of polyethylene, ultra high molecular weight polyethylene, polypropylene, polyamide, polybutadiene terephthalate and polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, polyphenylidensulfide, copolymers of these polymers and mixtures thereof. In addition ethylene alkyl acrylate copolymer (EAA), ethylene vinyl acetate copolymer (EVA), ethylene-butyl acrylate copolymer (EBA), ethylenemethyl acrylate copolymer (EMA), linear low density polyethylene (LLDPE), high density polyethylenes (HDPE), low density polyethylenes (LPDE) may be used. It is also possible to use polyisobutylene (PIB) or polyurethane (PU) and mixtures thereof. The adhesive or resin material may comprise one of the listed materials or mixtures of those materials.

The laminates, stacks and panels according to the invention can be applied in antiballistic applications as well as in composite applications, stand-alone or in combination with other materials.

The panels can be used for hard ballistics purposes like panel in cars or trucks, inserts and so on. These panels can also be used behind a hard strike surface, from e.g. metals, metal alloys, glass basalt fibers, glass fibers, and ceramics, e.g. aluminum oxide, boron carbide.

Two or more hard strike surface layers (e.g. from ceramic or steel) can also be combined with two or more of the panels, such as e.g. sandwiching the hard strike surface layers by the panels. The low adhesive content in the stack according to the invention, which has by nature a relatively high specific surface due to the many very small diameter filaments, in combination with the relatively small specific surface of the tapes, helps to absorb energy by delamination upon impact. The multifilament yarns and tapes separate from each other when hit by e.g. a bullet which enables the energy to be absorbed and dissipated.

A possible variation is to connect the layers to each other by surface-fusing of the material within the stack with the lowest melting temperature to achieve a bonding of the layers in the laminate.

It should be noted that the laminate according to the present invention may comprise more than 2, e.g. 3, 4 or up to 25, even up to 50 or up to 100 monolayers of polymeric tapes all stacked in such a way that the direction of the polymeric tapes is the same in every monolayer

It should be noted that an alternative embodiment could be that the tapes are not produced in a laminate by adding glue, but by thermobonding like hot compaction or selective melting.

A laminate of unidirectional arranged tapes has at least one of the following characteristics:

all tapes are arranged in the same direction a square meter weight of the laminate above 150 grams alternative: a square meter weight of the laminate above 200grams alternative: a square meter weight of the laminate above 300grams tapes with a tensile strength of 1.0 GPa or more - preferred: tapes with a tensile strength of 1.4 GPa or more

- preferred: tapes with a tensile strength of 2.0 GPa or more

- tapes made from PE

- tapes with a modulus of 60 GPa or more

- preferred: tapes with a tensile strength of 75 or more

- In all cases, the overlap of the tapes will be above 10%

- In all cases, the overlap of the tapes will be above 20%

- Glue can be used, see Novameer patents and OBC

- As well as no glue (hot compaction//selective melting)

- The mol weight of the PE where the tapes are constructed from have is at least 100k.

- The mol weight of the PE where the tapes are preferred at least 300k.

- The mol weight of the PE where the tapes are preferred at least 1 Mio.

- The strength to thickness ratio of one laminate is below 4,5 x 10¹³ N/m³

Example

The following panels are compared to each other.

Specification of the panels:

Polyethylene tapes with the dimensions 0.060mm x 3mm.

From these tapes, laminates were constructed of unidirectional positioned tapes.

For example 1 , the weight of one laminate was 60gram/square meter.

For example 2, the weight of one laminate was 180gram/square meter. These laminates were cross plied into stacks by laying the laminates 0-90-0-90deg etc on top of each other.

These stacks of laminates were pressed into a panel with identical pressure conditions (temperature, pressure, pressing time).

The total weight of the polyethylene in both panels is identical. The total panel weight of both panels was also identical.

The result were the 2 panels, identical in all aspects and the only difference was the square meter weight.

These panels were compared in a shooting test: Range conditions Range to target : 5m Temperature : 24,61⁰C Humidity : 40,78%

Clay : Roma Plastiline N°1

CaNb. type : NIJ-0101.04

Shooting Test Requirements N° of shots : 4

Projectile : 44Magnum

Type : JHP

Weight (grain) : 240grains Manufacturer : Remington

Powder : Rottweil P804

Clay calibration

Before session After session

Clay t° : 42,1⁰C Clay t° : 37,2°C

Min depth : 24,08mm Min depth : 18,27mm

Max depth : 22,15mm Max depth : 19,55mm

Average : 22,89mm Average : 18,88mm

CaNb. Result : OK CaNb. Result : OK Panel constructed by laminates which has individual weights of 60 gram/m^Λ2. Powder Velocity

No

Shot # (mmg) (m/sec) Perforation

Perforation

1 712 399 X

2 697 395 X

3 704 396 X

4 709 395 X

Panel constructed by laminates which has individual weights of 180 gram/m^Λ2.

Powder Velocity

No

Shot # (mmg) (m/sec) Perforation Perforation

1 810 400 X

2 783 410 X

3 788 415 X

4 763 425 X

Conclusion: significant performance increase with the 180gram/square meter laminates.

Claims

Smart LaminatesClaims:

1. A laminate for anti ballistic purposes which comprises unidirectionally placed polymeric tapes with a E-modulus of an individual polymeric tape of at least 50 GPa and a square meter weight of the laminate above 150 grams.

2. The laminate according to claim 1 with a square meter weight of at least 210 grams.

3. The laminate according to claim 1 with a square meter weight of at least 300 grams.

4. The laminate according to any one of claims 1 to 3, characterised in that the square meter weight of the tapes in the laminate is at least 150 grams.

5. The laminate according to any one of claims 1 to 3, characterised in that the square meter weight of the tapes in the laminate is at least 180 grams.

6. The laminate according to any one of claims 1 to 3, characterised in that the square meter weight of the tapes in the laminate is at least 210 grams.

7. The laminate according to any of the preceding claims with a tensile strength of at least 1.2 GPa.

8. The laminate according to any of the preceding claims with a tensile strength of at least 1.6 GPa.

9. The laminate according to any of the preceding claims with an E-modulus of an individual tape of 70 GPa.

10. The laminate according to any of the preceding claims wherein the overlap of individual tapes to each other in the laminate will be above 10%.

11.The laminate according to any of the preceding claims wherein the overlap of individual tapes to each other in the laminate will be above 20%.

12. The laminate according to any of the preceding claims wherein the tapes are connected to each other only by means of hot compaction or selective melting and no adhesive is used.

13. The laminate according to any of the preceding claims 1 to 11 wherein adhesives are used, to produce the laminate.

14.A laminate according to claim 13 wherein the content of the adhesive is at most 20%.

15. The laminate according to any of the preceding claims wherein the laminate is constructed from tapes which comprise polyethylene with an average molecular weight of 100.000.

16. The laminate according to any of the preceding claims wherein the laminate is constructed from tapes which comprise polyethylene with an average molecular weight of 300.000.

17. The laminate according to any of the preceding claims wherein the laminate is constructed from tapes which comprise polyethylene with an average molecular weight of 1000.000.

18. The laminate according to any of the preceding claims wherein the strength to thickness ratio of the laminate is below 4,0 x 10¹³ N/m³.

19. The laminate according to any of the preceding claims wherein the strength to thickness ratio of one tape is below 4,0 x 10¹³ N/m³.

20.A stack of at least two laminates from any of claim 1 to 19, wherein the draw direction of two subsequent laminates in the stack differs.

21.The stack according to claim 20, wherein the draw direction of the laminates differs by an angle between 45 and 135 deg, and more preferably between 80 and 100 deg.

22. The stack according to any of the claims 20 to 21 wherein at least one laminate comprises a plurality of unidirectional tapes of the drawn polymer, aligned such that they form a woven fabric.

23. The laminate or stack of any of the preceding claims, wherein the polymeric tapes comprise a highly drawn slitted film, an extruded mono-polymer, or bicomponent extruded drawn slitted films, skived film or co-extruded multilayer monofilament.

24. The laminate or stack of any of the preceding claims, wherein the polymers for the tapes are selected from a group consisting of polyethylene, polypropylene, PET (Polyethylene terephthalate), PEN (Polyethylene Naphthalate), Polyamide, PPS and/or mixtures thereof.

25. The laminate or stack of any of the preceding claims, wherein the stack exhibits an adhesive content between 0 % and 30 %, preferably between 5 and 12 %, of the weight of the total stack.

26. The laminate or stack of any of the preceding claims, wherein the adhesives are selected from a group consisting of lattices of Kraton, PU, Acrylics , dispersions of EAA, EMA, EVA ,OBC (Olefin Block Copolymer) (Infuse ® DOW) or various solvent based/water based adhesives with chloroprene and alike, polyethylene, ultra high molecular weight polyethylene, polypropylene, polyamide, polybutadiene terephthalate and polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, polyphenylidensulfide, alkyl acrylate copolymer (EAA), ethylene vinyl acetate copolymer (EVA), ethylene- butyl acrylate copolymer (EBA), ethylenemethyl acrylate copolymer (EMA), linear low density polyethylene (LLDPE), high density polyethylenes (HDPE), low density polyethylenes (LPDE), polyisobutylene (PIB) or polyurethane (PU), copolymers of these polymers and/or mixtures thereof.

27.A process for producing a laminate according to any of the claims by pre- tensioning the polymeric tapes and subsequently positioning the polymeric tapes under tension in a unidirectional, parallel manner and connect them to each other.

28. The process for producing a stack comprising laminates according to any of the preceding claims characterised in that at least two laminates are placed on top of another and consolidated to form a stack using pressure and heat.

29. The process for producing a panel comprising a stack of laminates according to any of the preceding claims, characterised in that at least two laminates are placed on top of another and consolidated to form the panel using pressure and heat.

30. Panel produced according to claim 29 characterised in that the panel is provided with one or more layers of an impact resistant material, the impact material is selected from one or more materials of the group consisting of metals, metal alloys, glass, basalt fibre, glass fibre or ceramics.

31. Producing a rigid formed part from laminates or stacks by applying pressure and heat.

32. Use of a laminate, stack, panel or formed part of any of the claims for anti ballistic applications.

33. Use of a laminate, stack, panel or formed part of any of the claims for composite applications.