GB2560235A

GB2560235A - Nanoscale coating for enhanced fabrics

Info

Publication number: GB2560235A
Application number: GB1800284.0A
Authority: GB
Inventors: Bennett Ian; Jenkins Steven
Original assignee: Aegis Engineering Ltd
Current assignee: Safariland UK Ltd
Priority date: 2017-01-06
Filing date: 2018-01-08
Publication date: 2018-09-05
Also published as: GB201700262D0; GB201800284D0

Abstract

The coating is produced by mixing a preheated, pressurised liquid carrier and a pressurised precursor solution (nano-scale precursor in a solvent) in reaction chamber. The pressure is preferably regulated by a back-pressure reactor coupled to an outlet of the reaction chamber. The preferred apparatus includes an injector and a fluidly coupled cooler. The preferred solvent is xylene. The treated apparel, especially body vests or anti-ballistic helmets, comprise woven aramid textiles. The nano-material used might include graphite plates, or gold or zinc oxide nanorods.

Description

(71) Applicant(s):

Aegis Engineering Limited 5 Chesford Grange, Woolston, WARRINGTON, WA1 4RQ, United Kingdom (56) Documents Cited:

WO 2015/149517 A1 CN 205856738 U CN 105342043 A US 20150107029 A1

WO 2004/103907 A1 CN 106113814 A CN 104748624 A (58) Field of Search:

INT CL B82Y, D06M, D06N Other: EPODOC; WPI (72) Inventor(s):

Ian Bennett Steven Jenkins (74) Agent and/or Address for Service:

Barker Brettell LLP

100 Hagley Road, Edgbaston, BIRMINGHAM, B16 8QQ, United Kingdom (54) Title of the Invention: Nanoscale coating for enhanced fabrics

Abstract Title: Producing a nanoscale coating for fabrics, especially protective garments (57) The coating is produced by mixing a preheated, pressurised liquid carrier and a pressurised precursor solution (nano-scale precursor in a solvent) in reaction chamber. The pressure is preferably regulated by a back-pressure reactor coupled to an outlet of the reaction chamber. The preferred apparatus includes an injector and a fluidly coupled cooler. The preferred solvent is xylene. The treated apparel, especially body vests or anti-ballistic helmets, comprise woven aramid textiles. The nano-material used might include graphite plates, or gold or zinc oxide nanorods.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

1/4

04 18

Downflow water

->

Pump 2

System Pressure - 250 bar

Product

Back

Pressure

Reactor

2/4

04 18

Figure 2

3/4

04 18

Figure 4

4/4

04 18

Figure 5c

NANOSCALE COATING FOR ENHANCED FABRICS

Methods and systems of producing a nanoscale coating for enhanced fabrics and associated products comprising enhanced fabrics are described. In particular, fabrics enhanced with coatings having micro/nanoscale constituents are described.

The present disclosure aims to at least ameliorate issues with existing fabrics, in particular fabrics that comprise a woven surface. Examples of fabrics of particular interest include woven aramid or polyethylene fibres, which includes para-aramid fibres such as Kevlar® and Twaron®, meta-aramid fibres such as Nomex® and other fibres exhibiting characteristics typical of aramid class fibres - namely manufactured fibres in which the fibre forming substance is a long-chain synthetic polyamide, in which at least 85% of the amide linkages, (-CO-NH-) are attached directly to two aromatic rings.

Some uses of such aramid fibres include use in protection materials, such as personal armour. Helmets, face masks, such as ballistic or bomb helmets and ballistic vests, are all examples of such uses.

According to a first aspect of the present invention, there is provided a system for producing a nanoscale coating for fabrics, said system comprising: a reactor chamber for mixing a stream of a pressurised liquid carrier and a stream of a pressurised precursor solution to form a nanoscale coating; a preheater for preheating the liquid carrier prior to entry into the reactor chamber; and wherein the precursor solution comprises a solvent and a nanoscale precursor.

This system provides a technique for producing and applying a nanoscale coating that can be tailored according to the desired characteristics by varying the nanoscale precursor. The nanoscale coating, once formed, may then be applied to a textile.

Typically, the nanoscale coating is a suspension that is precipitated out of solution of the precursor by the carrier solution using the system described. In some embodiments the carrier solution is a downflow stream and the precursor solution is an upflow stream.

In embodiments the reactor chamber may comprise an outlet through which the nanoscale coating is extracted out of the reactor chamber.

A back-pressure reactor sometimes called a back-pressure regulator may be used for regulating the pressure of the nanoscale coating as it exits the reactor chamber. The back-pressure reactor may act to draw the nanoscale coating out of the reactor chamber. The back-pressure reactor may be coupled to the outlet of the reactor chamber.

A cooler may be fluidly coupled to the outlet of the reactor chamber for cooling the nanoscale coating. This allows the nanoscale coating to be directly applied to a fabric or textile out of the system without damaging the fabric.

The stream of pressurised liquid carrier may be injected into the stream of pressurised precursor solution. This provides an increased mixing interface between the two streams.

The nanoscale coating may be formed at the mixing interface between the liquid carrier stream and the precursor stream. The pressure of the liquid carrier stream may be less than the pressure of the precursor stream. The nanoscale coating may be diverted in the direction of the precursor stream.

The nanoscale coating may directed onto a product such as a textile or fabric from the system. A sprayer, spreader or doper may be used to apply or impregnate the coating. The coating may be applied into voids between textile fibres when the fibres are interwoven into a fabric. The coating may be selectively applied into the voids, or it may residually accumulate within the voids.

The nanoscale coating may comprise nanoscale sized plates, rods or substantially spherical particles. The nanoscale precursor may be chosen to ensure that the desired nanoscale coating characteristic is displayed when the coating is applied to the fabric. For example, plate structures may provide a lubricating effect between adjacent fibres as the plates slide against each other, whilst substantially spherical particles may act to resist separation between particles by packing the gaps between the fibres. Rods may act in either manner, depending upon how they are aligned within the void.

Examples of plate-like nanoscale structures include graphite plates, sometimes called multi-layered graphene sheets. Nanoplatelets such as Exfoliated graphite nanoplatelets may also be used. Nanoscale rods include Au nanorods or ZnO nanorods. Nanoscale particles include any nanoscale sized particle.

According to a second aspect of the present invention, there is provided a method of producing a nanoscale coating for a fabric, comprising the steps of:

pre-heating a pressurised liquid carrier to an elevated temperature; supplying a pressurised precursor solution to the reactor chamber; supplying the pressurised liquid carrier to a reactor chamber; injecting the liquid carrier within the precursor solution such that a nanoscale coating is formed at the mixing interface;

extracting the nanoscale coating from the reactor chamber; and cooling the nanoscale coating;

The precursor solution may comprise a nanoscale precursor and a solvent. The nanoscale precursor constituents may be substantially rod-shaped. The nanoscale precursor constituents may be substantially substantially plateshaped. The nanoscale precursor constituents may be substantially substantially spherical particles. The solvent may be xylene.

The carrier may be pre-heated to one of: (a) 100 degrees Celsius; (b) 200 degrees Celsius; (c) 300 degrees Celsius; or (d) 400 degrees

Celsius.

The method may further comprise the step of regulating the pressure of the nanoscale coating to a pressure of approximately 250 bar (25 MPa).

According to a third aspect there is provided a method of coating a material for use in protective garments, comprising: producing a coating using the method of any of the second aspect; and applying the coating to a material.

The step of applying the coating to at least part of the material may be by spraying/spreading or doping the material using the coating.

According to a fourth aspect of the present invention, there is provided a method of producing a protective garment, comprising: weaving an aramid textile in a cross-layered configuration; coating at least part of the woven material using the method of the third aspect; and covering the coated material with carrier cloths.

According to a fifth aspect of the present invention there is provided a protective garment comprising one or more textiles having a coating produced according to any part of the second to fourth aspect.

According to a sixth aspect of the present invention, there is provided a protective garment, said protective garment comprising: one or more woven textiles, wherein said woven textiles are interwoven in a cross-layered configuration from aramid fibres, and wherein voids formed between the interwoven fibres are coated with a nanoscale coating.

The nanoscale coating may comprise nanoscale sized plate structures for lubricating the voids. The nanoscale coating may comprise nanoscale sized rod structures for at least partially resisting a lateral force applied to the voids. The nanoscale coating may comprise nanoscale sized particles for resisting a pulling force applied to the garments to prevent the fibres from separating.

It can be appreciated that, although certain examples and embodiments described above have been primarily described with respect to a single aspect, the features described are also applicable to the other aspects defined herein.

These and other aspects of the invention will be apparent from, and elucidated with reference to, the embodiments described hereinafter. The above discussion is not intended to represent every example embodiment or every implementation within the scope of the current or future Claim sets. The Figures and Detailed Description that follow also exemplify various example embodiments. Various example embodiments may be more completely understood in consideration of the following Detailed Description in connection with the accompanying Drawings.

Brief description of Drawings

Embodiments will be described, by way of example only, with reference to the drawings, in which figure 1 illustrates a system for producing a coating fluid from a precursor for coating a product;

figure 2 shows (clockwise from top left) SEM images of various coating precursors, namely plates, rods, nanoparticles, and nanoparticle aggregates. Inset images are digital representations of the plates, rods and nanoparticles respectively;

figure 3 shows a schematic of a vest incorporating a multi-layered structure, with the layered structure comprises a textile comprising fibres as shown in an inlay and images of the surface and cross-section shown;

figure 4 shows a representation of packing of plates (top), rods (middle) and nanoparticles (bottom) at an interface between the crossed-fibres of the textile of figure 3 after applying a coating prepared according to figure 1;

figure 5 shows the effect of the plates (figure 5a), rods (figure 5b) and nanoparticles (figure 5c) in response to a force, such as pulling, on one of the crossed figures shown in figure 4.

It should be noted that the Figures are diagrammatic and not drawn to scale. Relative dimensions and proportions of parts of these Figures have been shown exaggerated or reduced in size, for the sake of clarity and convenience in the drawings. The same reference signs are generally used to refer to corresponding or similar feature in modified and different embodiments.

Detailed description of embodiments

Figure 1 shows a schematic of a system for producing a coating according to the present disclosure. In the example shown, water is provided to a reactor using a pump, although any suitable carrier may be used. The water is preheated to a predefined temperature such as 100, 200, 300, 400 degrees Celsius. Additionally, a second pump is used to supply a precursor solution, typically at room temperature, such as 20 degrees Celsius. The precursor solution is provided to the reactor. The precursor solution typically comprises a nanoscale precursor, such as plates, rods or nanoparticles as will be described below. A suitable solvent is used with the precursor, such as xylene, although other suitable solvents may be used.

The system is maintained at an elevated pressure, such as 250 bar. Within the reactor the water and the precursor form a coating solution, which exits the reactor and is cooled by a cooler. A back pressure reactor regulates the pressure and allows the coating to be extracted.

Figure 2 shows exemplary precursors. SEM images show the relative size and shape of the precursor constituents available. Plates are shown in the top left image, rods in the top right, nanoparticles in the bottom right and an aggregate of nanoparticles in the bottom left. Insets show a digital representation of the various precursor constituents.

Figure 3 shows a potential use of the coating. A known garment, such as body armour can be provided that comprises a multi-layered structure as shown in the inset. Typically for body armour garments, carrier cloths are placed on top and/or around a layer of Kevlar® or other woven aramid textile. The aramid material is generally woven in a cross-layered configuration as shown in the surface and cross-sectional images of figure 3. The aramid material is coated with the coating described produced by the method and system shown in figure 1 and comprises at least one of the precursor constituents shown in figure 2. The coating may be undertaken using an application technique. Such techniques may include spraying, spreading or a doping system.

Once coated, the textile material is typically rolled for ease of storage and transport. The coated textile material is then cut to size for the appropriate application. Multiple layers may be used to improve the performance of the personal armour apparel or garment. As noted above, such garments or apparel can include body vests, anti-ballistic helmets, anti-bomb helmets and the like. In particular, apparel where stab and/or strike performance is important benefit from such coated textile materials.

Figure 4 shows a schematic representation of an interface between two strands of the coated woven textile material shown in figure 3. In particular interfaces between strands coated with plates (top), rods (middle) and nanoparticles (bottom) are shown.

Figure 5 shows the interfaces of figure 4 when a force, such as pulling at one of the threads occurs. Relative stress and/or reactive forces are shown. In figure 5a, the plates tend to provide opposing shear forces, potentially allowing the fibres to more easily pass over each other. This can provide a lubricating effect.

In figure 5b, the rods react to a lateral force applied to one of the threads - the rods act in a semi-random manner depending upon the relative orientation of the rods. Accordingly, the force tends to be partially resisted. In the final example in figure 5c, the nanoparticles act to resist the application of the force and the packing ratio of the nanoparticles within the cavity between the strands/threads/fibres increases. This acts to resist the pulling force. This can act to prevent the threads from separating, which can improve the performance of stab and or strike performance due to the increased resistance to the strands separating.

It can be appreciated that depending on the physical and chemical properties of the coating at a nano/microscale, the impact behaviour of the fabric will be different and may be tailored to the intended application. It may also be appreciated that the coating may be applied to cover the entire textile’s surface or to only act at or on a targeted section - additionally, multiple coatings may be applied to different areas or sections allowing sections of the garment to be tailored accordingly.

From reading the present disclosure, other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features which are already known in the art of enhanced fabrics, and which may be used instead of, or in addition to, features already described herein.

Although the description is directed to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalisation thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention.

Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The applicant hereby gives notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.

For the sake of completeness it is also stated that the term comprising does not exclude other elements or steps and the term a or an does not exclude a plurality.

Claims

1. A system for producing a nanoscale coating for fabrics, said system comprising:

a reactor chamber for mixing a stream of a pressurised liquid carrier and a stream of a pressurised precursor solution to form a nanoscale coating;

a preheater for preheating the liquid carrier prior to entry into the reactor chamber;

wherein the precursor solution comprises a solvent and a nanoscale precursor.

2. The system of claim 1, wherein the reactor chamber comprises an outlet through which the nanoscale coating is extracted out of the reactor chamber.

3. The system of claim 2, further comprising:

a back-pressure reactor for regulating the pressure of the liquid coating solution.

4. The system of claim 3, wherein the back-pressure reactor is coupled to the outlet of the reactor chamber.

5. The system of any one of claims 2 to 4, further comprising a cooler fluidly coupled to the outlet of the reactor chamber for cooling the nanoscale coating.

6. The system of any preceding claim, wherein the stream of pressurised liquid carrier is injected into the stream of pressurised precursor solution.

7. The system any preceding claim, wherein the nanoscale coating is formed at the mixing interface between the liquid carrier stream and the precursor stream.

8. The system of claim 7, wherein the pressure of the liquid carrier stream is less than the pressure of the precursor stream.

9. The system of claim 8, wherein the nanoscale coating is diverted in the direction of the precursor stream.

10. The system of any preceding claim, wherein the nanoscale coating is directed onto a product.

11. A method of producing a nanoscale coating for a fabric, comprising the steps of:

extracting the nanoscale coating from the reactor chamber; and cooling the nanoscale coating.

12. The method of claim 11, wherein the precursor solution comprises a nanoscale precursor and a solvent.

13. The method of claim 12, wherein the nanoscale precursor constituents are substantially rod-shaped.

14. The method of claim 12, wherein the nanoscale precursor constituents are substantially plate-shaped.

15. The method of claim 12, wherein the nanoscale precursor constituents are substantially spherical particles.

16. The method of any of claims 12 to 15, wherein the solvent is xylene.

17. The method of any preceding claim, wherein the carrier is pre-heated to one of:

(a) 100 degrees Celsius (b) 200 degrees Celsius (c) 300 degrees Celsius (d) 400 degrees Celsius.

18. The method of any preceding claim, further comprising the step of regulating the pressure of the nanoscale coating to a pressure of approximately 250 bar (25 MPa).

19. A method of coating a material for use in protective garments, comprising:

producing a coating using the method of any of claims 11 to 18; and applying the coating to a material.

20. The method of claim 19, wherein the step of applying the coating to at least part of the material is by spraying/spreading or doping the material using the coating.

21. A method of producing a protective garment, comprising: weaving an aramid textile in a cross-layered configuration;

coating at least part of the woven material using the method of claim 19 or claim 20; and covering the coated material with carrier cloths.

22. A protective garment comprising one or more textiles having a coating produced according to any preceding method claim.

23. A protective garment, said protective garment comprising:

one or more woven textiles, wherein said woven textiles are interwoven in a cross-layered configuration from aramid fibres, and wherein voids formed between the interwoven fibres are coated with a nanoscale coating.

5

24. The garment of claim 23, wherein the nanoscale coating comprises nanoscale sized plate structures for lubricating the voids.

25. The garment of claim 23, wherein the nanoscale coating comprises nanoscale sized rod structures for at least partially resisting a lateral force

10 applied to the voids.

26. The garment of claim 23, wherein the nanoscale coating comprises nanoscale sized particles for resisting a pulling force applied to the garments to prevent the fibres from separating.

Intellectual

Property

Office

Application No: GB1800284.0