High tenacity high modulus uhmwpe fiber and the process of making.

(54) Title: HIGH MODULE UHMWPE FIBER WITH HIGH TENACITY AND THE PROCESS TO PRODUCE IT.

(54) Title: HIGH TENACITY HIGH MODULUS UHMWPE FIBER AND THE PROCESS OF MAKING.

(57) Summary

Processes for the preparation of ultra-high molecular weight polyethylene (PE from UHMW) filaments and multi-filament yarns and the yarns and articles produced therefrom. Each process produces UHMW PE yarns having tensile strengths of 45g / denier to 60g / denier or more, at commercially viable throughput rates.

(57) Abstract

Processes for preparing ultra-high molecular weight polyethylene (UHMW PE) filaments and multi-filament yarns, and the yarns and articles produced therefrom. Each process produces UHMW PE yarns having tenacities of 45 g / denier to 60 g / denier or more at commercially viable throughput rafes.

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PATENT TITLE No. 347676

Holders): HONEYWELL INTERNATIONAL INC.

<td>Home:</td><td>Patent Services M / S AB / 2B, 101 Columbia Road, P O. Box 2245, Morristown, New Jersey, 07962-2245, USA</td>

<td>Denomination:</td><td>HIGH-MODULE UHMWPE FIBER WITH HIGH TENACITY AND THE PROCESS TO PRODUCE IT.</td>

<td>Classification:</td><td>CIP: D02G3 / 02; D01D5 / 06; D01F6 / 04 CPC: D02G3 / 02; D01D5 / 088; D01D11 / 00; D01F6 / 04; D04H1 / 70; D04H1 / 593; D04H13 / 00</td>

<td>Inventor (s):</td><td>THOMAS TAM; JOHN ARMSTRONG YOUNG; RALF KLEIN; MARK TALLENT; HENRY GERARD ARDIFF REQUEST</td>

Number: International Presentation Date:

MX / a / 2014/009998 February 14, 2013

<td></td><td colspan="2">PRIORITY</td>

<td>Country:</td><td>Date:</td><td>Number:</td>

<td>US</td><td>February 24, 2012</td><td> 61/602,963</td>

<td>US</td><td>February 13, 2013</td><td> 13/766,112</td>

Validity: Twenty years

Expiration Date: February 14, 2033

Issue Date: May 9, 2017,

The reference patent is granted on the basis of articles 12, 2 "section V, 6 ° section M and 59 of the Industrial Property Law.

In accordance with article 23 of the Industrial Property Law, this patent is valid for twenty years. Non-derogable, counted from the date of filing of the illegality and subject to payment of the fee to keep it in force. rights.

Whoever signs this title does so based on the provisions of articles 6 ° sections lll and 7 “bis 2 of the Industrial Property Law (Official Gazette of the Federation (DOF) 06/27/1091. amended on M / 06/1094, 10/25/1996, 12/26/1997, 05/17/1000, 01/26/2004, 06/16/2005, 01/25/2006, 05/06/2009, 01/06/2010, 06/18/2010, 06/28/2010, 01/27/2012 and 04/09/2012) 1 articles 1, 3 “fraooión, Vinciso a), 4 and 12 sections I and lll of the Regulations of the Mexican Institute of Industrial Property (D.OF. 12/14/1999, amended on 07/01/2002. 07/15/2004, 07/28/2004 and 09/07/2007); Articles 1, 3, 4, 5 fraction V subsection a), 16 fractions t and Hf and 00 of the Organic Statute of the Mexican Institute of Industrial Property (DOF 12/27/1999, amended on 10/10/2002, 07/29/2004, 08/04/2904 and 09/13/2007), &lt;1 «3 ° and Staawá) def Agreement that delegates powers to the Directors Deputy Generals, Coordinator, Divisional Directors, Titulare · of the Regional Offices, Divisional Subdirectors, Departmental Coordinators and other subordinates of the Mexican Institute of International Property. (DOF 12/15/1999, amended on 02/04/2000, 07/29/2004, 08/04/2004 and 09/13/2007).

This document is signed with an advanced electronic signature (FIEL), based on articles 7 BIS 2 of the Industrial Property Law; 3 of its Regulations, and 1 fraction lll, 2 fraction V, 26 BIS and 26 TER of the Agreement establishing the guidelines for the use of the Payment and Electronic Services Portal (PASE) of the Mexican Institute of Industrial Property, in the procedures indicated.

THE DIVISIONAL DIRECTOR OF PATENTS

NAHANNY CANAL REYES

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HIGH MODULE UHMWPE FIBER WITH HIGH TENACITY AND PROCESS

<img file="MX347676B_D0004.tif" />

IMPI

ΟβΤΠυΤΟ MEXICAN

OF THE INDUSTRIAL RAOHEDAT

TO PRODUCE IT

CROSS REFERENCE TO RELATED REQUEST

This application claims the benefit of co-pending United States provisional application Serial No. 61 / 602,963, filed February 24, 2012, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

TECHNICAL FIELD

This invention relates to processes for the preparation of ultra-high molecular weight (PE from UHMW) polyethylene filaments and multi-filament yarns, and articles produced therefrom.

DESCRIPTION OF THE RELATED TECHNIQUE

Ultra-high molecular weight poly (alpha-olefin) multi-filament yarns have been produced which have high strength properties such as toughness, tensile modulus, and breaking energy. The yarns are useful in applications that require shock absorption and bullet resistance, such as bulletproof vests, helmets, bibs, helicopter seats, splinter shields, composite sports equipment such as kayaks, canoes, and bicycle boats; and in fishing line, sails, ropes, sutures and fabrics.

Ultra-high molecular weight poly (alpha-olefins) include polyethylene, polypropylene, poly (butene-1), poly (4-methyl-pentene-1), their copolymers, blends, and adducts having a molecular weight of at least about 300,000 g / mol. Many different techniques are known for the manufacture of high tenacity filaments and the fibers formed from these polymers. High tenacity polyethylene fibers can be produced by spinning a solution containing ultra-high molecular weight polyethylene. The ultra-high molecular weight polyethylene particles are mixed with a suitable solvent, whereby the particles are swollen with, and dissolved by, the solvent to form a solution. The solution is then extruded through a spinner to form solution filaments, followed by cooling the solution filaments to a gel state to form gel filaments, then removing the spinning solvent to form solvent-free filaments. One or more of the solution filaments, gel filaments and solvent-free filaments are drawn or drawn to a highly oriented state in one or more stages. In general, such filaments are known as gel-spun polyethylene filaments. It is desirable that the process of

IMPI ^ iNsrrruT · Mexican

H LA HKWtBAB INDUSTRIAL - gel spun, as it prevents the formation of folded chain molecular structures and favors the formation of extended chain structures that more efficiently transmit tensile loads. Gel spun filaments also tend to have melting points higher than the melting point of the polymer from which they were formed. For example, high molecular weight polyethylene having a molecular weight of about 150,000 to about two million generally have melting points in the polymer at a volume of 138 ° C. The highly oriented polyethylene filaments produced from these materials have melting points from about 7 ° C to about 13 ° C higher. This slight increase in melting point reflects the crystalline perfection and higher crystalline orientation of the filaments compared to bulk polymer. Ultra-high molecular weight (PE from UHMW) polyethylene yarns are produced from multi-filament gel yarns, for example, by Honeywell International Inc.

Various methods for the formation of gel-spun polyethylene filaments have been described, for example, in US patents 4,413,110; 4,536,536; 4,551,296; 4,663,101; 5,032,338; 5,578,374; 5,736,244; 5,741,451; 5,958,582; 5,972,498; 6,448,359; 6,746,975; 6,969,553; 7,078,099; 7,344,668 and US Patent Application Publication 2007/0231572, all of which are incorporated herein by

<img file="MX347676B_D0005.tif" />

IMPI INSTITUTO MEXICANO ot la noHiDAS INDUSTRIAL reference to the extent that they are compatible with this.

For example, US patents 4,413,110 ', 4,6 é 3, 101 and

5,736,244 describe the formation of polyethylene gel precursors and the stretching of low porosity xerogels obtained therefrom to form high modulus fibers with high tenacity. US Patents 5,578,374 and 5,741,451 describe post-stretching a polyethylene fiber that has already been oriented by extraction at a given temperature and extraction rate. US patent 6,746,975 describes high modulus, high tenacity, multi-filament yarns formed from polyethylene solutions by extrusion through a multi-hole spinner into a cross-flow gas stream to form a flowable product. The liquid product is gelled, stretched and formed into a xerogel. The xerogel is then subjected to two-stage stretching to form the multi-filament yarns. US Patent 7,078,099 describes extracted, gel-spun multi-filament polyethylene yarns having increased perfection of molecular structure. The yarns are produced by an improved manufacturing process and are extracted under specialized conditions to produce multi-filament yarns that have a high degree of molecular and crystalline order. US patent 7,344,668 describes a process for extracting multi-filament yarns from

IMPI

ΙΝΠΤΠΙΤΟ MiXICANC Of LA ntOFIFOAD IWDUSTMA1 ~ gel-spun polyethylene essentially free of diluents in a forced convection air oven and the drawn yarns produced by it. The process conditions of extraction ratio, draw rate, residence time, furnace length, and feed rate are selected in specific relationship to each other in order to achieve higher efficiency and productivity.

Despite the teachings of the above documents, there remains a need in the art for a process for the preparation of high tenacity PE UHMW multi-filament yarns with increased productivity that is suitable for commercial scale manufacturing. The theoretical strength of UHMW PE yarn is around 200g / denier based on the CC bond calculation. However, fibers of such maximum tenacity are currently not achievable due to the processability limitations of the UHMW PE polymer. For example, UHMW PE fibers having high tensile strengths are understood to correspond to UHMW PE starting material having high molecular weight. Consequently, the toughness of UHMW PE fibers can theoretically be increased by increasing the molecular weight of the UHMW PE raw material from which they are manufactured. However, increases in polymer molecular weight lead to various processing drawbacks. For example, the Mexican ιχτιτη / το

K THE rWDREBAD u «» uynuAi fibers that have high tenacity require slower and more careful controlled fiber extraction to avoid fiber breakage during stretching. However, slower stretching of the fiber is undesirable as it limits fiber output and the commercial viability of the process. Increasing the molecular weight of the polymer also requires high extrusion temperatures and pressures to handle the higher molecular weight material, but these more stringent conditions can accelerate polymer degradation and limit achievable fiber tensile properties.

Due to these limitations, manufacturing UHMW PE high tenacity yarns, particularly those having a yarn tenacity of 45 g / denier or more, is a difficult and extremely time consuming task. Certainly any related art discusses the manufacture of PE fibers from

UHMW that have a toughness of 45 g / denier or more, such as US patent 4,617,233, refer to achievements that are not capable of being translated on a realistic, commercially viable scale. No related art method is currently known to be capable of manufacturing UHMW PE yarns having a tenacity of 45 g / denier or more, at a commercially viable rate of yield. Consequently, there remains a need in the art for a more efficient process for the production of strong PE yarns from

UHMW at high production capacity

IMPI

INSTITUTO MEXICANA! OF THE MOHEDA! ' INDUSTUM

The present

<img file="MX347676B_D0006.tif" />

The invention provides a solution to this problem in the art.

SUMMARY OF THE INVENTION

The invention provides an ultra-high molecular weight polyethylene (UHMW PE) multi-filament yarn with a tenacity of at least 45 g / denier, wherein said yarn is manufactured from a UHMW PE polymer having a intrinsic viscosity of at least about 21 dl / g and an intrinsic viscosity of the yarn that exceeds 90% relative to the intrinsic viscosity of the UHMW PE polymer; wherein said intrinsic viscosities are measured in decalin at 135 ° C according to ASTM D 1601-99.

The invention also provides a process for producing an ultra-high molecular weight polyethylene (PE from UHMW) multi-filament yarn with a tenacity of at least 45 g / denier, wherein said yarn is manufactured from a polymer UHMW PE having an intrinsic viscosity of at least about 21 dl / g and an intrinsic yarn viscosity that exceeds 90% relative to the intrinsic viscosity of the UHMW PE polymer; in which said intrinsic viscosities are measured in decalin at 135 ° C according to the ASTM D 1601-99 standard, the procedure comprising:

<img file="MX347676B_D0007.tif" />

IMPI ηστπντ

MLAnOVIVA industrial

a) providing a mixture comprising a UHMW PE polymer and a spin solvent, said UHMW PE polymer has an intrinsic viscosity of at least about 21 dl / g, measured in decalin at 135 ° C according to ASTM standard D 1601-99;

b) forming a solution from said mixture;

c) passing the solution through a spinner to form a plurality of solution filaments;

d) cooling the solution filaments to a temperature below the point of the UHMW PE polymer to thereby form a gel-gel spinning;

e) removing the spin solvent from the gel spinning to form a dry spinning; and

f) spreading at least one of the solution filaments, the gel filaments and the solid filaments in one or more stages to form a spin product having a tenacity greater than 45 g / d and wherein said spinning product has an intrinsic viscosity that exceeds 90% relative to the intrinsic viscosity of the UHMW PE polymer; wherein said intrinsic viscosities are measured in decalin at 135 ° C according to ASTM D1601-99.

The invention further provides a process for producing a multi-filament yarn of

<img file="MX347676B_D0008.tif" />

IMPI

IXJTHVTOMJXKANO

MtAWOWiPA »ΙΧΟΙΛΤ11Λ1 ultra-high molecular weight polyethylene (PE from UHMW) with a toughness of at least 45 g / denier, comprising:

a) providing a blend comprising a UHMW PE polymer and a spinning solvent, said UHMW PE polymer has an intrinsic viscosity of at least about 35 dl / g, measured in decalin at 135 ° C according to ASTM D 1601-99;

b) forming a solution from said mixture;

c) passing the solution through a spinner to form a plurality of solution filaments;

d) cooling the solution filaments to a temperature below the point of the UHMW PE polymer to thereby form a gel-gel spinning;

e) removing the spin solvent from the gel spinning to form a dry spinning; and

f) spreading at least one of the solution filaments, the gel filaments and the solid filaments in one or more stages to form a spinning product having a tenacity greater than 45 g / d, and in which said product of yarn has an intrinsic viscosity of at least about 21 dl / g; in which said intrinsic viscosities are measured in decalin at 135 ° C according to the ASTM standard

D 1601-99.

INSTITUTO M4XJCANO μ la nontDAD

INDUSTtlAL

Furthermore, an ultra-high molecular weight polyethylene (PE from UHMW) multi-filament yarn with a tenacity of at least 45 g / denier is provided, wherein said yarn is manufactured from a solution comprising PE from UHMW and an extractable solvent, wherein said UHMW PE comprises 6.5% or less by weight of said solution, said yarns have a denier per filament of 1.4 dpf to 2.2 dpf.

The invention also includes articles comprising the yarns of the invention.

DETAILED DESCRIPTION

For the purposes of the present invention, a fiber is an elongated body whose longitudinal dimension is much greater than the transverse dimensions of width and thickness. The cross sections of fibers for use in this invention can vary widely, and can be circular, flat or oblong in cross section. They can also be of irregular or regular multilobal cross section having one or more regular or irregular lobes projecting from the linear or longitudinal axis of the filament. Thus, the term fiber includes filaments, tapes, strips and the like that have a regular or irregular cross section. As used herein, the term yarn is defined as a single continuous strand consisting of multiple fibers or

INSTITUTO MEXICANO »f LA H &lt;OME * AD (NDusnuAi filaments. A single fiber can be formed from a single filament or from multiple filaments. A fiber formed from a single filament is referred to in this document as either a a single filament or a monofilament fiber, and a fiber formed from a plurality of filaments is referred to herein as a multifilament fiber. The definition of multifilament fibers herein also includes pseudo-monofilament fibers, which is a technical term that describes multifilament fibers 10 that are at least partially fused together and resemble monofilament fibers.

In general, fibers that have high strength properties are obtained from polyethylene that has a high intrinsic viscosity, but at higher intrinsic viscosities, to dissolve the polyethylene may require longer residence times, which affects the productivity of the process. manufacturing. The processes described in the present disclosure identify steps to improve the processing of high intrinsic viscosity polyethylenes, allowing the manufacture of high tenacity yarns at commercially viable throughput rates.

A commercially viable rate of yield is a relative term, since at 25-yarn tensile strengths of 45 g / denier and above, the high molecular weight of the UHMW PE raw material requires great care to avoid fiber breakage during manufacturing. Slower processing of higher molecular weight polymers leads to reduced throughput rates, so for example, a commercially viable throughput rate for 45 g / denier of UHMW PE fibers is higher than a throughput rate commercially viable for 50g / denier, 55g / denier yarn or 60g / denier yarn. In this regard, a commercially viable rate of return is taken into account for the cumulative performance of both the spinning speed of the partially oriented yarn as well as the extraction rate of the partially oriented post yarns. As used herein, the term "toughness" refers to tensile stress expressed as force (grams) per unit linear density (denier) of a non-tensile specimen. The toughness of a fiber can be measured by the methods of ASTM D2256.

The gel spinning processes described herein provide for continuous line production of partially oriented spinning at a spinning speed from about 25 g / min / spinning end to about 100 g / min / spinning end, depending on the intrinsic viscosity of the IVo polymer, and wherein the partially oriented yarn can be beneficially subsequently extracted at a rate of at least 3.0 g / minute

<img file="MX347676B_D0009.tif" />

IMPI fxsirnrroMixJCAMO ΜΙΑ⁰™? *? final tUPUSTMAL / yarn for g / denier UHMW PE yarn, at least 1.5 g / min / 50 g / denier yarn line of UHMW PE yarn, at least 0.8 g / min / 55 g yarn line / denier of PE UHMW yarns, and at least 0.5 g / min / yarn line for 60 g / denier PE UHMW yarns.

Conventional gel spinning processes involve the formation of a solution of a polymer and a spinning solvent, passing the solution through a spinning machine to form a solution spinning that includes a plurality of solution filaments (or fibers), cooling of the spinning solution to form a gel spinning, removing solvent spinning to form an essentially dry, solid spinning, and stretching of at least one of the solution spinning, spinning and dry gel spinning. Solution formation begins with the formation of a first suspension that includes the UHME PE polymer starting material and the spin solvent. The UHMW PE polymer is preferably provided in particulate form prior to combination with the spin solvent. As discussed in US Patent No. 5,032,338, the particle size and particle size distribution of the UHMW PE polymer can affect the degree to which the UHMW PE polymer dissolves in the spin solvent during the formation of the solution to be spun into gel. It is desirable that the PE polymer

<img file="MX347676B_D0010.tif" />

UHMW IMPI dissolves completely in solution. By

Consequently, in a preferred example, UHMW PE has a mean particle size of between about 100 microns (pm) to about 200 pm. In such an example, it is preferred that up to about, or at least about 90% of the UHMW PE particles have a particle size that is within 40 pm of the mean UHMW PE particle size. In other words, up to about, or at least about 90% of the UHMW PE particles have a particle size that is equal to the average particle size of plus or minus 40 ρπi. In another example, about 75% by weight to about 100% by weight of the UHMW PE particles used may have a particle size of from about 100 to about 400 pm pm, and preferably from about 85% by weight to about 100%. By weight the UHMW PE particles have a particle size of about 120 to 350 pm pn i. Furthermore, the particle size can be distributed on a substantially Gaussian curve of particle sizes centered at about 125 and 200 pm. It is also preferred that about 75% by weight to about 100% by weight of the UHMW PE particles used have a weight average molecular weight of from about 300,000 to about 7,000,000, more preferably from

INSTITUTO Mexicano DE LA non EDA »industrial - approximately 700,000 to approximately 5,000,000. It is also preferred that at least about 40% of the particles be retained on a No. 80 mesh screen.

Preferably, the UHMW PE polymer starting material has less than about 5 side groups per 1000 carbon atoms, more preferably less than about 2 side groups per 1000 carbon atoms, even more preferably less than about 1 side group per 1000 carbon atoms, and more preferably less than about 0.5 side groups per 1000 carbon atoms. Secondary groups can include, but are not limited to, Ci-Cio alkyl groups, vinyl terminated alkyl groups, norbornene, halogen, carbonyl, hydroxyl, epoxide and carboxyl atoms. The UHMW PE may contain small amounts, generally less than about 5% by weight, preferably less than about 3% by weight of additives such as antioxidants, heat stabilizers, colorants, flow promoters, solvents, etc.

The UHMW PE polymer selected for use in the first embodiment of the present gel spinning process preferably has an intrinsic viscosity in decalin at 135 ° C of at least about 21 dl / g, preferably greater than about 21 dl / g. The PE UHME polymer preferably has a viscosity

<img file="MX347676B_D0011.tif" />

IMPI οβτττυτο MUULAMC Dt THE intrinsic INDVJTXlAL MYOPHTY from about 21 dl / g to about 100 dl / g, more preferably from about 30 dl / g to about 100 dl / g, more preferably from about 35 dl / g to about 100 dl / g, most preferably from about 40 dl / g to about

100 dl / g, more preferably about 45 dl to about 100 dl / g, more preferably about 50 dl / g to about 100 dl / g. As used herein, all referenced intrinsic viscosities (IV) are measured in decalin at 135 ° C.

Preferably, the UHMW PE starting material has a ratio of weight average molecular weight to number average molecular weight (Mw / Mn) of 6 or less, more preferably 5 or less, still more preferably 4 or less, still more preferably 3 or less, even more preferably 2 or less, and even more preferably a Mw / Mn ratio of about 1.

The solvent spinning selected for use in the present gel spinning process can be any suitable spinning solvent, including, but not limited to, a hydrocarbon having a boiling point of greater than 100 ° C at atmospheric pressure. The spinning solvent can be selected from the group consisting of aliphatic hydrocarbons, such as cycloaliphatic and aromatic; and halogenated hydrocarbons such as dichlorobenzene and mixtures

IMPI μττγππ »mwcano

In some examples, the spinning solvent may have a boiling point of at least about 180 ° C at atmospheric pressure. In such examples, the spinning solvent can be selected from the group consisting of halogenated hydrocarbons, mineral oil, decalin, tetralin, naphthalene, xylene, toluene, dodecane, decane, undecane, nonane, octene, cisdecahydronaphthalene, trans-decahydronaphthalene, wax low molecular weight polyethylene, and mixtures thereof. Preferably, the solvent is selected from the group consisting of cis-decahydronaphthalene, trans-decahydronaphthalene, decalin, mineral oil, and mixtures thereof. The most preferred spin solvent is mineral oil, such as HYDROBRITE® 550 PO white mineral oil, commercially available from Sonneborn, LLC of Mahwah, NJ. PO HYDROBRITE® 550 Mineral Oil consists of approximately 67.5% paraffinic carbon to approximately 72.0% paraffinic carbon and approximately 28.0% to approximately 32.5% naphthenic carbon as calculated according to ASTM D3238.

The components of the suspension can be provided in any suitable form. For example, the slurry can be formed by combining the PEU HME and the spin solvent in a stirred mixing tank, followed by providing the blended and solvent spinning UHME PE to an extruder. UHMW PE particles and

<img file="MX347676B_D0012.tif" />

solvent can be fed

IMPI

INSTITVT »MEXICAN

SEE THE ΓΑΟηίΟΛΓ rnvusnuAL continuously to the mixing tank with the suspension formed being discharged to the extruder. The mixing tank can be heated. The suspension can be formed at a temperature that is lower than the temperature at which the UHME PE will melt and therefore also below the temperature at which the UHME PE will dissolve in the spin solvent. For example, the suspension can be formed at room temperature, or it can be heated to a temperature of up to about 110 ° C. The temperature and residence time of the suspension in the mixing tank are optionally such that the UHMW PE particles will absorb at least 5% by weight of solvent at a temperature below that at which the PE will dissolve. of UHMW. Preferably, the temperature of the slurry leaving the mixing tank is from about 40 ° C to about 140 ° C, more preferably from about 80 ° C to about 120 ° C, and more preferably from about 100 ° C to about 110 ° C. C.

Several alternative modes of feeding the extruder are contemplated. A UHMW PE suspension formed in a mixing tank can be fed to the extruder feed hopper under no pressure. Preferably, a slurry enters a feed zone of the sealed extruder under a positive pressure of at least about 20 kPa. The pressure of

IMPI

INSTITUTO MEXICANO M LA INDUSTRIAL CURRENCY feeding increases the transport capacity of the extruder.

<img file="MX347676B_D0013.tif" />

Alternatively, the suspension can be formed in the extruder. In this case, the UHMW PE particles can be fed into an open extruder feed hopper and the solvent is pumped into the extruder one or two barrel sections further forward in the machine.

In yet another alternative feed mode, a concentrated suspension is formed in a mixing tank. This enters the extruder into the feed zone. A stream of pure solvent preheated to a temperature above the melting temperature of the polymer enters the extruder several zones further forward. In this mode, part of the process heat load is transferred out of the extruder and its productive capacity is enhanced.

The extruder to which the suspension is provided can be any suitable extruder, including, for example, a twin screw extruder such as a rotary co-gear twin screw extruder. Conventional devices, including but not limited to a Banbury mixer, would also be suitable substitutes for an extruder. The gel spinning process may include extruding the slurry with the extruder to form a blend, preferably an intimate blend, of the UHMW PE polymer and the spin solvent. The extrusion of the suspension to form the mixture can be done at a

<img file="MX347676B_D0014.tif" />

IMPI οητπτυτο MixicxNO Bt THE INDVSTWAL CURRENCY temperature that is above the temperature at which the UHMW PE polymer will melt. The mixture of the UHMW PE polymer and the spin solvent that is formed in the extruder can therefore be a liquid mixture of the molten UHMW PE polymer and the spin solvent.

The temperature at which the liquid mixture of UHMW PE molten polymer and the spin solvent is formed in the extruder can be about 140^orC to about 320 ° C, preferably from about 200 ° C to about 320 ° C, and more preferably from about 220 ° C to about 280 ° C.

The productivity of the processes of the invention and the properties of the articles produced depend in part on the concentration of the UHMW PE solution. Higher polymer concentrations provide the potential for higher productivity, but are also more difficult to dissolve in the spin solvent. Each of the suspension, liquid mixture, and solution may include UHMW PE in an amount from about 1% by weight to about 50% by weight of the solution, preferably from about 1% by weight to about 30% by weight of the solution, more preferably from about 2% by weight to about 20% by weight of the solution, and even more preferably from about 3% by weight to about 10% by weight of the solution. In the

<img file="MX347676B_D0015.tif" />

IMPI

MEXICAN INSTITUTE

OF THE RBOFIDITY

Most preferred industrial embodiments the solution includes PE of UHMW in an amount of 6.5% or less by weight of the solution (i.e., the weight of the solvent plus the weight of the dissolved polymer), or more particularly 5.0% or less by weight of the solution. solution, or even more preferably 4.0% or less by weight of the solution. More preferably, the solution includes UHMW PE in an amount of from more than 3% by weight to less than 6.5% by weight of the solution, or more particularly from greater than 3% by weight to less than 5% by weight based on the weight of the UHMW PE polymer plus the weight of the solvent.

An example of a method for processing the suspension through an extruder is described in a commonly owned patent application publication by

United States 2007/0231572, which describes that the capacity of an extruder increases as approximately the square of the screw diameter. Therefore, a figure of merit for an extrusion operation is the ratio of the polymer yield rate to the square of the screw diameter. In at least one example, the slurry is processed such that the production rate of the UHMW PE polymer extruder in the solvent-spun polymer melt UHMW PE liquid mixture is at least 2.0 amount. D² grams per minute (g / min), where D represents the diameter of the extruder screw in centimeters. For example, the production rate of UHMW PE polymer extruder

IMPI

INSTITUTE MWCAW DC LA enOttWAP INDUSTRIAL

<img file="MX347676B_D0016.tif" />

can be 2.5 D² g / min or more, D² 5 g / min or more, or 10 D² g / min or more. The mean residence time in an extruder can be defined as the free volume of the extruder (minus screw barrel) divided by the volumetric throughput rate. For example, an average residence time in minutes can be calculated by dividing the free volume in cm³ by the rate of return in cm³/ min.

In the context of the present invention, three alternative methods are provided for the production of UHMW PE yarns having tensile strengths of at least 45 g / denier at commercially viable yield rates. In a first embodiment, said yarn is made of a UHMW PE polymer having an intrinsic viscosity (IVo) of at least about 21 dl / g, more preferably at least about 28 dl / g, and even more preferably at least about 21 dl / g. less about 30 dl / g, therefore, this IVo is maintained during the gel spinning process in such a way that the yarns made from them have an intrinsic viscosity of the yarn (IVf) that exceeds 90% in relation to the intrinsic viscosity of the UHMW PE polymer. . In a second embodiment, said UHMW PE yarn is made of a UHMW PE polymer having an IVo greater than in said first embodiment, that is, an intrinsic viscosity IVo of at least about 35 dl / g, but in the that IVf is not so tightly controlled to effectively limit polymer degradation during processing to less than 10% IVo. Each of these alternative methods is effective in achieving the goal of improving the output capacity of high tenacity yarn production. In a third embodiment, yarns having a tenacity greater than 45 g / denier at a denier per filament of 1.4 dpf to 2.2 dpf are made from a low concentration UHMW PE solution having less than 6.5% UHMW PE , preferably from more than 3% by weight to less than 6.5% by weight of the solution to form 50 g / denier yarns having a denier per filament of 1.4 dpf to 2.2 dpf. The yarns of this third modality are not limited to a specific PE retention percentage of UHMW IVo or IVq.

Intrinsic viscosity of a polymer is a measure of the average molecular weight of the polymer, and the toughness of the UHMW PE yarn depends on a measure of the molecular weight of the UHMW PE polymer. Generally, the higher the molecular weight of UHMW PE, the higher the tenacity of the UHMW PE yarn. However, the conditions of conventional gel spinning processes have a tendency to degrade the UHMW PE polymer, reducing the molecular weight of the polymer, reducing the intrinsic viscosity polymer IVo, and reducing the maximum achievable spinning toughness.

4

IMPI ^

ΙΜΓΠΤυΤΟ MUiCANO

Μ THE fNBUTnUAL raOtHDAD

In accordance with the first embodiment of the invention, process improvements are made to minimize polymer degradation and make yarns of higher tenacity. There are many opportunities during each step of the multi-stage gel spinning process to reduce or minimize polymer degradation. For example, the initial stage of the gel spinning process involves the formation of a UHMW PE polymer solution according to the following steps:

1) formation of a suspension, that is, a dispersion of solid polymer particles in a solvent capable of dissolving the polymer;

2) heating the suspension to melt the polymer and form a liquid mixture under conditions of intense distributive and dispersive mixing to thereby reduce the domain sizes of molten polymer and solvent in the mixture to microscopic dimensions; and

3) allow sufficient time for the diffusion of the solvent into the polymer and of the polymer into the solvent to be produced to thereby form a solution.

Limiting polymer degradation is possible during each of these measures to keep the polymer IVo. For example, a study by GR Rideal et al. entitled, The Thermal-Mechanical Degradation of High Density Polyethylene, J. Poly. Sci., Symposium No.

<img file="MX347676B_D0017.tif" />

37, 1-15 (1976) found that

IMPI

INSTITUTO MEXICANO H LA HOHUM: INDUSTRIAL the presence of oxygen during polymer processing promoted induced chain cleavage by shear stress, but that under nitrogen at temperatures below 290 ° C, long chain branching dominated and increased viscosity. Consequently, during any of these steps 1-3, by bubbling the solvent, the polymer-solvent mixture and / or the solution with nitrogen gas is expected to reduce or completely eliminate the presence of oxygen and retain the IVq polymer. In a preferred embodiment, the suspension was sparged with nitrogen according to any technique that is conventional in the art. Nitrogen sparging is preferably carried out continuously, such as by bubbling nitrogen continuously through the slurry tank. Nitrogen bubbling in the slurry tank can take place, for example, at a rate of about 29 liters / minute to about 58 liters / minute. Other means of reducing or eliminating the presence of oxygen from the polymer-solvent and / or polymer solution mixture during processing should be equally effective, such as incorporating an antioxidant into the polymer-solvent and / or solution mixture. The use of an antioxidant is taught in US Patent 7,736,561, which is commonly owned by Honeywell.

International Inc. In this modality, the concentration of

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INTTTTVro M1XJCANO m the namiMD iMournuAi ~ antioxidant should be sufficient to minimize the effects of accidental oxygen, but not so high as to react with the polymer. The weight ratio of the antioxidant to the solvent is preferably from about 10 parts per million to about 1000 parts per million. More preferably, the weight ratio of the antioxidant to the solvent is from about 10 parts per million to about 100 parts per million.

Useful antioxidants include not exclusively hindered phenols, aromatic phosphites, amines, and mixtures thereof. Preferred antioxidants include 2,6-di-tert-butyl-4-methyl-phenol, tetrakis [methylene (3,5-di-tert-butylhydroxyhydrocinnamate)] methane, tris (2,4-di-tert-butylphenyl) phosphite, 3,5 Octadecyl-di-tert-butyl-4-hydroxyhydrocinnamate, 1, 3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1, 3,5-triazine-2,4,6 ( 1H, 3H, 5H) trione, 2,5,7,8 tetramethyl 2 (4 ', 8', 12'-trimethyltridecyl) chroman-6-ol, and mixtures thereof. More preferably, the antioxidant is 2,5,7,8 tetramethyl-2 (4 ', 8', 12'-trimethyltridecyl) chroman-6-ol, commonly known as vitamin E or α-tocopherol.

Other additives can also optionally be added to the polymer / solvent mixture, such as processing aids, stabilizers, etc., as may be desirable to maintain polymer molecular weight and IVo.

<img file="MX347676B_D0018.tif" />

IMPI

INSTITUTO MUUCANO PE LA rSOTlEUM INDUSTRIAL

The degradation of the polymer can also be controlled during these initial stages 1-3 by controlling the harshness of the environment in which the polymer is processed. For example, stage 1 is typically carried out by forming the slurry in a slurry mixing tank, while stages 2 and / or 3 are often initiated or fully performed in an extruder under more intense heat and conditions. of mix with respect to the mix suspension tank. By reducing the residence time of the polymer in the extruder, it is desired to minimize polymer degradation. For example, transforming the polymer suspension into an intimate mixture of molten polymer and solvent, ideally with domain sizes of microscopic dimensions, requires that the extruder have sufficient heating and distributive mixing capabilities.

The extruder may be a single screw extruder, or it may be a non-gear twin screw extruder or a gear counter-rotating twin screw extruder. Preferably, the extruder is a co-rotating gear twin screw extruder, wherein the gear co-rotating twin screw extruder screw elements preferably forward conveying elements, preferably including non-back mixing or segment kneading. Although these extruder features are effective in melting the polymer and mixing the polymer

<img file="MX347676B_D0019.tif" />

IMPI

OWHVTO MEXICANO ocunonuMD INDUSTRIAL molten and solvent to form a liquid mixture, the intense heat and amount of shear stress in the polymer is detrimental to the molecular weight of the polymer.

To avoid this problem, while still efficiently forming a polymer solution, it may be desirable to initiate the formation of the liquid solvent polymer mixture by heating the slurry tank, thereby allowing some of the melt to form in a softer environment. This in turn will reduce the residence time of the polymer in the extruder, thus reducing thermal and shear degradation of the polymer. In addition to increasing the residence time of the polymer in the slurry tank, preferably a heated slurry tank, lowering the extruder temperature will help create the solution in a milder environment.

As is also known from common property patent application publication 2007/0231572, the residence time of the mixture in the extruder can also be limited by rapidly passing the polymer-solvent mixture out of the extruder and into a heated container, where it is provides the remaining time required for the solvent and polymer to fully disperse with each other and form a uniform homogeneous solution. Operating conditions that can facilitate the formation of a homogeneous solution include, for example, (1) raising the

IMPI

<img file="MX347676B_D0020.tif" />

the Mexican txrrmno DilAFKOHUXW INDUmUAL temperature of the liquid mixture of solvent-spun UHMW PE at a temperature near or above the melting temperature of UHMW PE, and (2) maintain the liquid mixture at said raised temperature for sufficient time to allow the spinning solvent to diffuse into the UHMW PE and for the UHMW PE to diffuse into the spinning solvent. When the solution is uniform, or sufficiently homogeneous, the final gel spinning fiber may have improved properties, such as increased toughness.

Preferably, the mean residence time in the extruder, which is defined as the ratio of free volume in the extruder to the volumetric throughput rate, is less than or equal to about 1.5 minutes, more preferably less than or equal to about 1.2 minutes. , and more preferably less than or equal to about 1.0 minutes. In the first mode process of the invention, the intrinsic viscosity of the polyethylene in the liquid mixture is reduced when passing through the twin screw extruder in an amount of less than 10%, that is, from a polymer of intrinsic viscosity initial IVo at an intrinsic yarn viscosity final IVf of 0.9 IVo &lt;IV_F&lt;1.0 IVo. In the second embodiment process of the invention, the initial intrinsic viscosity of the polyethylene in the liquid mixture is at least about 35 dl / g and can be

<img file="MX347676B_D0021.tif" />

IMPI

ΙΜΤΠνΤΟ MlUCAND t · M HtORtDAB tlDUITUM reduced by an amount greater than 10%, in passing, through the twin screw extruder, but not to the point that the final yarn intrinsic viscosity IVf is less than 21 dl / g .

The liquid mixture of UHMW PE and spin solvent exiting the extruder can be passed through a pump, such as a positive displacement pump, into the heated vessel. It is preferred that the container is a heated tube. The heated tube may have a straight length of tubing, or it may have curves, or it may be a helical coil. It may comprise sections of different lengths of chosen diameter so that the pressure drop through the pipe is not excessive. As the polymer / solvent mixture entering the tube is highly pseudoplastic, it is preferred that the hot tube contains one or more static mixers to redistribute flow through the cross section of the tube at intervals, and / or to provide the additional dispersion. The heated container is preferably maintained at a temperature of at least about 140 ° C, preferably from about 220 ° C to about 320 ° C, and more preferably from about 220 ° C to about 280 ° C. The heated container may have a sufficient volume to provide an average residence time for the liquid mixture as the container is heated to form

IMPIé ^ nWTHVTBMlXJCiMD η Μ HJOTfEDAP VtaaaMaíX imRiitual a solution of the PE of UHMW in the solvent. For example, the residence time of the liquid mixture in the heated container can be from about 2 minutes to about 120 minutes, preferably from about 6 minutes to about 60 minutes.

In an alternative example, the placement and use of the heated vessel and extruder can be reversed in forming the UHMW PE solution and solvent spinning. In such an example, a liquid mixture of UHMW PE and spun solvent can be formed in a heated vessel, and then can be passed through an extruder to form a solution that includes the UHMW PE and the spin solvent.

Each of these steps is intended to maximize polymer retention prior to IV extrusion or solution through a spinner to form solution filaments. There are more opportunities for retention of intrinsic viscosity in post-solution processing.

After the solution filaments are formed, post-solution processing conventionally includes the following steps:

4) passing the solution thus formed through a spinning machine to form solution filaments;

5) passing said solution through the filaments of a small gas space in a liquid quench bath in which said solution filaments are rapidly cooled to form gel filaments;

6) removing the solvent from the gel filaments to form solid filaments; and

7) The stretching of at least one of the solution filaments, the gel filaments and the solid filaments in one or more steps. As used herein, the terms "drawn fibers" or "draw fibers" are known in the art and are also known in the art as oriented or orienting fibers or drawn or stretching fibers. These terms are used interchangeably herein. Solid filament drawing includes a post-draw operation to increase final yarn tenacity. These terms are used interchangeably in this document. The stretching of the solid filaments includes a subsequent extraction operation to increase the tenacity of the final yarn. See, for example, US patents 6,969,553 and 7,370,395, and publications in the US 2005/0093200, 2011/0266710 and 2011/0269359, each of which is incorporated herein to the extent consistent herewith, describing post-extraction operations that are performed on partially oriented yarns / fibers to form highly oriented yarns / fibers. oriented of

<img file="MX347676B_D0022.tif" />

IMPI

Mexican Btsrnvro km non idas iNwrniUL superior tensile strengths. Post extraction is typically performed offline as a decoupled process using separate stretching equipment.

The process of supplying the UHMW PE polymer solution and solvent spinning from the heated vessel to the spinner may include passing the UHMW PE polymer solution and spinning the solvent through a metering pump, which it can be a gear pump. The solution-emitting fiber from the spinner may include a plurality of solution filaments. The spinner can form a solution fiber having any suitable number of filaments, including, for example, at least about 100 filaments, at least about 200 filaments, at least about 400 filaments, or at least about 800 filaments. In one example, the spinner can have from about 10 spinning holes to about 3000 spinning holes and the solution fiber can comprise from about 10 filaments to about 3000 filaments. Preferably, the spinner can have from about 100 spinning holes to about 2000 spinning holes and the solution fiber can comprise from about 100 filaments to about 2000 filaments. Swivel holes

IMPI may have a conical inlet, with the cone having a

OWnTUTO MWCANO Pt LA NORIDAD INDUSTRIAL included angle from about 15 degrees to about 75 degrees. Preferably, the included angle is from about 30 degrees to about 60 degrees. In addition, after the conical entry, the rotary holes can have a straight capillary hole that extends to the exit of the spinning hole. The capillary may have a length to diameter ratio of between about 10 to about 100, more preferably about 15 to about 40.

As the solution filaments pass through the gaseous space, they remain vulnerable to oxidation if the space contains oxygen, just as if the space is filled with air. To minimize polymer degradation and maximize spinning IVf, it may be desirable to fill the gas space with nitrogen or another inert gas such as argon to avoid any oxidation. Limiting the length of the gas space will also minimize the potential for oxidation, particularly if filling the vacuum with an inert gas is impractical. The length of the gaseous space between the spinner and the surface of the liquid quench bath is preferably from about 0.3 cm to about 10 cm, more preferably from about 0.4 cm to about 5 cm. If the residence time of the solution yarn in the

<img file="MX347676B_D0023.tif" />

he

IMPI

WJTTTTJTC MEXICAN

M THE «INDIVIDUAL OM4TY gaseous space is less than about 1 second, gaseous space can be filled with air, otherwise filling the space with an inert gas is the most preferred.

The liquid in the cooling bath is preferably selected from the group consisting of water, ethylene glycol, ethanol, isopropanol, a water soluble antifreeze, and mixtures thereof. Preferably, the temperature of the liquid cooling bath is about -35^ORC to about 35 ° C.

Once the filaments in the solution have cooled to gel filaments, the spinning solvent must be removed. Removal of the spinning solution can be carried out by any suitable method, including, for example, drying, or by extracting the spinning solvent with a second low-boiling solvent, followed by drying. The technique required to remove the spin solvent depends primarily on the type of spin solvent used. For example, a decalin spin solvent can be removed by evaporation / drying according to techniques that are conventional in the art. On the other hand, a mineral oil spinning solvent must be extracted with a second solvent. Extraction with a second solvent is carried out in a way that replaces the first solvent in the gel with the second solvent and without ικτπτντοMUJCANO

Μ U ηΟΠΙΟΑϋ

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significant changes in gel structure. Some swelling or shrinkage of the gel may occur, but preferably no substantial dissolution, coagulation or precipitation of the polymer occurs. When the first solvent is a hydrocarbon, suitable second solvents include hydrocarbons, chlorinated hydrocarbons, chloroflucinated hydrocarbons, and others, such as pentane, hexane, cyclohexane, heptane, toluene, methylene chloride, carbon tetrachloride, trichlorotrifluoroethane (TCTFE), diethyl ether. , dioxane, dichloromethane, and combinations thereof. Preferred low-boiling second solvents are volatile, non-flammable solvents with an atmospheric boiling point below about 80 ° C, more preferably below about 70 ° C, and more preferably below about 50 ° C. The second most preferred solvents are methylene chloride (BP = 39.8 ° C) and TCFE (BP = 47.5 ° C). Extraction conditions should remove the first solvent to less than 1% of the total solvent in the gel. After extraction, the extraction solvent can be removed from the fiber by evaporation / drying to form a dry yarn / fiber. The dry fiber preferably includes less than about 10 percent by weight of any solvent, including solvent spinning and any second solvent that is used in removing the spinning solvent. Preferably, the

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μιαηκχήβλ »tXDUTHUA The dry fiber includes less than about 5 percent by weight solvent, and more preferably less than about 2 percent by weight solvent.

A preferred extraction method using a second solvent is described in detail in commonly owned US Patent 4,536,536, the disclosure of which is incorporated herein by reference. Most preferably, the spinning solvents and extraction solvents are recovered and recycled. The use of a recycled spinning solvent is more specifically preferred as the solvent recovered in the extraction process is highly pure and not contaminated by oxygen.

The gel spinning process may include stretching the solution fiber exiting the spinner in an extraction ratio of about 1.1: 1 to 30: 1 to form a solution extracted fiber. The stretching of the solution yarn within the gas space between the spinner and the liquid quench bath is influenced by the length of the gas space. A longer gap can lead to a greater stretching of the solution yarns within the gap, so this variable can be controlled as desired if more or less stretching of the solution fiber is desired. The gel spinning process can include extraction of the gel fiber in one or more stages at a first extraction ratio DR1 of approximately 1.1:

to 30:

1.

IMPI ηοτπντ »M1X1CANO DCUNOHITY onwmui

<img file="MX347676B_D0024.tif" />

Stretching of the gel fiber in one or more stages in the first DR1 ratio can be accomplished by passing the gel fiber through a first series of rollers (rollers). Preferably, the extraction of the gel fiber in the first extracted ratio DR1 can be carried out without the application of heat to the fiber, and can be carried out at a temperature of less than or equal to about 25 ° C.

The extraction of the gel fiber may also include the extraction of the gel fiber in a second extraction ratio DR2. Extraction of the gel fiber in the second extraction ratio DR2 can also simultaneously include the removal of solvent spinning of the gel fiber in a solvent removal device, sometimes referred to as a washer, to form a dry fiber. Accordingly, the second extraction step DR2 can be carried out in the solvent removal device (for example the washer). The extraction in the washing machine is recommended but not mandatory. Preferably, the gel fiber is extracted at a second DR2 extraction ratio of from about 1.5: 1 to about 3.5: 1, more preferably at about 1.5: 1 to 2.5: 1, and most preferably at about a 2: extraction ratio. one.

<img file="MX347676B_D0025.tif" />

IMPI nwrmn · Mexican MlAnDPIKMD DCDUSniAL

The gel spinning process can also include extraction of the dry yarn at the third extraction ratio DR3 in at least one step to form a partially oriented spinning. The extraction of the dry yarn can be carried out at the third extraction ratio, for example, by passing the dry yarn through an extraction support. The third extraction ratio can be from about 1.10: 1 to about 3.00: 1, more preferably from about 1.10: l to about 2.00: 1. Extraction of spinning and dry gel spinning at extraction ratios DR1, DR2 and DR3 can be done online. In one example, the combined extraction of spinning and dry gel spinning, which can be determined by multiplying DR1, DR2, and DR3, and can be written as DR1 xDR2xDR3: 1 or (DR1) (DR2) (DR3): 1, in where DRlxDR2xDR3: 1 can be at least about 5: 1, preferably at least about 10: 1, more preferably at least about 15: 1, and most preferably at least about 20: one Preferably, the dry yarn drawn most in-line to the last drain stage is at a draw ratio of less than about 1.2: 1 Optionally, the last stage of dry yarn draw can be followed by relaxation of the partially oriented fiber

<img file="MX347676B_D0026.tif" />

from about 0.5 percent of its length to about 5 percent of its length.

Preferably, stretching is performed on all three of the solution filaments, the gel filaments, and the solid filaments. During yarn processing, drawing is performed on at least one of the solution filaments, the gel filaments, and the solid filaments in one or more stages at a combined draw ratio (draw ratio) of at least about 10: 1, wherein a span of at least about 2: 1 is preferably applied to the solid filaments to form a high strength UHMW PE spunbonded multifilament.

Additional post-extraction operations that include further extraction of the yarn can be carried out as described in commonly owned patent application publication US 2011/0266710, US patent 6,969,553, US patent 7,370,395 or US 7,344,668, each one of which is incorporated herein by reference to the extent that it is compatible herewith.

In addition to affecting the required solvent extraction method, it has been found that the type of spinning solvent employed also affects the denier of the resulting extracted fibers. As used herein, the term denier refers to the unit of

PREVENT

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WWUTTUAl.

linear density, equal to the mass in grams per 9000 meters of fiber or yarn. The denier of the yarn is determined by both the linear density of each filament that forms the yarn, that is, denier per filament (dpf) and the number of filaments that make up the yarn. Generally, once all drawing steps have been completed, the fibers / yarns of the invention will have a denier per filament of from about 1.4 to about 2.5 dpf dpf, more preferably from about 1.4 to about 2.2 dpf. Although these low dpf ranges are preferred, broader ranges may be useful, wherein the denier per filament of the yarn ranges preferably from 1.4 dpf to about 15 dpf, more preferably from about 2.2 dpf to about 15 dpf, more preferably from about 2.5 dpf to about 15 dpf. Other useful ranges include about 3 dpf to about 15 dpf, about 4 dpf to about 15 dpf, about 5 dpf to about 15 dpf. In order to obtain yarns comprising fibers having a post-stretch denier per filament as low as 1.4 dpf, the spinning solvent must be an extractable spinning solvent (i.e. a two-solvent system), not a spinning solvent. evaporatable (i.e., a one-solvent system). This is because the filament denier must be relatively low for the yarn to

<img file="MX347676B_D0027.tif" />

in solvent, e.g. decalin, fully evaporate to

IMPI

ΙΧΠΤΤΙΓΓΟ M4XJCANO M LA F * M * DM&gt; tXDwnw.

a reasonable and commercially viable regime. This specifically excludes decalin as a spinning solvent if yarns comprising filaments of more than 2 dpf are desired according to the processes described herein, in particular 2.2 dpf or more, more particularly yarns comprising filaments of 2.5 dpf or more. . Yarns having a denier per filament of&gt; 2.5 dpf are most preferably made using mineral oil as the spinning solvent.

The multifilament yarns / fibers of the invention preferably include 2 to about 1000 filaments, more preferably 30 to 500 filaments, even more preferably 100 to 500 filaments, and more preferably about 100 to about 250 filaments. The resulting multi-filament yarns of the invention having the aforementioned dpf ranges for the component filaments will preferably have a yarn denier ranging from about 50 to about 5000 denier, more preferably from about 100 to 2000 denier, and most preferably from about 150 to about 1000 denier.

Collectively, the above options are used effectively in the first embodiment of the invention to

<img file="MX347676B_D0028.tif" />

maintaining the intrinsic viscosity IVo of the UHMW PE polymer such that the intrinsic viscosity IVf of the UHMW PE polymer exceeds 90% relative to the intrinsic IVo and wherein the IVf is greater than 18 dl / g, more preferably so less about 21 dl / g and more preferably is at least about 28 dl / g.

As stated above, in the second embodiment of the invention, instead of making efforts to maintain the intrinsic viscosity IVo of the UHMW PE polymer such that the intrinsic viscosity IVf of the UHMW PE yarn exceeds 90% relative to the IVo Intrinsic, a polymer UHMW PE having the highest obtainable intrinsic viscosity IVo is used as a starting material and allowed to degrade to IV levels that are more manageable for manufacturing processes. For example, a UHMW PE polymer having an IVo of at least about 35 dl / g, more preferably an intrinsic viscosity of at least about 40 dl / g, even more preferably an intrinsic viscosity of at least about 45 dl / g, and more preferably an intrinsic viscosity of at least about 50 dl / g, is provided and allowed to degrade to a spinning IVf of at least about 21 dl / g, more preferably at a spinning IVf of at least about 25 dl / g, even more preferably at a spinning IVf of at least

IMPI ^ a

MEXICAN INSTITUTE

M THE PROPERTY Ό—. industrial jjfTjflr approximately 30 dl / g, and more preferably at an IV_F spinning of at least about 35 dl / g, wherein said intrinsic viscosities are measured in decalin at 135 ° C according to ASTM D 1601-99. The higher the IV_F the higher the yarn tenacity. A UHMW PE yarn of the invention having an IVf of 40 dl / g or greater will have a tenacity of at least about 55 g / denier, more specifically a tenacity of at least about 60 g / denier.

In the third embodiment, yarns having a tenacity of 45 g / denier at a denier per filament of about 1 dpf to about 4.6 dpf, are made from a low concentration UHMW PE solution having less than 5% by weight. UHMW PE which is more preferably dissolved in a mineral oil spinning solvent (or other extractable two-tool system, solvent).

Most preferably, the concentration of UHMW PE in the solvent solution spinning UHMW PE is from greater than 3% by weight to less than 5% by weight of the solution. The yarns obtained according to this process have a tenacity of 45 g / denier or more, more preferably 50 g / denier or more, even more preferably 55 g / denier or more, and more preferably a tenacity of 60 g / denier or more. . Such yarns have a preferred denier per filament of more than 2 dpf, more preferably 2.2 dpf or more, even more preferably of

2.5 dpf or more, and more preferably of

IMPI

INSTITUTO MIXICAN · MIAFROHIMJD XDUSHUM

2.5 dpf at

<img file="MX347676B_D0029.tif" />

4.6 dpf.

The yarns of this third modality are not limited to a specific percentage of retention of IV₀ PE of UHMW or IVo. Carrying out the gel spinning process at such low concentrations of UHMW PE allows the manufacture of partially oriented yarns at a spinning speed of up to about 90 grams / min / spinning end.

Gel spinning processes for all described modalities, above all, achieve the ability to produce UHMW PE yarns having tensile strengths of 45 g / denier and above at commercially viable throughput rates as defined herein . It should be understood, however, that while the process described in this document is capable of producing such yarns at such rates, it is not mandatory that the yarns be able to process at such percentages. The manufacturing process may also include winding the partially oriented yarn as fiber bundles, or on a beam, with winders. Weaving can preferably be achieved without twisting by being imparted to partially oriented yarn.

It should be understood that all references herein to the term "ultra high" with respect to the molecular weight of the polyolefins or polyethylenes of the invention are not intended to be limiting at the maximum end of the polymer viscosity and / or molecular weight.

<img file="MX347676B_D0030.tif" />

IMPI Μίτπυτ · MJUUCANO M LA nonitMc INDUSTRY!

of the polymer. The term ultra high is only intended to be limiting at the very low end of polymer viscosity and / or polymer molecular weight insofar as polymers useful within the scope of the invention are capable of being transformed into fibers having a toughness of at least 45 g / denier. It should also be understood that while the processes described herein are most preferably applied to the treatment of UHMW polyethylene, they are equally applicable to all other poly (alpha-olefins), ie, UHMW PO polymers.

The fibers described in this document can be used to produce bullet resistant composites and materials, and bullet resistant articles from such composites and materials. For purposes of the invention, bullet resistant composites, articles and materials describe those that exhibit excellent properties against deformable projectiles, such as bullets, and against the penetration of fragments, such as shrapnel. The invention particularly provides bullet resistant composites formed from one or more layers of fibers or layers of fibers, each deck / layers comprising yarns having a tenacity of at least 45 g / denier or more. Bullet resistant composites can comprise woven, nonwoven, or knitted fabrics, where the fibers

<img file="MX347676B_D0031.tif" />

IMPI ΜΙΤΠυΤΟ MIXJCANO HLAnOmDAD INDUSTKML that form said fabrics may optionally be coated with a woven polymeric binder material.

A layer of fibers as used herein may comprise a single layer of unidirectionally oriented fibers, a plurality of consolidated layers of unidirectionally oriented fibers, a woven fabric, a plurality of consolidated woven fabrics, or any other fabric structure that is It has formed from a plurality of fibers, including felts, carpets, and other structures that comprise randomly oriented fibers. In this regard, consolidated means that a plurality of fiber layers or layers are combined together, generally with a polymeric binder material, to form a single unitary layer. A layer generally describes a generally flat arrangement. Each fiber layer will have both an outer upper surface and an outer lower surface. Single-layer unidirectionally oriented fibers comprises an arrangement of fibers that are aligned in a unidirectional arrangement, substantially parallel. This type of fiber arrangement is also known in the art as a uni-tape, unidirectional tape, UD, or UDT. In the present description, an arrangement describes an ordered arrangement of fibers or yarns, which is unique to woven and knitted fabrics, and a parallel arrangement describes a

<img file="MX347676B_D0032.tif" />

coplanar parallel arrangement ordered from side to side of

IMPI

ΙΝΓΠΤυτΟ MiXJCANO

Ot LA PM&gt; RU »AD nousnuAL fibers or yarns. The term oriented as used in the context of oriented fibers refers to the direction of alignment of the fibers rather than an extension of the fibers. The term "woven" describes structures that can include one or more layers of fibers, with or without consolidation / molding of the layers, and can relate to a woven material, a non-woven material, or a combination thereof. For example, a nonwoven fabric formed from unidirectional fibers typically comprises a plurality of layers of nonwoven fibers that are stacked on top of each other in a substantially coextensive and consolidated manner. When used herein, a single layer structure refers to any monolithic fibrous structure composed of one or more individual layers or individual layers that have been fused by consolidation or molding techniques into a single unitary structure. The term "composite" refers to combinations of fibers, optionally, but preferably with a polymeric binder material.

The filaments / fibers / yarns of the invention are preferably at least partially coated with a polymeric binder material, also commonly known in the art as a polymeric arrangement material, to form a fibrous composite material. The terms

<img file="MX347676B_D0033.tif" />

polymeric binder and polymeric arrangement are used

IMPI

INSTTTUT · Mexican MLAFROiUDAO INDUSTNAL indistinctly in this document. These terms are conventionally known in the art and describe a material that bonds fibers to each other either through their inherent adhesive characteristics or after being subjected to well known heat and / or pressure conditions. As used herein, a polymeric binder material or arrangement includes resins and rubber. A polymeric arrangement or polymeric binder material can also provide a fabric with other desirable properties, such as resistance to abrasion and resistance to harsh environmental conditions, whereby it may be desirable to coat the fibers with such a binder material even when its properties of bonding are not important, as for example with woven fabrics.

Suitable polymeric binder materials include both low tensile modulus elastomeric materials and high tensile modulus rigid materials. As used throughout this document, the term "tensile modulus" means the modulus of elasticity, which for polymeric binder materials is measured by ASTM D638. A low or high modulus binder can comprise a variety of polymeric and non-polymeric materials. For the purposes of this invention, a low elastomeric modulus material has a tensile modulus measured at

<img file="MX347676B_D0034.tif" />

IMPI

Dernvro muucamo

M LA FROHMAD MDUmiAL approximately 6000 psi (41.4 MPa) or less according to ASTM D638 test procedures. A low modulus polymer is preferably an elastomer having a tensile modulus of about 4000 psi (27.6 MPa) or less, more preferably about 2400 psi (16.5 MPa) or less, even more preferably 1200 psi (8.23 MPa) or less, and more preferably about 500 psi (3.45 MPa) or less. The glass transition temperature (Tg) of the low elastomeric modulus material is preferably less than about 0 ° C, more preferably less than about -40 ° C, and more preferably less than about -50 ° C. The low modulus elastomeric material also has a preferred elongation at break of at least about 50%, more preferably at least about 100%, and more preferably at least about 300%.

A wide variety of materials and formulations can be used as a low modulus polymeric binder. Representative examples include polybutadiene, polyisoprene, natural rubber, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, polysulfide polymers, polyurethane elastomers, chlorosulfonated polyethylene, polychloroprene, plasticized polyvinyl chloride (acrylonitrile elastomers, acrylonitrile elastomers, isobutylene-co-isoprene), polyacrylates, polyesters,

<img file="MX347676B_D0035.tif" />

IMPI οατπυτο muucanc

OF THE PBOnKDAD

INDUTHUAL silicone elastomers, polyethers, fluoroelastomers, ethylene copolymers, polyamides (useful with some types of fibers), acrylonitrile butadiene styrene, polycarbonates, and combinations thereof, as well as other low modulus polymers and copolymers curable below the fiber melting point. Also useful are mixtures of different elastomeric materials, or mixtures of elastomeric materials with one or more thermoplastics.

Block copolymers of conjugated dienes and vinyl aromatic monomers are particularly useful. Conjugated diene elastomers such as butadiene and isoprene are preferred. Conjugated aromatic monomers such as styrene, vinyl toluene, and t-butyl styrene are preferred. Block copolymers incorporating polyisoprene can be hydrogenated to produce thermoplastic elastomers having saturated hydrocarbon elastomer segments. The polymers can be simple three-block copolymers of the ABA type, multi-block copolymers of the (AB) n type (n = 2-10) or radial configuration copolymers of the R- (BA) x (x = 3-150) type ; wherein A is a block of a vinyl aromatic monomer and B is a block of a conjugated diene elastomer. Many of these polymers are commercially produced by Kraton Polymers of Houston, TX and are described in Kraton's Thermoplastic Rubber bulletin, SC-68-81. Also useful are resin dispersions of

IMPI omrvro HUXKAMO OBMraoninw MMJSTIUAL

<img file="MX347676B_D0036.tif" />

styreneisoprene-styrene block copolymer (SIS) sold under the trademark

PRINLIN® and is commercially available from Henkel Technologies, based in Dusseldorf, Germany. Conventional polymeric low modulus binder polymers employed in bullet resistant composites include polystyrene-polyisoprene-polystyrene block copolymers sold under the Kraton trademark produced commercially by Kraton Polymers.

Although low modulus polymeric binder materials are preferred for the formation of flexible armor materials, high modulus polymeric binder materials are preferred for the formation of rigid armor articles. Rigid, high-modulus materials generally have an initial tensile modulus greater than 6000 psi (41.4 MPa). Useful high modulus polymeric binder materials include rigid epoxy polyurethanes (based on both ether and ester), polyacrylates, phenolic / polyvinyl butyral (PVB) polymers, vinyl ester polymers, styrene-butadiene block copolymers, as well as polymer blends such as vinyl and diallyl phthalate ester or phenol formaldehyde and polyvinyl butyral. A particularly useful rigid polymeric binder material is a thermoset polymer that is soluble in carbon-carbon saturated solvents, such as methyl ethyl ketone, and innnyvoMnxuNo.

CC LA MtOrTKMD dcmtuai possessing a high tensile modulus when cured of at least about IxlO⁶ psi (6895 MPa), measured by ASTM D638. Particularly useful rigid polymeric binder materials are those described in US Patent 6,642,159, the disclosure of which is incorporated herein by reference.

Most preferred are specifically polar resins or polar polymers, particularly polyurethanes within the range of both soft and rigid materials in a tensile modulus ranging from about 2000 psi (13.79 MPa) to about 8000 psi (55.16 MPa). Preferred polyurethanes are applied as aqueous polyurethane dispersions which are more preferably, but not necessarily, free co-solvent. They include, as such, aqueous anionic polyurethane dispersions, aqueous cationic polyurethane dispersions and aqueous non-ionic polyurethane dispersions. Anionic aqueous polyurethane dispersions are particularly preferred; Aqueous aliphatic polyurethane dispersions, and more preferred are aqueous anionic, aliphatic polyurethane dispersions, all of which are preferably free cosolvent dispersions. They include as such aqueous anionic polyester based polyurethane dispersions; aliphatic aqueous dispersions based on polyurethane polyester; and aliphatic polyurethane dispersions,

<img file="MX347676B_D0037.tif" />

IMPI rxrrmrro mwcano

DtUnOflUMD

INBUmiAL aqueous anionic, polyester based, all of which are preferably are free dispersions' cosolvents. Also included are aqueous polyether anionic polyurethane dispersions; aliphatic aqueous dispersions based on polyether polyurethane; and aqueous anionic aliphatic polyether-based polyurethane dispersions, all of which are preferably cosolvent-free dispersions. Similarly preferred corresponding variations (polyester based; polyester-aliphatic based; polyether based; aliphatic polyether based, etc.) are all of aqueous cationic and nonionic aqueous dispersions. More preferred is an aliphatic polyurethane dispersion having a 100% modulus of elongation of about 700 psi (4.82 MPa) or more, with a particularly preferred range of 700 psi (4.82 MPa) to about 3000 psi (20.68 MPa). More preferred are aliphatic polyurethane dispersions having a 100% modulus of elongation of about 1000 psi (6.89 MPa) or more, and even more preferably about 1100 psi (7.58 MPa) or more. More preferred is an aliphatic, polyether-based anionic polyurethane dispersion having a modulus of 1000 psi (6.89 MPa) or more, preferably 1100 psi (7.58 MPa) or more. The stiffness, impact, and ballistic properties of articles formed from the fabric composites of the invention

5

IMPI

UWTTTUTO MWCAXO PÍLArWOPIUMD IWUJT1ML are affected by the tensile modulus of the polymeric binder polymer coating of the fibers.

The stiffness, impact and ballistic properties of articles formed from the fabric composites of the invention are affected by the tensile modulus coating of the polymeric binder polymer of the fibers. For example, US patent 4,623,574 discloses that fiber-reinforced composites constructed with elastomeric matrices that have tensile moduli of less than about 6000 psi (41,300 kPa) have superior ballistic properties compared to both composites constructed with higher modulus polymers, and also compared with the same fiber structure without a polymeric binder material. However, low tensile modulus polymeric binder material polymers also produce lower stiffness composites. Furthermore, in certain applications, particularly those in which a function of most compounds in both antiballistic and structural modes, a superior combination of ballistics and stiffness is not needed. Consequently, the most appropriate type of polymeric binder polymer to use will vary depending on the type of article to be formed from the fabrics of the invention. In order to achieve a compromise in both properties, a suitable polymeric binder can

IMPI

INSTITUTO MEXICANO m la noniiMD INDUSTRIAL

<img file="MX347676B_D0038.tif" />

combine both low modulus and high modulus materials to form a single polymeric binder.

Methods for applying a polymeric fiber binder material to thereby impregnate fiber layers / layers with the binder are well known and readily determined by one of ordinary skill in the art. The term impregnated is considered herein to be synonymous with embedded, coated, or otherwise applied with a polymeric coating in which the binder material diffuses into the fiber layer / layer and is not simply on one surface of the deck / cap. Any appropriate application method can be used to directly apply the polymeric binder material to the fiber and the particular use of a term such as coated is not intended to limit the method by which it is applied onto the filaments / fibers. Useful methods include, for example, spraying, extruding, or roller coating polymers or polymer solutions onto the fibers, as well as transporting the fibers through a polymer or molten polymer solution.

Alternatively, the polymeric binder material may be extruded onto the fibers using conventionally known techniques, such as through a slot die, or by other techniques, such as the direct etch, Meyer rod and twmvro MU1CANO knife systems.

MIA PKOmBAD induttual air, which are well known in the art. Another method is to apply a neat polymer of the binder material onto the fibers, either as a liquid, a sticky solid or suspended particles, or as a fluidized bed. Alternatively, the coating can be applied as a solution, emulsion or dispersion in a suitable solvent that does not adversely affect the properties of the fibers at application temperature. For example, the fibers can be transported through a solution of the polymeric binder material to substantially coat the fibers and then dried.

Generally, it is necessary for a polymeric binder coating to efficiently fuse, ie, consolidate, a plurality of layers of nonwoven fiber. The polymeric binder material can be applied over the entire surface of the individual fibers or only on a partial surface of the fibers. More preferably, the coating of the polymeric binder material is applied over substantially the entire surface area of ​​each individual fiber to form a woven or non-woven fabric of the invention, the coating of substantially each of the individual filaments / fibers that form a layer of fiber or fiber layer. When the fabrics comprise a plurality of yarns, each forming a single strand of filament yarn it is preferably coated with the polymeric binder material. However, as is the case with woven fabric substrates, nonwoven fabrics can also be coated with additional matrix / polymeric binder materials after the aforementioned consolidation / molding steps onto one or more fabric surfaces that are desired by an expert in the art. Most preferred are methods that substantially coat or encapsulate each of the individual fibers and cover all or substantially the entire surface area of ​​the fiber with the polymeric binder material, wherein the fibers are thus coated in, impregnated with , embedded in, or otherwise applied with the coating

When coating filaments / fibers / yarns with a polymeric binder, the polymeric binder coating can be applied simultaneously or sequentially to a plurality of fibers. The fibers can be coated before forming a fabric or after forming a fabric. For example, the fibers may be coated when in the form of a fiber web (for example, a parallel arrangement or a felt) to form a coated web, or they may be coated on at least one fiber arrangement that is not part of a fiber web to form a coated arrangement. The fibers can also be coated after they have been spun into a woven fabric to form a coated woven fabric. In this

<img file="MX347676B_D0039.tif" />

IMPI distitut · auxjcano

M THE HiOFlKAAD

INDUSTRIAL one-way woven fiber, polymeric binder layer coating is generally not required, but fiber fabric layers are preferably coated with a polymeric binder when it is desired to consolidate a plurality of woven fiber layers into a structure of a single layer similar to that carried out when consolidating woven fiber layers. The invention is not intended to be limited by the stage in which the polymeric binder is applied to the fibers, or by the means used to apply the polymeric binder.

When a binder is used, the total weight of the binder in a composite material preferably comprises from about 2% to about 50% by weight, more preferably from about 5% to about 30%, more preferably from about 7% to about 20%, and more preferably from about 11% to about 16% by weight of the fibers plus the weight of the binder. A lower binder content is appropriate for woven / knit fabrics where a polymeric binder content greater than zero but less than 10% by weight of the fibers plus the weight of the binder is more particularly preferred, but this is not intended to be a strict limitation. For example, phenolic / PVB impregnated woven aramid fabrics are sometimes manufactured with a high resin content of about

<img file="MX347676B_D0040.tif" />

20% to about 30%, although a

IMPI

MUJCANO INSTITUTE

ΜΙΛ IMMISTMAL noniDAD content of approximately 12%. Either a low modulus material or a high modulus material, the polymeric binder can also include fillers such as carbon black or silica, it can be extended with oils, or it can be vulcanized by sulfur, peroxide, metal oxide or systems. radiation cure as is well known in the art.

The methods of forming woven fabrics, nonwovens, and knitted fabrics are well known in the art. Fabrics can be formed using techniques that are well known in the art using any fabric of the fabric, such as plain weave, houndstooth weave, basket weave, satin weave, twill, three dimensional weave, and any of its various variants. Flat weave is more common, where the fibers are interlaced in a 0 ° / 90 ° orthogonal orientation, and is preferred. More preferred are flat weave fabrics with equal warp and weft count. In one embodiment, a single woven fabric layer preferably has from about 15 to about 55 yarn / fiber ends per inch (about 5.9 to about 21.6 ends per cm) in both the warp and weft directions, and more preferably about 17 to about 45 yarns per inch (about 6.7 to about 17.7 yarns per cm). The fibers / yarns that

<img file="MX347676B_D0041.tif" />

IMPI INSTTTVT · MEXICANO M LA nOPUBAD MXJITMAL form the woven fabric preferably have a denier of about 375 to about 1300. The result is a woven fabric that preferably weighs from about 5 to about 19 ounces per square yard (about 169.5 to about 644.1 g / m²), and more preferably from about 5 to about 11 ounces per square yard (about 169.5 to about 373.0 g / m2²).

The knitted structures are manufactured according to conventional methods, and are preferably oriented knit structures having straight drawn yarns held together by fine fine denier stitches. Coating knitted fabric or fabrics with a polymeric binder will facilitate fusion of a plurality of layers of woven / knitted fabric or fusion with other mixed woven / knitted or nonwoven materials. Typically, the weaving or knitting of fabrics is carried out prior to coating the fibers with an optional polymeric binder, wherein the fabrics are subsequently impregnated with the binder. Multiple woven or knitted fabrics can be interconnected to each other by 3D weaving methods, such as warp and weft strands woven into a stack of woven fabrics both horizontally and vertically. A plurality of pieces of tissue may also be joined together by other means, such as adhesive bonding through

<img file="MX347676B_D0042.tif" />

IMPI

MEXICAN INSTITUTE

Dt LA noniDAD

INDUSTUAL of an intermediate adhesive film between fabrics, mechanical stitching / needle piercing of fabrics together in the z direction, or a combination thereof. More preferably, a composite fabric of the invention is formed by impregnating / coating a plurality of individual layers of woven fabric with a polymeric binder, followed by stacking a plurality of the impregnated fabrics on one another in a substantially coextensive manner, and then melting the pile into a single layer structure by low pressure consolidation or high pressure molding. Such a woven composite will typically include from about 2 to about 100 of these woven fabric layers, more preferably about 2 to about 85 layers, and more preferably from about 2 to about 65 woven fabric layers. Again, similar techniques and preferences apply to the fusion of a plurality of knitted fabrics.

A nonwoven composite material of the invention can be formed by methods conventional in the art. For example, in a preferred method of forming a nonwoven fabric, a plurality of fibers are arranged in at least one arrangement, typically they are arranged as a fiber network comprising a plurality of fibers aligned in a substantially parallel, unidirectional arrangement. .

IMPI οατπυτο Mexican

OF THE RUBBING

INDUSTRIAL

<img file="MX347676B_D0043.tif" />

In a typical process, the fiber bundles are supplied from a rail and driven through guides and one or more spreader bars on a collimation comb. This is followed by coating the fibers with a polymeric binder material. A typical fiber bundle will have from about 30 to about 2000 individual fibers. The spreader bars and collimation comb spread and spread the packed fibers, rearranged from side to side in a coplanar fashion. The ideal fiber dispersion results in individual filaments or individual fibers that are placed next to each other in a single fiber plane, forming a substantially unidirectional array, of fibers in parallel and without fibers overlapping each other. Similar to woven fabrics, a single layer of woven fabric preferably has about 15 to about 55 yarn / fiber ends per inch (about 5.9 to about 21.6 ends per cm), and more preferably about 17 to about 45 ends. per inch (around 6.7 to about 17.7 strands per cm). A 0 ° / 90 ° 2-ply nonwoven fabric will have the same number of yarn / fiber ends per inch in both directions. The fibers / yarns that make up the nonwoven layers also preferably have a denier of from about 375 to about 1300.

ΙΜΡΙ ^ 3 Mexican nurmiTo

MIA ηΟΛΙΟΛΛ CVe ^ VÍX

INBUSTRIAL

Next, if the fibers are coated, the coating is typically dried followed by forming the coated fibers into a single layer of a desired length and width. The uncoated fibers can be bonded together with an adhesive film, by bonding the fibers together with heat, or any other known method, to thereby form a single layer. Several of these individual non-woven layers are stacked on top of each other in a coextensive manner and are fused together.

More typically, nonwoven fabric layers include from 1 to about 6 layers, but can include as many as about 10 to about 20 layers, as desired for various applications. The higher the number of layers translates into greater resistance to bullets, but also to greater weight. A nonwoven composite material will typically include from about 2 to about 100 of these layers of fabrics, more preferably about 2 to about 85 layers, and more preferably about 2 to about 65 layers of nonwoven fabric.

As is conventionally known in the art, excellent bullet resistance is achieved when the individual fiber layers that are stacked on one another coextensively are cross-folded in such a way that the shape that the unidirectionally oriented fibers in

IMPI tNrrrruTtj mxjucano

Say LA PDOMIDAD

INBUJTIUAL

<img file="MX347676B_D0044.tif" />

Each fibrous layer is oriented in a longitudinal fiber in a non-parallel direction relative to the direction of the longitudinal fiber of each adjacent layer. More preferably, the fiber layers are folded transversely] is orthogonally at angles of 0 ° and 90 °, but adjacent layers may be aligned at any angle between about 0 ° and about 90 ° with respect to the direction of the longitudinal fiber of another cap. For example, a five-layer nonwoven structure may have layers oriented at an angle of 0 ° / 45^or/ 90 ° / 45 ° / 0 ° or at other angles. Such rotated unidirectional alignments are described, for example, in US patents 4,457,985; 4,748,064; 4,916,000; 4,403,012; 4,623,574; and 4,737,402, all of which are incorporated herein by reference to the extent that they are not inconsistent herewith. Typically, the fibers in adjacent layers will be oriented at an angle of 45 ° to 90 °, preferably 60 ° to 90 °, more preferably 80 ° to 90 °, and most preferably about 90 ° relative to each other, wherein the The angle of the alternate layer fibers is preferably substantially the same.

Methods of consolidating fabrics or fiber layers are well known, such as by the methods described in US Patent 6,642,159. When forming composites of the invention, conditions conventional in the art are used to

<img file="MX347676B_D0045.tif" />

Merge individual layers / layers into single layer composite material structures. No-pressure or low-pressure fusion is often referred to in the art as consolidation, while high-pressure fusion is often referred to as casting, but these terms are often used interchangeably. Each stack of layers of non-woven fibers, layers of woven fabric, or layers of knitted fabric are overlapped by melting under low heat and pressure, or by adhering the coatings of individual fiber layers, to form a single layer, monolithic element . Consolidation can occur through drying, cooling, heating, pressure, or a combination thereof. Heat and / or pressure may not be necessary, as the fibers or fabric layers can only be glued together, as is the case in a wet lamination process.

Consolidation can be carried out at temperatures ranging from about 50 ° C to about 175 ° C, preferably from about 105 ° C to about 175 ° C, and at pressures ranging from about 5 psig (0.034 MPa) to about 2500 psig ( 17 MPa), for from about 0.01 seconds to about 24 hours, preferably from about 0.02 seconds to about 2 hours. Upon heating, it is possible that the polymeric binder coating may be

IMPI smssíss ntBUSTBMX

<img file="MX347676B_D0046.tif" />

sticking or flowing without fully melting. However, generally, if the polymeric binder material is melted, relatively little pressure is required to form the composite material, whereas if the binder material is only heated to a friction point, typically more pressure is required. As is conventionally known in the art, consolidation can be carried out in a calendered assembly, a flat bed mill, a press, or in an autoclave. Consolidation can also be accomplished by molding the material in a mold that is placed under a vacuum. Vacuum molding technology is well known in the art. Typically, a plurality of orthogonal fiber webs are glued together with the binder polymer and operate through a flat bed mill to improve bond strength and uniformity. Furthermore, the consolidation and polymer bonding / application measures may comprise two separate stages or a single consolidation / lamination stage.

Alternatively, consolidation can be achieved by molding under heat and pressure in a suitable molding apparatus. Generally, molding is performed at a pressure of about 50 psi (344.7 kPa) to about 5000 psi (34,470 kPa), more preferably about 100 psi (689.5 kPa) to about 3000 psi (20,680 kPa), more preferably about 150 psi (1,034 kPa) to

<img file="MX347676B_D0047.tif" />

approximately 1500 psi (10,340 kPa). Molding can alternatively be carried out at higher pressures from about 5000 psi (34,470 kPa) to about 15,000 psi (103,410 kPa), more preferably from about 750 psi (5,171 kPa) to about 5000 psi, and more preferably from about 1000 psi to approximately 5000 psi. The molding step can take from about 4 seconds to about 45 minutes.

Preferred molding temperatures range from about 200 ° F (~ 93 ° C) to about 350 ° F (~ 177 ° C), more preferably at a temperature of about 200 ° F (~ 93 ° C) to about 300 ⁰ F (140.89 ° C) and more preferably at a temperature from about 200 ° F (~ 93 ° C) to about 280 ° F (137.78 ° C). The pressure under which the fiber layers are molded has a direct effect on the stiffness or flexibility of the resulting molded product. In particular, the higher the pressure at which they are molded, the greater the stiffness, and vice versa. In addition to molding pressure, the amount, composition, and thickness of the fiber layers and coating-type polymeric binder also directly affect the stiffness of the composite material.

While each of the molding and consolidation techniques described in this document are similar, each process is different. In particular, molding is a

IMPI

MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

<img file="MX347676B_D0048.tif" />

Batch process and consolidation is a generally continuous process. Furthermore, molding typically involves the use of a mold, such as a shaped mold or a matching die mold when forming a flat panel, and does not necessarily result in a flat product. Consolidation is typically done in a flat bed mill, pressure calendering assembly or as a wet mill to produce soft body (flexible) armor fabrics. Molding is typically reserved for the manufacture of hard armor, for example rigid plates. In any of the processes, the appropriate temperatures, pressures and times generally depend on the type of coating materials, polymeric binder content of polymeric binder, process used, and the type of fiber.

The thickness of each fabric / composite formed herein corresponds to the thickness of the individual fibers and the number of fiber layers / layers incorporated into the composite. For example, a preferred knit / woven fabric composite will have a preferred thickness of from about 25 µm to about 600 µm per deck / layer, more preferably from about 50 µm to about 385 µm, and more preferably from about 75 to about 255 µm. pm per deck / layer. A preferred non-woven bilayer fabric composite will have a thickness

IMPI πητπντο MUUGANO ot the IWBUSTUAl rwortiDAD

<img file="MX347676B_D0049.tif" />

preteri from about 12 pm to about t&gt; uu pW; This is preferably about 50 pm to about 385 pm and more preferably about 75 pm to about 255 pm. While such thicknesses are preferred, it is to be understood that other thicknesses can be produced to meet a particular need and still be within the scope of the present invention.

After the formation of the individual layers or after consolidation of multiple layers into a consolidated single-layer article, the polymer layer may optionally be bonded to each of the outer surfaces of the composites via conventional methods. Suitable polymers for such a polymer layer include not exclusively thermoplastic and thermoset polymers. Suitable thermoplastic polymers can not exclusively be selected from the group consisting of polyolefins, polyamides, polyesters, polyurethanes, vinyl polymers, fluoropolymers and copolymers and mixtures thereof. Of these, "polyolefin layers" are preferred. The preferred polyolefin is a polyethylene. Examples of non-limiting polyethylene films are Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), Linear Medium Density Polyethylene (LMDPE), Linear Polyethylene High Grade 71

IMPI ^

MEXICAN INSTITUTE

BE LA nsniDAB INDUSTRIAL low density (VLDPE), linear ultra low density polyethylene (ULDPE), high density polyethylene (HDPE). Of these, the most preferred polyethylene is LLDPE. Suitable thermoset polymers include not exclusively allyls, amines, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, rigid polyurethanes, silicones, thermoset vinyl esters, and their copolymers and blends, such as those described in US Pat. 6,846,758, 6,841,492 and 6,642,159, all of which are incorporated herein by reference to the extent that they are not inconsistent herewith. As described herein, a polymer film includes polymer coatings. Also suitable as outer polymer films are discontinuous thermoplastic webs, and non-woven fabrics or discontinuous meshes. Examples are SPUNFAB® heat activated nonwoven adhesive meshes, commercially available from Spunfab, Ltd., of Cuyahoga Falls, Ohio (registered trademark of Keuchel Associates, Inc.); THERMOPLAST ™ and HELIOPLAST ™ meshes, nets and films, commercially available from Protechnic SA of Cernay, France, as well as others. Any thermoplastic polymer layers are preferably very thin, with layer thicknesses of from about 1 pm to about 250 pm having been preferred, more preferably from about 5 pm to about 25 pm and more.

IMPI

INUTruT · MEXICAN “laFk» nu&gt; A «iNousnuAt

<img file="MX347676B_D0050.tif" />

preferably from about 5 pm to about 9 pm. Discontinuous webs such as SPUNFAB® Nonwovens are preferably applied at a basis weight of 6 grams per square meter (gsm). While such thicknesses are preferred, it is to be understood that other thicknesses can be produced to meet a particular need and still be within the scope of the present invention.

The polymer film layers are preferably bonded to the consolidated single layer network, using known lamination techniques. Typically, lamination is accomplished by placing the individual layers together under conditions of sufficient heat and pressure to cause the layers to combine into a unitary film. The individual layers are placed one on top of the other, and the combination is typically passed through the nip of a pair of heated lamination rolls by techniques well known in the art. Heat lamination can be performed at temperatures ranging from about 95 ° C to about 175 ° C, preferably from about 105 ° C to about 175 ° C, at pressures ranging from about 5 psig (0.034 MPa) to about 100 psig (0.69 MPa), for about 5 seconds to about 36 hours, preferably from about 30 seconds to about 24 hours. If included, the polymer film layers preferably comprise from about 2% to about 25% by weight of the overall fabric, more preferably from about 2% to about 17% by weight of the overall fabric, and most preferably from 2% to 12%. The weight percent of the polymer film layers will generally vary depending on the number of tissue layers included. Furthermore, while the lamination and consolidation steps of the outer polymer layer are described herein as two separate steps, they may alternatively be combined into a single consolidation / lamination step by means of techniques conventional in the art.

The composites of the invention also exhibit good peel strength. Peel strength is an indicator of bond strength between fiber layers. As a general rule, the lower the polymer content of the arrangement, the lower the bond strength, but the higher the fragment strength of the material. However, below a critical bond strength, the ballistic material loses durability during material cutting and assembly of articles, such as a vest, and also results in reduced long-term durability of the articles. In the preferred embodiment, the peel strength for the fabrics of the invention in a type of SPECTRA® Shield configuration (0^or, 90 °) is

4

<img file="MX347676B_D0051.tif" />

IMPI

ΓΝΓΠΤυΤΟ M4JUCANO M LA P »* WU&gt; A» tN «U * TUAL preferably at least about 0.17 lb / ft²(0.83 kg / m²), more preferably at least about 0.188 pound / ft² (0.91 kg / m²), and more preferably at least about 0.206 pounds / ft²(1.00 kg / m²). The best peel strengths achieved for fabrics of the invention have been found to be at least about 11%.

Fabrics of the invention will have a preferred areal density of about 20 grams / m2² (0.004 lb / ft²(PSF)) to approximately 1000 gsm (0.2 pounds per square foot). Most preferable area densities for fabrics of the present invention will range from about 30 gsm (0.006 pounds per square foot) to about 500 gsm (0.1 pounds per square foot). The most preferred areal density for the fabrics of this invention will range from about 50 gsm (0.01 pounds per square foot) to about 250 gsm (0.05 pounds per square foot). Articles of the invention comprising multiple individual layers of fabric stacked on top of one another will further have a preferred areal density of from about 1000 gsm (0.2 pounds per square foot) to about 40,000 gsm (8.0 pounds per square foot), more preferably from about 2000 gsm (0.40 pounds per square foot) to about 30,000 gsm (6.0 pounds per square foot), more preferably about 3000 gsm (0.60 pounds per

<img file="MX347676B_D0052.tif" />

square foot) to about 20,000 gsm (4.0 pounds per square foot), and more preferably from about 3750 gsm (0.75 pounds per square foot) to about 10,000 gsm (2.0 pounds per square foot).

Fabrics of the invention can be used in various applications to form a variety of different bullet resistant articles using well known techniques. For example, techniques suitable for the formation of bullet resistant articles are described in, for example, US Pat. 4,623,574, 4,650,710, 4,748,064, 5,552,208, 5,587,230, 6,642,159, 6,841,492 and 6,846,758, all of which are incorporated herein by reference to the extent that they are not inconsistent herewith. Composite materials are particularly useful for the formation of armor, flexible soft articles, including garments such as vests, pants, hats or other articles of clothing and covers or blankets, used by military personnel to deal with a number of ballistic threats, such as 9mm full metal jacketed (FMJ) bullets and a variety of fragments generated by the explosion of hand grenades, artillery shells, Improvised Explosive Devices (IEDs) and other such devices found on military missions and to maintain peace.

In the present description, the soft or flexible shield is a shield that does not hold its shape when used.

<img file="MX347676B_D0053.tif" />

IMPI INSTITUTO MEXICANO M LA FRQflIDA »MDUnUU undergoes a significant amount of stress. The structures are also useful for the formation of rigid hard armor articles. By hard armor is meant an item, such as helmets, panels for military vehicles, or protective shields, that has sufficient mechanical strength to maintain structural rigidity when subjected to a significant amount of stress and is capable of being self-supporting without collapse. The structures can be cut into a plurality of discrete sheets and stacked for formation into an article or they can be formed into a precursor that is subsequently used to form an article. Such techniques are well known in the art.

Garments of the invention can be formed by methods conventionally known in the art. Preferably, a garment can be formed from the bullet resistant articles of the invention that are attached to a garment. For example, a vest can comprise a generic woven vest that is contiguous with the bullet resistant structures of the invention, wherein the structures of the invention are inserted into strategically placed pockets. This allows for the maximization of bullet protection, while minimizing the weight of the vest. As used herein,

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Adjacent or contiguous terms are intended to include fixation, such as by stitching or adhesion and the like, as well as unconnected mating or juxtaposition with other fabric, such that bullet-resistant articles may optionally be easily removable from vest or other article of clothing. Articles used in the formation of flexible structures such as flexible sheets, vests and other garments are preferably formed from the use of a low tensile modulus binder material. Hard articles such as helmets and armor are preferably, but not exclusively, formed using a high tensile modulus binder material.

Bullet resistance properties are determined using standard test procedures that are well known in the art. In particular, the penetration power or protective resistance of a bullet resistant composite material is normally expressed by citing the impact velocity at which 50% of the projectiles penetrate the composite material while 50% is stopped by the composite material. , also known as the V50 value. As used herein, the penetration resistance of an article is the resistance to penetration by a designated threat, such as physical objects, including

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bullets, shrapnel fragments, and the like. For composites of equal area density, which is the weight of the composite divided by its area, the higher the V50, the better the bullet resistance of the composite.

The resistance to penetration of designated threats can also be expressed by the total specific energy absorption (SEAT) of the bullet resistance material. The total SEAT is the kinetic energy of the threat divided by the surface density of the composite material. The higher the SEAT value, the better the resistance of the composite material to the threat. The bullet resistant properties of the articles of the invention will vary depending on many factors, in particular the type of fibers used to manufacture the fabrics, the weight percentage of the fibers in the composite material, the suitability of the physical properties. of the coating materials, the number of layers of fabric that make up the composite, and the total surface density of the composite.

The following examples serve to illustrate the invention.

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EXAMPLE 1 (COMPARISON)

A solvent spinning and a PE polymer of

UHMW were mixed to form a slurry inside a slurry tank that was heated to 100 ° C. The UHMW PE polymer had an intrinsic viscosity IVo of approximately 30 dl / g. A solution of the suspension was formed in an extruder set at an extruder temperature of 280 ° C and in a heated vessel set at a temperature of 290 ° C. The concentration of the polymer in the suspension to enter the extruder was approximately 8%. After forming a homogeneous spinning solution through the extruder and heated container, the solution was spun through a 240 hole spinner, through a 1.5 inch (3.8 cm) long air gap, and into a rapid cooling bath with water. The spinner holes have hole diameters of 0.35mm and length / diameter (L / D) ratios of 30: 1. The spinning solution was drawn in the 1.5 inch (3.8 cm) air gap at an extraction ratio of approximately 2: 1 and then quenched in the water bath having a water temperature of approximately 10 ° C. The cold gel spinning was spread with sets of rollers at a 3: 1 extraction ratio prior to

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IMPI purchase a solvent removal device. In the solvent removal device, where the solvent is extracted with an extraction solvent, the ΐχπτυτο MUUCANO mlanohumd mwurruAL gel fiber was made at approximately a 2: 1 extraction ratio. The resulting dry yarn, which had a spinning IVf of 16 dl / g, was pulled by four sets of rollers in three stages to form a partially oriented yarn (POY) with a tenacity of about 20 g / denier. The POY was extracted at 150 ° C in a 25 meter oven. The POY feed speed was 6.7 meters / min and the feed rate to was approximately 30 m / min. The tenacity of the highly oriented yarn (TODAY) produced was 45 g / d, with a modulus of approximately 1350 g / d.

EXAMPLE 2

Example 1 is repeated except the suspension tank was continuously purged with a nitrogen feed tube in the tank at a rate of at least about 2.4 liters / minute. Nitrogen was bubbled under the suspension to bubble out as much as oxygen as possible to avoid IV degradation. The POY spinning made by this process had an increase of 4 dl / g in IV (from 16 dl / g to 20 dl / g) compared to Example 1, with a polymer IVo of approximately 30 dl / g. TO

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EXAMPLE 3

A POY spinning was made according to the procedure of Example 2 except that the concentration of the polymer in the slurry going into the extruder was about 5% instead of 8%. The lower polymer concentration helps maintain IV during the spinning process. The POY IV yarn in this case was 21.2 dl / g.

EXAMPLE 4

A POY spinning was performed as in Example 2, except that the extruder temperature was reduced from 280 ° C to 240 ° C. The POY yarn had an IV of 23.7 dl / g, an increase of 8 dl / g in relation to Example 1 of this POY yarn of 23.7 dl / g that can be completed according to the stretching conditions of US patent 7,344,668 for form a highly oriented yarn (TODAY) that has a tenacity greater than 50 g / d and the tensile modulus is greater than 1650 g / d.

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EXAMPLE 5

A POY spinning is performed as in Example 3 but with a UHMW PE polymer having a starting IVo of 40 dl / g and with a polymer concentration in the suspension of about 3% by weight. The POY yarn made under these conditions is approximately 30 dl / g. This 30 dl / g POY yarn is then extracted according to the extraction conditions of US Pat. 7,344,668 to form a highly oriented yarn (TODAY) having a tenacity of 55 g / d and tensile modulus of approximately 1700 g / d.

Example 6

A POY spinning is performed as in Example 4, but the extruder rpm was decreased from 300 rpm to 220 rpm and an additive such as 2,5,7,8-tetramethyl-2 (4 ', 8', 12'-trimethyltridecyl ) chroman-6-ol is added to prevent degradation IV. The POY yarn thus made has an IV of 35 dl / g. This high IV POY yarn is then drawn according to the extraction conditions of US Pat. 7,344,668 to form a highly oriented yarn (TODAY) having a tenacity of 60 g / d and a tensile modulus of approximately 1850 g / d.

Although the present invention has been shown and described particularly with reference to embodiments

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preferred, it will be readily appreciated by those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The claims are intended to be construed to cover the described embodiment, those alternatives that have been discussed above, and all equivalents thereof.

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