CA2101834A1 - A stretchable metallized nonwoven web of non-elastomeric thermoplastic polymer fibers and process to make the same - Google Patents

Abstract

ABSTRACT
Disclosed is a stretchable metallized nonwoven web composed of at least one nonwoven web of non-elastomeric thermoplastic polymer fibers, the nonwoven web having been heated and then necked so that it is adapted to stretch in a direction parallel to neck-down at least about 10 percent more than an identical untreated nonwoven web of fibers; and a metallic coating substantially covering at least a portion of at least one side of the nonwoven web. The nonwoven web of non-elastomeric thermoplastic polymer fibers can be a nonwoven web of non-elastomeric meltblown thermoplastic polymer fibers. The stretchable metallized nonwoven web may be joined with other materials to form multi-layer laminates. Also disclosed is a process of making a stretchable metallized nonwoven web.

Description

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PATENT
FIELD OF THE INVENTION
This invention relates to flexible metallized materials and a process to prepare flexible metallized materials.
BACKGROUND OF THE INVENTION
Metallic coatings ranging in thickness from less than a nanometer up to several microns have been added to sheet materials to provide a decorative appearance and/or various physical characteristics such as, for example, electrical conductivity, static charge resistance, chemical resistance, thermal reflectivity or emissivity, and optical reflectivity. ~ -~
In some situations, metallized sheet materials can be applied to or incorporated in some or all portions of a product instead of metallizing the product itself. This may be especially desirable for products that are, for example, large, temperature sensitive, vacuum sonsitive, difficult to handle in a metallizing process, or hav- complex topographies.
In th- pa~t, such u~e of metallized sheet materials may have been restricted by the limitations o~ the substrate sheet. In the past, metallic coatings have typically been applied to sheet-like substrates that are considered to be relatively stretch-resistant and inelastic so that the substrate would not deform and cau~e the metallic coating to detach or flake off.
Accordlngly, such metallized materials may possess inadequate flexibility, ~tretch and recovery, so$tness and/or drape properties for many applications. For example, U.S. Patent Nos.
4,999,222 and 5,057,351 describe m~tallized polyethylene plexifilamentary film-fibril sheet~ that are inelastic and have relatively poor drape and soPtnes~ which may make them unsuited for applications where stretch and recovery, drape and softness ar- required. European Patent Publication 392,082-A2 de~cribes a method of manufacturing a metallic porous sheet suitable for U~- a8 an electrod- plat- of a battery. According to that 3S publication, m-tal may be d-posited on a porous sheet (foam sheet, nonwoven web, mesh fabric or combinations o~ the same) utilizing processes such as vacuum evaporation, electrolytic plating and electroless plating. -2 ~ 2~

Thus, a need exists for a stretchable metallized sheet material which has desirable flexibility, stretch and recovery, drape, and softness. There is a further need for a stretchable metallized sheet material which has the desired properties described above and which is so inexpensive that it can be discarded after only a single use. Although metallic coatings have been added to inexpensive sheet materials, such inexpensive metallized sheet materials have generally had limited application because of the poor flexibility, stretch and recovery, drape and softness of the original sheet material.

DEFINITIONS
As used herein, the terms "stretch" and "elongation" refer to the difference between the initial dimension of a material and that same d$mension after the material is stretched or extended following the application of a biasing force. Percent stretch or elongation may be expressed as [(stretched length - initial ~ample length) / initial sample length] x 100. For example, if a m~terial having an initial length of 1 inch is stretched 0.85 inch, that is, to a stretched or extended length of 1.85 inches, that material can be said to have a stretch of 85 percent.
A~ used herein, the term "recovery" re~ers to the contraction of a stretched or elongated material upon termination o~ a blasing ~orce following stretching o~ the material from some . initial measurement by application o~ the biasing force. For example, if a material having a relaxed, unbiased length of one (1) inch i~ elongated 50 percent by stretching to a length of one-and-one-half (1.5) inche~, the material is elongated 50 percent (0.5 inch) and has a stretched length that i~ 150 percent of it~ relaxed length. If thi~ ~tretched material contracts, that i~, recover~ to a length o~ one-and-one-tenth (1.1) inche~
aft-r release of the bia~ing and ~tretchin~ force, the material has recovered 80 percent (0.4 inch) of its one-half (0.5) inch elongation. Percent recovery may be expressed a~ [(maximum stretch length - final sample length) / (maximum stretch length -initial sample length)] x 100.

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As used herein, the term "non-recoverable stretch" refers to elongation of a material upon application of a biasing force which is not followed by a contraction of the material as described above for "recovery". Non-recoverable stretch may be expressed as a percentage as follows:
Non-recoverable stretch = 100 - recovery when the recovery is expressed in percent.
AS used herein, the term "nonwoven web" refers to a web that has a structure of individual fibers or filaments which are lo interlaid, but not in an identifiable repeating manner. Nonwoven webs have been, in the past, formed by a variety of processes known to those skilled in the art such as, for example, meltblowing, spunbonding and bonded carded web processes.
As used herein, the term "spunbonded web" refers to a web of small diameter fibers and/or filaments which are formed by extruding a molten thermoplastic material as ribers and/or ~llament- rrom a plurallty Or rine, usually circular, capillaries ln a splnnerette with the diameter Or the extruded rlbQrs and/or tilament~ then belng rapidly reduced, ~or example, by non-eductive or eductive fluid-drawing or other well known spunbonding mechanisms. The production Or spunbonded nonwoven webs is illu~trated in patents ~uch as Appel, et al., U.S. Patent No. 4,340,563; Dorschner et al., U.S. Patent No. 3,692,618;
Kinney, U.S. Patent Nos. 3,338,992 and 3,341,394; Levy, U.S.
Patent No. 3,276,944; Peterson, U.S. Patent No. 3,502,538;
Hartman, U.S. Patent No. 3,502,763; Dobo et al., U.S. Patent No.

3,542,615; and Harmon, Canadian Patent No. 803,714.
A- u~ed h-rein, the term "meltblown ribers~ means ~ibers rormed by extrudlng a molten thermoplastic material through a plurality Or rine, usually clrcular, dle capillarie~ a~ molten threads or rllaments lnto a hlgh-veloclty gas (e.g. air) stream whlch attenuates the rilaments o~ molten thermoplastic material to reduce thelr dlameters, whlch may be to mlcroriber dlameter.
Therearter, the meltblown ribers ar- carrled by the hlgh-velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed meltblown f$bers. The meltblown process is well-known and is described in various patents and 2 ~ ~ 3. ~

publications, including NRL Report 4364, "Manu~acture of Super-Fine Organic Fibers" by V.A. Wendt, E.L. 800ne, and C.D.
Fluharty; NRL Report 5265, "An Improved Device for the Formation of Super-Fine Thermoplastic Fibers" by K.D. Lawrence, R.T. Lukas, and J.A. Young; and U.S. Patent No. 3,849,241, issued November 19, 1974, to Buntin, et al.
As used herein, the term "microfibersU means small diameter fibers having an average diameter not greater than about 100 microns, for example, having a diameter of from about 0.5 microns to about 50 microns, more specifically microfibers may also have an average diameter of from about l micron to about 20 microns.
Microfibers having an average diameter of about 3 microns or less are commonly referred to as ultra-fine microfibers. A
description of an exemplary process of making ultra-fine microfibers may be found in, for example, U.S. Patent application Serial No. 07/779,929, entitled "A Nonwoven Web With Improved Barrier Propertiesn, filed November 26, 1991, incorporated herein by r-f-r-n~- in it~ entirety.
A used herein, the term "thermoplastic material" refers to a high polymer that softens when exposed to heat and returns to it~ original condition when cooled to room temperature. Natural substances which exhibit this behavior are crude rubber and a number of waxes. Other exemplary thermoplastic materials include, without limitation, polyvinyl chloride, polyesters, nylons, polyfluorocarbons, polyethylene, polyurethane, polystyrene, polypropylene, polyvinyl alcohol, caprolactams, and cellulosic and acrylic re~ins.
A. u~ed h-rein, th- term "disposable" i~ not limited to ~ingle u~e article~ but also refQrs to article~ that can be di~carded if they become soiled or otherwise unusable after only a ~ew u~e~.
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AB u-ed herein, the term "machine direction" refers to the dir-ction of travel o~ the forming ~ur~ace onto which fibers are depo~it-d during formation o~ a nonwoven web.
A8 u-ed herein, the term "croa--machine direction" refer~ to the direction which is perpendicular to the machine direction defined above.

- 2 1 0 1 8 ~ 1 The term "~-transition" as used herein refers a phenomenon that occurs in generally crystalline thermoplastic polymers. The ~-transition denotes the highest temperature transition below the melt transition (Tm) and is often referred to as pre-melting.
Below the ~-transition, crystals in a polymer are fixed. Above the ~-transition, crystals can be annealed into modified structures. The ~-transition is well known and has been described in such publications as, for example, Nechanical Properties of Polymers and Composites (Vol. 1) by Lawrence E.
Nielsen; and Polymer Nonographs, ed. H. Moraweitz, (Vol. 2 -Polypropylene by H.P. Frank). Generally speaking, the ~-tran~ition is determined using Differential Scanning Calorimetry technigues on equipment such as, for example, a Mettler DSC 30 Differential Seanning Calorimeter. Standard conditions for typical measurements are as follows: Heat profile, 30C to a temperatur- about 30C above the polymer melt point at a rate of 10-C/~inute; Atmosphere, Nitrogen at 60 Standard Cubic Centimeter~ (SCC)/minute; Sample size, 3 to 5 milligrams.
The expression "onset of melting at a liquid fraetion of five percent" refers to a temperature which corre~pond~ to a speeified magnitude of phase change in a generally crystalline polymer near it- melt transition. The onset of m lting occurs at a temperature which is lower than the melt transition and is eharacterized by different ratios of liquid fraetion to solid fraetion in th- polymer. The onset of melting is determined uslng Differential Seanning Calorimetry teehniques on equipment sueh a~, for example, a Mettler DSC 30 Differential Scanning Calori~ ter. Standard eonditions for typical mea~urements are a- follow : Heat profile, 30 to a temperature about 30-C above the polymer melt point at a rate of 10C/minute; Atmosphere, Nitrogen at 60 Standard Cubie Centimeters (SCC)/minute; Sample siz-, 3 to 5 milligrams.
A- u-ed herein, th- term "neekable material" means any material whieh ean be neeked.
As used herein, the term "necked material" refers to any material which has been eonstrieted in at least one dimension by proeegses such as, for example, drawing.

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As used herein, the term "stretch direction" refers to the direction of stretch and recovery As used herein, the term "percent neck-down" refers to the ratio determined by measuring the difference between the pre-necked dimension and the necked dimension of a neckable material and then dividing that difference by the pre-necked dimension of the neckable material; this quantity multiplied by lOo For example, the percent neck-down may be represented by the following expression p rc~nt n~ do~ l~pr neclud di~ian n~elt d di~i~ pre neck d d~ior~ x 100 As used herein, the term "polymer" generally includes, but is not limited to, homopolymers, copolymers, such as, for example, block, graft, random and alternating copolymers, terpolymers, etc and blends and modifieations thereof Furthermore, unless otherwise specifically limited, the term "polymer" shall inelude all possible geometrical configuration~
o~ th material These configurations inelude, but are not llmited to, isotactie, syndiotaetie and random symmetries A~ u~ed herein, the term "eonsisting essentially o~ does not oxelude the presenee of additional materials whieh do not ~igni~ieantly a~ect the de~ired eharaeteristies o~ a given eo~positlon or produet Exemplary materials o~ this sort would lnelud , without limitation, pigments, sur~aetant-, waxes, n ow pro~ot-r-, partieulates and materials added to enhanee proe---ability o~ the eompo~ition SU~U~E~ OF TH~ INVENTIO~
Th present invention addresse~ the above-deseribed problems by providing a stretehable metallized nonwoven web eomposed of at l-a~t one nonwoven web o~ non-elastomerie thermoplastie polymer ~ibers, the nonwoven web having been heated and then neek-d o that it i~ adapted to streteh in a direetion parallel to n-ek-down at least about 10 percent more than an identieal untr-ated nonwov n web o~ ~ib r~; and a m tallle eoatlng eovering sub-tantially at lea~t a portion o~ at lea~t one ~ide o~ the nonwoven web ~ ,!,; '.'. . 1 ' ' ' ` ' ' "' ~` 2~01~3~

The nonwoven web of non-elastomeric thermoplastic polymer fibers may be a nonwoven web of meltblown fibers, a bonded-carded web, or a spun-bonded web The nonwoven web of meltblown fibers may include meltblown microfibers For example, at least about 50 percent, as determined by optical image analysis, of the meltblown microfibers have an average diameter of less than 5 microns It is contemplated that embodiments of the stretchable metallized nonwoven web of the present invention may be manufactured so inexpensively that it may be economical to dispose of the materials after a limited period of use According to the present invention, the stretchable metallized nonwoven web may have a basis weight ranging from about 6 to about 400 grams per square meter For example, the stretchable metallized nonwoven web may have a basis weight ranging from about 30 to about 250 grams per square meter More particularly, the stretchable metallized nonwoven web may have a ba~is weight ranging from about 35 to about 100 grams per sguare meter In one aspect of the present invention, the non-elastomeric thermoplastic polymer fibers may be formed from a polymor selected from polyolerlns, polyesters, and polyamides Nore particularly, the polyolefins may be, for example, one or more Or polyethylen-, polypropylene, polybutene, ethylene copolymers, propylene copolymers, and butene copolymers According to one embodiment of the invention, where the non-ela~tic thermoplastic polymer fibers are meltblown fibers, m ltblown ~ibers may be mixed with one or more other materials such as, ~or example, wood pulp, textile fibers, and particulates Exemplary textile fibers include polyester fibers, polyamid- fibers, glas- ribers, polyolerin ribers, cellulosic d-riv d riber-, multi-compon-nt ribers, natural riber~, absorbent riber-, lectrically conductive ~ibers or blend~ Or two or more Or such ribers Exemplary particulates include activated charcoal, clays, starches, metal oxides, super-absorbent materials and mixtures of such materials Generally speaking, the thic~ness of the metallic coating on the nonwoven web may range from about 1 nanometer to about 5 microns. For example, the thickness of the metallic coating may range from about S nanometers to about 1 micron. More particularly, the thickness of the metallic coating may range from about 10 nanometers to about SOO nanometers.
Generally speaking, the stretchable metallized nonwoven web retains much of its metallic coating when stretched in a direction generally parallel to neck-down at least about 25 percent. That i5, there is little or no flaking or 1088 of metal observable to the unaided eye when a stretchable metallized nonwoven web of non-elastomeric thermoplastic polymer fibers of the present invention covered with at least at low to moderate levols of motallic coating is sub~ected to normal handling.
lS The metallic coating may cover substantially all of one or both sides of the stretchable nonwoven web or the metallic eoatlng may be limited to portions of one or both sides of the tr-tehabl- nonwoven w b. For example, the stretchable nonwoven web may be masked during the metal coating process to produce discrote portions of stretchable metallized nonwoven web. One or more layers of the same or different metals may be eoated onto th- nonwoven web. The coating may be any motal or metallie alloy whieh ean be deposited onto a stretchable nonwoven web of non-elastom rie thermoplastie polymer ~ibers and whieh bonds to the w b to form a durabl- eoating. Exemplary metals ineludo aluminum, eopper, tin, zine, lead, niekel, iron, gold, silver and th like. Exemplary metallie alloys inelude eopper-basod alloy-, aluminum based alloys, titanium based alloys, and ~ron ba~ed alloys. Conventional fabrie finishes may be applied to the stretehable metallized nonwoven web. For examplo, laeguors, shellaes, sealants and/or polymers may be applied to the stretehabl- m-tallized nonwoven web.
Th- pr-sent lnvention eneompasses multilayer materials whieh eontain at lea~t one layer whieh is a stretehable metallized nonwoven wob. For example, a stretchable metallized nonwoven web of meltblown fibers may be laminated with one or more webs of 2 1 ~

spunbonded filaments. The stretchable metallized nonwoven web may even be sandwiched between other layers of materials.
According to the present invention, a stretchable metallized nonwoven web may be made by a process whieh includes the S following steps: (1) providing at least one nonwoven web of non-elastomeric thermoplastic polymer fibers, the nonwoven web having been heated and then necked so that it is adapted to stretch in a direetion parallel to neck-down at least about 10 percent more than an idontical untreated nonwoven web of fibers; and (2) metallizing at least ono portion of at least one side of the nonwoven web 80 that portion is substantially covered with a metallic eoating.
The metallizing of the nonwoven web may be aeeomplished by any proeess whieh ean be used to deposit metal onto a nonwoven web and whieh bonds the metal to the nonwoven web. The metalllzing step may be carried out by techniques such as metal vapor deposltion, metal sputtering, plasma treatmonts, electron b a~ tr-~tments or other treatments which deposit metals.
Alternatlvely and/or addltlonally, the flbers may be covered wlth eertain eompounds whleh ean be ehemically reacted (e.g., via a reduetion reaetlon) to produee a metallie eoating. Before the m tallie eoating is added to the nonwoven web, the surraeo of the web and/or individual fiber~ may be modified utilizing teehnique~
sueh a~, for example, plasma diseharge or eorona dlseharge tr-atment~. Aeeordlng to one embodlment of the proeess of the present inventlon, the nonwoven web of non-elastomerie thermoplastie polymer fibers, for example, a nonwoven web of non-ela-tomerle meltblown flSers, may bo ealondered or bonded oither be~ore or after the metalllzing step.
B~ F DESCRIPTION OF THE D~ GS
FIG. 1 1~ an illustratlon of an exemplary proeoss for making a stretehable m talllzed nonwoven web o~ non-elastomerlc thermoplastle polymer ~lbers.
FIG. 2 is an illustration of an exemplary proees~ for making a stretchable nonwoven web of non-elastomeric thermoplastie polymer fibers.

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, , FIG 3 is a microphotograph of an exemplary stretchable metallized nonwoven web of non-elastomeric thermoplastic polymer fibers FIG 4 is a microphotograph of an exemplary stretchable S metallized nonwoven web of non-elastomeric thermoplastic polymer fibers De3AII~LLL~CRIPIIoN E-TH~ I~VENTIO~
Referring to the drawings and in particular to Figure 1, there is shown at 10 an exemplary process of making the stretchable metallized nonwoven web of non-elastomeric thermoplastic polymer fibers of the present invention within an evacuatQd chamber 12 Metal vapor deposition typically takes place in the evacuated chamber 12 at an absolute pressure from -~
about 10~ to about 10~ Torr (i e, millimeters of Hg (mercury)) A supply roll 14 o~ a stretchable nonwoven web of non-elastomeric th-r~opla-tic polymer ~ibers 16 located within the evacuated chamber 12 is unwound The nonwoven web 16 travels in the direction indicated by the arrow associated therewith as the supply roll 14 rotates in the direction of the arrow associated therewith The nonwoven web 16 passes through a nip of an S-roll arrangement 18 formed by two stack rollers 20 and 22 It i~ contemplated that the nonwoven w b of non-elastomeric thermopla~tic polymer ~lbers may be formed by web forming proc~ - such a~, ~or example, meltblowing processes or spunbond$ng proces~e~, be heated treated to have stretch and r-cov ry propertie~ and then passed directly through the nip of th- 8-roll arrangement 18 without first being stored on a supply roll Fro~ the reverse S path of the S-roll arrangement 18, th nonwoven web 16 pa~ses over an idler roller 24 and then contact~
a portion o~ a chill roll 26 while it i~ exposed to metal vapor 28 manating ~rom a molt-n metal bath 30 Metal vapor ¢ondens-s on th- nonwoven web 16 ~orming a stretchable metallized nonwoven web 32 Although a chill roll 26 is not required to practice the present invention, it has been found to be useful in some situations to avoid physical deterioration of the nonwoven web 2 1 ~

16 during exposure to the metal vapor 28 and/or to minimize deterioration of the stretch and recovery properties imparted to the nonwoven web during heat treatment. For example, a chill roll would be desirable when the nonwoven web is exposed to the metal vapor for a relatively long period. Multiple metal baths and chill roll arrangements (not shown) may be used in series to apply multiple coatings of the same or different metals.
Additionally, the present invention is meant to encompass other types of metallizing processes such as, for example, metal -sputtering, electron beam metal vapor deposition and the like.
Metal may also be deposited on the nonwoven web by means of a chemic~l reaction such as, for example, a chemical reduction reaction. Generally speaking, any process which deposits metal on the nonwoven web with minimal deterioration of the nonwoven web and its stretch and recovery properties may be employed. The metallizing processes described above may be used in combination in the practice of the present invention.
Th metallic coatlng substantially covers at least a portion o~ at l-ast one side of the nonwoven web 16. For example, the metallic coating may substantially cover all of one or both sides Or the nonwoven web 16. The nonwoven web 16 may be masked with one or more patterns during exposure to the metal vapor 28 so that only desired portions of one or both sides of the nonwoven web have a metallic coating.
The stretchable metallized nonwoven web 32 passes over an idler roller 34 and through nip of a drive roller arrangement 36 formed by two drive rollers 38 and 40. The peripheral linear spe-d of the rollers of the S-roll arrangement 18 is controlled to be about the same as the peripheral linear speed of the rollers of the drive roller arrangement 36 so that tension generated in the nonwoven web 16 between the S-roll arrangement 18 and th- drive roller arrangement 36 is sufricient to carry out th- proc-a- and maintain the nonwoven w b 16 in a n-cked condition.
The ~tretchable metallized nonwoven web 32 pa~ses through the S-roll arrangement 18 and the bonder roll arrangement 36 and , ~

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then the stretchable metallized nonwoven web 32 is wound up on a winder 42.
Conventional fabric post-treatments may be applied to the stretchable metallized nonwoven web provided they do not harm the metallic coating. For example, shellacs, lacquers, sealants and/or sizing may be applied. Alternatively and/or additionally, a polymer coating such as, for example, a polyurethane coating, may be applied to the stretchable metallized nonwoven web.
Generally speaking, the nonwoven web of non-elastomeric thermoplastic polymer fibers may be any nonwoven web which can be heat treated to impart stretch and recovery properties.
Exemplary webs include bonded carded webs, nonwoven webs of meltblown fibers and spunbonded filament webs. Desirably, the nonwoven web of non-elastomeric thermoplastic polymer fibers is a nonwoven web Or meltblown fibers.
Referring to FIG. 2 Or the drawings there is schematically illustrated at 110 an exemplary process for making a nonwoven web o~ non-elastomeric thermoplastic polymer ribers having stretch and recovery properties. FIG. 2 depicts a process in which the nonwoven web of non-elastomeric thermoplastic polymer fibers is sub~ected to a heat treatment utilizing a series or heated drums.
In FIG. 2, a nonwoven neckable material 112 is unwound from a ~upply roll 114 and travel~ in the direction indicated by the arrow associated therewith as the supply roll 114 rotates in the dir-ction Or the arrows associated therewith.
The nonwoven neckabl- material 112 may be formed by one or more meltblowing processes and passed directly to a heated drum 116 without flrst being stored on a supply roll 114.
The neckable material 112 passes over a series o~ heated drum~ (e.g., steam cans~ 116-126 in a series of rev rse S-loop~.
Th- ~tea~ cans 116-126 typically have an outslde diameter Or about 24 inche~ ~lthough other ~ized cans may b- used. ~h-contact time or residence time of the neckable materlal on th-stea~ cans to efrect heat treatment will vary depending on factors such as, for example, steam can temperature, type and/or bai~i~ weight of material, and diameter of the meltblown fibers in the material. The contact time should be sufficient to heat the nonwoven neckable material 112 to a temperature at which the peak total energy absorbed by the neckable material is at least about 250 percent greater than the amount absorbed by the neckable material 112 at room temperature For example, the contact time should be sufficient to heat the nonwoven neckable material 112 to a temperature at which the peak total energy absorbed by the neckable material is at least about 275 percent greater than the amount absorbed by the neckable material at room temperature As a further example, the neckable material can be heated to a temperature at which the peak total energy absorbed by the neckable material is from about 300 percent greater to more than about 1000 percent greater than the amount absorbed by the neckable material at room temperature Generally speaking, when the nonwoven neckable material 112 is a nonwoven web of meltblown thermoplastic polymer fibers form d from a polyolefin such as, for example, polypropylene, the r--id-nc- timo on the ~team cans should be sufficient to heat the m ltblown fibers to a temperature ranging from greater than the polymer'~ a-transition to about 10 percent below the onset of melting at a liguid fraction of 5 percent For example, a nonwoven web of meltblown polypro W lene fibers ~ay b passed ov r a series of steam cans heated to a measured surfac- temperature from about 90 to about 150C (194-302F) for a contact tim Or about 1 to about 300 seconds to provide the de~lred heatlng of the web Alternatively and/or additionally, th nonwoven web may be heated by infra-red radiation, mlcrowaves, ultrasonic energy, flame, hot gases, hot liquid~ and the llke For example, the nonwoven web may be passed through a hot oven Although the inventors should not be held to a particular theory, lt 1~ believed that heating a nonwoven web of meltblown th-rmoplastic non-elastomeric, generally crystalline polymer rlber- to a temp-rature greater than the polymer's a-transition before applying tension is important Above the a-transitlon, crystals in the polymer fibers can be annealed into modified structures which, upon cooling in fibers held in a tensioned configuration, enhance the stretch and recovery properties (e g , `` 2101~

recovery from application of a stretching force) of a nonwoven web composed of such fibers It is also believed that the meltblown fibers should not be heated to a temperature greater than the constituent polymer's onset of melting at a liquid fraction of five (5) percent Desirably, this temperature should be more than ten (10) percent below the temperature determined for the polymer's onset of melting at a liquid fraction of 5 percent One way to roughly estimate a temperature approaching the upper limit of heating i~ to multiply the polymer melt temperature (expressed in degrees Kelvin) by 0 95 Important~y, it is believed that heating the meltblown fibers within the specified temperature range permits the fibers to become bent, extended and/or drawn during necking rather than merely slipping over one another in response to the tensioning ~orce From the steam can~, the heated neckable material 112 passes through the nip 128 o~ an S-roll arrangement 130 in a reverse-8 path as indicated by the rotation direction arrows associated with th- stack rollQrs 132 and 134 From the S-roll arrangement 130, the h-ated neckable material 112 passes through the nip 136 o~ a drive roller arrangement 138 formed by the drive rollers 140 and 142 Because the peripheral linear speed o~ the rollers o~
the S-roll arrangement 130 is controlled to be less than the p-ripheral linear speed o~ the rollers o~ the drive roller arrangel ent 138, the heated neckable material 102 i~ tensioned b twe-n the S-roll arrangement 130 and the nip of the drive roll arrang ~ent 138 By ad~usting the di~erence in the speeds of the rollers, the heated neckable material 112 i8 tensioned 80 that it necks a desired amount and is maintained in such t-nsioned, necked condition while it is cooled Other ~actors a~-cting the neck-down o~ the heated neckable material are the di~tance between tho rollers applying the tension, the number o~
drawing stago~, and the total length o~ heated material that is malntained under tension Cooling may be enhanced by the use of a cooling fluid such as, for example, chilled air or a water spray ~"'`` ~`".

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210183~

Generally speaking, the difference in the speeds of the rollers is sufficient to cause the heated neckable material 112 to neck-down to a width that is at least about 10 percent less than its original width (i.e., before application of the tensioning force). For example, the heated neckable material 112 may be necked-down to a width that is from about lS percent to about 50 percent less than its original width.
The present invention contemplates using other methods of tensioning the heated neckable material 112. For example, tenter frames or other cross-machine direction stretcher arrangements that expand the neckable material 112 in other directions such as, for example, the cross-machine direction so that, upon cooling, the resulting material 144 will have stretch and recovery properties in a direction generally parallel to the direction that the material is necked. It is also contemplated that web-formation, neck-down and heat treatment can be accompllshed in-line with the metallization step. Alternatively and/or additionally, it is contemplated that the heat treatment step may use heat from the molten metal bath to accomplish or a~ist the heat treatment o~ the necked-down nonwoven web. Other techniques may be used to impart stretch and recovery properties to a nonwoven web of non-elastomeric thermoplastic polymer fibers. For example, a technique in which a nonwoven web of non-ela~tomeric thermoplastic polymer fibers is necked-down and then heat treated i9 disclosed in, for example, U.S. Patent No.

4,96S,122, entitled "Reversibly Necked Material", the contents of which are incorporated herein by reference.
An important feature of the pre~ent invention is that a metallic coating is deposited onto a nonwoven web of non-ela~tomeric thermoplastic polymer fibers that has been treated to have stretch and recovery properties. For example, it is g-nerally thought that a nonwoven web Or meltblown polypropylene ~lber~ and/or meltblown polypropylene microfibers tend~ to resist necking because of its highly entangled fine fiber network. It is this same highly entangled network that is permea~le to air and water vapor and yet is xelatively impermeable to liquids : .

-`` 21~18c3~

and/or particulates while providing an excellent surface for depositing a metallic coating.
In one aspect of the present invention, the continuity of the metallic coating on the highly entangled network of meltblown fibers creates a nonwoven web that is electrically conductive while also maintaining stretch and recovery properties. --Gross changes in this fiber network such as rips or tears would limit and may destroy the conductivity of the stretchable metallized nonwoven web of meltblown non-elastomeric thermoplastic polymer fibers. Unfortunately, because they are relativ~ly unyielding and resist necking, highly entangled networks of non-elastic meltblown fibers respond poorly to stretehing forees and tend to rip or tear.
However, by heating the meltblown fiber web as described above, neeking the heated material and then eooling it, a useful l-v-l o~ stretch and reeovery, at least in the direetion parallel to neck-down, ean be imparted to this web. This eharaeteristie i~ believed to be useful in maintaining the eleetrieal eonductivity Or the nonwoven web, especially when the web is sub~ected to stretching forces in the direction parallel to neck~
down.
Thus, the stretehable metallized nonwoven webs of the present inventlon ean eombine electrieal conduetivity with an ability to streteh in a direetion generally parallel to neck-down at least about 10 pereent more than an identieal untreated nonwoven web and reeover at least about S~ pereent when stretched that amount.
A~ an example, the stretehable metallized nonwoven web may be adapted to streteh in a direetion generally parallel to neek-down ~rom about 15 pereent to about 60 pereent and reeover at lea~t about 70 percent when stretehed 60 percent. AJ another ex~pl-, th- stretehable metallized nonwoven web may be adapted to ~treteh in a dlreetion generally parallel to neek-down from about 20 pereent to about 30 pereent and reeover at le~t about 7S pereent when stretehed 30 pereent. As yet another example, the stretehable metallized nonwoven webs of the present invention web may be electrically conductive and have the ability to stretch in a direction generally parallel to neck-down from about ':

`' 210183~
~. ., 15 percent to about 60 percent more than an identical untreated nonwoven web and recover at least about 50 percent when stretched 60 percent. Desirably, the stretchable metallized nonwoven web may be adapted to remain electrically conductive when stretched in a direction generally parallel to neck-down at least about 25 percent. More desirably, the stretchable metallized nonwoven web may be adapted to remain electrically conductive when stretched in a direction generally parallel to neck-down from about 30 percent to about lO0 percent or more. It is contemplated that the stretchable metallized nonwoven webs of the present invention may, alterna~ively and/or additionally to being electrically conductive, have other characteristics such as, for example, thermal resistivity (e.g., insulative properties), chemical resistance, weatherability and abrasion resistance. For example, the metal coating may be used to impart light (e.g., ultraviolet llght) stabillty to nonwoven wQbs made from light (e.g., ultravlolet light) sensitive polymers such as, for example, polypropylene.
Furthermore, the stretchable metallized nonwoven webs of the present invention may have a porosity exceeding about 15 ft~/min/rt2 (CFM/ft2). For example, the stretchable metallized nonwoven webs may have a porosity ranging from about 30 to about 250 CFM/~t2 or greater. As another example, th- ~tretchable metallized nonwoven webs may have a porosity ranging from about 75 to about 170 CFM/ft2. Such levels of porosity permit the tretchabl- metallized nonwoven webs of the prQsent invention to be partlcularly useful in applications such as, for example, workwear garments.
Desirably, the stretchable metallized nonwoven webs have a ba~is weight of from about 6 to about 400 grams per square meter.
For example, the basis w ight may range from about 10 to about 150 gram~ p-r squar- m-t-r. A~ another example, the ba~is weight may range from about 20 to about 90 grams per square met-r.
The stretchable metallized nonwoven webs of th- pr-sent invention may also be ~oined to one or more layers of another -~
material to form a multi-layer laminate. The other layers may be, for example, woven fabrics, knit fabrics, bonded carded webs, . ~.
;:

210183 ~

continuous filaments webs (e g , spunbonded filament webs), meltblown fiber webs, and combinations thereof Generally, any suitable non-elastomeric thermoplastic polymer fiber forming resins or blends containing the same may be utilized to form the nonwoven webs of non-elastomeric thermoplastic polymer fibers employed in the invention The present invention may be practiced utilizing polymers such as, for example, polyolefins, polyesters and polyamides Exemplary polyolefins include one or more of polyethylene, polypropylene, polybutene, ethylene copolymers, propylene copolymers and butene copolymers Polypropylenes that have been found useful include, for example, polypropylene available from the Himont Corporation under the trade designation PF-OlS and polypropylene available 'rom the Exxon Chemical Company under the trade designation Exxon 3445G Chemical characteristics of these materials are available from their respectlve manufacturers Th- nonwoven web of meltblown fibers may be formed utilizing conventional meltblowing processes Desirably, the meltblown f'ibers of the nonwoven web will include meltblown microfibers to provide enhanced barrier properties and/or a better surface for metallization For example, at least about 50 percent, as determined by optical image analysis, of the meltblown microfib~r~ may have an average diameter of' 1Q88 than about 5 mlcrons A- yet another xample, at least about 50 percent of' the m-ltblown fiber~ may be ultra-fine microfibers that may have an averag- di~meter of' less than about 3 micron~ As a further ex~ople, from about 60 percent to about 100 percent of the meltblown microf'ibers may have an average diameter of less than 5 micron~ or may be ultra-fine microfibers An example of an ultra-fine meltblown microfiber web may be found in previously r-fer-nce~ U S Patent application Serial No 07/779,929, entltl-d "A Nonwoven Web Wlth Improved Barrier Propertl-~", f'lled November 26, 1991 The present inventlon al~o contemplate~ that th- nonwoven web may be, f'or example, an anisotropic nonwoven web Disclosure of such a nonwoven web may be found in U S
Patent application Serial No 07/864,808 entitled "Anisotropic ,.~

2~1 g3~

Nonwoven Fibrous Web", filed April 7, 1992, the entire contents of which is incorporated herein by reference. -The nonwoven web may also be a mixture of meltblown fibers --and one or more other materials. As an example of such a nonwoven web, reference is made to u.s. Patent Nos. 4,100,324 and 4,803,117, the contents of each of which are incorporated herein by reference in their entirety, in which meltblown fibers and other materials are commingled to form a single coherent web of randomly dispersed fibers and/or other materials. Such mixtures may be formed by adding fibers and/or particulates to the gas stream in which meltblown fibers are carried so that an intimate entangled commingling of the meltblown fibers and other materials oeeurs prior to eollection of the meltblown fibers upon a colleetion deviee to form a eoherent web of randomly dispersed meltblown fibers and other materials. Useful materials which may be used in euch nonwoven composite webs include, for example, wood pulp fiber~, text~le and/or staple length fib-rs from natural and synthetie sourees (e.g., cotton, wool, asbestos, rayon, polyester, polyamlde, glass, polyolefin, cellulose derivative~ and the like), multi-component fibers, absorbent fiber~, eleetrieally eonductive fibers, and particulates such as, for exaople, activated charcoal/carbon, clays, starehee, metal oxide~, super-absorbent materials and mixtures of sueh materials.
Other type~ of nonwoven composite webs may be used. For example, a hydraulieally entangled nonwoven composite web may be used such a~ dlseloeed in U.S. Patent Nos. 4,931,355 and 4,950,531 both to Radwanski, et al., the eontents of whieh are ineorporated herein by referenee in their entirety.
If the stretehable metallized nonwoven web of non-elastomerie thormoplastie polymer fibers is a nonwoven web of meltblown fiber~, the meltblown fibers may range, for example, from about 0.1 to about 100 mierons in diameter. However, if barrier propertie- are important in the stretehable metallized nonwoven web (for example, i~ it is important that the rinal material have inereased opaeity and/or insulation and/or dirt proteetion and/or llguid repelleney) then finer fibers which may range, for ~::
., , ~ ` 21018~

example, from about 0 05 to about 20 microns in diameter can be used The nonwoven web of non-elastomeric thermoplastic polymer fibers may be pre-treated before the metallizing step For example, the nonwoven web may be calendered with a flat roll, point bonded, pattern bonded or even saturated in order to aehieve desired physical and/or textural characterist$es It is contemplated that liquid and/or vapor permeability may be modified by flat thermal calendering or pattern bonding some type~ o~ nonwoven webs Additionally, at least a portion o2 the surface of the individual fibers or filaments of the nonwoven web may be modified by various known surface modification technique~
to alter the adhesion of the metallic coating to the non-elastomeric thermoplastic polymer fibers Exemplary surface modification techniques include, for example, chemical etching, ehemieal oxidation, ion bombardment, plasma treatments, flame tr-atment~, h-at treatments, and eorona diseharge treatments On- important ~eature of the present invention is that the ~tretehable m tallized nonwoven web is adapted to retain mueh of it~ m tallie eoatinq when stretehed in a direetion generally parall-l to n-ek-down at least about 15 pereent That i8, there i~ little or no flaking or 1058 of metal observabl- to th-unaid d ey- wh n a str-tehable metalliz-d nonwoven web of th-pro~-nt invention eovered with at lQast at low to mod-rate levels o~ m tallie eoating is sub~eeted to normal handling For xampl-, a ~tr-tehable metallized nonwoven web having a metallie eoating from about 5 nanometers to about ~00 nanomet-rs may be adapted to r-t~in mueh of its metallie coating when ~treteh-d in a direetion g-n-rally parallel to neek-down from about 25 pereent to mor- than 50 pereent (e g , 65 p-reent or mor-) Mor-partieularly, sueh a ~tretehabl- metallized nonwoven web may be adapt-d to r-tain mueh of it~ metallie eoating when str-tehed in a dlr-etlon generally parallel to neek-down ~rom about 35 p-r¢ent to about 75 pereent Th- thiekness of the deposited metal depends on several faetors ineluding, for example, exposure time, the pressure inside the evaeuated chamber, temperature of the molten metal, surface temperature of the nonwoven web, size of the metal vapor "cloud", and the distance between the nonwoven web and molten metal bath, the number of passes over through the metal vapor ~cloud~, and the speed of the moving web. Generally speaking, lower process speeds tend to correlate with heavier or thicker metallic coatings on the nonwoven web but lower speeds increase the exposure time to metal vapor under conditions which may deteriorate the nonwoven web. Under some process conditions, exposure times can be less than about 1 second, for example, less ¦ 10 than about 0.75 seconds or even less than about 0.5 seconds.
Generally speaking, any number of passes through the metal vapor "cloud" may be used to increase the thickness of the metallic coating.
The nonwoven web is generally metallized to a metal thickness ranging from about 1 nanometer to about 5 microns. Desirably, th- thickness of the metallic coating may range from about 5 nanom ters to about 1 micron. More particularly, the thicknes~
o~ th- metallic coating may be from about 10 nanometers to about 500 nanometers.
Any metal which is suitable for physical vapor deposition or m tal sputtering processes may be used to form metallic coating~
on the nonwoven web. Exemplary metals include aluminum, copper, tin, zinc, lead, nickel, iron, gold, silver and the like.
Exemplary metallic alloys include copper-based alloys (e.g., 2S bronze, monel, cupro-nickel and aluminum-bronze); aluminum based alloys (aluminum-~ilicon, aluminum-iron, and their ternary relative~); titanium based alloys; and iron based alloys. Useful metallic alloy~ include magnetic materials (e.g., nickel-iron and aluminum-nickel-iron) and corrosion and/or abrasion resistant alloy~.
FIGS. 3 and 4 are scanning electron microphotographs of an exemplary stretchable metallized nonwoven web of th- pre~ent lnventlon. The ~tretchable metalllzed nonwoven web shown in FIG8. 3 and 4 was made from a 51 gsm nonwoven web of ~punbonded polypropylene fiber/filaments formed utllizing conventional spunbonding process equipment. Stretch and recovery properties were imparted to the nonwoven web of meltblown polypropylene - ~ 2~

fibers by passing the web over a series of steam cans to the nonwoven web to a temperature of about 110 Centigrade for a total contact time of about 10 seconds; applying a tensioning force to neck the heated nonwoven web about 30 percent (i.e., a neck-down of about 30 percent); and cooling the necked nonwoven web. The stretch and recovery properties of the materials are in a direction generally parallel to the direction of neck-down.
A metal coating was added to the webs utilizing conventional techniques. The scanning electron microphotographs were obtained directly from the metal coated nonwoven web without the pre-treatment conventionally used in scanning electron microscopy.
Nore particularly, FIG. 3 is a 401X (linear magnification) microphotograph of a stretchable metallized nonwoven spunbonded polypropylene fiber/filament web with a metallic aluminum coating. ~he sample was metallized while it was in the unstretched condition and is shown in the microphotograph in the un~tretched condition.
FIG. 4 is a 401X (linear magnification) microphotograph of the material shown in FIG. 3 after the material has been sub~ected to 5 cycle~ of stretching to about 25 percent and r-covery. The sample shown in the microphotograph is in un~tretched condition.
, A ~tretchable metallized nonwoven web material was made by depo~iting a metallic coating onto a nonwoven web of spunbonded polypropylene fibers/filaments which was sub~ected to heat treatm nt to impart strotch and recovery propertie~ to the nonwoven web. The nonwoven web wa~ a nonwoven web of polypropylene filaments formed utilizing conventional spunbonding t-chnique~ from Exxon 344S polypropylene available from the Exxon Ch-mical Company. That material wa~ heated to 230F ~110C) and th-n ne¢ked-down about 30 percent to make the stretchable ~ nonwoven web. An aluminum metal coating was depo~ited utilizing ¦ 35 conventional metal deposition techniques.
~ In particular, a sample of a stretchable nonwoven web of ¦ polypropylene spunbonded filaments having a basis weight of about ` 2101~3~
.

51 gsm and measuring about 7 inches by 7 inches was coated with aluminum metal utilizing a conventional small scale vacuum metallizing process. This sample was placed in a Denton Vacuum DV502A vapor deposition apparatus available from Denton Vacuum Corporation of Cherry Hill, New Jersey. The sample was held in a rotating brace at the top of the bell jar in the vacuum apparatus. The chamber was evacuated to a pressure of less than about 105 Torr (i.e., millimeters of Hg). Electrical current was used to evaporate an aluminum wire (99+% aluminum, available from the Johnson Mathey Electronics Corp., Ward Hill, Massachusett~) to produce metal vapor inside the vacuum chamber.
The procedure could be viewed through the bell jar. A metallic coating was deposited on one side of the stretchable nonwoven web. The web was turned over and the process was repeated to coat the other side of the web. The thickness of the aluminum coating was mea~ured as 4.SKA (4,500 Angstroms) on each side utilizing a Denton Vacuum DTM-100 thickness monitor also available ~rom the Denton Vacuum Corporation of Cherry Hill, New Jer~ey. Various properties of the stretchable metallized nonwoven web were measured as described below.
Tho drape sti~fness was determined using a stiffne~s tester available from Testing Machines, Amityville, Long Island, New York 11701. Test results were obtained in accordance with ASTM
~tandard te~t Dl388-64 u~ing the method described under Option A (Cantllever Te-t).
The basis weight of each stretchable metallized nonwoven web sa~pl- was determined essentially in accordance with Method 5041 o~ Federal Test Method Standard No. 191A.
The air permeability or "porosity" of the stretchable metallized nonwoven web was determined utilizing a Frazier Air P-rmeability Te~ter available from the Frazier Precision In~tr~m-nt Company. Th- Frazier porosity wa~ measured in accordance with Federal Test Method 5450, Standard No. l91A, except that the sample size was 8" X 8" instead o~ 7" X 7".
The electrical conductivity o~ the stretchable metallized nonwoven web was determined utilizing a Sears digital multitester Model 82386 available from Sears Roebuck & Company, Chicago, : :

` 2101~3~

Illinois. Probes were placed from about 0.5 to about 1 inch apart and conductivity was indicated when the meter showed a reading of zero resistance.
Peak load, peak total energy absorbed and peak elongation measurements of the stretchable metallized nonwoven web were made utilizing an Instron Model 1122 Universal Test Instrument essentially in accordance with Method 5100 of Federal Test Method Standard No. 191A. The sample width was 3 inchesi, the gage length waa 4 inches and the cross-head speed was set at 12 inches per minute.
Peak load refers to the maximum load or force encountered while elongating the sample to break. Measurements of peak load were made in the machine and cross-machine directions. The results are expressed in units of force (gramsfO,e.) for samples that measured 3 inches wide by about 7 inches long using a gage longth o~ 4 inches.
Elongatlon refers to a ratio determined by measuring the difference between a nonwoven web'~ initial unextended length and it~ extended length in a particular dimension and dividing that difference by the nonwoven web's initial unextended length in that s~me dimension. This value is multiplied by 100 percent when elongation is expressed as a percent. The peak elongation i~ the elongation measured when the material has been ~tretched to about its peak load.
Peak total energy absorbed refers to the total area under a stres~ versus strain (i.e., load vs. elongation) curve up to the point o~ peak or maximum load. Total energy absorbed is expres~-d in units of work/(length)2 such as, for example, (inch lbs~c~)/(inch) 2 .
When the stretchable metallized nonwoven web was removed ~rom the vacuum chamber, there was little or no flaking or 10~8 of metal ob~ervablo to the unaided eye during normal handling. The stretchable metallized nonwoven web was examined by 8canning electron microscopy both before and after five (5) cycles of being stretched in the direction parallel to neck-down at a rate of about 0.1 inches per minute to about 25 percent stretch and then recovering to about its initial necked-down dimensions.

.

- 2 1 ~

Scanning electron microphotographs of this material is shown in FIGS. 3 and 4.
The following properties were measured for the stretchable nonwoven web of spunbonded polypropylene filaments that was metallized as described above and for an un-metallized control sample of the same stretchable nonwoven web of spunbonded polypropylene filaments: Peak Load, Peak Total Energy Absorbed, -~
Frazier Porosity, Elongation, and Basis Weight. The results are identi~ied for measurements ta~en in the machine direction (MD) and the cross-machine direction (CD) where appropriate~ Results of these measurements are reported in Table 1. It should be noted that a su~ficient number of control webs were tested to be ~-able to measure the standard deviation of most of the test ~ -results. Although a standard deviation was not determined for -~
lS te~t re~ults o~ the metallized web, it is believed that the ~`
~t~nd~rd deviatlon should be similar.
, .
~ABLE 1 -~
Stretchable Stretchable Control ~eb M~alllzed~bb Bas1s ~elght (gsm) 51 51 Frazler Poros1ty 155 3 150 4 (cfm/ft2) Pe~k Total En~rgy Absorbed (lnch-lbs/ln ) (MD) 0 797 +0 208 0 863 (CD) 1 319 +0 472 0 808 Peak Load, grams~O~ (MD) 23 786 +2 122 24 367 (CD) 15 103 +1 514 14 071 Peak Elongatlon, (percent) (MD) 21 51 +3 61 23 28 (CD) 65 61 +13 73 48 00 Bend1ng Length (MD) 8 5 9 2 (centlmeters) (CD) 9 2 4 4 Drape St1ffness (MD) 4 3 4 6 (cent~meters) (CD) 2 6 2 2 ,""

21~3~

The stretchable metallized nonwoven web was also tested to measure the amour.t of material (e.g., metal flakes and particles as well as fibrous materials) shed during normal handling.
Materials were evaluated using a Climet Lint test conducted in accordance with INDA Standard Test 160.0-83 with the following modifications: (1) the sample size was 6 inch by 6 inch instead of 7 inch by 8 inch; and (2) the test was run for 36 seconds instead of 6 minutes. Results are reported for other types of commercially available fibrous webs for purposes of comparison.
As shown in Table 2, there was some detectable flaking or detachment of the metallic coating and/or fibrous material from the stretchable metallized nonwoven web of the present invention.
Desplte the detectable flaking, the results are believed to show that most of the metallic coating adheres to the stretchable no~woven web. Additionally, the relatively low level of partlcle~ detected by the test indicates the stretchable ~etallized nonwoven web may have properties that could be useful for applications such as, for example, clean-rooms, surgical procedures, laboratories and the like.

:~ 2101~3~

Material 0 5~ Partiç~es 10~ Part1cles Control Stretchable Spunbonded7993 246 Polypropylene Web Stretchable Metallized Spunbonded 12,998 1,543 Polypropylene Web (Chicopee Mfg Co )~ Workwell- 8487 2,063 154 (Chicopee Mfg Co J~ Solvent Wipe~ 8700 1,187 2 (Fort Howard Paper Co )Z W1pe Away- 119,628 3,263 (IFC)3 L1ke Rags- 1100 7,449 127 (James R1ver Paper Co )4 Clothmaster- 824 2,183 139 (James R1ver Paper Co )4 Maratuff 860W 36,169 377 (K-C)5 K1mtex- 2,564 100 (K-C)5 Crew- 33330 1,993 42 (K-C)5 Ki~w1pes- 34133 37,603 2,055 (K-C)5 K1~wipes- EXL 31,168 2,240 (K-C)5 Kaydry- 34721 10,121 1,635 (K-C)5 Terl- 34785 21,160 3,679 (K-C)s Terl- Plus 34800 14,178 730 (K-C)5 K1mtowels- 47000 106,014 46,403 (Scott Paper Co )6 Wypall- 5700 22,858 1,819 Ch1copee Manufactur1ng Co (Subs of Johnson ~ Johnson), M1lltown, New Jersey 2 Fort Howard Paper Co , Green Bay, W1scons1n IFC Nonwovens Inc , Jackson, Tennessee James Rlver Paper Co , R1chmond, Vtrg1n1a K~mberly-Clark Corporatlon, Neenah, Wlsconsln Scott Paper Co , Philadelphia, Pennsylvania - 2~01~3~

While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the sub~ect matter encompassed by way of the present invention i8 not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims.

Claims (20)

1. A stretchable metallized nonwoven web comprising:
at least one nonwoven web of non-elastomeric thermoplastic polymer fibers, the nonwoven web having been heated and then necked so that it is adapted to stretch in a direction parallel to neck-down at least about 10 percent more than an identical untreated nonwoven web of fibers; and a metallic coating substantially covering at least a portion of at least one side of the nonwoven web.

2. The stretchable metallized nonwoven web of claim 1 wherein the nonwoven web of non-elastomeric thermoplastic polymer fibers is selected from a nonwoven web of non-elastomeric meltblown thermoplastic polymer fibers, a nonwoven web of non-elastomeric spunbonded thermoplastic polymer fiber/filaments and a nonwoven bonded carded web of non-elastomeric thermoplastic polymer fibers.

3. The stretchable metallized nonwoven web of claim 2 wherein the meltblown fibers include meltblown microfibers.

4. The stretchable metallized nonwoven web of claim 3 wherein at least about 50 percent, as determined by optical image analysis, of the meltblown microfibers have an average diameter of less than 5 microns.

5. The stretchable metallized nonwoven web of claim 2 wherein the non-elastomeric meltblown thermoplastic polymer fibers comprises a polymer selected from the group consisting of polyolefins, polyesters, and polyamides.

6. The stretchable metallized nonwoven web of claim 5 wherein the polyolefin is selected from the group consisting of one or more of polyethylene, polypropylene, polybutene, ethylene, copolymers, propylene copolymers, and butene copolymers.

7. The stretchable metallized nonwoven web of claim 2 wherein the nonwoven web further comprises one or more other materials selected from the group consisting of wood pulp, textile fibers, and particulates.

8. The stretchable metallized nonwoven web of claim 7, wherein the textile fibers are selected from the group consisting of polyester fibers, polyamide fibers, glass fibers, polyolefin fibers, cellulosic derived fibers, multi-component fibers, natural fibers, absorbent fibers, electrically conductive fibers or blends of two or more of said nonelastic fibers.

9. The stretchable metallized nonwoven web of claim 7, wherein said particulate materials are selected from the group consisting of activated charcoal, clays, starches, metal oxides, and super-absorbent materials.

10. The stretchable metallized nonwoven web of claim 1 wherein the nonwoven web has a basis weight of from about 6 to about 400 grams per square meter.

11. The stretchable metallized nonwoven web of claim 1 wherein the thickness of the metallic coating ranges from about 1 nanometer to about 5 microns.

12. The stretchable metallized nonwoven web of claim 11 wherein the thickness of the metallic coating ranges from about 5 nanometers to about 1 micron.

13. The stretchable metallized nonwoven web of claim 1 wherein the metallic coating is selected from the group consisting of aluminum, copper, tin, zinc, lead, nickel, iron, gold, silver, copper based alloys, aluminum based alloys, titanium based alloys, and iron based alloys.

14. The stretchable metallized nonwoven web of claim 1 wherein the metallic coating comprises at least two layers of metallic coating.

15. The stretchable metallized nonwoven web of claim 1 wherein the stretchable metallized nonwoven web is adapted to be electrically conductive.

16. The stretchable metallized nonwoven web of claim 15 wherein the nonwoven web is adapted to remain electrically conductive when stretched at least about 25 percent.

17. The stretchable metallized nonwoven web of claim 16 wherein the nonwoven web is adapted to remain electrically conductive when stretched from about 30 percent to about 100 percent.

18. A multilayer material comprising:
at least one layer of a stretchable metallized nonwoven web, the stretchable metallized nonwoven web comprising at least one nonwoven web of non-elastomeric thermoplastic polymer fibers, the nonwoven web having been heated and then necked so that it is adapted to stretch in a direction parallel to neck-down at least about 10 percent more than an identical untreated nonwoven web of fibers; and a metallic coating substantially covering at least a portion of at least one side of the nonwoven web; and.

19. The multilayer material of claim 18 wherein the other layer is selected from the group consisting of woven fabrics, knit fabrics, bonded carded webs, continuous spunbond filament webs, meltblown fiber webs, and combinations thereof.

20. A process of making a stretchable metallized nonwoven web comprising:
providing at least one nonwoven web of non-elastomeric thermoplastic polymer fibers, the nonwoven web having been heated and then necked so that it is adapted to stretch in a direction parallel to neck-down at least about 10 percent more than an identical untreated nonwoven web of fibers; and metallizing at least one portion of at least one side of the nonwoven so that said portion is substantially covered with a metallic coating.