Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/62—Plasma-deposition of organic layers
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/001—Treatment with visible light, infrared or ultraviolet, X-rays
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/02—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements ultrasonic or sonic; Corona discharge
  • D06M10/025—Corona discharge or low temperature plasma
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/04—Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/06—Inorganic compounds or elements
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/04—Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/08—Organic compounds
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M10/00—Physical treatment of fibres, threads, yarns, fabrics, or fibrous goods made from such materials, e.g. ultrasonic, corona discharge, irradiation, electric currents, or magnetic fields; Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/04—Physical treatment combined with treatment with chemical compounds or elements
  • D06M10/08—Organic compounds
  • D06M10/10—Macromolecular compounds

Definitions

• the present invention relates to a durably wettable, liquid pervious web that is particularly suitable as a topsheet for absorbent articles More particularly, the invention relates to a polymeric film or nonwoven to which is applied a thin coatmg of organic mate ⁇ al onto at least one surface of the film or nonwoven The thin organic coating is applied by a plasma-induced chemical vapor deposition process. The thin organic coating renders the web more permanently hydrophilic than other methods known in the art.
• the invention further relates to a process for making the durably wettable, liquid pervious web, and to articles containing the durably wettable, liquid pervious web as a topsheet.
• Polymeric and nonwoven webs are common components of disposable absorbant articles, dryer sheets and the like. More particularly, macroscopically expanded, three-dimensional, polymeric films have been utilized as topsheet mate ⁇ als for disposable absorbent articles.
• macroscopically expanded when used to desc ⁇ be three-dimensional webs, refers to webs which have been caused to conform to the surface of a three-dimensional forming structure so that both surfaces thereof exhibit the three-dimensional pattern of the forming structure or webs that have an inherent three- dimensional pattern arising from their structure Regardless of whether the three-dimensional pattern is inherent or generated by application of a forming process, the pattern is readily visible to the naked eye when the perpendicular distance between the viewer's eye and the plane of the web is about 12 inches
• the term “planar”, when utilized herein to desc ⁇ be nonwovens and polymeric films refers to the overall condition of the web when viewed by the naked eye on a macroscopic scale.
• planar webs may include webs having fine-scale surface aberrations on one or both sides, the surface aberrations not being readily visible to the naked eye when the perpendicular distance between the viewer's eye and the plane of the web is about 12 inches or greater
• Thompson describes a macroscopically expanded, three dimensional web (e g., a topsheet) comp ⁇ sed of liquid impermeable mate ⁇ al, but provided with a pattern of tapered capillaries, the capilla ⁇ es having a base opening in the plane of the topsheet and an apex opening remote from the plane of the topsheet, the apex opening being m intimate contact with the absorbent pad utilized in the disposable absorbent article
• the Thompson topsheet allows the free transfer of liquids from the wearer's body into the absorbent element of the device while inhibiting the reverse flow of these liquids.
• plastic webs of the aforementioned type can be made by applying a pressure differential to the web while it is supported on a three-dimensional forming structure until the web is macroscopically expanded to comply with the three-dimensional cross-section of the forming structure on which it is supported
• the pressure (vacuum is desc ⁇ bed) differential is applied continuously until such time as apertu ⁇ ng of the web in areas coinciding with the apertures m the forming structure has been completed
• a multi-phase, liquid-based process such as that desc ⁇ bed in U S Patent No 4,609,518, issued
• the treated films lose their ability to transport liquid away from the skin and mto the article's core after repeated wettings.
• RIS suffers from some degree of surfactant wash-off during use and/or during manufacture, particularly if liquid pressure differentials are used to form the web's apertures.
• hydrophilic webs formed using RIS techniques are not immediately wettable, and depending on the relationship between the resm and the surfactant and environmental conditions, may not become wettable for finite pe ⁇ ods of tune. Similarly,
• the present invention relates to a durably wettable, liquid pervious web that is particularly useful as a topsheet material for absorbent articles
• the inventions relates to a durably-wettable, liquid pervious web which comprises 105 (l) a web selected from the group consistmg of polymeric films and nonwovens;
• a substantially contmous hydrophilic coating less than about 2.5 microns thick, on at least one surface of the web, wherein said hydrophilic coating is applied to the web by plasma polyme ⁇ zation, wherein at least one surface of the durably-wettable, liquid pervious web has a Post Aging contact angle 110 that is not more than about 60 degrees greater than the Pre Agmg contact angle.
• At least one surface of the treated web will have a Post Washing contact angle that is not more than about 60 degrees greater than the Pre Washmg contact angle.
• both conditions will exist in a single web
• the invention also relates to an absorbent article comp ⁇ sing a durably wettable, liquid pervious 115 topsheet, the topsheet comp ⁇ sing a web and a hydrophilic coating on at least one surface of the web, wherein the hydrophilic coating is applied to the substrate by plasma polymerization.
• the invention relates to a plasma polyme ⁇ zation process for making the durably wettable, liquid pervious webs described herein
• the present invention relates to a durably wettable web that is prepared by applying a hydrophilic coating to a starting polymeric film or nonwoven, using a plasma polymerization process
• the term "web” refers to the starting substrate (i.e., a polymeric film or nonwoven) 125 to which the hydrophilic coating is applied
• the terms "durably wettable, liquid pervious web” or “treated web” refer to the final product - the polymer film or nonwoven having the durable hydrophilic coating
• liquid pervious refers to the ability of a web or treated web to transport liquids from one surface of the web or treated web to the opposite surface of the web or treated web in a 130 sufficiently efficient manner so as to allow the treated web to be used as a component of a disposable article
• Webs may be inherently liquid pervious or may be made liquid pervious by application of a processing step, such as, apertu ⁇ ng
• substantially contmuos means sufficiently contmuos to provide the hydrophilic or wettable properties as defined by the stated or claimed contact angle limitations. 135
• hydrophilic and wettable are used interchangeably and refer to surfaces that are wettable by aqueous liquids (e.g., aqueous body liquids) deposited on these surfaces.
• Hydrophilicity and wettability are typically defined in terms of contact angle and the surface tension of the liquids and solids involved. This is discussed in detail in the Amencan Chemical Society publication entitled Contact Angle, Wettability and Adhesion, edited by Robert F Gould (Copyright 1964)
• a web 140 surface is said to be wetted by a liquid (I e., hydrophilic) when either the contact angle between the liquid and the web surface is less than 90°, or when the liquid tends to spread spontaneously across the surface of the web, both conditions normally co-existing
• a surface is considered to be hydrophobic if the contact angle is greater than 90° and the liquid does not spread spontaneously across the surface of the web
• the durably wettable, liquid pervious webs of the present invention are "durably wettable", insofar as the hydrophilic character engendered to the otherwise more hydrophobic film is maintained over time and after exposure to liquids.
• p ⁇ or approaches directed at making hydrophobic films wettable result in initial improvements in wettability, but suffer from the negative attribute that wettability is lost over time and/or exposure to liquids. While not being bound by theory, it is believed that typical
• hydrophilic polymer and surface-treated polymer systems go through a "hydrophobic recovery” process.
• surface wettability tends to decay over time because thermodynamics favors the exposure of lower surface energy molecular chain segments at polymer surface.
• hydrophilic molecular segments reo ⁇ ent and embed themselves and expose hydrophobic segments at polymer surface. If chemical crosslinkrng is induced at the polymer
• the cross nking tends to limit polymer chain mobility, thus significantly slowing the "hydrophobic recovery” process and therefore preserving polymer surface wettability over tune. Since Applicants' invention provides for polymer chemical crosslinkrng, via a radiation curing process, a durably wettable, liquid pervious web can be produced.
• Durable wettability is described herein in terms of the ability of a durably wettable, liquid pervious
• Post Aging wettable character after agmg
• Post Washing wettable character after agmg
• the durable wettability of the present durably wettable, liquid pervious webs is
• Plasma is often referred to as the fourth state of matter.
• a solid e.g., a polymeric film or nonwoven
• the solid can undergo a transition to the liquid state. If further energy is applied, the liquid becomes a gas. If additional energy of the proper kind is applied, the gas dissociates and becomes plasma.
• Plasmas exist m a variety of forms.
• the prefe ⁇ ed plasma useful herein is a low pressure or vacuum process, which allows processing of the web at or near ambient
• Suitable plasma systems for use m the present invention incorporate a parallel plate electrode design where materials to be treated are exposed directly to the primary field of RF energy, but are not part of the circuitry.
• the subsequent p ⁇ mary plasma is particularly more uniform and more efficient since the part is exposed in all three dimensions to the glow discharge.
• some form of gas delivery system designed to create a uniform laminar flow of process gas throughout the entire chamber volume is beneficial
• Solid state components and microprocessor control of the system parameters of process time, flow rate, power level, 185 and working pressure, will also ensure process uniformity, efficiency, and repeatability.
• the preferred plasma process utilizes a matching network to constantly tune the plasma impedance to the output impedance of the RF generator Advanced plasma systems suitable for use m the present invention are available from HIMONT Plasma Science, Foster City,
• the low temperature plasma is generated in a gaseous atmosphere at reduced pressure of from about 0.001 to about 10 Ton, preferably from about 0 01 to about 5 Torr, more preferably from about 0.05 to about 1 Torr, and most preferably from about 0.05 to about 0.4 Ton.
• the elect ⁇ c power can be supplied
• the elect ⁇ c power delivered to the apparatus can vary over a range of from about 10 to about 10,600 watts; preferably from about 50 to about 5,000 watts, more preferably from about 250 to about 3000 watts, most preferably from about 500 to about 2500 watts.
• the power used is somewhat
• the plasma treatment time varies from a few seconds to several mmutes, preferably from about 20 seconds to about 30 minutes, most preferably from about 60 seconds to about 20 minutes.
• the hydrophilic coating layer is deposited onto the surface of a suitable web (either previously
• the monomers will be silicon-containing compounds having one to three silicon atoms, which compounds are selected from the group consisting of (I) silanes of the formula S ⁇ R 4 where each R is the same or different and is selected from H, a C C s linear or branched alkyl or alkoxy; a C 6 -C, 0
• R' and R" groups are hydrogen, and n is 1, 2 or 3; and (in) mixtures thereof.
• Representative silicon compounds include, but are not limited to, hexamethyldisiloxane (HMDSO), methylt ⁇ methoxy silane (MTMS), vmylt ⁇ methoxy silane (VTMS), vinylt ⁇ ethoxy silane (VTES), ethylmethoxy silane (EMS), ethylt ⁇ methoxy silane (ETMS), tetraethoxy silane (TES), cyclohexylmethyl-dimethoxy silane (CMDMS), dicyclopentyl-dimethoxy silane (DCDMS),
• HMDSO hexamethyldisiloxane
• MTMS methylt ⁇ methoxy silane
• VTMS vmylt ⁇ methoxy silane
• VTES vinylt ⁇ ethoxy silane
• EMS ethylmethoxy silane
• ETMS ethylt ⁇ methoxy silane
• TES tetraethoxy silane
• CDMS cycl
• the silicon compounds employed are introduced into the plasma deposition chamber in the gaseous state Prior to being introduced into the chamber, the silicon compound is heated to a temperature of from about 40° to about 100°C, generally from about 40° to about 60°C, to vaporize the compound and create sufficient vapor pressure such that the coatmg is deposited at a
• Oxygen in gaseous form and argon are fed into the deposition chamber simultaneously with, but each with a separate feedmg means and mass flow controller, the gaseous silicon compound
• the 0 ; flow rate ranges from about 25 standard cubic centimeter/minute ("seem") to about 1200 seem, the gaseous silicon compound flow is from about 10 seem to about 250 seem, and Ar flow is from about 1 seem to about 150 seem Argon is used to enhance the rate of deposition
• Oxygen is essential to the plasma deposition process with the silicon compounds according to this invention Without oxygen, it is not possible to obtain a plasma-induced hydrophilic coating using the aforementioned silicon compounds Whatever oxidizing effect it has, it appears to be necessary to utilize oxygen if one is to obtain the hydrophilic coatings of this invention
• the deposition of the hydrophilic coating layer is about 0 04 to about 0 5 Torr, preferably about 0 35 to about 0 45 Ton, most preferably about 0 4 Torr
• the process pressure must be such that a low bias potential on the RF-d ⁇ ven electrode is achieved
• the total vapor pressure for the hydrophilic coating layer is from about 0 04 to about 0 4 Ton, preferably from about 0 06 to about 0 13 Ton, depending on the process used and the substrate being treated
• monomer deposition may be achieved via the flash vapo ⁇ zation technique that is desc ⁇ bed in U S Patent No 4,842,893 issued to Yiahzis on Apr 29, 1988, the disclosure of which is incorporated by reference herein
• the web to be subjected to plasma polymerization may be flat (two dimensional) or complex (three dimensional, including previously apertured films and nonwovens) That is, plasma treatment may
• plasma treatment will be conducted after aperture formation, so as to better preserve a uniform hydrophilic coating on the web's surface
• the plasma treatment time for obtaining the desired hydrophilic coatings is from typically about 1 minute to about 10 minutes, preferably about 1.5 to about 4 mmutes, most preferably about 1.5 to about 2.5 minutes; and the RF power used to cause reaction of the vapor is typically from about 200 to about 1500 watts, preferably about 1000 to about 1400 watts, most preferably about 1100 to about 1300 watts.
• the RF power used to cause reaction of the vapor is typically from about 200 to about 1500 watts, preferably about 1000 to about 1400 watts, most preferably about 1100 to about 1300 watts.
• 265 power typically employs ranges from about 1200 to about 2500 watts and depends on the substrate being treated and the throughput requirements.
• the resulting hydrophilic coatmgs can be produced in different thicknesses, but are typically from about 0.1 to about 2.5 microns, preferably about 1 to about 2 microns.
• the plasma induced hydrophilic coating exhibits a contact angle for water of less than about 90 degree, such that any water placed on the treated web will tend to spread spontaneously over
• the treated web may be further treated by exposure to a low temperature plasma gas composition (also refened to herein as a "surface modifying gas stream") or an energy source (also refened herein as "radiation cu ⁇ ng”) such as an apparatus that emits, including but not limited to, infra red, electron beam, thermionic or ultra violet radiation.
• a low temperature plasma gas composition also refened to herein as a "surface modifying gas stream”
• an energy source also refened herein as "radiation cu ⁇ ng”
• Apparatuses that are suitable as energy sources in the present invention are disclosed in U.S. Patent No. 4,842,893 issued to
• the gas stream preferably comprises N ; 0 and CO : , to enhance the durability of the hydrophilic coating
• the plasma gas composition will comprise from about 80 to about 40 mol % N ; 0 and from about 20 to about 60 mol % CO : , preferably from about 70 to about 45 mol % N : 0 and from about 30 to about 55 mol % CO,, most
• 280 preferably from about 60 to about 45 mol % N : 0 and from about 40 to about 55 mol % CO : , where the amount of N : 0 and CO : in the mixture equals 100 to 10 mol %, for a time sufficient to modify the surface of the hydrophilic coating to enhance its durability.
• the radiation source is preferably a gas discharge electron beam gun
• the gun directs a flow of electrons through a emitter window onto the monomer, thereby
• Curing is controlled by matching the electron beam voltage to the dielectric thickness of the monomer coating. For example, a 10 Kv electron voltage will penetrate about 1 micron of deposited monomer.
• the plasma process is generally practiced as follows.
• the starting web to be treated is placed into a vacuum chamber and the chamber pressure is reduced, typically to about 0.005 Ton.
• 290 gas mixture employed is introduced to the chamber and the chamber pressure is stabilized at a pressure of 0.04-0.4 Ton.
• the interior dimension of the work area is approximately 1.73 X 0.76 X 1.02 meters (width x height x depth) for a total working volume of 1.34 cubic meters
• a suitable high frequency form of energy typically 13.56 MHz radio frequency energy, is used to create the plasma; in the system desc ⁇ bed, this is achieved with a total power input capacity of up to 2500 watts.
• the RF energy dissociates the gas,
• an initial step is performed The purpose of this step is to clean the web's surface to promote adhesion of the hydrophilic coating onto the web.
• 310 subsequently deposited thin hydrophilic coating Cleaning may be accomplished by subjecting the web's surface to radiation (herein refened to as radiation cleanmg) from an energy source including but not limited to, infra red, electron beam, thermionic or ultra violet radiation or by plasma cleaning.
• radiation cleanmg an energy source including but not limited to, infra red, electron beam, thermionic or ultra violet radiation or by plasma cleaning.
• Apparatuses that are suitable as energy sources in the present invention are disclosed in U.S. Patent No. 4,842,893 issued to Yiahzis on Apr 29, 1988 In the radiation cleaning embodiment, the radiation source is
• 315 preferably a gas discharge electron beam gun.
• the gun directs a flow of electrons through a emitter window onto the web's surface, thereby abstracting atoms or breaking bonds, thus creating free radicals
• These free radicals are unstable and seek to satisfy a more stable state thus they serve as bonding sites for the monomers that are used to produce the web's hydrophilic coatmg Cleaning is controlled by matchmg the electron beam voltage to the dielectric thickness or depth of cleaning that is desired For example, a 10
• the gases are usually either Ar alone, 0 2 alone, or mixtures (e g , 1 1 ratio) of Ar and 0 2
• Gas flow rates are typically in the range of about 20 to about 100 seem (standard cc/mm), preferably about 40 to about 80 seem, and most preferably about 50 to about 60 seem RF power is approximately 1100 watts, and process pressure is about 0 040 Ton.
• the next step is the plasma deposition of the hydrophilic coating, as described above and in more detail in the examples below Often, but not always, a step subsequent to the CO : and N 2 0 surface treating step is used to enhance the durability or uniformity of the plasma coating.
• Useful process gases are Ar and/or 0 2 Process times are usually about 1 to about 3 mmutes, with about 2 minutes typically being optimum. Gas flows range from about 40 to about 250 seem, with process
• thermoplastic polymer any thermoplastic polymer which can be used for the preparation of films.
• thermoplastic polymers include, by way of illustration only, end-capped polyacetals, such as
• poly(vmyhdene fluoride), poly(vmyl fluoride), and the like polyamides, such as poly(6- aminocaproic acid) or poly( ⁇ -caprolactam), poly(hexamethylene adipamide), poly(hexamethylene sebacamide), poly(l l-ammoundecano ⁇ c acid), and the like; polyaramides, such as poly( ⁇ m ⁇ no-l,3- phenyleneiminoisophthaloyl) or poly(m-phenylene lsophthalamide), and the like, polyarylenes, such as poly-p-xylylene, poly(chloro- ⁇ -xylylene), and the like; polyaryl ethers, such as poly(oxy-2,6-d ⁇ methyl-l,4-
• polystyrene resin such as poly(ethylene terephthalate), poly(tetramethylene terephthalate), poly(cyclohexylene-
• polystyrene resin 350 1 ,4-d ⁇ methylene terephthalate) or poly(oxymethylene-l,4-cyclohexyl-enemethyleneoxyterephthaloyl), and the like, polyaryl sulfides, such as poly(p-phenylene sulfide) or poly(th ⁇ o- 1 ,4-phenylene), and the like, polyimides, such as poly(pyromelht ⁇ m ⁇ do-l,4-phenylene), and the like, polyolefins, such as polyethylene, polypropylene, poly(l-butene), poly(2-butene), poly(l-pentene), poly(2-pentene), poly(3-methyl-l- pentene), poly(4-methyl-l-pentene), l,2-poly-l,3-butad ⁇ ene, l,4-poly-l,3-butad ⁇ ene, polyisoprene,
• polychloroprene polyacrylonitrile, poly(v ⁇ nyl acetate), poly(v ⁇ nyhdene chloride), polystyrene, and the like; copolymers of the foregoing, such as acrylonit ⁇ le-butadiene-styrene (ABS) copolymers, and the like.
• ABS acrylonit ⁇ le-butadiene-styrene
• Prefened polymers are polyolefins and polyesters, with polyolefins being more prefened. Even more prefened are those polyolefins which contain only hydrogen and carbon atoms and which are prepared by the addition polymerization of one or more unsaturated monomers Examples of such
• 360 polyolefins include, among others, polyethylene, polypropylene, poly(l-butene), poly(2-butene), ⁇ oly(l- pentene), poly(2-pentene), poly(3-methyl-l-pentene), ⁇ oly(4-methyl-l-pentene), l,2-poly-l,3-butad ⁇ ene, 1,4-poly- 1,3 -butadiene, polyisoprene, and the like.
• such term is meant to include blends of two or more polyolefins and random and block copolymers prepared from two or more different unsaturated monomers. Because of their commercial importance, the most prefened polyolefins are polyethylene and
• Inorganic fibers such as glass and metal can be used alone or in combination or further combined with organic fibers
• staple fibers fiber length vanes from about 1/4 inch to about 2 or more inches.
• spun bonded webs the fiber lengths are indefinite.
• the staple fibers used in hydroentangled, needled and polyme ⁇ cly bound nonwovens are processed through conventional textile machinery.
• a cardmg machine may be used to form a contmuous length of rather two-dimensional loosely associated fibers known as a carded web.
• These webs may be assembled to form a multiple layer or three-dimensional fibrous web of significant weight, e.g., from about several grams to thousands of grams per yard.
• the textile fibers are anayed at va ⁇ ous angles to the lengthwise axis of the web.
• the fibers are usually predommantly oriented m the machme direction and. on the other hand, lsotropic webs may be formed such as by air-lay mg.
• the fibrous webs desc ⁇ bed above are typically impregnated with a polymeric binding agent (polymencly bound).
• the polyme ⁇ c binders are applied as emulsions of acrylic, polyvinylacetate, or similar polymeric nature, and mixtures thereof.
• the fibers are unwoven and substantially haphazardly
• Hydroentangled and needled webs are distinct from polyme ⁇ cly bound webs as they rely principally on the physical entanglement of their fibers to provide web lnteg ⁇ ty.
• spun bond webs typically are composed of fibers of infinite length that are bound together through solvent or melt processes.
• the webs may be in the form of a flat film or may be a previously apertured three dimensional film.
• the coatings are durable and mcrease the surface energy of the web to render the treated web more wettable.
• the coating is durable, in that it is maintained over time, even after exposure to water or other aqueous liquids.
• the webs of the present invention are desc ⁇ bed m one respect in terms of their ability to remain wettable over time and/or after exposure to liquids. The ability to remain
• 395 wettable over time is assessed by measu ⁇ ng the web's Post Aging contact angle.
• This measurement involves sto ⁇ ng the treated web at 60° C for 16 hours, to artificially age the treated web, before measu ⁇ ng contact angle.
• the ability to remain wettable after exposure to liquids is assessed by measunng the web's Post Washing contact angle.
• This measurement involves placing a 2 in. x 2 in. sample of treated web in a 250 ml water bath at 65°C for 90 sec. with vigorous agitation prior to measuring contact angle.
• the treated web of the present invention will have a Post Agmg contact angle that is
• the treated web will have a Post Agmg contact angle that is not more than about 40 degrees, more preferably not more than about 20 degrees, still more preferably not more than about 10 degrees, greater than the Pre Aging contact angle.
• the treated web of the present invention will have a Post Washing contact angle that is not more
• the treated web will preferably have a Post Washing contact angle that is not more than about 40 degrees, more preferably not more than about 20 degrees, still more preferably not more than about 10 degrees, greater than the Pre Washmg contact angle.
• the treated web will preferably have a Post Washing contact angle that is not more than about 40 degrees, more preferably not more than about 20 degrees, still more preferably not more than about 10 degrees, greater than the Pre Washmg contact angle.
• the treated webs of the present mvention will exhibit either (preferably both) a Post Aging or a Post Washmg contact angle of less than about 90 degrees, preferably not more than about 70 degrees, more preferably not more than about 50 degrees, still more preferably not more than about 30 degrees, and most
• absorbent article refers generally to devices used to absorb and contain
• absorbent article is intended to include diapers, catamenial pads, tampons, sanitary napkms, incontinent pads, training pants and the like, as well as wipes, bandages and wound dressings.
• dispenser is used herein to describe absorbent articles which are not intended to be laundered or otherwise restored or reused
• a "unitary" absorbent article refers to absorbent articles which are formed as a single structure or as separate parts united together to form a coordinated entity so that they do not require separate manipulative parts such as a separate holder and pad.
• absorbent articles will also comp ⁇ se an absorbent core for retention of any absorbed body liquids.
• Exemplary absorbent structures for use as the absorbent core in the present invention are described in U.S Patent No 4,950,264 issued to Osborn on August 21, 1990; U.S. Patent No 4,610,678 issued to Weisman et al. on September 9, 1986; U.S. Patent No. 4,834,735 issued to Alemany et al. on May 30, 1989, European Patent Application No. 0 198 683, the
• the absorbent core may further comp ⁇ se the dual core system containing an acquisition/distribution core of chemically stiffened fibers positioned over an absorbent storage core as detailed in U.S. Patent No. 5,234,423, entitled "Absorbent Article With Elastic Waist Feature and Enhanced
• a prefened embodiment of a unitary disposable absorbent article made in accordance herewith is a catamenial pad, or sanitary napkin As used herem, the term “sanitary napkm” refers to an absorbent
• the sanitary napkm has two flaps each of which are adjacent to and extend laterally from the side edge of the absorbent core.
• the flaps are
• the flaps serve at least two purposes. First, the flaps help serve to prevent soiling of the wearer's body and panties by menstrual liquid, preferably by forming a double wall banier along the edges of the panty. Second, the flaps are preferably provided with attachment means on their garment surface so that the flaps can be folded back under the panty and attached
• the flaps serve to keep the sanitary napkm properly positioned in the panty.
• the flaps can be constructed of vanous mate ⁇ als including materials similar to the topsheet, backsheet, tissue, or combmation of these materials Further, the flaps may be a separate element attached to the mam body of the napkm or can comp ⁇ se extensions of the topsheet and backsheet (i.e., unitary).
• an acquisition layer(s) may be positioned
• the acquisition layer may serve several functions includmg improving wicking of exudates over and into the absorbent core. There are several reasons why the improved wicking of exudates is important, including providmg a more even distribution of the exudates throughout the absorbent core and allowing the sanitary napkin to be made relatively thin.
• the wicking refened to herein may encompass the transportation of liquids in one, two or all directions (i.e., in the x-y
• the acquisition layer may be comp ⁇ sed of several different mate ⁇ als including nonwoven or woven webs of synthetic fibers including polyester, polypropylene, or polyethylene, natural fibers including cotton or cellulose; blends of such fibers; or any equivalent matenals or combinations of materials.
• sanitary napkms having an acquisition layer and a topsheet are more fully described in U.S. Patent No 4,950,264 issued to Osborn and U.S. Patent Application Se ⁇ al No.
• the acquisition layer may be joined with the topsheet by any of the conventional means for joining webs together, most preferably by fusion bonds as is more fully desc ⁇ bed in the referenced Cree application.
• Catamenial pads may be constructed as follows Onto sihcone-coated release paper a spiral pattern of H2031 Findlay hot melt adhesive is applied at 0.04 g/m ⁇ This adhesive layer is transfened onto the top (wearer-facing) side of a secondary topsheet by rolling the secondary topsheet and coated release paper together with a hand roller.
• the secondary topsheet is formed of a nonwoven mate ⁇ al known as Fort James Airlaid Tissue, Grade 817, commercially available from the Fort James Corp. of Green Bay, Wisconsin.
• topsheet of the present invention is applied to the adhesive side of the secondary topsheet and the two are bonded by gently pressing them together with a hand roller. Two strips of one-quarter-inch double-sided tape are applied along both long edges of a polyethylene backsheet. The absorbent core is added to construct the complete absorbent structure.
• the term "diaper” refers to a garment generally worn by infants and incontinent
• a diaper of the present invention will comprise a liquid pervious topsheet of the present invention; a liquid impervious backsheet joined with the topsheet; and an absorbent core positioned between the topsheet and the backsheet. Additional
• structural features such as elastic members and fastening means for securing the diaper in place upon a wearer (such as tape tab fasteners) may also be included.
• topsheet While the topsheet, the backsheet, and the absorbent core can be assembled in a variety of well known configurations, a prefened diaper configuration is desc ⁇ bed generally in U.S. Patent No. 3,860,003 (Buell), issued January 14, 1975, the disclosure of which is incorporated by reference. Alternatively,
• the absorbent core of the diaper is positioned between the topsheet and the backsheet.
• absorbent core can be manufactured m a wide variety of sizes and shapes (e.g., rectangular, hourglass, asymmet ⁇ cal, etc )
• the total absorbent capacity of the absorbent core should, however, be compatible with the design liquid loading for the intended use of the absorbent article or diaper. Further, the size and absorbent capacity of the absorbent core can vary to accommodate wearers rangmg from infants through adults.
• the absorbent core may include a liquid dist ⁇ bution member.
• the absorbent core preferably further mcludes an acquisition layer or member m liquid communication with the liquid dist ⁇ bution member and located between the liquid distribution member and the topsheet
• the acquisition layer or member may be comprised of several different mate ⁇ als mcludmg nonwoven or woven webs of synthetic fibers includmg polyester, polypropylene, or polyethylene, natural
• fibers including cotton or cellulose, blends of such fibers, or any equivalent matenals or combmations of materials.
• the diaper will comp ⁇ se elasticized leg cuffs.
• the elasticized leg cuffs can be constructed in a number of different configurations, mcludmg those desc ⁇ bed m U.S. Patent No. 3,860,003, U.S Patent No 4,909,803, issued to Aziz et al. on Mar. 20, 1990; U.S. Patent No 4,695,278,
• the diaper is applied to a wearer by positioning the back waistband region under the wearer's back, and drawing the reminder of the diaper between the wearer's legs so that the front waistband region is positioned across the front of the wearer.
• the tape-tab or other fasteners are then secured
• Example 2 the mass flow controller used to deliver the silicon- containing monomer compound for the deposition processes was calibrated for the flow rate of HMDSO
• Example 1 This example illustrates the plasma treatment process and benefit of this mvention in applymg a permanent hydrophilic coating to a flat polyethylene film Flat polyethylene (PE) film having a 1 mil
• 560 average thickness is obtained from Tredegar Film Products, Inc (Tene Haute, IN) with material composition designation code X-8318-1
• Three-step plasma treatments are conducted in a plasma reactor (Advanced Plasma System, Model D, radio frequency (RF) 40 KHz), with the gas input and process conditions indicated m Table 1
• Rapid aging condition refers to conditioning the web sample at 60° C for 16 hours prior to wettability measurement Water contact angle, measured with a goniometer (Model # 100-
• This example illustrates the alternate plasma treatment process and benefit of this invention in applying a permanent hydrophilic coating to a flat PE film
• Flat PE film having a 1 mil average thickness is obtained from Tredegar Film Products, Inc (Tene Haute, IN) with mate ⁇ al composition designation code X-8318-1.
• Three-step plasma treatments are conducted in a plasma reactor (Plasma Science PS0500D), with gas input and process conditions indicated m Table 3.
• the resulting plasma treated web samples are then evaluated for surface wettability before and after the water wash test.
• Water wash test refers to immersing a 2 in, x 2 in. web sample in a 250 ml water bath at 65° C for 90 sec with vigorous agitation (with a Teflon coated stir bar).
• Water contact angle measured with a goniometer (model # 100-00, Rame-Hart, Inc., Mountam Lakes, N.J.), is used to assess the webs' wettability. Strong wetting durability of HMDSO-denved plasma coating is established, as is demonstrated by compa ⁇ ng contact angle between pre-washed and post-washed samples (see Table 4).

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Absorbent Articles And Supports Therefor (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Laminated Bodies (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Materials For Medical Uses (AREA)
• Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)

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• 1999
  • 1999-09-20 WO PCT/US1999/021709 patent/WO2000016913A1/en active IP Right Grant
  • 1999-09-20 JP JP2000573866A patent/JP2002526219A/ja active Pending
  • 1999-09-20 CA CA002340972A patent/CA2340972C/en not_active Expired - Fee Related
  • 1999-09-20 AU AU60511/99A patent/AU6051199A/en not_active Abandoned
  • 1999-09-20 AT AT99969355T patent/ATE241433T1/de not_active IP Right Cessation
  • 1999-09-20 EP EP99969355A patent/EP1115505B1/de not_active Expired - Lifetime
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