Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/02—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/04—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
  • D04H1/587—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives characterised by the bonding agents used
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
  • D01D5/098—Melt spinning methods with simultaneous stretching
  • D01D5/0985—Melt spinning methods with simultaneous stretching by means of a flowing gas (e.g. melt-blowing)
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4282—Addition polymers
  • D04H1/4291—Olefin series
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
  • D04H1/64—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives the bonding agent being applied in wet state, e.g. chemical agents in dispersions or solutions
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
  • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/005—Synthetic yarns or filaments
  • D04H3/007—Addition polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H5/00—Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2321/00—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D10B2321/02—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins
  • D10B2321/022—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins polypropylene

Definitions

• the present disclosure relates to (co)polyrneric fibers, including a crystalline polyolefin, (co)polymer and a hydrocarbon tackifier resin, and more particularly,to nonwoven fibrous webs including such fibers, and methods for preparing such webs.
• Melt-blowing is a process for forming nonwoven fibrous webs of thermoplastic (co)polymeric fibers.
• one or more thermoplastic (co)polymer streams are extruded through a die containing closely arranged orifices and attenuated by convergent streams of high-velocity hot air to form micro-fibers which are collected to form a melt-blown nonwoven fibrous web.
• melt-blown nonwoven fibrous webs include polyethylene (PE) and polypropylene (PP).
• PE polyethylene
• PP polypropylene
• melt-blown nonwoven fibrous webs are used in a variety of applications, including acoustic and thermal insulation, filtration media, surgical drapes, and wipes, among others.
• the present disclosure describes a nonwoven fibrous web, including A multiplicity of (co)polymeric fibers including from about 50%.w/W to about 99%o why of at least one crystalline polyolefin(co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin, wherein the nonwoven fibrous web exhibits a Heat of Fusion measured using Differential Scanning calorimetry of greater than 50 Joules/g.
• the at least one crystalline polyolefin (co)polymer is selected from polyethylene, isotactic polypropylene, syndiotactic polypropylene, isotactic polybutylene, syndiotactic polybutylene, poly-4-methyl pentene), and mixtures thereof.
• the at least one crystalline polyolefin (co)polymer exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.
• the at least one crystalline polyolefin (co)polymer is selected to be isotactic polypropylene, syndiotactic polypropylene and mixtures thereof.
• the at least one hydrocarbon tackifier resift is a saturated hydrocarbon.
• the at least one hydrocarbon tackifier resin is selected from C 5 piperylene derivatives, C 9 resin oil derivatives, and mixtures thereof.
• the at least one hydrocarbon tackifier resin makes up from 2% to 40% by weight of the (co)polymeric fibers, more preferably from 5% to 30% by weight of the (co)polymeric fibers, even more preferably from 7% to 20% by weight of the (co)polymeric fibers.
• the multiplicity of (co)polymeric fibers exhibits a mean Actual Fiber Diameter of from about 100 nanometers to about 10 micrometers, more preferably from 100 nanometers to 1 micrometer, inclusive. In other exemplary embodiments, the multiplicity of (co)polymeric fibers exhibits a mean Effective Fiber Diameter of between about 1 micrometer and about 100 micrometers, more preferably greater than 1 micrometer to about 20 micrometers.
• the (co)polymer fibers further include between about 0 to 30% w/w of at least one plasticizer.
• the at least one plasticizer is selected from oligomers of C 5 to C 14 olefins, and mixtures thereof.
• the, present disclosure describes a process for making a nonwoven fibrous web, including heating a mixture of about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin to at least a Melting Temperature of the mixture to form a molten mixture, extruding the molten mixture through at least one orifice to form at least one filament, applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers, and cooling the plurality of discrete discontinuous fibers to a temperature below the Melting Temperature of the molten mixture to form a nonwoven fibrous web, wherein at least one of the crystalline polyolefin (co)polymer or the nonwoven fibrous web exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than
• applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers is accomplished using a process selected from melt-blowing, gas jet fibrillation, and combinations thereof.
• the process further includes at least one of addition of a plurality of staple fibers to the plurality of discrete, discontinuous fibers, or addition of a plurality of particulates to the plurality of discrete, discontinuous fibers.
• the process further includes collecting the plurality of discrete, discontinuous fibers as the nonwoven fibrous web on a collector.
• the process further includes'processing the collected nonwoven fibrous web using a process selected from autogenous bonding, through-air bonding, electret charging, embossing, needle-punching, needle tacking, hydroentangling, or a combination thereof.
• Exemplary embodiments according to the present disclosure may have certain surprising and unexpected advantages over the art.
• One such advantage of exemplary embodiments of the present disclosure relates to increased tensile strength exhibited by the webs; even when prepared at low Basis Weight (i.e., less than or equal to 50 g/m 2 , “gsm”).
• Increased tensile strength for low Basis Weight webs is important for many insulation applications, for example, thermal or acoustic insulation, more particularly acoustic or thermal insulation mats used in motor vehicles (e.g., aircraft, trains, automobiles, trucks, ships, and submersibles).
• exemplary nonwoven fibrous webs as described herein may advantageously exhibit a Maximum Load in the Machine Direction of at least 5 Newtons as measured with the Tensile Strength Test as defined herein.
• the nonwoven fibrous webs exhibit a Basis Weight of from 1 g/m 2 (gsm) to 400 gsm, more preferably from 1 gsm to 200 gsm, even more preferably from 1 gsm to 100 gsm, or even 1 gsm to about 50 gsm.
• Another advantage of exemplary embodiments may be to limit or eliminate the possibility of newly formed fibers breaking and forming fiber fragments ((i.e., “fly”) which can fall onto the collected nonwoven web and damage the web where they land.
• An additional advantage of exemplary embodiments relates to an ability to use a higher melt temperature for the melt-blown process; which leads to a lower mean Effective Fiber Diameter (EFD) of about 5 thicrometers or less, and may even permit the production of sub-micrometer fibers (i.e., nanofibers) having a mean Actual Fiber Diameter (AFD) of one micrometer or less.
• EFD Effective Fiber Diameter
• AFD mean Actual Fiber Diameter
• Such nonwoven fibrous webs including sub-micrometer fibers achieve better acoustic and/or thermal insulation performance at equal or lower Basis Weight than comparable microfiber webs, thus leading to improved insulation performance at a lower production cost.
• Embodiments of the present disclosure may exhibit higher production rates due to the lower melt viscosities achieved during melt-blowing of the fibers.
• a plurality of (co)polymeric fibers comprising from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and
• Embodiment O, Q, R or S wherein applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers is accomplished using a process selected from the group consisting of melt-blowing, gas jet fibrillation, and combinations thereof.
• (co)polymer or “(co)polymers” includes homopolymers and copolymers, as well as homopolymers or copolymers that may be formed in a miscible blend, e.g., by coextrusion or by reaction, including, e.g., transesterification.
• copolymer includes random, block and star (e.g. dendritic) copolymers.
• molecularly same (co)polymer means one or more (co)polymers that have essentially the same repeating molecular unit, but which may differ in molecular weight, method of manufacture, commercial form, and the like.
• nonwoven fibrous web means a fibrous web characterized by entanglement or point bonding of a plurality of fibers.
• self-supporting means a nonwoven fibrous web having sufficient coherency and strength so as to be drapable and handleable without substantial tearing or rupture.
• melt-blowing and “melt-blown process” mean a process for forming a nonwoven fibrous web by extruding a fiber-forming material through one or more orifices to form filaments while contacting the filaments with air or other attenuating fluid to attenuate the filaments into discrete discontinuous fibers, and thereafter collecting a layer of the attenuated discrete discontinuous fibers.
• die means a processing assembly including one or more orifices to form filaments for use in (co)polymer melt processing and fiber extrusion processes, including but not limited to melt-blowing processes.
• melt-blown fibers means discrete fibers prepared using a melt-blowing process.
• machine direction means the Longitudinal direction in which a nonwoven fibrous web of indeterminate length is moved or wound onto a collector, and is distinguished from the “cross-web” direction, which is the lateral direction extending between the two lateral edges of the nonwoven fibrous web.
• crossweb direction is orthogonal to the machine direction for a rectangular nonwoven fibrous web.
• composite nonwoven fibrous web means a nonwoven web having an open-structured entangled mass of melt-blown fibers, for example, sub-micrometer melt-blown fibers and optionally melt-blown microfibers.
• a particle or particulate means a small distinct piece or individual part of a material in finely divided form.
• a particulate may also include a collection of individual particles associated or clustered together in finely divided form.
• individual particles used in certain exemplary embodiments of the present disclosure may chimp, physically intermesh, electro-statically associate, or otherwise associate to form particulates.
• particulates in the form of agglomerates of individual particles may be intentionally formed such as those described in U.S. Pat. No. 5,332,426 (Tang et al.).
• particle-loaded nonwoven fibrous web means a nonwoven fibrous web containing particles bonded to the fibers or enmeshed among the fibers, the particles optionally being absorbent and/or adsorbent.
• the term “enmeshed” means that particles are distributed and physically held in the fibers of the web. Generally, there is point and line contact along the fibers and the particles so that nearly the full surface area of the particles is available for interaction with a fluid.
• autogenous bonding means bonding between fibers at an elevated temperature as obtained in an oven or with a through-air bonder without application of solid contact pressure such as in point-bonding or calendering
• rollers means a process of passing a product, such as a polymeric absorbent loaded web through rollers to obtain a compressed material.
• the rollers may optionally be heated.
• Densification means a process whereby fibers which have been deposited either directly or indirectly onto a filter winding arbor or mandrel are compressed, either before or after the deposition, and made to form an area, generally or locally, of lower porosity, whether by design or as an artifact of some process of handling the forming or formed filter. Densification also includes the process of calendering webs.
• Actual Fiber Diameter or “AFD” means the mean number diameter on a population of melt-blown fibers determined by measuring 500 individual fibers using Scanning Electron Microscopy (SEM).
• Effective Fiber Diameter means the apparent diameter of the fibers in a nonwoven fibrous web based on an air permeation test in which air at 1 atmosphere and room temperature is passed at a face velocity of 5.3 cm/sec through a web sample of known thickness, and the corresponding pressure drop is measured. Based on the measured pressure drop, the Effective Fiber Diameter is calculated set forth in Davies, C. N., The Separation of Airborne Dust and Particles, Institution of Mechanical Engineers, London Proceedings, 1B (1952).
• microfibers means a population of fibers having a mean diameter of at least one micrometer ( ⁇ m) and preferably less than 1.000 ⁇ m.
• microfibers means a population of microfibers having a mean diameter of at least 10 ⁇ m and preferably less than 1,000 ⁇ m.
• fine microfibers means a population of microfibers having a mean diameter of from one ⁇ m to less, than 10 ⁇ m.
• ultrafine microfibers means a population of microfibers having a mean diameter of 2 ⁇ m or less.
• nanofibers means a population of fibers having a mean diameter of 1 ⁇ m or less.
• sub-micrometer fibers means a population of fibers having a mean diameter of less than 1 ⁇ m.
• microfibers means a stream of microfibers produced from a microfiber-forming apparatus (e.g., a melt-blowing die) positioned such that the microfiber stream is initially spatially separate (e.g., over a distance of about 1 inch (25 mm) or more from, but will merge in flight and disperse into, a stream of larger size microfibers.
• a microfiber-forming apparatus e.g., a melt-blowing die
• homogeneous means exhibiting only a single phase of matter when observed at a macroscopic scale.
• Web Basis Weight is calculated from the weight of a 10 cm ⁇ 10 cm web sample.
• Web Thickness is measured on a 10 cm ⁇ 10 cm web sample using a thickness testing gauge having a tester foot with dimensions of 5 cm ⁇ 12.5 cm at an applied pressure of 150 Pa.
• Polymer Density is the mass per unit volume of the (co)polymer or (co)polymer blend that is used to form the nonwoven fibers of a nonwoven fibrous web.
• the Polymer Density for a (co)polymer may generally be found in the literature, and the Polymer Density of a (c)polymer blend may be calculated from the weighted average of the component (co)polymer Polymer Densities, based upon the weight percentages of the individual (co)polymers used to make up the (co)polymer blend.
• the Polymer Density of polypropylene resin is 0.91 g/cm 3 and the Polymer Density of the hydrocarbon tackifier resins used herein is about 1.00 g/cm 3 .
• Solidity provided herein using the following formula, a Polymer Density of 0.91 g/cm 3 was used.
• Solidity ⁇ ⁇ ( % ) [ 3.937 * Web ⁇ ⁇ Basis ⁇ ⁇ Weight ⁇ ⁇ ( g ⁇ / ⁇ m 2 ) ] [ Web ⁇ ⁇ Thickness ⁇ ⁇ ( mils ) * Polymer ⁇ ⁇ Density ⁇ ⁇ ( g ⁇ / ⁇ cm 3 ) ]
• one mil is equivalent to 25 micrometers.
• Melting Temperature is the highest magnitude peak among principal and any secondary endothermic melting peaks in a cooling after first heating heat flow curve plotted as a function of temperature, as obtained using Differential Scanning Calorimetry (DSC).
• joining with reference to a particular layer in a multilayer nonwoven fibrous web means joined with attached to another layer, in a position wherein the two layers are either next to (i.e., adjacent to) and directly contacting each other, or contiguous with each other but not in direct contact (i.e., there are one or more additional layers intervening between the layers).
• a viscosity of “about” 1 Pa-sec refers to a viscosity from 0.95 to 1.05 Pa-Sec, but also expressly includes a viscosity of exactly 1 Pa-sec.
• perimeter that is “substantially square” is intended to describe a geometric shape having four lateral edges in which each lateral edge has a length which is from 95% to 105% of the length of any other lateral edge but which also includes a geometric shape in which each lateral edge has exactly the same length.
• a substrate that is “substantially” transparent refers to a substrate that transmits more radiation (e.g. visible light) than it fails to transmit (e.g. absorbs and reflects).
• a substrate that transmits more than 50% of the visible light incident upon its surface is substantially transparent, but a substrate that transmits 50% or less of the visible light incident upon its surface is not substantially transparent.
• orientation such as “atop”, “on”, “over,” “covering”, “uppermost”, “underlying” and the like for the location of various elements in the disclosed coated articles, we refer to the relative position of an element with respect to a horizontally disposed, upwardly-facing substrate. However, unless otherwise indicated, it is not intended that the substrate or articles should have any particular orientation in space during or after manufacture.
• the disclosure describes a nonwoven fibrous web, comprising a plurality of (co)polymeric fibers comprising from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin, wherein the nonwoven fibrous web exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.
• the nonwoven fibrous webs as described herein may advantageously exhibit improved tensile strength, as evidenced by a Maximum Tensile Load in the Machine Direction as measured with the Tensile Strength Test as defined herein, of at least 5 Newtons (N), at least 6 N, at least 7 N, at least 8N, at least 9 N, or even at least 10 N.
• a Maximum Tensile Load in the Machine Direction as measured with the Tensile Strength Test as defined herein is less than 20 N, less than 15 N, less than 14 N, or even less than 12 N.
• Nonwoven fibrous webs of the present disclosure generally include fibers that may be regarded as discrete discontinuous fibers.
• the discrete discontinuous fibers in the non-woven fibrous webs or composite webs comprise microfibers and may advantageously exhibit a mean Effective Fiber Diameter (determined using the test method described below) of between about 1 micrometer and about 100 micrometers, more preferably greater than 1 micrometer to about 20.0 micrometers, inclusive, even more preferably from greater than 1 micrometer to about 10.0 micrometers.
• the discrete discontinuous fibers in the nonwoven fibrous webs or composite webs may comprise sub-micrometer fibers or nanofibers and may advantageously exhibit a mean Actual Fiber Diameter (determined using the test method described below) of from about 100 nanometers (nm) to about 5 micrometers inclusive, more preferably from 100 nm to 1 ⁇ m, inclusive, even more preferably from about 100 nm, to about 900 nm, or even 200 nm to 750 nm, or 250 nm to 500 nm, inclusive.
• the nonwoven fibrous web May take a variety of forms; including mats, webs, sheets; scrims; fabrics, and a combination thereof.
• Melt-blown nonwoven fibrous webs or webs of the present disclosure comprise fibers comprising from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w at least one hydrocarbon tackifier resin.
• a single crystalline polyolefin (co)polymer) may be mixed with a single hydrocarbon tackifier resin.
• a single crystalline polyolefin (co)polymer may be advantageously mixed with two or more hydrocarbon tackifier resins.
• two or more crystalline polyolefin (co)polymers may be mixed with a single hydrocarbon tackifier resin.
• two or more crystalline polyolefin (co)polymers may be advantageously mixed with two or more hydrocarbon tackifier resins.
• the crystalline polyolefin (co)polymers useful in practicing embodiments of the present disclosure are generally crystalline polyolefin (co)polymers with a moderate level of crystallinity.
• (co)polymer crystallinity arises from stereoregular sequences in the (co)polymer, for example stereoregular ethylene; propylene, or butylene sequences.
• the (co)polymer can be: (A) a propylene homopolymer in which the stereoregularity is disrupted in some manner such as by regio-inversions; (B) a random propylene copolymer in which the propylene stereoregularity is disrupted at least in part by co-monomers; or (C) a combination of (A) and (B).
• the at least one crystalline polyolefin (co)polymer is selected from polyethylene, isotactic polypropylene, syndiotactic polypropylene, isotactic polybutylene, syndiotactic polybutylene, poly-4-methyl pentene, and mixtures thereof.
• the at least one crystalline polyolefin (co)polymer preferably exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 5.0 Joules/g.
• the at least one crystalline polyolefin (co)polymer is selected to be isotactic polypropylene, syndiotactic polypropylene, and mixtures thereof.
• the crystalline polyolefin (co)polymer is a (co)polymer that includes a non-conjugated diene monomer to aid in vulcanization and other chemical modification of the blend composition.
• the amount of diene present in the (co)polymer is preferably less than 10% by weight, and more preferably less than 5% by weight.
• the diene may be any non-conjugated diene which is commonly used for the vulcanization of ethylene propylene rubbers including, but not limited to, ethylidene norbornene, vinyl norbornene, and dicyclopentadiene.
• the crystalline polyolefin (co)polymer is a random copolymer of propylene and at least one co-nonomer selected from ethylene; C 4 -C 12 alpha-olefins, and combinations thereof.
• the copolymer includes ethylene-derived units in an amount ranging from a lower limit of 2N, 5%, 6%, 8%, or 10% by weight to an upper limit of 20%, 25%, 0.28% by weight.
• This embodiment also includes propylene-derived units present in the copolymer in an amount ranging from a lower limit of 72%, 75%, or 80% by weight to an upper litnit of 98%, 95%, 94%; 92%, or 90% by weight. These percentages by weight are based on the total weight of the propylene and ethylene-derived units; i.e., based on the sum of weight percent propylene-derived units and weight percent ethylene-derived units being 109%.
• the crystalline polyolefin (co)polymer is a random propylene copolymer having a narrow compositional distribution.
• the crystalline polyolefin (co)polymer is a random propylene copolymer exhibiting a Heat of Fusion determined using DSC of greater than 50 J/g.
• the copolymer is described as random because for a copolymer comprising propylene, co-monomer, and optionally diene, the number and distribution of co-monomer residues is consistent with the random statistical polymerization of the monomers.
• stereoblock structures the number of block monomer residues of any one kind adjacent to one another is greater than predicted from a statistical distribution in random copblymers with a similar composition.
• Historical ethylene-propylene copolymers with stereoblock structure have a distribution of ethylene residues consistent with these blocky structures rather than a random statistical distribution of the monomer residues in the (co)polymer.
• the intramolecular composition distribution (i.e., randomness) of the copolymer may be determined by 13 C NMR, which locates the co-monomer residues in relation to the neighboring propylene residues.
• the crystallinity of the crystalline polyolefin (co)polymers may be expressed in terms of heat of fusion.
• Embodiments of the present disclosure include crystalline polyolefin (co)polymers exhibiting a heat of fusion as determined using differential scanning Calorimetry (DSC) greater than 50 J/g, greater than 51 J/g, greater than 55 J/g, greater than 60 J/g, greater than 70 J/g, greater than 80 J/g, greater than 90 J/g, greater than 100 J/g, or even about 110 J/g.
• DSC differential scanning Calorimetry
• the crystalline polyolefin (co)polymers exhibit a heat of fusion as determined using.
• DSC less than 210 J/g, less than 200 J/g, less than 190 J/g, less than 180 J/g, less than 170 J/g, less than 160 J/g, less than 150 J/g, less than 140 J/g, less than 130 J/g, less than 120 J/g, less than 110 J/g, or even less than 100 J/g.
• the (co)polymer has a single Melting Point.
• a sample of propylene (co)polymer will show secondary melting peaks adjacent to the principal peak, which are considered together as a single Melting Point. The highest of these peaks is considered to be the Melting Point.
• the crystalline polyolefin (co)polymer preferably has a melting point determined using DSC ranging from an upper limit of 300° C., 275° C., 250° C., 200° C., 175° C., 150° C., 125° C., 110° C., or even about 105° C., to a lower limit of about 105° C., 110° C., 120° C. , 125° C., 130° C. 140° C. 150° C., 160° C., 175, 180° C., 190° C., 200° C., 225° C., or even about 250° C.
• the crystalline polyolefin (co)polymers used in the disclosure generally have a weight average molecular weight (M w ) within the range having an upper limit of 5,000,000 Daltons (Da or g/mol), 1,000,000 Da, or 500,000 Da, and a lower limit of 10,000 Da, 20,000 Da, or 80,000 Da, and a molecular weight distribution M w /M n (MWD), sometimes referred to as a “polydispersity index” (PDI), ranging from a lower limit of 1.5, 1.8, or 2.0 to an upper limit of 40, 20, 10, 5, or 4.5.
• M w and MWD can be determined by a variety of methods, including those in U.S. Pat. No.
• At least one crystalline polyolefin (co)polymer is generally present in an amount from about 50% w/w (50.0% w/w, 55% w/w, 60% w/w, 65% w/w, 70% w/w, 75% w/w, 80% wlw, 85% w/w, or even about 90% w/w) to about 99% w/w (99.0% w/w, 98% w/w 97% w/w, 96% w/w, 95% w/w, 90% w/w, 85% w/w, 80% w/w, 75% w/w, 70% w/w. 65% w/w, or even about 60% w/w) based on the total weight of the composition.
• the hydrocarbon tackifier resin is selected to be miscible (i.e., forms a homogenous melt) with the crystalline polyolefin (co)polymer(s) when the mixture is in a molten state, that is, when the mixture of the at least one crystalline polyolefin (co)polymer and the at least one hydrocarbon tackifier resin is heated to a temperature at or above the Melting Temperature (as determined using DSC) of the mixture.
• Suitable resins include, but are not limited to, natural rosins and rosin esters, hydrogenated rosins and hydrogenated rosin esters, coumarone-indene resins, petroleum resins, polyterpene resins, and terpene-phenolic resins.
• suitable petroleum resins include, but ate not limited to aliphatic hydrocarbon tackifier resins, hydrogenated aliphatic hydrocarbon tackifier resins, mixed aliphatic and aromatic hydrocarbon tackifier resins, hydrogenated mixed aliphatic and aromatic hydrocarbon tackifier resins, cycloaliphatic hydrocarbon tackifier resins, hydrogenated cycloaliphatic resins, mixed cycloaliphatic and aromatic hydrocarbon tackifier resins, hydrogenated mixed cycloaliphatic and aromatic hydrocarbon tackifier resins, aromatic hydrocarbon tackifier resins, substituted aromatic hydrocarbons, and hydrogenated aromatic hydrocarbon tackifier resins.
• hydrocarbonated includes fully, substantially and at least partially hydrogenated resins.
• Suitable aromatic resins include aromatic modified aliphatic resins, aromatic modified cycloaliphatic resin; and hydrogenated aromatic hydrocarbon tackifies resins. Any of the above resins may be grafted with an unsaturated ester or anhydride to provide enhanced properties to the resin. Examples of grafted resins and their Manufacture are described in the chapter titled Hydrocarbon Resins, Kirk-Othmer, Encyclopedia of Chemical Technology, 4th Ed, v. 13, pp. 717-743 (J. Wiley & Sons, 1995).
• Hydrocarbon tackifier resins suitable for use as described herein include EMPR 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 116, 117, and 118 resins, OPPERATM resins, and EMFR resins available from Exxon-Mobil Chemical. Company (Spring, Tex.); ARKONTM P140, P125, P115, M115, and M135 and SUPER ESTERTM rosin esters available from Arakamid.
• the hydrocarbon tackifier resin has a number average molecular weight (M n ) within the range having an upper limit of 5,000 Da, or 2,000 Da, or 1,000 Da, and a lower limit of 200 Da, or.400 Da, or 500 Da; a weight average molecular weight (M w ) ranging from 500 Data 10,000 Da or 600 to 5,000 Da or 700 to 4,000 Da; a Z average molecular weight (M z ) ranging from 500 Da to 10,000 Da, and a polydispersity index (PDI) as measured by M w /M n , of from 1.5 to 3.5, where M n , M w , and M z are determined using size exclusion chromatography (SEC), or as provided by the supplier.
• M n number average molecular weight
• M w weight average molecular weight
• M z Z average molecular weight
• PDI polydispersity index
• the hydrocarbon tackifier resin has a lower molecular weight than the crystalline polyolefin (co)polymer.
• hydrocarbon tackifier resins of the present disclosure are generally selected to be miscible with the crystalline polyolefin (co)polymer in a molten state.
• Hydrocarbon tackifier resins useful in embodiments of the present disclosure may have a softening point within the range having an upper limit of 180° C., 150° C., or 140° C., and a lower limit of 80° C., 120° C., or 125° C. Softening point (° C.) is measured using a ring and ball softening point device according to ASTM E-28 (Revision 1996).
• the hydrocarbon tackifier resin is a saturated hydrocarbon.
• the hydrocarbon tackifier resin is selected from C 5 piperylene derivatives, C 9 resin oil derivatives, and mixtures thereof.
• the hydrocarbon tackifier'resin makes up from about 2% w/w (2.0% w/w, 3% w/w, 4% w/w, 5% w/w, 10% w/w, 15% w/w, 20% w/w) to about 40% (40.0% w/w, 35% w/w, 30% w/w, or even 25% w/w) based on the weight of the (co)poymeric fibers in the nonwoven fibrous web, more preferably from 5% to 30% by weight of the (co)polymeric fibers, even more preferably from 7% to 20% by weight of the (co)polymeric fibers.
• the nonwoven melt-blown fibrous webs of the present disclosure may further comprise one or more optional components.
• the optional components may be used alone or in any combination suitable for the end-use application of the nonwoven melt-blown fibrous webs.
• Three non-limiting, currently preferred optional components include optional electret fiber components, optional non-melt-blown fiber components, and optional particulate components as described further below.
• the (co)polyineric fibers further include a plasticizer in an amount between about 0% to about 30% w/w of the fiber composition, more preferably from 1% to 20% w/w, 1% to 10% w/w, 1% to 5%, or even 1% to 2.5%.
• the plasticizer is selected from oligomers of C 5 to C 14 olefins, and mixtures thereof.
• plasticizers include SHF and SUPEERSYNTm available from Exxon-Mobil Chemical Company (Houston, Tex.); STNFLUIDTM available from Chevron-Phillips Chemical Co, (Pasadena, Tex.); DURASYNTM available from BP-Amoco Chemicals (London, England); NEXBASETM available from Fortuin Oil and Gas Co. (Espoo, Finland); SYNTONTM available from Crompton Corporation (Middlebury, Conn.); EMERYTM available from BASF GmbH (Ludwigshafen, Germany), formerly. Cognis Corporation (Dayton, Ohio).
• the nonwoven melt-blown fibrous webs of the present disclosure may optionally comprise electret fibers.
• Suitable electret fibers are described in U.S. Pat. Nos. 4,215,682; 5,641,555; 5,643,507; 5,658,640; 5,658,641; 6,420,024; 6,645,618, 6,849,329; and 7,691,168, the entire disclosures of which are incorporated herein by reference.
• Suitable electret fibers may be produced by meltblowing fibers in an electric field, e.g. by melting a suitable dielectric material such as'a (co)polymer or wax that contains polar molecules, passing the molten Material through a melt-blowing die to form discrete fibers, and then allowing the molten (co)polymer to re-solidify while the discrete fibers are exposed to a powerful electrostatic field.
• Electret fibers may also be made by embedding excess charges into a highly insulating dielectric material such as a (co)polymer or wax, e.g. by means of an electron beam, a corona discharge, injection from an electron, electric breakdown across a gap or a dielectric barrier, and the like.
• Particularly suitable electret fibers are hydro-charged fibers.
• the nonwoven fibrous web optionally further comprises a plurality of non-melt-blown fibers.
• the nonwoven fibrous web may additionally comprise discrete non-melt-blown fibers.
• the discrete non-melt-blown fibers are staple fibers.
• the discrete non-melt-blown fibers act as filling fibers, e.g. to reduce the cost or improve the properties of the melt-blown nonwoven fibrous web.
• Non-limiting examples of suitable non-met-blown filling fibers include single component synthetic fibers, semi-synthetic fibers, polymeric fibers, metal fibers; carbon fibers, ceramic fibers, and natural fibers.
• Synthetic and/or semi-synthetic polymeric fibers include those made of polyester (i.e., polyethylene terephthalate), nylon (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic (formed from a (co)polymer of acrylonitrile), rayon, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, vinyl chloride-acrylonitrile copolymers, and the like.
• Non-limiting examples of suitable metal fibers include fibers made from any metal or metal alloy, for example, iron, titanium, tungsten, platinum, copper, nickel, cobalt, and the like.
• Non-limiting examples of suitable carbon fibers include graphite fibers, activated carbon fibers, poly(acrylonitrile)-derived carbon fibers, and the like.
• Non-limiting examples of suitable ceramic fibers include any metal oxide, metal carbide, or metal nitride, including but not limited to silicon oxide, aluminum oxide, zirconium oxide, silicon carbide, tungsten carbide, silicon nitride, and the like.
• Non-limiting examples of suitable natural fibers include those of bamboo, cotton, wool, jute, agave, sisal, coconut, soybean, hemp, and the like.
• the fiber component used may be virgin fibers or recycled waste fibers, for example, recycled fibers reclaimed from garment cuttings, carpet manufacturing, fiber manufacturing, textile processing, or the like.
• the size and amount of discrete non-melt-blown filling fibers, if included, used to form the nonwoven fibrous web will generally depend on the desired properties (i.e., loftiness, openness, softness, drapability) of the nonwoven fibrous web 100 and the desired loading of the chemically active particulate. Generally, the larger the fiber diameter, the larger the fiber length, and the presence of a crimp in the fibers will result in a more open and lofty nonwoven article. Generally, small and shorter fibers will result in a more compact nonwoven article.
• the nonwoven fibrous web further comprises a plurality of particulates.
• Exemplary nonwoven fibrous webs according to the present disclosure may advantageously include a plurality of chemically active particulates.
• the chemically active particulates can be any discrete particulate, which is a solid at room temperature, and which is capable of undergoing a chemical interaction with an external fluid phase. Exemplary chemical interactions include adsorption, absorption, chemical reaction, catalysis of a chemical reaction, dissolution, and the like.
• the chemically active particulates may advantageously be selected from sorbent particulates (e.g. adsorbent particulates, absorbent particulates, and the like), desiccant particulates (e.g. particulates comprising a hygroscopic substance such as, for example, calcium chloride, calcium sulfate, and the like, that induces or sustains a state of dryness in its local vicinity), biocide particulates, microcapsules, and combinations thereof.
• sorbent particulates e.g. adsorbent particulates, absorbent particulates, and the like
• desiccant particulates e.g. particulates comprising a hygroscopic substance such as, for example, calcium chloride, calcium sulfate, and the like, that induces or sustains a state of dryness in its local vicinity
• biocide particulates e.g. adsorbent particulates, absorbent particulates, and the like
• the chemically active particulates may be selected from activated carbon particulates, activated alumina particulates, silica gel particulates anion exchange resin particulates, cation exchange resin particulates, molecular sieve particulates, diatomaceous earth particulates, anti-microbial compound particulates, metal particulates, and combinations thereof.
• the chemically active particulates are sorbent particulates.
• sorbent particulates include mineral particulates, synthetic particulates, natural sorbent particulates or a combination thereof. Desirably the sorbent particulates will be capable of absorbing or adsorbing gases, aerosols, or liquids expected to be present under the intended use conditions.
• the sorbent particulates can be in any usable form including beads, flakes, granules or agglomerates.
• Preferred sorbent particulates include activated carbon; silica gel; activated alumina and other metal oxides; metal particulates (e.g., silver particulates) that can remove a component from a fluid by adsorption or chemical reaction; particulate catalytic agents such as hopcalite (which can catalyze the oxidation of carbon monoxide); clay and other minerals treated with acidic solutions such as acetic acid or alkaline solutions such as aqueous sodium hydroxide; ion exchange resins; molecular sieves and other zeolites; biocides; fungicides and virucides.
• Activated carbon and activated alumina are presently particularly preferred sorbent particulates.
• Mixtures of sorbent particulates can also be employed, e.g., to absorb mixtures of gases, although in practice to deal with mixtures of gases it may be better to fabricate a multilayer sheet article employing separate sorbent particulates in the individual layers.
• the chemically active sorbent particulates are selected to be gas adsorbent or absorbent particulates.
• gas adsorbent particulates may include activated carbon, charcoal, zeolites, molecular sieves, an acid gas adsorbent, an arsenic reduction material, an iodinated resin, and the like.
• absorbent particulates may also include naturally porous particulate materials such as diatomaceous earth, clays, or synthetic particulate foams such as melamine, rubber, urethane, polyester, polyethylene, silicones, and cellulose.
• the absorbent particulates may also include superabsorbent particulates such as sodium polyacrylates, carboxymethyl cellulose, or granular polyvinyl alcohol.
• the sorbent particulates comprise liquid an activated carbon, diatomaceous earth, an ion exchange resin (e.g. an anion exchange resin, a cation exchange resin, or combinations thereof), a molecular sieve, a metal ion exchange sorbent, an activated alumina, an antimicrobial compound, or combinations thereof.
• an ion exchange resin e.g. an anion exchange resin, a cation exchange resin, or combinations thereof
• a molecular sieve e.g. an anion exchange resin, a cation exchange resin, or combinations thereof
• a metal ion exchange sorbent e.g. an anion exchange resin, a cation exchange resin, or combinations thereof
• the web has a sorbent particulate density in the range of about 0.20 to about 0.5.g/cc.
• sorbent chemically active particulates may be used to create a nonwoven fibrous web.
• the sorbent particulates have a mean size greater than 1 mm in diameter; In an other exemplary embodiment, the sorbent particulates have a mean size less than 1 cm in diameter. In further embodiments; a combination of particulate sizes can be used.
• the sorbent particulates include a mixture of large particulates and small particulates.
• the desired sorbent particulate size can vary a great deal and usually will be chosen based in part on the intended service conditions.
• sorbent particitlates partitularly useful for filtration applications may vary in size from about 0.001.to about 3000 ⁇ m mean diameter.
• the sorbent particulates are from about 0.01 to about 1500 ⁇ m mean diameter, more generally from about 0.02 to about 750 ⁇ m mean diameter, and most generally from about 0.05 to about 300 ⁇ 5 m mean diameter.
• the sorbent particulates may comprise nano-particulates having a population mean diameter less than 1 ⁇ m.
• Porous nano-particulates may have the advantage of providing high surface area for sorption of contaminants from a fluid medium (e.g., absorption and/or adsorption).
• the particulates are adhesively bonded to the fibers using an adhesive, for example a hot melt adhesive, and/or the application of heat to the melt-blown nonwoven fibrous web (i.e., thermal bonding).
• sorbent particulates having different size ranges can also be employed, although in practice it may be better to fabricate a multilayer sheet article employing larger sorbent particulates in an upstream layer and smaller sorbent particulates in a downstream layer. At least 80 weight percent sorbent particulates, more generally at least 84 weight percent and most generally at least 90 weight percent sorbent are enmeshed in the web.
• the sorbent particulate loading level may for example be at least about 500 gsm for relatively fine (e.g., sub-micrometer-sized) sorbent particulates, and at least about 2,000 gsm for relatively coarse (e.g., micron-sized) sorbent particulates.
• the chemically active particulates are metal particulates.
• the metal particulates may be used to create a polishing nonwoven fibrous web.
• the metal particulates may be in the form of short fiber or ribbon-like sections or may be in the form of grain-like particulates.
• the metal particulates can include any type of metal such as but not limited to silver (which has antibacterial/antimicrobial properties), copper (which has properties of an algaecide), or blends of one or more of chemically active metals.
• the chemically active particulates are solid biocides or antimicrobial agents.
• solid biocide and antimicrobial agents include halogen containing compounds such as sodium dichloroisocyanurate dihydrate, benzalkonium chloride, halogenated dialkylhydantoins, and triclosan.
• the chemically active particulates are microcapsules.
• Microcapsules are described in U.S. Pat. No. 3,516,941 (Matson), and include examples of the microcapsules that can be used as the chemically active particulates.
• the microcapsules may be loaded with solid or liquid biocides or antimicrobial agents.
• One of the main qualities of a microcapsule is that by means of mechanical stress the particulates can be broken in order to release the material contained within them. Therefore, during use of the nonwoven fibrous web, the microcapsules will be broken due to the pressure exerted on the nonwoven fibrous web, which will release the material contained within the microcapsule.
• useful particulates may comprise a (co)polymer, for example, a thermoplastic (co)polymer, which may be in the form of discontinuous fibers.
• Suitable polymers include polyolefins, particularly thermoplastic elastomers (TPE's) (e.g., VISTAMAXXTM, available from Exxon-Mobil. Chemical Company, Houston, Tex.).
• particulates comprising a TPE may be preferred, as TPE's are generally somewhat tacky, which may assist bonding together of the particulates to form a three-dimensional network before addition of the fibers to form the nonwoven fibrous web.
• particulates comprising a VISTAMAXXTM TPE may offer improved resistance to harsh chemical environments, particularly at low pH (e.g, pH no greater than about 3) and high pH (e.g., pH of at least about 9) and in organic solvents.
• Suitable particulates may have .a variety of physical forms (e.g, solid particulates, porous particulates, hollow bubbles, agglomerates, discontinuous fibers, staple fibers, flakes, and the like); shapes (e.g., spherical, elliptical, polygonal, needle-like, and the like); shape uniformities (e.g. monodisperse, substantially. uniform, non-uniform or irregular; and the like); composition (e,g. inorganic particulates, organic particulates, or combination thereof); and size (e.g., sub-micrometer-sized, micro-sized, and the like).
• physical forms e.g, solid particulates, porous particulates, hollow bubbles, agglomerates, discontinuous fibers, staple fibers, flakes, and the like
• shapes e.g., spherical, elliptical, polygonal, needle-like, and the like
• shape uniformities e.g. monodisperse, substantially
• particulate size in some exemplary embodiments, it may be desirable to control the size of a population of the particulates.
• particulates are physically entrained or trapped in the fiber nonwoven fibrous web.
• the population of particulates is generally selected to have a mean diameter of at least 50 ⁇ m, more generally at least 7.5 ⁇ m, still more generally at least 100 ⁇ m.
• the particulates may be preferred to use finer particulates that are adhesively bonded to the fibers using an adhesive, for example a hot melt adhesive, and/or the application of heat to one or both of thermoplastic particulates or thermoplastic fibers (i.e., thermal bonding).
• an adhesive for example a hot melt adhesive
• the particulates have a mean diameter of at least 25 ⁇ , more generally at least 30 ⁇ m, most generally at least 40 ⁇ m.
• the chemically active particulates have a mean size less than 1 cm in diameter. In other embodiments, the chemically active particulates have a mean size of less than 1 mm, more generally less than 25 micrometers, even more generally less than 10 micrometers.
• the particulates may comprise a population of sub-micrometer-sized particulates having a population mean diameter of less than one micrometer ( ⁇ m) more generally less than about 0.9 ⁇ m, even more generally less than about 0.5 ⁇ m, most generally less than about 0.25 ⁇ m.
• ⁇ m micrometer
• Such sub-micrometer-sized particulates may be particularly useful in applications where high surface area and/or high absorbency and/or adsorbent capacity is desired.
• the population of sub-micrometer-sized particulates has a population mean diameter of at least 0.001 ⁇ m, more generally at least about 0.1 ⁇ m, most generally at least about 0.1 ⁇ m, most generally at least 0.2 ⁇ m.
• the particulates comprise a population of micro-sized particulates having a population mean diameter of at most about 2,000 ⁇ m, more generally at most about 1,000 ⁇ gm, most generally at most about 500 ⁇ m. In other exemplary embodiments, the particulates comprise a population of micro-sized particulates having a population mean diameter of at most about 10 ⁇ m, more generally at most about 5 ⁇ m, even more generally at most about 2 ⁇ m (e.g., ultrafine micro-fibers).
• particulates may also be used within a single finished web. Using multiple types of particulates, it may be possible to generate continuous particulate webs even if one of the particulate types does not bond with other particulates of the same type.
• An example of this type of system would be one where two types are particulates are used, one that bonds the particulates together (e.g., a discontinuous polymeric fiber particulate), and another that acts as an active particulate for the desired purpose of the web (e.g., a sorbent particulate such as activated carbon).
• a sorbent particulate such as activated carbon
• the chemically active particulates may be used relative to the total weight of the fibrous web.
• the chemically active particulates comprise less than 90% wt. of the total nonwoven article weight. In one embodiment, the chemically active particulates comprise at least 10% wt. of the total nonwoven article weight.
• the chemically active particulates may be advantageously distributed throughout the entire thickness of the nonwoven fibrous web. However, in some of the foregoing embodiments, the chemically active particulates are preferentially distributed substantially on a major surface of the nonwoven fibrous web.
• the present disclosure describes a process for making a nonwoven fibrous web, comprising heating a mixture of about 50% w/w to about 99% w/w of a crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w of a hydrocarbon tackifies resin to at least a Melting Temperature of the mixture to form a molten mixture, extruding the molten mixture through at least one orifice to form at least one filament, applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers, and cooling the plurality of discrete discontinuous fibers to a temperature below the Melting Temperature of the molten mixture to form a nonwoven fibrous web, wherein at least one of the crystalline polyolefin (co)polymer or the nonwoven fibrous web exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Jo
• a number of processes may be used to produce a microfiber stream, including, but not limited to, melt-blowing, gas jet fibrillation, or a combination thereof. Suitable processes for forming microfibers are described in U.S. Pat. Nos. 6,315,806 (Torobin), 6,114,017 (Fabbricante et al.), 6,382,526 B1 (Reneker et al.), and 6,861.025 B2 (Erickson et al.).
• a population of microfibers may be formed or converted to staple fibers and combined with a population of sub-micrometer fibers using, for example, using a process as described in U.S. Pat. No. 4,118,531 (Hauser).
• a number of processes may be used advantageously to produce a sub-micrometer fiber stream from the molten (co)polymer mixture, including, but not limited to meIt-blowing, gas jet fibrillation, or a combination thereof.
• Particularly suitable processes include, but are not limited to, processes disclosed in U.S. Pat. Nos.
• Sub-micrometer fibers separately formed using processes other than melt-blowing and/or gas jet fibrillation may also be combined with a population of microfibers and/or sub-micrometer fibers formed by melt-blowing and/or gas jet fibrillation.
• Suitable processes for separately forming sub-micrometer include electrospinning processes, for example, those processes described in U.S. Pat. No. 1,975,504 (Formhals).
• the crystalline polyolefin (co)polymer/hydrocarbon resin tackifier mixture is melted to form a molten mixture, which is then extruded through one or more orifices of a melt-blowing die, applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers.
• the melt-blowing should be performed within a range of temperatures hot enough to enable the crystalline polyolefin (co)polymer/hydrocarbon resin tackifier mixture to be melt-blown but not so hot as to cause unacceptable deterioration of the crystalline polyolefin (co)polymer/hydrocarbon resin tackifier mixture.
• the melt-blowing can be performed at a temperature that causes the molten mixture of the crystalline polyolefin (co)polymer and hydrocarbon resin tackifier to reach a processing temperature at least 40-50° C. above the melting temperature.
• the processing temperature of the molten mixture is selected to be 200° C., 225° C., 250° C., 260° C., 270° C., 280° C., or even at least 290° C.; to less than or equal to about 360° C., 350° C., 340° C., 330° C., 320° C., 310° C., or even 300° C.
• the process further includes at least one of addition of a plurality of staple fibers to the plurality of discrete, discontinuous fibers, or addition of a plurality of particulates to the plurality of discrete, discontinuous fibers, to form a composite nonwoven fibrous web.
• the method of making a composite nonwoven fibrous web comprises combining the microfiber or coarse microfiber population with the fine microfiber population, the ultrafine microfiber population, or the sub-micrometer fiber population by mixing fiber streams, hydroentangling, wet forming, plexifilament formation, or a combination thereof.
• nonwoven composite fibrous webs may be formed exhibiting various desired concentration gradients and/or layered structures.
• the population of fine, ultrafine or sub-micrometer fibers may be combined with the population of microfibers or coarse microfibers to form an inhomogenons mixture of fibers.
• at least a portion of the population of fine, ultrafine, or sub-micrometer fibers is intermixed with at least a portion of the population of microfibers.
• the population of fine, ultrafine or sub-micrometer fibers maybe formed as an overlayer on an underlayer comprising the population of microfibers.
• the population of microfibers may be formed as an overlayer or an underlayer comprising the population of fine, ultrafine or sub-micrometer fibers.
• substantially uniform distribution of particles throughout the web is desired.
• non-uniform distributions may be advantageous.
• a particulate density gradient may advantageously be created within the composite nonwoven fibrous web. For example, gradients through the depth of the web may create changes to the pore size distribution that could be used for depth filtration. Webs with a surface loading of particles could be formed into a filter where the fluid is exposed to the particles early in the flow path and the balance of the web provides a support structure and means to prevent sloughing of the particles. The flow path could also be reversed so the web can act as a pre-filter to remove some contaminants prior to the fluid reaching the active surface of the particles.
• the optional particulates could be added to a nonwoven fiber stream by air laying a fiber web, adding particulates to the fiber web (e.g., by passing the web through a fluidized bed of particulates), optionally with post heating of the particulate-loaded web to bond the particulates to the fibers.
• a pre-formed web could be sprayed with a pre-formed dispersion of particulates in a volatile fluid (e.g. an organic solvent, or even water), optionally with post heating of the particulate-loaded web to remove the volatile fluid and bond the particulates to the fibers.
• a volatile fluid e.g. an organic solvent, or even water
• the process further includes collecting the plurality of discrete, discontinuous fibers as the nonwoven fibrous web on a collector.
• the composite nonwoven fibrous web may be formed by depositing the population of fine, ultrafine or sub-micrometer fibers directly onto a collector surface; or onto an optional support layer on the collector surface, the support layer optionally comprising microfibers, so as to form a population of fine; ultrafine or sub-micrometer fibers on the porous support layer.
• the process may include a step wherein the optional support layer, which optionally may comprise polymeric microfibers, is passed through a fiber stream of fine, ultrafine or sub-micrometer fibers. While passing through the fiber stream, fine, ultrafine or sub-micrometer fibers may be deposited onto the support layer so as to be temporarily or permanently bonded to the support layer. When the fibers are deposited onto the support layer, the fibers may optionally bond to one another, and may further harden While on the support layer.
• the optional support layer which optionally may comprise polymeric microfibers
• the fine, ultrafine or sub-micrometer fiber population is combined with an optional porous support layer that comprises at least a portion of the coarse microfiber population.
• the microfibers forming the porous support layer are compositionally the same as the population of microfibers that forms the first layer.
• the fine, ultrafine or sub-micrometer fiber population is combined with an optional porous support layer and subsequently combined with at least a portion of the coarse microfiber population.
• the porous support layer adjoins the second layer opposite the first layer.
• the porous support layer comprises a nonwoven fabric, a woven fabric, a knitted fabric, a foam layer, a screen, a porous film, a perforated film, an array of filaments; or a combination thereof.
• the porous support layer comprises a thermoplastic mesh.
• the process further includes processing the collected nonwoven fibrous web using a process selected from autogenous bonding (e.g., through-air bonding, calendering, and the like), electret charging, embossing, needle-punching, needle tacking, hydroentangling, or a combination thereof.
• autogenous bonding e.g., through-air bonding, calendering, and the like
• electret charging embossing
• needle-punching needle tacking
• hydroentangling hydroentangling
• some bonding may occur between the fibers themselves (e.g., autogenous bonding) and between the fibers and any optional particulates, before or during collection.
• further bonding between the fibers themselves and between the fibers and any optional particulates in the collected web may be desirable to provide a matrix of desired coherency, making the web more handle-able and better able to hold any sub-micrometer fibers within the matrix (“bonding” fibers, themselves means adhering the fibers together firmly, so they generally do not separate when the web is subjected to normal handling).
• a blend of microfibers and sub-micrometer fibers may be bonded together. Bonding may be achieved, for example, using thermal bonding, adhesive bonding, powdered binder, hydroentangling, needle-punching, calendering, or a combination thereof. Conventional bonding techniques using heat and pressure applied in a point-bonding process or by smooth calender rolls can be used, though such processes may cause undesired deformation of fibers or excessive compaction of the web.
• a presently preferred technique for bonding fibers, particularly microfibers, is the autogenous bonding method disclosed in U.S. Patent Application Publication No. U.S. 200810038976 A1.
• the melt-blown fibers may be advantageously electrostatically charged.
• the melt-blown fibers may be subjected to an electret charging process.
• An exemplary electret charging process is hydro-charging. Hydro-charging of fibers may be carried out using a variety of techniques including impinging, soaking or condensing a polar fluid onto the fiber, followed by drying, so that the fiber becomes charged. Representative patents describing hydro-charging include U.S. Pat. Nos. 5,496,507; 5,908,598; 6,375,886 B1; 6,406,657 B1; 6,454,986 and 6,743,464 B1.
• water is employed as the polar hydro-charging liquid, and the media preferably is exposed to the polar hydro-charging liquid using jets of the liquid or a stream of liquid droplets provided by any suitable spray means.
• Devices useful for hydraulically entangling fibers are generally useful for carrying out hydro-charging, although the operation is carried out at lower pressures in hydro-charging than generally used in hydro-entangling.
• U.S. Pat. No. 5,496,507 describes an exemplary apparatus in which jets of water or a stream of water droplets are impinged upon the fibers in web form at a pressure sufficient to provide the subsequently-dried media with a filtration-enhancing electret charge.
• the pressure necessary to achieve optimum results may vary depending on the type of sprayer used, the type of (co)polymer from which the fiber is formed, the thickness and density of the web, and whether pretreatment such as corona charging was carried out before hydro-charging. Generally, pressures in the range of about 69 kPa to about 3450 kPa are suitable.
• the water used to provide the water droplets is relatively pure. Distilled or deionized water is preferable to tap water.
• the electret fibers may be subjected to other charging techniques in addition to or alternatively to hydro-charging, including electrostatic charging (e.g., as described in U.S. Pat. Nos. 4,215,682, 5,401,446 and 6,119,691), tribo-charging (e.g., as described in U.S. Pat. No. 4,798,850) or plasma fluorination (e.g., as described in U.S. Pat. No. 6,397,458 131).
• electrostatic charging e.g., as described in U.S. Pat. Nos. 4,215,682, 5,401,446 and 6,119,691
• tribo-charging e.g., as described in U.S. Pat. No. 4,798,850
• plasma fluorination e.g., as described in U.S. Pat. No. 6,397,458 131
• Corona charging followed by hydro-charging and plasma fluorination followed by hydro-charging are particularly suitable
• Various processes conventionally used as adjuncts to fiber-forming processes may be used in connection with fibers as they exit from one or more orifices of the belt blowing die. Such processes include spraying of finishes, adhesives or other materials onto the fibers, application of an electrostatic charge to the fibers, application of water mists to the fibers, and the like.
• various materials may be added to a collected web, including bonding agents, adhesives, finishes, and other webs or films.
• extruded fibers or fibers may be subjected to a number of additional processing steps, e.g., further drawing, spraying, and the like.
• Various fluids may also be advantageously applied to the fibers before or during collection, including water sprayed onto the fibers, e.g., heated water or steam to heat the fibers, or cold water to quench the fibers.
• the collected mass may additionally or alternatively be wound into a storage roll for later processing if desired.
• the collected melt-blown nonwoven fibrous web may be conveyed to other apparatus such as a calender, embossing stations, laminators, cutters and the like; or it may be passed through drive rolls and wound into a storage roll.
• a surface treatment or other composition e.g., a fire-retardant composition, an adhesive composition, or a print layer
• Nonwoven fibrous webs can be made using the foregoing processes.
• the nonwoven fibrous web or composite web takes the form of a mat, web, sheet, a scrim, or a combination thereof.
• the nonwoven fibrous web or composite web may advantageously include charged melt-blown fibers, e.g., electret fibers.
• the melt-blown nonwoven fibrous web or web is porous.
• the nonwoven fibrous web or composite web may advantageously be self-supporting.
• the melt-blown nonwoven fibrous web or composite web advantageously may be pleated, e.g., to form a filtration medium, such as a liquid (e.g., water) or gas (e.g., air) filter, a heating, ventilation or air conditioning (HVAC) filter, or a respirator for personal protection.
• a filtration medium such as a liquid (e.g., water) or gas (e.g., air) filter, a heating, ventilation or air conditioning (HVAC) filter, or a respirator for personal protection.
• HVAC heating, ventilation or air conditioning
• Webs of the present disclosure may be used by themselves, e.g., for filtration media, decorative fabric, or a protective or cover stock. Or they may be used in combination with other webs or structures, e.g., as a support for other fibrous layers deposited or laminated onto the web, as in a multilayer filtration media, or a substrate onto which a membrane may be cast. They may be processed after preparation as by passing them through smooth calendering rolls to form a smooth surfaced web, or through shaping apparatus to form them into shapes.
• a nonwoven fibrous web or composite web of the present disclosure can further comprise at least one or a plurality of other types of fibers (not shown) such as, for example, staple or otherwise discontinuous fibers, melt spun continuous fibers or a combination thereof.
• the present exemplary fibrous webs can be formed, for example, into a non-woven web that can be wound about a tube or other core to form a roll, and either stored for subsequent processing or transferred directly to a further processing step. The web may also be cut into individual sheets or mats directly after the web is manufactured, or sometime thereafter.
• the melt-blown nonwoven fibrous webs or composite webs can be used to make any suitable article such as, for example, a thermal insulation article, an acoustic insulation article, a fluid filtration article, a wipe, a surgical drape, a wound dressing, a garment, a respirator, or a combination thereof.
• the thermal or acoustic insulation articles may be used as an insulation component for vehicles. (e.g.,trains, airplanes, automobiles and boats).
• Other articles such as, for example, bedding, shelters, tents, insulation, insulating articles, liquid and gas filters, wipes, garments, garment components, personal protective equipment, respirators, and the like, can also be made using melt nonwoven fibrous webs of the present disclosure.
• nonwoven fibrous webs may be preferred for certain applications, for examples as furnace filters or gas filtration respirators.
• Such nonwoven fibrous webs typically have a density greater than 75 kg/m 3 and typically greater than 100 kg/m 3 or even 120 kg/m 3 .
• open, lofty nonwoven fibrous webs suitable for use in certain fluid filtration applications generally have a maximum density of 60 kg/m 3 .
• the nonwoven fibrous webs exhibit a Basis Weight of from 1 gsm to 400 gsm, more preferably from 1 gsm to 200 gsm, even more preferably from 1 gsm to 100 gsm, or even 1 gsm to about 50 gsm.
• Certain presently-preferred nonwoven fibrous webs according to the present disclosure may have a Solidity less than 50%, 340%, 30%, 20%, or more preferably less than 15%; even more preferably less than10%.
• Solvents and other reagents used may be obtained from Sigma-Aldrich Chemical Company (Milwaukee, Wis.).
• the tensile properties of webs in the Examples were measured by pulling to failure a 1 inch by 6 inch sample (2.5 cm by 15.2 cm). The thickness of the nonwoven fibrous web samples was about 0.15 cm.
• the Tensile Strength. Test was carried out using commercially available tensile test apparatus designated as Instron Model 5544, available from Instron Company (Canton, Mass.). The gauge length was 4 inches (10.2 cm), and the cross-head speed was 308 millimeters/per minute. The. Maximum Tensile Load (in Newtons) was determined in the machine direction of the nonwoven fibrous web.
• the Actual Fiber Diameter was determined using a Scanning Electron Microscope (SEM).
• SEM Scanning Electron Microscope
• the samples were sputter coated with gold in a vacuum chamber (Denton Vacuum, Moorestown, N.J.).
• the specimens were then analyzed using a Phenom Pure SEM (Phenom-World, Eindhoven, Netherlands).
• the AFD is the average (mean) number diameter determined from measurements taken on 500 individual fibers in the nonwoven fibrous web sample using. SEM.
• the Effective Fiber Diameter was determined using an air flow rate of 32 L/min (corresponding to a face velocity of 5.3 cm/sec), using the method set forth in Davies, C. N., “The Separation of Airborne Dust and Particles,” Institution of Mechanical Engineers, London, Proceedings IB. 1952.
• the Actual Fiber Diameter was determined using a Scanning Electron Microscope (SEM). The samples were sputter coated in a vacuum chamber (Denton Vacuum, Moorestown, N.J.). The specimens were then analyzed using a Phenom Pure SEM (Phenom-World, Eindhoven, Netherlands). The AFD is the average (mean) fiber diameter determined from measurement of 500 individual fibers.
• SEM Scanning Electron Microscope
• DSC Differential Scanning Calorimetry
• the DSC analysis was carried out using a Model DSC Q2000 available from Ta Instruments Co. (New Castle, Del.). Approximately 1.5 mg to 10 mg of the crystalline polyolefin, the mixture of the crystalline polyolefin with the hydrocarbon tackifier resin, or the nonwoven fibrous web produced from the mixture, was loaded and sealed in an aluminum pan and placed in the DSC Q2000 apparatus.
• DSC measurements on each sample was carried out using the following sequential Heating-Cooling-Heating cycle.
• Each sample was initially heated from ⁇ 20° C. to 250° C. (or at least 30° C. above the Melting Temperature of the sample) at a rate of 10° C./minute.
• Each sample was then held for 1 minute at 250° C., and then subsequently cooled down to ⁇ 20° C. (or at least 50° C. below the crystallization temperature of the sample) at a rate of 20° C./min.
• Each sample was then held for 1 minute at ⁇ 20° C. and then subsequently heated from ⁇ 20° C. to 200° C. at 10° C./min.
• the temperature corresponding to the highest-temperature endothermic peak was reported as the Melting Temperature (° C.), and the area tinder the same highest-temperature endothermic peak was reported as the Heat of Fusion.
• a melt-blown (blown microfiber, BMF) nonwoven fibrous web was made using a crystalline polypropylene (crystalline polyolefin (co)polymer) resin having a 1200 melt flow rate (MFR), commercially available as METOCENETM MF650X from Lyondell-Basell (Houston, Tex.X).
• MFR melt flow rate
• METOCENETM MF650X commercially available as METOCENETM MF650X from Lyondell-Basell (Houston, Tex.X).
• a conventional melt-blowing process was employed, similar to that described, for example, in Wente, Van A., “Superfine Thermoplastic Fibers” in Industrial Engineering Chemistry, Vol.48, pages 1342 et seq. (1956) or in Report No.4364 of the Naval Research Laboratories, published May 25, 1954, entitled “Manufacture of Superfine Organic Fibers” by Wente, Van A.; Boone, C. D.; and Fluharty, E. L.
• the melt-blowing die had circular smooth surfaced orifices, spaced 10 to the centimeter, with a 5:1 Length to diameter ratio.
• Molten (c)polymer was delivered to the die by a 20 mm twin screw extruder commercially available from Steer of Uniontown, Ohio. This extruder was equipped with two weight loss feeders to control the feeding of the (co)polymer resins to the extruder barrel, and a gear pump to control the (co)polymer melt flow to a die.
• the extruder temperature was at about 250° C. and it delivered the melt stream to the BMF die, which itself maintained at 250° C.
• the gear pump was adjusted so that a 0.268 kg/hr/cm die (1.5 lb/hr/inch die width) (co)polymer throughput rate was maintained at the die.
• the primary air temperature of the air knives adjacent to the die orifices was maintained at approximately 325° C.
• a BMF web was prepared generally as described in Comparative Example C-1, except that the polymer was a blend at a (95/5) ratio of METOCENETM MF650X and a hydrocarbon tackifier resin commercially available as OPPERATM PR100A from Exxon Mobil Corp. of Irving, Tex.
• the web thus produced had b. Basis Weight of approximately 55 g/m 2 , and a Solidity of approximately 4.37%. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 1, except that the extruder temperature was about 275°C., the BMF die was maintained at approximately 275° C. and the primary air temperature was at approximately 375° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described iii Example 1, except that the extruder temperature was about 285° C., the BMF die was maintained at approximately 285° C. and the primary air temperature was at approximately 375° C. No fly was visually observed with the un-aided human eyp under illumination with fluorescent lighting at a distance olabout 30cm.
• a BMF web was made as described in Example 3, except that the web was made using a blend of METOCENETM MF650X and OPPERATM PR100A at a (90/10) ratio. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 4, except web was collected at2 BMF die to collector distance of 35.6 cm. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting ata distance of about 34 cm.
• a BMF web was made as described in Example 5, except that the web was made using a blend of METOCENETM MF650X and OPPERATM PR100A ata (85/15) ratio. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 5, except that the extruder temperature was about 295° C., the. BMF die was maintained at approximately 295° C. and the primary air temperature was at approximately 400° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 6, except that the extruder temperature was about 295° C., the BMF die was maintained at approximately 295° C. and the primary air temperature was at approximately 400° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Comparative Example C-1, except for the following details.
• the polymer used was a polypropylene resin commercially available as METOCENETM MF650Y from Lyondell-Basell (Houston. Tex.).
• the extruder temperature was approximately 255° C. and it delivered the METOCENETM MF650X melt stream to the BMF die maintained at 255° C.
• the primary air temperature was maintained at approximately 335° C.
• the die to collector distance was about 17 inches (43.18 cm).
• a BMF web was generally as described in Comparative Example C-2, except for the following details.
• the polymer was a blend at a (95/5) ratio of METOCENETM MF650Y and a hydrocarbon tackifier resin commercially available as OPPERATM PR100A from Exxon Mobil Corp. of Irving, Tex.
• the extruder temperature was approximately 260° C. and it delivered the blend melt stream to the BMF die maintained at 260° C.
• the primary air temperature was maintained at approximately 335° C.
• the resulting web had a Basis Weight of approximately 55 g/m 2 . No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example. 9, except that the blend ratio of METOCENETM MF650Y to OPPERATM PR100A was (90/10). No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting ata distance of about 30 cm.
• a BMF web was made as described in Example 10, except the extruder temperature was at about 270° C. and it delivered the blend melt stream to the BMF die maintained at 270° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 11, except that the blend ratio of METOCENETM MF650Y to OPPERATM PR100A was (85/15). No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made generally as described in Example 9, except for the following details.
• the blend ratio of METOCENETM MF650Y to OPPERATM PR100A was (90/10).
• the extruder temperature was at approximately 270° C. and it delivered the blend melt stream to the BMF ‘die maintained at 270° C.
• The.gearpurnp was adjusted so that a 0.536 kg/hr/em die width (3.0 lb/hr/inch die width) polymer throughput rate was maintained at the BMF die.
• the primary air temperature was maintained at approximately 335° C.
• the resulting web had a Basis Weight of approximately 55 g/m 2 . No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 13, except that the blend ratio of METOCENETM MF650Y to OPPERATM PR100A was (85/15). No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made generally as described in Example 10, except for the following details.
• the METOCENETM MF650Y resin was blended with a cycloaliphatic hydrocarbon tackifier resin commercially available as ESCOREZTM 5400 from Exxon Mobil Corp., at blend ratio of (90/10).
• the extruder temperature was at approximately 250° C. and it delivered the blend melt stream to the.
• BMF die maintained at 250° C.
• the gear pump was adjusted so that a. 0.268 kg/fir/cm die (1.5 lb/hr/inch die width) polymer throughput rate was maintained at the BMF die.
• the primary air temperature was maintained at approximately 335° C.
• a BMF web was made generally as described in Example 15, except for the following details.
• the ESCOREZTM 5400 was replaced by ESCOREZTM 5415, commercially available from Exxon Mobil Corp. (Houston, Tex.).
• the resulting web had a Basis Weight of approximately 60 g/m 2 . No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made generally as described in Example 15, except for the following details.
• the ESCOREZTM 5400 was replaced by a hydrocarbon tackifier resin commercially available as ARKONTM P-100 from Arakawa Chemical of Osaka, JP.
• the resulting web had a Basis Weight of approximately 61 g/m 2 . No fly was visually observed with the un-aided human eye under illumination with fluorescent Hating at a distance of about 30 cm.
• a composite web was made using an apparatus generally as disclosed in FIG. 2 of U.S. Pat. No. 7,989,371. Blown microfibers were included in the composite web using a blend of PP 650Y and OPPERATM PR100A at a (90/10) ratio. These fibers had an EFD of approximately 4.7. Crimped 6 denier polyethylene terephthalate staple fibers, commercially available from Invista of Wichita, Ks., were also included in the composite web, with the ratio of blown microfibers to staple fibers being approximately 65 to 35. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made generally according to Comparative Example C-1, except for the following details.
• the polymer used was a polypropylene resin commercially available as TOTAL Polypropylene 3860X from TOTAL, Houston, Tex.
• the extruder temperature was set at about 310° C. and it delivered the melt stream to the BMP die maintained at 310° C.
• the gear pump was adjusted so that a 0.268 kg/hr/cm die (1.5 lb/hr/inch die width) polymer throughput rate was maintained at the BMF die.
• the primary air temperature was maintained at approximately 400° C.
• the resulting web was collected at a BMF die to collector distance of 19 inches (48.3 cm) and had a Basis Weight of approximately 54 g/m 2 .
• the web had a Solidity of approximately 6.97%.
• Significant fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made, generally according to Comparative Example C-3, except for the following details.
• the extruder was charged with using a blend of polypropylene and polymethyl pentene polymer where the polymethyl pentene used had a melt flow rate of 180, commercially available as TPX DX820 from Mitsui Chemicals of. Tokyo, JP, PP3860 and TPX DX820 were blended at a (95/5) ratio.
• the resulting web had a Basis Weight of approximately 53 g/m 2 .
• the web had a Solidity of approximately 6.90%. No fly was visually observed with the un-aided human eye under illumina.tion with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 19, except that the PP3860/TPX DX820 blend ratio was (90/10) and the extruder and die temperatures were maintained at 315° C.
• the resulting web had a Basis Weight of approximately 56 g/m 2 .
• the web had a Solidity of approximately 7.21%. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 20, except that Oppera PR100A was added to the polymer blend at the ratio PP3860/TPX DX820/OPPERATM PR100A (90/5/5).
• the resulting web had a Basis Weight of approximately 54 g/m 2 .
• the web had a Solidity of approximately 9.93%. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 9, except for the following details.
• the BMF die used in the example consists of small orifice size ranging from 150 um and high orifice density of 10 hole/cm (25 hole/inch).
• the molten polymer was delivered to the die by a 12.7 mm single screw.
• the extrusion rate was maintained at 0.09 kg/hr/cm (0.5 lb/hr/inch die width).
• the extruder temperature was approximately 260° C. and it delivered the METOCENETM MF650Y melt stream to the BMF die maintained at 270° C.
• the primary air temperature was maintained at approximately 240° C. Significant fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Comparative Example C-4, except that METOCENETM MF 650Y was blended with OPPERATM PR100A.
• the blend ratio of METOCENETM MF650Y to OPPERATM PR100A was (95%/5% w/w). No fly was visually observed with the unaided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 22, except that the extrusion temperature was about 280° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in. Example 22, except that the blend ratio of METOCENETM MF650Y to OPPERATM PR100A was (90/10 w/w) and the extrusion temperature was 295° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting at a distance of about 30 cm.
• a BMF web was made as described in Example 22, except that the blend ratio'of METOCENETM MF650Y to OPPERATM PR100A was (85/15 w/w) and the extrusion temperature was 315° C. No fly was visually observed with the un-aided human eye under illumination with fluorescent lighting ata distance of about 30 cm.
• DSC Differential Scanning Calorimetry

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• 2018
  • 2018-07-30 CN CN201880048644.4A patent/CN110945165A/zh active Pending
  • 2018-07-30 US US16/621,292 patent/US20200115833A1/en not_active Abandoned
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