Coating processes – Direct application of electrical – magnetic – wave – or... – Electrostatic charge – field – or force utilized
Reexamination Certificate
1996-06-10
2001-09-25
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Electrostatic charge, field, or force utilized
C427S213000, C427S213320, C427S224000, C427S353000, C427S357000, C427S359000, C427S372200, C427S385500, C427S460000, C427S461000, C427S470000, C427S482000, C427S485000, C427S508000, C427S513000
Reexamination Certificate
active
06294222
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to composite nonwoven materials and a method to make the same. More particularly, the present invention relates to sheet or web materials that incorporate particulate materials and a method to make the same.
BACKGROUND OF THE INVENTION
Sheet and/or web materials are widely used in many types of products such as, for example, personal care products, garments, medical fabrics and the like. Some sheets or webs made from certain inexpensive raw materials could have an even wider range of applications in these products if the sheets or webs could be designed to have enhanced properties or attributes.
For example, polyolefins are widely used in the manufacture of sheet or web materials. Polyolefin sheets or webs tend to be hydrophobic and relatively inert. In the past, topical or internal additives have been used with polyolefin fibers to impart desired functional characteristics to fibrous webs. For example, liquid coatings have been applied to sheets and/or webs. These coatings and internal additives have limits to the types of functional characteristics that can be economically imparted to sheets or webs.
Particulates (e.g., finely divided solid materials and/or short fibers) may be physically mixed with fibrous material to impart some desired characteristics to sheets or webs. The finely divided solids tend to form “clumps” within the “carrier” material (e.g., the sheet or web). It can be difficult to bond or otherwise securely fix finely divided solids in the unevenly distributed clumps to the carrier material. The clumps are often held in place by physical entrapment or entanglement and may disintegrate or release much solid materials if sufficiently disturbed. Bonding with heat or adhesives tends to fix only the clumps and may also fail to secure finely divided solids within the clumps.
Some materials such as, for example, some sandpapers and/or some flocked materials can be manufactured by grossly attaching particulates to a charged substrate. These materials can be characterized by a relatively thick layer of particulates joined to an adhesive which covers the exterior of a substrate. Such materials and processes are not directed to securing a relatively uniform distribution of particulates (e.g., finely divided solid materials and/or short fibers) to individual exposed surfaces (e.g., individual fiber surfaces) of relatively permeable sheets and/or webs.
Thus, there is a need for a practical process for securing a relatively uniform distribution of particulates (e.g., finely divided solid materials and/or short fibers) to individual exposed surfaces of sheets and/or webs (e.g., relatively permeable materials) by substantially non-transient bonding. There is also a need for a practical continuous process suitable for high-speed manufacturing processes that secures a relatively uniform distribution of particulates (e.g., finely divided solid materials and/or short fibers) to individual exposed surfaces of sheets and/or webs (e.g., relatively permeable materials) by substantially non-transient bonding.
Furthermore, there is a need for fibrous composite structure composed of a matrix of fibrous material having individual exposed surfaces substantially throughout the matrix and a relatively uniform distribution of particulate material attached to at least a portion of the individual exposed surfaces of the fibrous material by substantially non-transient bonding. There is also a need for a film-like composite structure composed of a apertured film-like material having individual exposed surfaces and a relatively uniform distribution of particulate material attached to at least a portion of the individual exposed surfaces of the apertures film-like material by substantially non-transient bonding.
DEFINITIONS
As used herein, the term “nonwoven web” refers to a web that has a structure of individual fibers or filaments which are interlaid, but not in an identifiable repeating manner. Nonwoven webs have been, in the past, formed by a variety of processes known to those skilled in the art such as, for example, meltblowing, spunbonding and bonded carded web processes.
As used herein, the term “spunbond web” refers to a web of small diameter fibers and/or filaments which are formed by extruding a molten thermoplastic material as filaments from a plurality of fine, usually circular, capillaries in a spinnerette with the diameter of the extruded filaments then being rapidly reduced, for example, by non-eductive or eductive fluid-drawing or other well known spunbonding mechanisms. The production of spunbonded nonwoven webs is illustrated in patents such as Appel, et al., U.S. Pat. No. 4,340,563; Dorschner et al., U.S. Pat. No. 3,692,618; Kinney, U.S. Pat. Nos. 3,338,992 and 3,341,394; Levy, U.S. Pat. No. 3,276,944; Peterson, U.S. Pat. No. 3,502,538; Hartman, U.S. Pat. No. 3,502,763; Dobo et al., U.S. Pat. No. 3,542,615; and Harmon, Canadian Patent No. 803,714.
As used herein, the term “meltblown fibers” means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into a high-velocity gas (e.g. air) stream which attenuates the filaments of molten thermoplastic material to reduce their diameters, which may be to microfiber diameter.
Thereafter, the meltblown fibers are carried by the high-velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed meltblown fibers. The meltblown process is well-known and is described in various patents and publications, including NRL Report 4364, “Manufacture of Super-Fine Organic Fibers” by V. A. Wendt, E. L. Boone, and C. D. Fluharty; NRL Report 5265, “An Improved Device for the Formation of Super-Fine Thermoplastic Fibers” by K. D. Lawrence, R. T. Lukas, and J. A. Young; and U.S. Pat. No. 3,849,241, issued Nov. 19, 1974, to Buntin, et al.
As used herein, the term “microfiberts” means small diameter fibers having an average diameter not greater than about 100 microns (&mgr;m), for example, having a diameter of from about 0.5 microns to about 50 microns, more specifically microfibers may also have an average diameter of from about 1 micron to about 20 microns. Microfibers having an average diameter of about 3 microns or less are commonly referred to as ultra-fine microfibers. A description of an exemplary process of making ultra-fine microfiberts may be found in, for example, U.S. Pat. Nos. 5,213,881 and 5,271,883, entitled “A Nonwoven Web With Improved Barrier Properties”, incorporated herein by reference in their entirety.
As used herein, the term “thermoplastic material” refers to a high polymer that softens when exposed to heat and returns to its original condition when cooled to room temperature. Natural substances which exhibit this behavior are crude rubber and a number of waxes. Other exemplary thermoplastic materials include, without limitation, polyvinyl chloride, polyesters, nylons, polyfluorocarbons, polyethylene, polyurethane, polystyrene, polypropylene, polyvinyl alcohol, caprolactams, and cellulosic and acrylic resins.
As used herein, the term “apertured film-like material” refers to a generally flat or planar layer of material which has been punched, drilled, apertured, stretched, perforated, embossed, patterned, crinkled or processed so that it has relatively gross or visible openings and in some cases a pattern or texture in the thickness dimension (i.e., Z-direction) of the material. Exemplary apertured film-like materials include, but are not limited to, perf-embossed films, textured apertured films, reticulated apertured films, contoured apertured films, film-nonwoven apertured laminates, and expanded plexi-filamentary films.
As used herein, the term “electrically charged sites at individual exposed surfaces” refers to locations of electrostatic charge on or beneath the surface of a dielectric material due to electret formation or by constant application of an electric field to the surface of a non-dielectric material.
As used herein, the term “sint
Cohen Bernard
Faass Judith Katherine
Gipson Lamar Heath
Jameson Lee Kirby
Kimberly--Clark Worldwide, Inc.
Pianalto Bernard
Sidor Karl V.
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