U.S. patent application number 09/894731 was filed with the patent office on 2002-09-05 for fibers having low and high coefficients of friction surfaces.
Invention is credited to Gunn, Robert T..
Application Number | 20020122940 09/894731 |
Document ID | / |
Family ID | 25403457 |
Filed Date | 2002-09-05 |
United States Patent
Application |
20020122940 |
Kind Code |
A1 |
Gunn, Robert T. |
September 5, 2002 |
Fibers having low and high coefficients of friction surfaces
Abstract
The present invention relates to fibers having both relatively
low and relatively high coefficient of friction characteristics.
The fibers of the present invention are useful for toothbrush
bristles and dental floss.
Inventors: |
Gunn, Robert T.; (New York,
NY) |
Correspondence
Address: |
Samuel H. Megerditchian
FROMMER LAWRENCE & HAUG LLP
745 Fifth Avenue
New York
NY
10151
US
|
Family ID: |
25403457 |
Appl. No.: |
09/894731 |
Filed: |
June 28, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09894731 |
Jun 28, 2001 |
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09661235 |
Sep 13, 2000 |
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09661235 |
Sep 13, 2000 |
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09021325 |
Feb 10, 1998 |
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6143368 |
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Current U.S.
Class: |
428/397 ;
264/147; 264/172.14; 428/364 |
Current CPC
Class: |
D01F 8/04 20130101; A46D
1/00 20130101; D01D 5/426 20130101; Y10T 428/2913 20150115; A61C
15/041 20130101; Y10T 428/2973 20150115 |
Class at
Publication: |
428/397 ;
264/147; 264/172.14; 428/364 |
International
Class: |
D01D 005/32; D01D
005/42 |
Claims
What is claimed is:
1. A fiber comprising a relatively low coefficient of friction
portion and a relatively high coefficient of friction portion,
wherein the relatively low coefficient of friction portion is
adjacent to the relatively high coefficient of friction portion
2. A fiber comprising a relatively low coefficient of friction
portion and a relatively high coefficient of friction portion,
wherein when the fiber is viewed in cross-section, the relatively
low coefficient of friction portion is about 50% of the total
cross-section of the fiber, and wherein the relatively low
coefficient of friction portion is adjacent to the relatively high
coefficient of friction portion.
3. A dental floss comprising a continuous relatively high
coefficient of friction area spaced between two continuous
relatively low coefficient of friction areas.
4. A dental floss comprising a plurality of filaments, wherein each
filament comprises a relatively low coefficient of friction portion
and a relatively high coefficient of friction portion.
5. A dental floss comprising a plurality of filaments, wherein each
filament comprises a relatively low coefficient of friction portion
and a relatively high coefficient of friction portion, and wherein
the total low coefficient of friction portion of the plurality of
filaments is about 50% of the cross sectional area of the
floss.
6. A dental floss comprising first and second filaments, wherein
the first filament has a relatively high coefficient of friction
and the second filament has a relatively low coefficient of
friction, wherein the first and second filaments are each about 50%
of the total volume of the dental floss, and wherein the first and
second filaments are substantially evenly dispersed throughout the
dental floss.
7. A dental floss comprising an inner core surrounded by an outer
core, wherein the inner core comprises filaments having a
relatively high coefficient of friction, and wherein the outer core
comprises filaments having a relatively low coefficient of
friction.
8. A method of producing a fiber, comprising the steps of: forming
a sheet of material through coextrusion, said coextruded sheet
having at least a first outer layer, a second outer layer, and a
center layer; wherein said center layer is made up of a material
having a higher coefficient of friction than the material making up
at least one of said outer layers; and orienting and slitting the
coextruded sheet to form fibers, such that the top surface of said
fibers are made-up of the same material as said first outer layer,
the bottom surface of said fibers are made up of the same material
as said second outer layer, and the side surfaces of said fibers
are made up of the same material as said center layer.
Description
RELATED APPLICATIONS
[0001] This is a continuation-in-part of application Ser. No.
09/661,235, filed on Sep. 13, 2000, which, in turn, is a divisional
of application Ser. No. 09/021,325, filed on Feb. 10, 1998, both of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to fibers having both a relatively
low coefficient of friction surface and a relatively high
coefficient of friction surface and methods for producing such
fibers. The fibers may be used as dental floss and may be
incorporated into articles such as tooth brushes, floss picks and
apparel.
BACKGROUND OF THE INVENTION
[0003] A major health concern involves gum disease and the
resulting decay or loss of teeth. Gum disease, normally referred to
as gingivitis, is caused by bacterial action from the formation of
plaque about the teeth and/or the entrapment of food particles in
the spaces between and under the teeth. Removal of plaque and
entrapped food particles reduces the risk of gingivitis, and
improves oral hygiene as well. Brushing and flossing are the two
ways that plaque and entrapped food can be removed from the teeth
and gums.
[0004] Tooth brushes and dental floss are made from fibers. Fibers
are typically structures whose length is significantly greater than
any of their other dimensions, usually their length is at least 100
times as large as their diameter. Fibers may be natural, synthetic,
organic or inorganic. Often, the bulk polymers from which synthetic
fibers are formed, may be useful as plastics or films depending
upon the type and degree of molecular orientation, and the relative
dimensions of the finished structure.
[0005] Dental floss is conventionally made from sinuous strands of
filaments that are bulked together. The filaments are generally of
the same type and can contain additives, such as flavorings, or
compounds that make it easier for the floss to be inserted between
the teeth.
[0006] Dental floss is available in either a waxed or unwaxed
variety. Waxed dental floss is generally comprised of multifilament
yarns coated with a white or colorless wax usually having a melting
point of from about 140 to 200.degree. F. It is believed by some
that flossing with a waxed floss may leave residues of wax on the
teeth which may be harmful, whereas others merely do not like the
waxy sensation in their mouths. Unwaxed dental floss is generally
composed of multifilament yams twisted together and coated with a
non-wax bonding material. While satisfactory for many users, such
floss presents problems for some who find it difficult to insert
the floss in tight spaces between the teeth. This is due in part to
the inability of the various filaments to easily slide over one
another as the floss is forced between contacting teeth as well as
in part due to the absence of wax. The sliding of the filaments
over the tooth surface and over one another is inhibited by the
nature of the materials from which commercially available floss
products are made. These include a plurality of individual
filaments made from substances such as nylon 6, nylon-6, 6-rayon,
polyester, acetate polymers, polypropylene and similar plied
multifilament yams, as well as cotton, wool and other staple
yams.
[0007] With respect to the fibers claimed and disclosed in the
present invention, reference is made to U.S. Pat. No. 5,904,152.
This patent relates to dental flosses, including multicomponent
coextruded filaments and/or filaments having a multilobal
cross-section. The flosses are capable of bulking.
[0008] Further, U.S. Pat. No. 5,518,012 relates to expanded PTFE
dental floss. The floss contains a fiber of increased thickness so
that the floss is maintained in an unfolded orientation.
[0009] U.S. Pat. No. 5,209,251 relates to dental floss produced
from expanded PTFE and coated with a microcrystalline wax to
increase the friction coefficient of the floss.
[0010] U.S. Pat. No. 5,033,488 relates to porous, expanded PTFE
coated with microcrystalline wax. The floss may also contain one or
more actives and/or dentally acceptable agents.
[0011] The flosses discussed in these references contain a base
fiber coated with a wax for ease of insertion between the teeth and
gums. Such low frictional wax flosses, however, do not incorporate
a relatively higher coefficient of friction portion that imparts to
the floss an abrasive characteristic for, for example, dislodging
and removing food particles.
[0012] Fibers are usually produced by drawing, spinning or
stretching a bulk material so that the molecules are predominantly
aligned in the drawn, spun, or stretched direction. Subsequent
drawing of the fiber below its melt temperature significantly
alters the fiber's mechanical properties.
[0013] Fibers may also be produced by slitting an oriented film or
sheet. If prepared from oriented sheet, the slit sheet will require
subsequent drawing to obtain the required fiber properties.
[0014] Most synthetic fibers may be produced as long continuous
filament or as staple. Staple is produced by cutting continuous
filament into short lengths. Most natural fibers are produced as
staple, with silk being a notable exception.
[0015] Continuous filament and staple are often post treated to
alter their surface characteristics. Such surface treatments may
include scouring by surface active agents to remove surface
impurities, sizing by a surface coating to protect the fiber during
weaving, dyeing to modify the color of the fiber and lubricating by
refined petroleum products to reduce static and the coefficient of
friction.
[0016] It is apparent in the prior art that coating a staple or
filament will usually provide a fiber having a surface completely
covered by the coating. In cases where a low coefficient of
friction is desired, this may sometimes be undesirable. For
applications in which a low coefficient of friction might be needed
on the top and/or bottom surface of a fiber, uniformly low friction
fibers and uniformly coated fibers might not provide the optimum
balance of properties for application in dental floss and tooth
brushes.
[0017] Furthermore, uniformly low friction fibers or uniformly
coated fibers may not provide desired properties for use in
apparel. Most apparel is made out of many materials, natural and
man-made. They include cotton, wool, silk, linen, leather, vinyl,
nylon--polyamides and polyamide co-polymers, LYCRA SPANDEX in
different filament configurations, orlon polyvinylidene fluoride,
such as KYNAR and polyester, for example, polyethylene
terepthalate, glycol modified polyesters, such as PETG, KODURA,
rayon, orlon cellulosic fiber blends, and the like, as well as
blends of the above.
[0018] Of course, apparel, either directly or indirectly, contacts
the body surface of the wearer. The movement of the wearer causes
frictional contact between the wearer's body surface and the
apparel. This frictional contact can cause irritation, blisters,
and callouses and is particularly a problem in sporting apparel
wherein the formation of irritations, blisters, and callouses is
exacerbated by the rapid and/or repetitious body movements related
to the particular activity. Additionally, it is noted that most
apparel has specific areas of high body surface/apparel contact
which produces a majority of the irritations, blisters, and
callouses.
[0019] One way to overcome the problems caused by frictional
contact between an article of clothing and the wearer is to make
the clothing from low friction fabric. Such fabric may be made from
fibers that have a low friction outer surface. However, when the
low friction fibers are woven together to produce a fabric the low
fiber-to-fiber coefficient of friction is likely to decrease fabric
stability by enabling the fibers to easily slide among themselves.
This problem is recognized in U.S. Pat. No. 5,035,111 to Hogenboom
et al. Hogenboom attempts to overcome the problem by spinning yams
or fibers having a low coefficient of friction with yarns or fibers
having a high coefficient of friction. However, Hogenboom does not
disclose modifying the fibers themselves. Moreover, Hogenboom's
fibers are not made through coextrusion, lamination, and/or coating
of a film, sheet or fiber, whereby only a portion of the fiber
surface exhibits a low coefficient of friction.
OBJECTS AND SUMMARY OF THE INVENTION
[0020] It is an object of the present invention to provide a fiber
having both relatively low and relatively high coefficient of
friction areas.
[0021] It is a further object of the present invention to provide a
dental floss with a relatively low coefficient of friction area and
a relatively high coefficient of friction area that imparts the
dental floss with the ability to easily get between teeth yet
effectively clean away plaque and tartar.
[0022] It is still another object of the present invention to
provide a fiber comprising a relatively low coefficient of friction
portion and a relatively high coefficient of friction portion,
wherein the relatively low coefficient of friction portion is
adjacent to the relatively high coefficient of friction
portion.
[0023] It is another object of the present invention to provide a
fiber comprising a relatively low coefficient of friction portion
and a relatively high coefficient of friction portion, such that
when the fiber is viewed in cross-section, the relatively low
coefficient of friction portion makes up about 50% of the total
cross-sectional area and the relatively low coefficient of friction
portion is adjacent to the relatively high coefficient of friction
portion.
[0024] It is another object of the present invention to provide a
dental floss comprising a continuous relatively high coefficient of
friction portion spaced between two continuous relatively low
coefficient of friction portions, such that each continuous portion
traces a path along the length of the fiber.
[0025] It is another object of the present invention to provide a
dental pick comprising a continuous relatively high coefficient of
friction portion spaced between two continuous relatively low
coefficient of friction portions, such that each continuous portion
traces a path along the length of the pick.
[0026] It is yet another object of the present invention to provide
a dental floss comprising a plurality of filaments, wherein each
filament comprises a relatively low coefficient of friction portion
and a relatively high coefficient of friction portion.
[0027] It is still another object of the present invention to
provide a dental floss comprising a plurality of filaments, wherein
each filament comprises a relatively low coefficient of friction
portion and a relatively high coefficient of friction portion, and
wherein the total low coefficient of friction portion of the
plurality of filaments makes up about 50% of the cross sectional
area of the floss.
[0028] It is yet another object of the present invention to provide
a dental floss comprising first and second filaments, wherein the
first filament has a relatively high coefficient of friction and
the second filament has a relatively low coefficient of friction,
wherein the first and second filaments are each 50% of the total
volume of the dental floss, and wherein the first and second
filaments are substantially evenly dispersed throughout the dental
floss.
[0029] Yet another object of the present invention is to provide a
dental floss comprising an inner core surrounded by an outer core,
wherein the inner core comprises filaments having a relatively high
coefficient of friction, and wherein the outer core comprises
filaments having a relatively low coefficient of friction.
[0030] It is still another object of the present invention to
provide a method of producing fibers having low coefficient of
friction surfaces or smooth surfaces for incorporating into fabrics
while retaining the properties desirable for weaving the fiber into
a fabric.
[0031] Specifically, it is an object of the present invention to
provide a fiber having low coefficient of friction surfaces that
retains the fabric stability after being woven into a fabric.
[0032] More specifically, it is an object of the present invention
to produce through coextrusion, lamination, and/or coating a fiber
having at least one low coefficient of friction surface and one
relatively high coefficient of friction surface.
[0033] It is still another object of the present invention to
provide a durable high tensile-strength fiber having at least one
low coefficient of friction surface and being suitable for use in
weaving a fabric having at least one low coefficient of friction
surface.
[0034] An aspect of this invention is to provide fibers prepared
from oriented film or sheet. The film/sheet is formed through
coextrusion, lamination, and/or coating such that the top and/or
bottom surfaces have a different coefficient of friction than the
center or internal layer(s) of material. Such fibers may be twisted
in preferred sequences and/or orientations such that the center
layer(s), having a higher coefficient of friction, interact with
other members of the fabric construction to provide increased woven
fabric construction stability. This stability is realized by having
the higher coefficient of friction surfaces of the coextruded,
laminated, and/or coated fiber contact additional surfaces of the
gross fabric structure.
[0035] Another aspect of this invention is to partially coat a
"base fiber" with a low coefficient of friction material such that
the coated surface of the base fiber has a lower coefficient of
friction than the non-coated surface. Like the fibers prepared from
film or sheet, the partially coated fibers may be twisted in
preferred sequences and/or orientations such that the non-coated
surfaces, having a higher coefficient of friction than the coated
surfaces, interact with other members of the fabric construction to
provide increased woven fabric construction stability.
[0036] Still another aspect of this invention is to provide
coextruded, laminated, and/or coated fibers in which the core
layer/base fiber has shock absorbing characteristics (e.g., core
layer(s) are open or closed celled foams). Such fibers provide
increased cushioning values in addition to a low coefficient of
friction on their treated surfaces.
[0037] Yet another aspect of this invention is to provide fibers in
which the core layer/base fiber provides desirable thermal
characteristics. For example, the core layer/base fiber may include
an insulating material for restricting the escape of heat energy,
or a radiant material for facilitating the escape of heat
energy.
[0038] It is apparent that the fibers of the present invention may
be used to create fabrics having enhanced woven fabric stability,
shock absorption capacity and/or thermal properties. Thus the
present invention provides for a decrease in intra- and
extra-fabric coefficient of friction, while at the same time
increasing fabric stability and enhancing thermal
characteristics.
[0039] By using low coefficient of friction materials during either
the coextrusion, lamination, and/or coating processes, a novel
fiber is produced, with at least a portion of the surface of the
novel fiber exhibiting low coefficient of friction characteristics
and the remaining surface portion of the fiber exhibiting
relatively higher coefficient of friction characteristics.
[0040] The novel fiber can be incorporated into a fabric to produce
a fabric having a smooth surface, and the smooth surface fabric
can, in turn, be incorporated into clothing to produce clothing
having a smooth surface.
[0041] Other objects, features and advantages according to the
present invention will become apparent from the following detailed
description of the illustrated embodiments when read in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a cross sectional view of a fiber having low
coefficient of friction surfaces according to the present
invention; wherein the coefficient of friction of the top surface
is the same as the coefficient of friction of the bottom surface,
and both the top and bottom surfaces have a coefficient of friction
that is lower than the coefficient of friction of the center
layer/side surface.
[0043] FIG. 2 is a cross sectional view of a fiber having low
coefficient of friction surfaces according to the present
invention; wherein the coefficient of friction of the top surface
is different from the coefficient of friction of the bottom
surface, and either one of, or both of, the top and bottom surfaces
has a coefficient of friction that is lower than the coefficient of
friction of the center layer/side surfaces.
[0044] FIG. 3 is a cross sectional view of a fiber having low
coefficient of friction surfaces and an expanded center layer
according to the present invention; wherein the coefficient of
friction of the top surface is different from the coefficient of
friction of the bottom surface, and either one of, or both of, the
top and bottom surfaces has a coefficient of friction that is lower
than the coefficient of friction of the center layer/side
surfaces.
[0045] FIG. 4 is an isometric view of a base fiber that is
partially coated with a low coefficient of friction material
according to the present invention.
[0046] FIG. 5 is a cross sectional view of a tooth brush bristle
having relatively low and relatively high coefficient of friction
surfaces according to the present invention.
[0047] FIG. 6 is a monofilament dental floss having relatively low
and relatively high coefficient of friction surfaces according to
the present invention.
[0048] FIG. 7 is a multifilament dental floss having a plurality of
filaments wherein each of the filaments have both relatively low
and relatively high coefficient of friction surfaces according to
the present invention.
[0049] FIG. 8 is a multifilament dental floss having a plurality of
filaments wherein about 50% of the filaments have a relatively low
coefficient of friction and about 50% of the filaments have a
relatively high coefficient of friction according to the present
invention.
[0050] FIG. 9 is a multifilament dental floss having an inner core
of predominantly relatively high coefficient of friction filaments
surrounded by an outer layer of predominantly relatively low
coefficient of friction filaments according to the present
invention.
[0051] FIG. 10 is a floss pick having both a low coefficient of
friction portion and a relatively high coefficient of friction
portion according to the present invention.
DETAILED DESCRIPTION
[0052] The fibers of the present invention may be used to provide
improved dental flosses and toothbrush bristles. One of the
advantages of such improved flosses and bristles is that they are
more effective at cleaning plaque from the teeth. Other advantages
include ease of gripping, ease of insertion between the teeth, and
low cost.
[0053] The fibers of the present invention may be comprised of
mono- or multi-filaments. In one embodiment, reference is made to
FIG. 6 wherein a monofilament dental floss is presented having
relatively low and relatively high coefficient of friction surfaces
according to the present invention.
[0054] In another embodiment, reference is made to FIG. 7 wherein a
multifilament dental floss is presented having a plurality of
filaments wherein each of the filaments have both relatively low
and relatively high coefficient of friction surfaces according to
the present invention.
[0055] In a further embodiment, reference is made to FIG. 8 wherein
a multifilament dental floss is presented having a plurality of
filaments wherein about 50% of the filaments have a relatively low
coefficient of friction and about 50% of the filaments have a
relatively high coefficient of friction according to the present
invention.
[0056] In a still further embodiment, reference is made to FIG. 9
wherein a core of relatively high coefficient of friction fibers
are surrounded by fibers having a relatively low coefficient of
friction. The low friction fibers assist in the ease of insertion
of the floss between the teeth. During the insertion process, the
low friction fibers partially separate exposing the relatively high
coefficient of friction fibers to the gums. The high friction
fibers come into contact with the, for example, food particles
between the teeth and gums and remove the particles and massage the
gums.
[0057] The fiber of the present invention is produced by known
methods in the art. The fiber of the present invention is
preferably produced by slitting oriented film or sheet, and more
preferably produced by orienting and slitting extruded film or
sheet, the extruded film or sheet being formed via a coextrusion
process. Alternatively, a single or multi-layer film or sheet may
be laminated to other materials such that its top and/or bottom
surfaces are different from the core layer(s). As an additional
alternative, a single or multi-layer film may be coated with one or
more materials such that its top and/or bottom surfaces are
different from the core layer(s). As still another alternative, a
"base fiber" may be partially coated with a low coefficient of
friction material such that the coated surface of the base fiber
has a lower coefficient of friction than the non-coated surface. A
still further method includes extrusion. Some fibers suitable for
use in the current invention are discussed in U.S. patent
application Ser. No. 09/021,325, which is incorporated herein by
reference.
[0058] Another method includes sheath and core. In the sheath and
core method, exemplified in FIG. 9, the floss comprises an outer
sheath which is soft, slippery, or abrasive, to improve the ease of
insertion, comfort and cleaning capability, respectively, of the
floss, and an inner core that provides other desired physical
properties, such as strength and resiliency and/or serves as a
carrier for additives, such as flavors, scents and medicaments.
Thus, the sheath may comprise one or more relatively low
coefficient of friction components, whereas the core may comprise
one or more relatively high coefficient of friction components.
[0059] In the film/sheet embodiment, low coefficient of friction
materials are used to form the top and/or bottom surfaces of the
film or sheet, such that the top and/or bottom fiber surfaces
exhibit low coefficient of friction characteristics. Accordingly,
the fibers that result from slitting the film/sheet having top
and/or bottom surfaces that exhibit low coefficient of friction
characteristics, and side surfaces that exhibit relatively higher
coefficient of friction characteristics.
[0060] The relatively high coefficient of friction portion is
comprised of polyester, nylon, acrylics, aramids, polyethylene,
polyurethane and plastic copolymers. Suppliers include, for
example, DuPont, Nylestar, Wellman and Foss. One of ordinary skill
in the art would understand in light of the present disclosure that
more than one relatively high friction polymeric component may be
used, such as, for example, a blend of two, three or four different
polymeric components may be used.
[0061] The materials that may be used to form relatively low
coefficient of friction portion include, but are not limited to,
polytetrafluoroethylene (PTFE), boron, HALAR.TM., molybdenum
sulfide, ultrahigh molecular weight silicone, siloxane,
silicone/silane modified polymers, graphite, fluorinated high
molecular weight polyolefins or cyclic organic compounds,
non-modified polyolefins, or other fluorinated polymers. Suppliers
of such low low-friction materials include, for example, DuPont,
Dow Corning, Ausimont and General Electric.
[0062] The low coefficient of friction materials must exhibit
surface properties that reduce the coefficient of friction.
Preferably, the low coefficient of friction material is selected
from the group consisting of silicone, silicone copolymers,
silicone elastomers, polytetrafluoroethylene, homopolymers and
copolymers thereof, graphite, boron, polypropylene and
polyethylene.
[0063] The most preferred low coefficient of friction material
added during coextrusion/lamination/coating and later incorporated
into dental floss, tooth brushes, or a fabric that comprises an
article of clothing is a polytetrafluoroethylene ("PTFE"), also
known by its trademark Teflon.TM.. PTFE is a linear polymer with
each polymer chain having a low coefficient of friction. PTFE is a
fluorocarbon polymer, which is defined in the Condensed Chemical
Dictionary, 8th Edition, as including polytetrafluoroethylene,
polymers of chlorotrifluoroethylene, fluorinated ethylenepropylene
polymers, polyvinylidene fluoride, hexafluoropropylene, etc. Also
preferred for the present invention are polymers and copolymers
based on chlorotrifluoroethylene, poly (vinyl fluoride) and poly
(vinylidene fluoride). Copolymers of ethylene and/or additional low
coefficient of friction silicone polymers are also acceptable.
[0064] Moreover, the fibers of the invention may also comprise
additives. Such additives include, for example, anti-microbials,
baking soda, peroxide abrasives, flavorings and pigments. The
advantages of such additives include, for example, whitening of the
teeth, ease of handling and pleasing taste.
[0065] The "exposed surfaces" of a fiber according to the present
invention are formed as a result of slitting the oriented
film/sheet, or as a result of only partially coating the base
fiber. As mentioned above, these exposed surfaces can have a higher
coefficient of friction than the "unexposed surfaces", due to the
exposure of the core material/base fiber. More specifically, the
exposed surfaces have coefficients of friction ranging from 1.10 to
5.00 or more times the coefficient of friction of the unexposed
surfaces. The exposed surface coefficient of friction depends upon
the exposed area, the chemical make-up of the exposed area and the
surface characteristics of the exposed area. Advantageously, the
fibers of the invention are less prone to detract from the
stability and durability of fabric then are coated filament or
stable, because unlike coated filament and stable, the fibers of
the invention have exposed surfaces of a relatively high
coefficient of friction.
[0066] In the film/sheet embodiment, typical exposed surfaces
consist of "tie-layers" such as adhesives (e.g., Admer.TM. and
Bynel.TM.) adjoining the primary strength layers. Fillers, such as
mica, calcium carbonate, talc or other particulates may be added to
any of the layers to affect adhesion, barrier and/or ergonomic
factors. Combinations of fillers and foaming agents may also be
used as the core layers. The core layers may also consist of
engineering resins (e.g., Nylon, Polyester) or natural fibers,
modified to improve the performance of such layers.
[0067] Moreover, the core layers/base fiber may be selected to
impart the fiber of the invention with desirable characteristics.
In one embodiment, the core layer/base fiber has shock absorbing
characteristics (e.g., core layer(s) are open or closed celled
foams) to provide increased cushioning values in addition to a low
coefficient of friction on the treated surface. In another
embodiment, the core layer/base fiber provides desirable thermal
characteristics in addition to a low coefficient of friction on the
treated surface. For example, the core layer/base fiber may include
an insulating material for restricting the escape of heat energy,
or a radiant material for facilitating the escape of heat
energy.
[0068] Additionally in the film/sheet process, by using materials
having different coefficients of friction for respective sides of
the film/sheet the resulting coefficient of friction of the fiber
can be controlled so that the coefficients of friction of the top
and bottom surfaces of the fiber differ. In turn, such fibers may
be used to form a fabric wherein the coefficient of friction of the
top and bottom surface of the fabric differ. For example, any of
the previously mentioned low friction materials can be used to
create the low friction surface of the fabric, while a high
friction material such as rubber, cotton, elastomers,
polyacrylates, polymethacrylates, and polyurethanes can be used to
create the relatively high friction surface of the fabric. More
generally, the relatively high friction materials may include any
materials having a coefficient of friction greater than 0.3. In one
possible embodiment a bathing suit can be designed to have a low
coefficient of friction on the suit surface exposed to water, to
increase swimming speed, and a high coefficient of friction on the
surface exposed to the wearer, to minimize suit movement on the
body. Such a bathing suit could readily be produced using fabrics
made up of fibers obtained from the previously described
films/sheets.
[0069] Exemplary embodiments of the invention are illustrated in
FIGS. 1 to 10 in which FIGS. 1-4 are discussed in Ser. No.
09/661,285. FIG. 5 is one embodiment of the present invention and
depicts a cross sectional view of a tooth brush bristle having
relatively low and relatively high coefficient of friction
surfaces. FIG. 6 is another embodiment of the present invention and
depicts a monofilament dental floss is contemplated having
relatively low and relatively high coefficient of friction
surfaces. FIG. 7 is yet another embodiment of the present invention
and depicts a multifilament dental floss having a plurality of
filaments wherein each of the filaments have both relatively low
and relatively high coefficient of friction surfaces. FIG. 8 is
still another embodiment of the present invention and depicts a
multifilament dental floss having a plurality of filaments wherein
about 50% of the filaments have a relatively low coefficient of
friction and about 50% of the filaments have a relatively high
coefficient of friction. FIG. 9 is a further embodiment of the
present invention and depicts a multifilament dental floss having
an inner core of predominantly relatively high coefficient of
friction filaments surrounded by an outer layer of predominantly
relatively low coefficient of friction filaments. FIG. 10 is a
still further embodiment of the present invention and depicts a
floss pick having both a low coefficient of friction portion and a
relatively high coefficient of friction portion.
[0070] One embodiment according to the present invention is a
multilayered fiber with one surface having a low coefficient of
friction characteristic and a second surface having a "hand
enhanced" characteristic. Fabrics woven from such multilayered
fibers are ideal for use in socks, garments, wound treatments,
diving apparel and other garments or devices in which a low
coefficient of friction material is undesirable on the inner
surface as it would feel uncomfortable on the skin, but is
desirable on the, outer surface because it would permit more
movement or gliding action.
[0071] Multilayered fibers could be produced in which the low
coefficient of friction surface is opposed by a surface which is
porous to allow either the migration of medicines into the skin or
the absorption of moisture from the skin. Uniformly low coefficient
of friction coated continuous filament or staple would be
significantly less desirable in such applications because the
uniformly low coefficient of friction filament/staple is more
costly.
[0072] The fibers of the present invention, which are made from one
or more low coefficient of friction materials, are more cost
effective than standard low coefficient of friction filaments and
staple. This is because only a portion of the invention's fibers
contain low coefficient of friction material, while many of the
standard low coefficient of friction filaments and staple are
completely coated or surrounded with low coefficient of friction
materials. Since low coefficient of friction material is a premium
product and the fibers of the invention contain less such material
than the standard low coefficient of friction filaments and staple,
the fibers of the invention are relatively cheaper than the
standard low coefficient of friction filaments and staple.
[0073] Another embodiment of the present invention, as seen in FIG.
10, is a dental pick comprising a relatively high coefficient of
friction portion spaced between two, continuous, relatively low
coefficient of friction portions, such that each continuous portion
traces a path along the length of the pick. It is envisioned that
the thickness of the dental pick is from about 5 mil to about 100
mil; preferably, from about 8 mil to about 30 mil; most preferably,
from about 12 mil to about 20 mil. The relatively high coefficient
of friction portion is comprised of polyester, nylon, acrylics,
aramids, polyethylene, polyurethaene and plastic copolymers.
Suppliers include, for example, DuPont, Nylestar, Wellman and Foss.
One of ordinary skill in the art would understand in light of the
present disclosure that more than one relatively polymeric
component may be used, such as, for example, a blend of two, three
or four different polymeric components may be used. The relatively
low coefficient of friction portion is comprised of, but is not
limited to, PTFE, boron, HALAR.TM., molybdenum sulfide, ultrahigh
molecular weight silicone, siloxane, silicone/silane modified
polymers, graphite, fluorinated high molecular weight polyolefins
or cyclic organic compounds, non-modified polyolefins, or other
fluorinated polymers. Suppliers of the low friction portion
include, for example, DuPont, Dow Coming, Ausimont and General
Electric.
[0074] Although preferred embodiments of the present invention and
modifications thereof have been described in detail herein, it is
to be understood that this invention is not limited to those
precise embodiments and modifications, and that other modifications
and variations may be affected by one skilled in the art without
departing from the spirit and scope of the invention as defined by
the appended claims.
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