U.S. patent application number 10/736271 was filed with the patent office on 2004-09-02 for hollow fiber fabrics.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Bond, Eric Bryan, Gorley, Ronald Thomas.
Application Number | 20040170836 10/736271 |
Document ID | / |
Family ID | 32713316 |
Filed Date | 2004-09-02 |
United States Patent
Application |
20040170836 |
Kind Code |
A1 |
Bond, Eric Bryan ; et
al. |
September 2, 2004 |
Hollow fiber fabrics
Abstract
The present invention is directed to fibrous fabric comprising
hollow fibers. Preferably, the fibrous fabrics will have an opacity
greater than a fibrous fabric with an equivalent basis weight and
made with the same material and the same fiber diameter. The
fibrous fabric comprising hollow fibers may also have an opacity
greater than a higher basis weight fibrous fabric containing the
same material and having an equivalent fiber diameter and the same
number of fibers. The perimeter of the hollow region of the hollow
fibers is substantially non-concentric to the outer perimeter of
the hollow polymeric fibers. The hollow fibers can be monocomponent
and multicomponent, as well as monoconstituent or multiconstituent.
These hollow fibers are then consolidated into woven and nonwoven
fibrous fabrics that are then converted into articles.
Inventors: |
Bond, Eric Bryan;
(Maineville, OH) ; Gorley, Ronald Thomas;
(Cincinnati, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Assignee: |
The Procter & Gamble
Company
|
Family ID: |
32713316 |
Appl. No.: |
10/736271 |
Filed: |
December 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60438350 |
Jan 7, 2003 |
|
|
|
Current U.S.
Class: |
428/398 ;
428/365; 428/397; 442/194; 442/338 |
Current CPC
Class: |
D01D 5/24 20130101; Y10T
428/2915 20150115; Y10T 428/2973 20150115; Y10T 442/3106 20150401;
Y10T 442/612 20150401; Y10T 428/2975 20150115 |
Class at
Publication: |
428/398 ;
428/365; 428/397; 442/338; 442/194 |
International
Class: |
D04H 003/00; D02G
003/00 |
Claims
What is claimed is:
1. A fibrous fabric comprising hollow polymeric fibers comprising
an outer perimeter and a hollow region having a perimeter, wherein
the perimeter of the hollow region is substantially non-concentric
to the outer perimeter of the hollow polymeric fiber.
2. The fibrous fabric of claim 1, wherein the perimeter of the
hollow region of the hollow polymeric fibers is substantially
non-circular.
3. The fibrous fabric of claim 1, wherein the hollow region of the
hollow polymeric fiber is from about 5% to about 40%.
4. The fibrous fabric of claim 1, wherein the hollow polymeric
fiber has a diameter of from about 10 microns to about 100
microns.
5. The fibrous fabric of claim 1, wherein the hollow polymeric
fiber is comprised of a thermoplastic polymeric material selected
from the group consisting of polypropylene, polyethylene,
polyester, polyamide, polyimide, polylactic acid,
polyhydroxyalkanoate, polyvinyl alcohol, polyacrylates, and
mixtures thereof.
6. The fibrous fabric of claim 1, wherein the hollow polymeric
fiber is comprised of a non-thermoplastic material selected from
the group consisting of viscose rayon, lyocell, cotton, wood pulp,
and mixtures thereof.
7. The fibrous fabric of claim 1, wherein the polymeric material is
blended with particulates comprised of materials selected from the
group consisting of titanium dioxide, calcium carbonate, colored
pigments, and mixtures thereof.
8. The fibrous fabric of claim 5, wherein the hollow polymeric
fiber is blended with non-thermoplastic polymeric fibers.
9. The fibrous fabric of claim 8, wherein the non-thermoplastic
polymeric fibers have a hollow region.
10. The fibrous fabric of claim 9, wherein a perimeter of the
hollow region of the hollow non-thermoplastic polymeric fibers is
substantially non-concentric to an outer perimeter of the hollow
non-thermoplastic polymeric fibers.
11. A fibrous fabric comprising hollow polymeric fibers which
comprise a polymeric material and have a hollow region, wherein the
fibrous fabric has an opacity greater than a fibrous fabric
produced with the same polymeric material at an equivalent fiber
diameter and basis weight.
12. The fibrous fabric of claim 11, wherein the hollow region has a
perimeter and the perimeter of the hollow region is substantially
non-concentric to an outer perimeter of the hollow polymeric
fibers.
13. The fibrous fabric of claim 11, wherein the perimeter of the
hollow region of the hollow polymeric fibers is substantially
non-circular.
14. A wet wipe comprising the fibrous fabric of claim 1.
15. The wet wipe of claim 14 having a wet opacity greater than a
wet wipe comprising the same polymeric material at an equivalent
fiber diameter and basis weight.
16. A wet wipe comprising the fibrous fabric of claim 10.
17. The wet wipe of claim 16 that has a wet opacity greater than a
wet wipe comprising the same polymeric material at an equivalent
fiber diameter and basis weight.
18. The fibrous fabric of claim 1 wherein the fibrous fabric has an
opacity greater than a fibrous fabric comprising concentric hollow
fibers comprising the same material and having an equivalent fiber
diameter and basis weight.
19. The fibrous fabric of claim 10 wherein the fibrous fabric has
an opacity greater than a fibrous fabric comprising concentric
hollow fibers comprising the same material and having an equivalent
fiber diameter and basis weight.
20. The fibrous fabric of claim 1 wherein the hollow polymeric
fiber has a multicomponent configuration.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/438,350, filed Jan. 7, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates to fibrous fabrics containing
hollow fibers and processes of making hollow fibers.
BACKGROUND OF THE INVENTION
[0003] Commercial woven and nonwoven fabrics are typically
comprised of synthetic polymers formed into fibers. These fabrics
are typically produced with solid fibers that have a high inherent
overall density, typically 0.9 g/cm.sup.3 to 1.4 g/cm.sup.3. The
overall weight or basis weight of the fabric is often dictated by a
desired opacity of the fabric to promote an acceptable thickness,
strength and protection perception.
[0004] One reason for the increased usage of polyolefinic polymers
(polypropylene and polyethylene) is that their bulk density is
significantly lower than polyester, polyamide and regenerated
cellulose fiber. The polypropylene density is around 0.9
g/cm.sup.3, while the regenerated cellulose and polyester density
values can be higher than 1.35 g/cm.sup.3. The lower bulk density
means that at equivalent basis weight and fiber diameter, more
fibers are available to promote a thickness, strength and
protection perception for the lower density polypropylene. Many of
these attributes can be correlated with opacity. Therefore,
manipulating the inherent opacity of the fiber and fabric in a
consumer product can lead to better overall user acceptability.
[0005] A great deal of effort has been spent to address improve
consumer acceptance by increasing the opacity of a fabric by
reducing the overall fiber diameter. In woven fabrics, the spread
of "microfiber" technology for improved softness and strength has
become fashionable. In nonwoven fabrics, the use of "micro" fiber
spunbond and meltblown technologies has allowed improvements in
opacity by reducing the fiber diameter.
[0006] The present invention has found that using hollow fibers
provides substantial improvements in opacity at equivalent outer
fiber diameter and basis weight, through a reduction in overall
bulk density of the fiber.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to fibrous fabric
comprising hollow fibers. Preferably, the fibrous fabrics will have
an opacity greater than a fibrous fabric with an equivalent basis
weight and made with the same material and the same fiber diameter.
The fibrous fabric comprising hollow fibers may also have an
opacity greater than a higher basis weight fibrous fabric
containing the same material and having an equivalent fiber
diameter and the same number of fibers. The perimeter of the hollow
region of the hollow fibers is substantially non-concentric to the
outer perimeter of the hollow polymeric fibers. The hollow fibers
can be monocomponent and multicomponent, as well as monoconstituent
or multiconstituent. These hollow fibers are then consolidated into
woven and nonwoven fabrics that are then converted into
articles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features, aspects and advantages of the
present invention will become better understood with regard to the
following description, appended claims, and accompanying drawing
where:
[0009] FIG. 1 illustrates a hollow fiber of the present
invention.
[0010] FIG. 2 illustrates a concentric hollow fiber.
[0011] FIGS. 3, 4, 5, and 6 illustrate several variations of
non-concentric hollow fiber of the present invention.
[0012] FIG. 7 is a photograph of a non-concentric hollow fiber of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] All percentages, ratios and proportions used herein are by
weight percent of the composition, unless otherwise specified.
Examples in the present application are listed in parts of the
total composition.
[0014] The specification contains a detailed description of (1)
materials of the present invention, (2) configuration of the
fibers, (3) material properties of the fibers, (4) processes, and
(5) articles.
[0015] (1) Materials
[0016] Thermoplastic polymeric and non-thermoplastic polymeric
materials may be used in the present invention. The thermoplastic
polymeric material must have rheological characteristics suitable
for melt spinning. The molecular weight of the polymer must be
sufficiently high to enable entanglement between polymer molecules
and yet low enough to be melt spinnable. For melt spinning,
thermoplastic polymers having molecular weights below 1,000,000
g/mol, preferably from about 5,000 g/mol to about 750,000 g/mol,
more preferable from about 10,000 g/mol to about 500,000 g/mol and
most preferably from about 50,000 g/mol to about 400,000 g/mol.
[0017] The thermoplastic polymeric materials must be able to
solidify fairly rapidly, preferably under extensional flow, and
form a thermally stable fiber structure, as typically encountered
in known processes such as a spin draw process for staple fibers or
a spunbond continuous filament process. Preferred polymeric
materials include, but are not limited to, polypropylene,
polyethylene, polyester, polyamide, polyimide, polylactic acid,
polyhydroxyalkanoate, polyvinyl alcohol, ethylene vinyl alcohol,
polyacrylates, and copolymers thereof and mixtures thereof. Other
suitable polymeric materials include ethylene acrylic acid,
polyolefin carboxylic acid copolymers, and combinations
thereof.
[0018] The hollow fibers of the present invention may be comprised
of a non-thermoplastic polymeric material. Examples of
non-thermoplastic polymeric materials include, but are not limited
to, viscose rayon, lyocell, cotton, wood pulp, regenerated
cellulose, and mixtures thereof. The non-thermoplastic polymeric
material may be produced via solution or solvent spinning. The
regenerated cellulose is produced by extrusion through capillaries
into an acid coagulation bath.
[0019] Depending upon the specific polymer used, the process, and
the final use of the fiber, more than one polymer may be desired.
The polymers of the present invention are present in an amount to
improve the mechanical properties of the fiber, improve the
processability of the melt, and improve attenuation of the fiber.
The selection of the polymer and amount of polymer will also
determine if the fiber is thermally bondable and affect the
softness and texture of the final product.
[0020] Optionally, other ingredients may be incorporated into the
spinnable composition. The optional materials may be used to modify
the processability and/or to modify physical properties such as
opacity, elasticity, tensile strength, wet strength, and modulus of
the final product. Other benefits include, but are not limited to,
stability including oxidative stability, brightness, color,
flexibility, resiliency, workability, processing aids, viscosity
modifiers, and odor control. Examples of optional materials include
titanium dioxide, calcium carbonate, colored pigments, and
combinations thereof. Further additives including inorganic fillers
such as the oxides of magnesium, aluminum, silicon, and titanium
may be added as inexpensive fillers or processing aides. Other
inorganic materials include hydrous magnesium silicate, titanium
dioxide, calcium carbonate, clay, chalk, boron nitride, limestone,
diatomaceous earth, mica glass quartz, and ceramics. Additionally,
inorganic salts, including alkali metal salts, alkaline earth metal
salts, phosphate salts, may be used.
[0021] (2) Configuration
[0022] The hollow fibers of the present invention will have a
hollow region. FIG. 1 illustrates a hollow fiber 10. The hollow
region 20 has a perimeter 22. The solid region 30 of the hollow
fiber 10 surrounds the hollow region 20. The perimeter of the
hollow region 22 is also the inside perimeter of the solid region.
The outside perimeter 32 of the solid region 30 is also the outside
perimeter of the hollow fiber 10. The circumscribed diameter of the
hollow fiber may also be the outside perimeter 32.
[0023] The hollow region is defined as the part of the fiber that
does not contain the fiber material. It may also be described as
the void area, void volume, or empty space. The hollow region may
be filled with air or possibly a liquid. The hollow region will
comprise from about 2% to about 60% of the fiber. Preferably, the
hollow region will comprise from about 5% to about 40% of the
fiber. More preferably, the hollow region comprises from about 5%
to about 30% of the fiber and most preferably from about 10% to
about 30% of the fiber. The percentages are given for a cross
sectional region of the hollow fiber (i.e. two dimensional). If
described in three-dimensional terms, the percent void volume of
the fiber will be equivalent to the percent of hollow region.
[0024] The percent of hollow region must be controlled for the
present invention. The percent hollow is preferably not below 2% or
the benefit of the hollow region is not significant. However, the
hollow region must not be greater than 60% or the fiber may
collapse. The desired percent hollow depends upon the materials
used, the end use of the fiber, and other fiber characteristics and
uses.
[0025] The fiber "diameter" of the hollow fiber of the present
invention is defined as the circumscribed diameter of the outer
perimeter 32 of the hollow fiber. The diameter is not of the hollow
region. Preferably, the hollow fiber will have a diameter of less
than 100 micrometers. More preferably the fiber diameter will be
from about 10 micrometers to about 100 micrometers and preferably
from about 10 micrometer to about 50 micrometers. Fiber diameter is
controlled by spinning speed, mass throughput, temperature,
spinneret geometry, and blend composition, among other things.
[0026] Preferably, the hollow region of the hollow fibers will be
of a particular shape. The perimeter or outside edge of the cross
section of the hollow region will be substantially non-concentric
to the outer perimeter or outer edge of the solid region or hollow
fiber. As used herein, the term "non-concentric" is used to mean
not having the same center point and/or not having the same shape
or curvature (i.e. slope differential). Therefore, a hollow fiber
is defined as being non-concentric if either the center point of
the hollow region is not the same as the center point of the hollow
fiber or if the perimeter of the hollow region is not the same
shape or curvature as the outside perimeter of the hollow fiber.
Most preferably, the shape of the hollow region is substantially
non-circular. For example, the hollow region may be triangular or
square in shape. The triangular or square shape will typically have
rounded edges.
[0027] Without being bound by theory, it is believed that the
hollow core allows for increased benefits in optical
characteristics which increase opacity. The increase in opacity of
the fibrous fabric may be due to changes in at least one light
characteristic selected from the group consisting of reflection,
refraction, diffraction, absorption, scattering, and combinations
thereof. This increase in opacity may be even greater when the
fibers are non-concentric hollow fibers versus solid fibers or
concentric hollow fibers.
[0028] FIG. 2 is used to illustrate what is a concentric hollow
fiber and not a "non-concentric" hollow fiber. As shown, the center
of the hollow region and the center of the hollow fiber are the
same. Additionally, the shape or curvature of the perimeter of the
hollow region and the hollow fiber are the same. FIG. 3 illustrates
non-concentric hollow fibers having several different shapes of the
hollow region. These non-concentric hollow fibers are illustrative
of not having the same curvature or shape in the hollow region as
compared to the hollow fiber. As shown, these shapes may have
straight or curved edges. Additionally, part of the perimeter of
the hollow region may have the same curvature as the hollow fiber
as long as the entire curvature is not the same. The hollow regions
may or may not have the same center point as the hollow fiber. FIG.
4 illustrates that the shape of the hollow fiber need not be
circular.
[0029] FIG. 5 illustrates other non-concentric hollow fibers where
the hollow region does not have the same center point as the hollow
fiber. The perimeter of the hollow region and the outer perimeter
of the hollow fiber may be of the same curvature. FIG. 6
illustrates non-concentric hollow fiber having a variety of shapes
for the hollow region. The hollow region may contain one or more
regions. FIG. 7 is a photograph showing a non-circular, partially
square shaped, hollow region.
[0030] The mono and multiconstituent hollow fibers of the present
invention may be in many different configurations. Constituent, as
used herein, is defined as meaning the chemical species of matter
or the material. Fibers may be of monocomponent or multicomponent
in configuration. Component, as used herein, is defined as a
separate part of the fiber that has a spatial relationship to
another part of the fiber.
[0031] The hollow fibers of the present invention may be
multicomponent hollow fibers. Multicomponent fibers, commonly a
bicomponent fiber, may be in a side-by-side, sheath-core, segmented
pie, ribbon, or islands-in-the-sea configuration. The sheath may be
non-continuous or continuous around the core. The hollow fibers of
the present invention may have different geometries that include
round, elliptical, star shaped, rectangular, multi-lobal, and other
various eccentricities. The hollow regions in the fibers may be
singular in number or multiple. The holes may also be produced by
dissolving out a water-soluble component, such as PVOH, EVOH and
starch, for non-limiting examples.
[0032] (3) Material Properties
[0033] The fibrous fabrics of the present invention will have a
basis weight and opacity that can be measured. Opacity can be
measured using TAPPI Test Method T 425 om-01 "Opacity of Paper
(15/d geometry, Illuminant A/2 degrees, 89% Reflectance Backing and
Paper Backing)". The opacity is measured as a percentage. The
opacity of the fibrous fabric containing hollow fibers will be
several percentage points of opacity greater than the fibrous
fabric containing solid fibers. The opacity may be from about 2 to
about 50 percentage points greater and commonly from about 4 to
about 30 percentage points greater.
[0034] Basis weight is the mass per unit area of the substrate.
Independent measurements of the mass and area of a specimen
substrate are taken and calculation of the ratio of mass per unit
area is made. Preferably, the basis weight of the fibrous fabrics
of the present invention will be from about 4 grams per square
meter (gsm) to about 70 gsm depending upon the use of the
fabric.
[0035] Additionally, the fibrous fabrics produced from the hollow
fibers will also exhibit certain mechanical properties,
particularly, strength, flexibility, elasticity, extensibility,
softness, thickness, and absorbency. Measures of strength include
dry and/or wet tensile strength. Flexibility is related to
stiffness and can attribute to softness. Softness is generally
described as a physiologically perceived attribute that is related
to both flexibility and texture. Absorbency relates to the
products' ability to take up fluids as well as the capacity to
retain them.
[0036] (4) Processes
[0037] The first step in producing a fiber is the compounding or
mixing step. In the compounding step, the raw materials are heated,
typically under shear. The shearing in the presence of heat will
result in a homogeneous melt with proper selection of the
composition. The melt is then placed in an extruder where the
material is mixed and conveyed through capillaries and fibers are
formed. A collection of fibers is combined together using heat,
pressure, chemical binder, mechanical entanglement, hydraulic
entanglement, and combinations thereof resulting in the formation
of a nonwoven web or fabric. The nonwoven is then assembled into an
article. Alternatively, the fibers can be consolidated together in
a textile process to produce a woven web.
[0038] Equipment
[0039] The equipment used to produce the fibers in the examples
came from one of three different types of spinning equipment. The
smallest is a four-hole bicomponent spinline made by Hills Inc. The
second line has 82 holes and contains Hills Inc. bicomponent
technology, modified from an original Alex James bicomponent
spinline. The third line contains at least 144 holes (nominally
288) and is located at Hills Inc, with their bicomponent spinning
technology. With these three small lines, fiber can either be
collected via mechanical winding at low or high speed. These fibers
can then be mechanically drawn to further decrease their diameter.
Heat is frequently used in the drawing process. These fibers are
then crimped, if desired, and cut to the desired length. These
fibers are then converted into a fabric.
[0040] Although the exact equipment is not important for
manifesting the invention of using hollow fiber in fabrics for
better opacity, hollow fibers are typically produced using a
special spinneret that divides the polymer melt stream as it exits
the spin pack. In the case of the Hills Inc. spinneret technology,
the melt stream is separated into four segments that converge after
the exit of the spinneret. Other designs may make use of two or
three segments that converge after exiting the spinneret. The size
of the void can also be affected by pumping some low-pressure gas
into the void. The exact process for producing the fiber is not
critical to this invention.
[0041] Spinning
[0042] The present invention utilizes the process of melt spinning
in its most preferred embodiment. In melt spinning, there is no
mass loss in the extrudate. Solution spinning may be used for
producing fibers from cellulose, cellulosic derivatives, starch,
and protein.
[0043] Spinning will occur at 100.degree. C. to about 300.degree.
C. Fiber spinning speeds of greater than 100 meters/minute are
required. Preferably, the fiber spinning speed is from about 500 to
about 14,000 meters/minute. The spinning may involve direct
spinning, using techniques such as spunlaid or meltblown, as long
as the fibers are mostly non-continuous in nature. Continuous
fibers are hereby defined as having length to width ratio greater
than 5000. The fiber may also, be produced using a spin and draw
technique, where the fiber is spun at a relatively slow speed and
mechanically drawn, with or without heat, to reduce the fiber
diameter.
[0044] Multiconstituent blends or polymeric materials can be melt
spun into fibers on conventional melt spinning equipment. The
temperature for spinning ranges from about 100.degree. C. to about
300.degree. C. The processing temperature is determined by the
chemical nature, molecular weights and concentration of each
component. The fibers spun can be collected using conventional
godet winding systems or through air drag attenuation devices. If
the godet system is used, the fibers can be further oriented
through post extrusion drawing at temperatures from about 50 to
about 200.degree. C.
[0045] Multiconstituent blends may also be spun into fibers. For
example, blends of polyethylene and polypropylene can be mixed and
spun using this technique. Another example would be blends of
polyesters with different viscosities or termonomer content.
Multicomponent fibers can also be produced that contain
differentiable chemical species in each component.
[0046] The fibers and fabrics made in the present invention often
contain a finish applied after formation to improve performance or
tactile properties. These finishes typically are hydrophilic or
hydrophobic in nature and are used to improve the performance of
articles containing the finish. For example, Goulston Technologies'
Lurol 9519 can be used with polypropylene and polyester to impart a
semi-durable hydrophilic finish.
[0047] (5) Articles
[0048] The hollow fibers may be converted to fabrics by different
bonding methods. In a spunbond or meltblown process, the fibers are
consolidated using industry standard spunbond type technologies
while staple fibers can be formed into a web using industry
standard carding, airlaid, or wetlaid technologies. Typical bonding
methods include: calender (pressure and heat), thru-air heat,
mechanical entanglement, hydraulic entanglement, needle punching,
and chemical bonding and/or resin bonding. Thermally bondable
fibers are required for the pressurized heat and thru-air heat
bonding methods. Fibers may also be woven together to form sheets
of fabric. This bonding technique is a method of mechanical
interlocking.
[0049] The hollow fibers of the present invention may also be
bonded or combined with thermoplastic or non-thermoplastic fibers
to make nonwoven articles. The thermoplastic polymeric fibers,
typically synthetic fibers, or non-thermoplastic polymeric fibers,
often natural fibers, may be blended together in the forming
process or used in discrete layers. Suitable synthetic fibers
include fibers made from polypropylene, polyethylene, polyester,
polyacrylates, and copolymers thereof and mixtures thereof. Natural
fibers include lyocell and cellulosic fibers and derivatives
thereof. Suitable cellulosic fibers include those derived from any
tree or vegetation, including hardwood fibers, softwood fibers,
hemp, and cotton. Also included are fibers made from processed
natural cellulosic resources such as rayon.
[0050] The hollow fibers of the present invention may be used to
make nonwovens, among other suitable articles. Nonwoven or fibrous
fabric articles are defined as articles that contains greater than
15% of a plurality of fibers that are non-continuous or continuous
and physically and/or chemically attached to one another. The
nonwoven may be combined with additional nonwovens or films to
produce a layered product used either by itself or as a component
in a complex combination of other materials, such as a baby diaper
or feminine care pad. Preferred articles are disposable, nonwoven
articles. The resultant products may find use in filters for air,
oil and water; vacuum cleaner filters; furnace filters; face masks;
coffee filters, tea or coffee bags; thermal insulation materials
and sound insulation materials; nonwovens for one-time use sanitary
products such as diapers, feminine pads, and incontinence articles;
biodegradable textile fabrics for improved moisture absorption and
softness of wear such as micro fiber or breathable fabrics; an
electrostatically charged, structured web for collecting and
removing dust; reinforcements and webs for hard grades of paper,
such as wrapping paper, writing paper, newsprint, corrugated paper
board, and webs for tissue grades of paper such as toilet paper,
paper towel, napkins and facial tissue; medical uses such as
surgical drapes, wound dressing, bandages, dermal patches and
self-dissolving sutures; and dental uses such as dental floss and
toothbrush bristles. The fibrous web may also include odor
absorbents, termite repellants, insecticides, rodenticides, and the
like, for specific uses. The resultant product absorbs water and
oil and may find use in oil or water spill clean-up, or controlled
water retention and release for agricultural or horticultural
applications. The resultant fibers or fiber webs may also be
incorporated into other materials such as saw dust, wood pulp,
plastics, and concrete, to form composite materials, which can be
used as building materials such as walls, support beams, pressed
boards, dry walls and backings, and ceiling tiles; other medical
uses such as casts, splints, and tongue depressors; and in
fireplace logs for decorative and/or burning purpose. Preferred
articles of the present invention include disposable nonwovens for
hygiene applications, such as facial cloths or cleansing cloths,
and medical applications. Hygiene applications include wipes, such
as baby wipes or feminine wipes; diapers, particularly the top
sheet or back sheet; and feminine pads or products, particularly
the top sheet. Other preferred applications are wipes or cloths for
hard surface cleansing. The wipes may be wet or dry.
[0051] STAPLE FIBER EXAMPLES
[0052] The Examples below further illustrate the present invention.
The crystalline PLA has an intrinsic viscosity of 0.97 dL/g with an
optical rotation of -14.2. The amorphous PLA has an intrinsic
viscosity of 1.09 dL/g with an optical rotation of -12.7. The
poly(3-hydroxybutyrate co-alkanoate), PHA, has a molecular weight
of 1,000,00 g/mol before compounding. The polyhydroxybutyrate (PHB)
was purchased from Goodfellow as BU 396010. The polyvinyl alcohol
copolymer (PVOH) was purchased from Air Products Inc. and is a 2000
series polymer. One polypropylene was purchased from FINA as FINA
3860.times.. Three polypropylenes were purchased from Basell,
Profax PH-835, Profax PDC-1298 and Profax PDC-1274. The
polyethylene was purchased from Dow Chemical as Aspun 6811A. Five
polyester resins were purchased from Eastman Chemical F61HC, 9663,
12822 as well as two copolyester resins 14285 and 20110.
Comparative Example 1
Fibrous Web Containing Solid Fibers
Dry Measurements
[0053] A polypropylene/Lyocell carded hydroentangled fabric was
produced by blending 60 wt % of Basell PH-835 staple fibers with 40
wt % Lyocell. The Basell PH-835 fibers were spun, drawn and crimped
to an average fiber diameter of 20 .mu.m. The Lyocell fiber is 1.5
d, roughly 12 .mu.m in diameter. The following nonwoven fabrics
were produced, along with the opacity of the nonwoven measured on
the samples in which the basis weight was determined.
1 Basis Weight Opacity (gsm) (%) 61.7 53.19 67.6 56.52 57.1 49.23
52.5 47.86 32.1 30.68 29.5 29.47
[0054] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen.
Comparative Example 2
Fibrous Web Containing Solid Fibers
Wet Measurements
[0055] A polypropylene/Lyocell carded hydroentangled fabric was
produced by blending 60 wt % of Basell PH-835 staple fibers with 40
wt % Lyocell. The Basell PH-835 fibers were spun, drawn and crimped
to an average fiber diameter of 30 .mu.m. The Lyocell fiber is 1.5
d, roughly 121 .mu.m in diameter. The following nonwoven fabrics
were produced and are measured wet after addition of 315 wt % of
water, along with the opacity of the nonwoven measured on the
samples in which the basis weight was determined.
2 Dry Basis Weight Opacity (gsm) (%) 61.8 41.0 63.8 41.8 65.9
41.4
[0056] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628.
[0057] Three measurements are made on one specimen.
Example 1
Fibrous Web Containing Non-Concentric Hollow Fibers
Dry Measurements
[0058] A polypropylene/Lyocell carded hydroentangled fabric was
produced by blending 60 wt % of Basell PH-835 hollow staple fibers
with 40 wt % Lyocell. The percent void area of the Basell PH-835
hollow staple fibers is 20%. The Basell PH-835 fibers were spun,
drawn and crimped to an average fiber diameter of 20 .mu.m. The
Lyocell fiber is 1.5 d, roughly 12 .mu.m in diameter. The following
nonwoven fabrics were produced, along with the opacity of the
nonwoven measured on the samples in which the basis weight was
determined.
3 Basis Weight Opacity (gsm) (%) 49.1 55.07 55.8 58.17 55.5 57.93
56.4 61.11 47.7 54.06 46.8 53.54 30.6 40.54 25.9 34.82
[0059] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen.
[0060] The increase in opacity as shown in this example versus
Comparative Example 1 can be seen with this data. The following
graph illustrates this difference.
Example 2
Fibrous Web Containing Non-Concentric Hollow Fibers
Wet Measurements
[0061] A polypropylene/Lyocell carded hydroentangled fabric was
produced by blending 60 wt % of Basell PH-835 hollow staple fibers
with 40 wt % Lyocell. The Basell PH-835 fibers were spun, drawn and
crimped to an average fiber diameter of 30 .mu.m. The percent void
area of the Basell PH-835 hollow staple fibers is 15%. The Lyocell
fiber is 1.5 d, roughly 12 .mu.m in diameter. The following
nonwoven fabrics were produced and are measured wet after addition
of 315 wt % of water, along with the opacity of the nonwoven
measured on the samples in which the basis weight was
determined.
4 Dry Basis Weight Opacity (gsm) (%) 61.8 47.8 64.2 50.1 66.4
51.5
[0062] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen.
[0063] The increase in opacity as shown in this example versus
Comparative Example 2 can be seen.
Example 3-22
[0064] The following table provides examples of fibers and fabrics
composed of various polymers. Examples 3-11 illustrate single
component fibers and Examples 12-22 illustrate bicomponent fibers.
The bicomponent fibers typically have a sheath to core ratio of
from about 20:80 to about 80:20. The fibers are produced either a
direct spin process or spin and draw process. The table also
provides the void volume of the hollow region. The void volumes
ranges can be made depending on the mass through-put per hole and
melt temperature. As the mass through-put increases and as the melt
temperature decreases, the void volume generally increases. These
fiber can be blended with other synthetic staple fibers or
regenerated cellulose fibers.
5 Example Number Polymer Void volume 3 PLA - Biomer L9000 5-25% 4
Basell PDC-1274 5-30% 5 Basell PDC-1298 5-40% 6 Dow Aspun 6811A
5-20% 7 Eastman F61HC 5-20% 8 Eastman 9663 5-35% 9 Eastman 12822
5-40% 10 Eastman 14285 5-35% 11 Eastman 20110 5-25% 12 Sheath - Dow
Aspun 6811A 5-25% Core - Basell PH-835 13 Sheath - Dow Aspun 6811A
5-35% Core - Basell PDC-1274 14 Sheath - Dow Aspun 6811A 5-25% Core
- Eastman F61HC 15 Sheath - Basell PH-835 5-25% Core - Eastman
F61HC 16 Sheath - Eastman 20110 5-25% Core - Eastman F61HC 17
Sheath - Dow Aspun 6811A 5-25% Core - Eastman 9663 18 Sheath -
Eastman 14285 5-25% Core - Eastman F61HC 19 Sheath - Eastman 14285
5-30% Core - Eastman 9663 20 Sheath - Eastman 14285 5-30% Core -
Basell PDC-1274 21 Sheath - Biomer L9000 5-30% Core - Basell
PDC-1274 22 Sheath - Basell PH-835 5-30% Core - Basell PDC-1274
[0065] Many examples have been shown and given here to demonstrate
the breadth of fibers that can be produced to illustrate the
invention. The benefit of the hollow fibers of the present
invention is demonstrated using Graph 1. Graph 1 shows a plot of
Opacity vs Basis Weight for Comparative Example 1 and Example
1.
[0066] Graph 1 shows that for the same resin, Basell PH-835, that
hollow fibers have better opacity at equivalent basis weight than
solid fibers. Another way of interpreting the Graph 1 is to say
that the basis weight of the hollow fabric can be reduced from 58
gsm to 44 gsm and maintain the same level of opacity.
[0067] Continuous Fiber Examples
[0068] The Examples below further illustrate the present invention.
The crystalline PLA was purchased from Biomer as Biomer L9000. The
amorphous PLA was purchased from Birmingham Polymer and has an
intrinsic viscosity of 1.09 dL/g with an optical rotation of -12.7.
The poly (3-hydroxybutyrate co-alkanoate), PHA, has a molecular
weight of 1,000,00 g/mol before compounding. The
polyhydroxybutyrate (PHB) was purchased from Goodfellow as BU
396010. The polyvinyl alcohol copolymer (PVOH) was purchased from
Air Products Inc. and is a 2000 series polymer. One polypropylene
was purchased from FINA as FINA 3860.times.. Three polypropylenes
were purchased from Basell, Profax PH-835, Profax PDC-1298 and
Profax PDC-1274. The polyethylene was purchased from Dow Chemical
as Aspun 6811A. Five polyester resins were purchased from Eastman
Chemical F61HC, 9663, 12822 as well as two copolyester resins 14285
and 20110.
Comparative Example 23
Fibrous Web Containing Solid Fibers
[0069] A polypropylene spunbond fabric was produced using solid
fiber made from Basell PH-835. The through-put per hole was 0.65
ghm using 2016 hole spinneret. The fibers were attenuated to an
average fiber diameter of 14 .mu.m. These fibers were thermally
bonded together using heat and pressure. The following nonwoven
fabrics were produced, along with the opacity of the nonwoven
measured on the samples in which the basis weight was
determined.
6 Basis Weight Opacity (gsm) (%) 25.9 .+-. 1.3 26.4 .+-. 2.8 24.2
.+-. 1.7 23.8 .+-. 2.5 17.6 .+-. 0.4 18.5 .+-. 1.7
[0070] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen. The data presented here is the average of three specimens
for each material.
Comparative Example 24
Fibrous Web Containing Solid Fibers
[0071] A polypropylene spunbond fabric was produced using solid
fiber made from Basell PH-835. The through-put per holes was 0.65
ghm using 2016 hole spinneret. The fiber were attenuated to an
average fiber diameter of 16 .mu.m. These fibers were thermally
bonded together using heat and pressure. The following nonwoven
fabrics were produced, along with the opacity of the nonwoven
measured on the samples in which the basis weight was
determined.
7 Basis Weight Opacity (gsm) (%) 21.1 .+-. 1.1 18.5 .+-. 1.7 25.9
.+-. 1.3 23.8 .+-. 2.8
[0072] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen. The data presented here is the average of three specimens
for each material.
Comparative Example 25
Fibrous Web Containing Solid Fibers
[0073] A polypropylene spunbond fabric was produced using solid
fiber made from FINA 3860.times.. The through-put per holes was
0.40 ghm using 2016 hole spinneret. The fibers were attenuated to
an average fiber diameter of 13 .mu.m. The following nonwoven
fabrics were produced, along with the opacity of the nonwoven
measured on the samples in which the basis weight was
determined.
8 Basis Weight Opacity (gsm) (%) 20.8 .+-. 1.3 21.7 .+-. 4.7 18.3
.+-. 1.7 18.8 .+-. 2.3 16.7 .+-. 0.4 16.4 .+-. 4.2
[0074] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen. The data presented here is the average of three specimens
for each material.
Example 23
Fibrous Web Containing Hollow Fibers
[0075] A polypropylene spunbond fabric was produced using hollow
fibers made from Basell PH-835. The through-put per holes was 0.40
ghm using 1008 hole spinneret. The fibers were attenuated to an
average fiber diameter of 17 .mu.m. These fibers have an average
void volume of 20%. The following nonwoven fabrics were produced,
along with the opacity of the nonwoven measured on the samples in
which the basis weight was determined.
9 Basis Weight Opacity (gsm) (%) 18.7 .+-. 1.2 23.7 .+-. 1.8 16.3
.+-. 0.8 20.0 .+-. 2.0
[0076] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen. The data presented here is the average of three specimens
for each material.
Example 24
Fibrous Web Containing Hollow Fibers
[0077] A polypropylene spunbond fabric was produced using hollow
fibers made from Basell PH-835. The through-put per holes was 0.40
ghm using 1008 hole spinneret. The fibers were attenuated to an
average fiber diameter of 19 .mu.m. These fibers have an average
void volume of 20%. The following nonwoven fabrics were produced,
along with the opacity of the nonwoven measured on the samples in
which the basis weight was determined.
10 Basis Weight Opacity (gsm) (%) 22.2 .+-. 1.2 26.9 .+-. 1.8 18.7
.+-. 0.8 23.5 .+-. 2.0 16.3 .+-. 1.2 20.0 .+-. 1.8 13.9 .+-. 0.8
17.2 .+-. 2.0
[0078] The opacity measurements are made on an Opacimeter Model
BNL-3 Serial Number 7628. Three measurements are made on one
specimen. The data presented here is the average of three specimens
for each material.
Example 25-44
[0079] The following table provides examples of continuous fibers
and fabrics composed of various polymers. Examples 25-33 illustrate
single component fibers and Examples 34-44 illustrate bicomponent
fibers. The bicomponent fibers typically have a sheath to core
ratio of from about 20:80 to about 80:20. The fibers are produced
either a direct spin process or spin and draw process. The table
also provides the void volume of the hollow region. The void
volumes ranges can be made depending on the mass through-put per
hole and melt temperature. As the mass through-put increases and as
the melt temperature decreases, the void volume generally
increases.
11 Example Number Polymer Void volume 25 PLA - Biomer L9000 5-25%
26 Basell PDC-1274 5-30% 27 Basell PDC-1298 5-40% 28 Dow Aspun
6811A 5-20% 29 Eastman F61HC 5-20% 30 Eastman 9663 5-35% 31 Eastman
12822 5-40% 32 Eastman 14285 5-35% 33 Eastman 20110 5-25% 34 Sheath
- Dow Aspun 6811A 5-25% Core - Basell PH-835 35 Sheath - Dow Aspun
6811A 5-35% Core - Basell PDC-1274 36 Sheath - Dow Aspun 6811A
5-25% Core - Eastman F61HC 37 Sheath - Basell PH-835 5-25% Core -
Eastman F61HC 38 Sheath - Eastman 20110 5-25% Core - Eastman F61HC
39 Sheath - Dow Aspun 6811A 5-25% Core - Eastman 9663 40 Sheath -
Eastman 14285 5-25% Core - Eastman F61HC 41 Sheath - Eastman 14285
5-30% Core - Eastman 9663 42 Sheath - Eastman 14285 5-30% Core -
Basell PDC-1274 43 Sheath - Biomer L9000 5-30% Core - Basell
PDC-1274 44 Sheath - Basell PH-835 5-30% Core - Basell PDC-1274
[0080] Many examples have been shown and given here to demonstrate
the breadth of fibers can be produced to illustrate the invention.
The benefit of the invention can be shown g two graphs. Graph 2
shows a plot of Opacity vs Basis Weight for Comparative Example 24
and Example 23. One additional data point has been added for each,
the requirement that the opacity at zero basis weight is zero. The
data in Graph 3 shows a composite plot of Comparative Example 23,
Comparative Example 25 and Example 24.
[0081] Graph 2 shows that for the same resin, Basell PH-835, that
slightly larger diameter hollow fibers have better opacity at
equivalent basis weight than solid fibers. Another way of
interpreting the Graph 2 shows that the basis weight of the hollow
fabric can be reduced from 20 gsm to 14 gsm and maintain the same
level of opacity.
[0082] Graph 3 illustrates the full effect of the invention. The
much smaller solid fiber produced with FINA 3860.times. and Basell
PH-835 do not match the opacity of a nonwoven produced with larger
diameter hollow fibers made with Basell PH-835. This graph shows
that the basis weight of the hollow fiber fabric can be reduced
from 20 gsm to 16 gsm and match the much smaller diameter
fabric.
[0083] The disclosures of all patents, patent applications (and any
patents which issue thereon, as well as any corresponding published
foreign patent applications), and publications mentioned throughout
this description are hereby incorporated by reference herein. It is
expressly not admitted, however, that any of the documents
incorporated by reference herein teach or disclose the present
invention.
[0084] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is intended to cover in the appended claims all such
changes and modifications that are within the scope of the
invention.
* * * * *