U.S. patent application number 10/135897 was filed with the patent office on 2002-09-12 for system and method for reconstituting fibers from recyclable waste material.
This patent application is currently assigned to Hannagan-Tobey LLC. Invention is credited to Hirsch, Gary F..
Application Number | 20020124366 10/135897 |
Document ID | / |
Family ID | 25039511 |
Filed Date | 2002-09-12 |
United States Patent
Application |
20020124366 |
Kind Code |
A1 |
Hirsch, Gary F. |
September 12, 2002 |
System and method for reconstituting fibers from recyclable waste
material
Abstract
A system is provided for structurally reconstituting fibers from
recycled waste fabric material, including cotton denim waste,
wherein the reconstituted fibers are incorporated into a
hydroentangled or needle punched product without binders or
additives. A tearing line includes the application of steam and
enzymes at a rate sufficient to remove surface additives from the
fibers. The process completely opens the fibers and eliminates
fraying, twisting and nonconformities. A fiber finishing process
provides fibers which are substantially uniform with respect to a
desired characteristic such as length, weight, type, or a desired
blend thereof. The finishing process also provides a fiber web
characterized by a uniform directional orientation of fibers,
making the fibers more amenable to hydroentanglement. The resulting
nonwoven product is characterized by high strength, fiber integrity
and high uniformity and can be cross lapped to thereby provide
greatly increased strength and absorbency.
Inventors: |
Hirsch, Gary F.; (Woodside,
CA) |
Correspondence
Address: |
Crowe & Dunlevy
1800 Mid-America Tower
20 North Broadway
Oklahoma City
OK
73102-8273
US
|
Assignee: |
Hannagan-Tobey LLC
|
Family ID: |
25039511 |
Appl. No.: |
10/135897 |
Filed: |
April 29, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10135897 |
Apr 29, 2002 |
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09755523 |
Jan 5, 2001 |
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6378179 |
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Current U.S.
Class: |
28/103 ; 28/100;
28/102 |
Current CPC
Class: |
D04H 1/732 20130101;
Y10T 442/689 20150401; D04H 1/74 20130101; D04H 1/492 20130101;
D04H 1/4274 20130101 |
Class at
Publication: |
28/103 ; 28/100;
28/102 |
International
Class: |
D04H 001/06 |
Claims
We claim:
1. A cross-lapped hydroentangled material made by the process
comprising: cutting fabric scrap material including cotton denim
waste to a desired size; conveying the cut material through a
series of rotary pin cylinders for successively cutting the
material to form a first web of constituent fibers; each cylinder
comprising a plurality of cutting pins disposed about a
circumference of said cylinder, such that a cutting angle of the
pins of each cylinder can be varied independently to increase or
decrease cutting action depending upon the strength and thickness
of the fibers, whereby successive cutting action of the cylinders
opens the fibers; applying steam and enzymes at a temperature and
rate sufficient to further open and cleanse the fibers of surface
additives and bacteria, yet not saturate the web, such that
unopened fibers are kept to a range of less than 10% and preferably
to a range of about 0% to 1%; forcing said opened and cleaned
fibers through a web-laying machine at a desired angle to produce a
second web of fibers characterized by substantially unidirectional
fiber orientation and uniform fiber density hydroentangling or
needle punching the web of unidirectional fibers to produce a
hydroentangled material capable of being cross lapped to provide
greatly increased strength and absorbency.
2. A hydroentangled product made according to claim 1 further
comprising: laminating and coating the resulting hydroentangled
material with a polyurethane laminate barrier, for providing a
barrier to blood -borne pathogens.
3. A hydroentangled material made according to the process of claim
1 further comprising providing three or more independently
controlled cutting pin cylinders C1, C2, Cn for successively
opening the scrap fibers, wherein the speed of cylinders C1, C2,
Cn, can be varied to obtain different cutting results with respect
to different types of fabrics.
4. A needle punched product made according to the process of claim
1 wherein the second web of unidirectionally oriented fibers is
conveyed to a needle punching machine.
5. A process for reconstituting fibers from recycled scrap fabric
or waste material, including 100 percent cotton denim waste
comprising: conveying the scrap on a conveyor along a direction of
travel to a series of Piret cutters; cutting the material with the
Piret cutters to cause a preferential fiber orientation in the
lengthwise direction parallel to the direction of travel;.
sequentially cutting the preferentially oriented fibers to a
desired length in a tearing line using a series of rotary screen
cutters, which are arranged orthogonally with respect to the
direction of travel, adding steam and enzymes at a sufficient rate
and quantity in the tearing line to open, untwist and clean fibers
without breaking; cutting the opened, untwisted fibers
substantially across their diameter in a second tearing line;
forming a web of substantially uniform density comprising the
opened fibers; and hydroentangling the web to provide a
hydroentangled product characterized by uniform structure and
consistent disbursement of fibers.
Description
BACKGROUND
[0001] The field of the invention relates generally to methods for
recycling fibers. In particular, the field of the invention relates
to a system and method for providing structurally reconstituted
fibers from surplus fabric material such as cotton denim, wherein
the fibers are opened, cleaned and structurally engineered for
delivery to a card without defects such as fiber bundles (neps) or
unopened threads. The reconstituted fibers are then used without
binders to produce a finished nonwoven material having structural
properties enabling it to be cross lapped and laminated, and
exhibiting greater uniformity, strength, and higher absorption
characteristics than was previously possible.
[0002] Increasing expenses associated with obtaining raw materials
and constantly increasing consumption of textile products provide a
strong economic incentive for developing methods for recycling
surplus or unused textile material which would otherwise go to
waste to be burned or buried. Large amounts of cloth scrap,
clippings, and loose sample scraps are created at "cut and sew"
plants where garments are manufactured. These scraps are waste
material that comprise approximately 15-30% of all types of fabric
manufactured for use in garments. Unless recycled into insulating
materials or nonwoven matting, these cloth scraps and clippings
become waste and are sent to landfills. Presently over 200 million
pounds of cotton denim scrap material are burned or buried in
landfills annually. Such reclaimed fibers are of importance in
providing a foundational material for nonwoven fabric technologies
that can be designed to replace traditional woven textiles.
[0003] In the past, surplus or recycled denim material was rejected
as a base for producing fibers for a finished nonwoven product.
Cotton denim is one of the toughest fabrics produced and is
typically woven so tightly that its fibers cannot adequately be
opened or regenerated for reuse. Conventional recycling methods
cannot open surplus denim fibers sufficiently for reuse in a
hydroentangled product. Conventional methods leave so many unopened
threads and neps that a web containing such unopened fibers would
be unsuitable for hydroentanglement. Conventional processes for
opening denim result in fibers which are too short for
hydroentanglement. Such fibers could only be used in conjunction
with binders for rough material such as carpet underlayment.
[0004] New fabric formation techniques and advanced finishing
processes are being used to accomplish fiber to fabric manipulation
to provide a final product comprising nonwoven material. One method
for producing a nonwoven material is accomplished by
hydroentangling or spunlacing a fiber web. Conventional methods of
fiber processing form the fiber web, which can be dry laid or wet
laid after which the fibers are hydroentangled by means of a
plurality of fine water jets under high pressure.
[0005] Conventional methods of recycling cloth scraps involve the
use of high percentages of virgin (non-waste) carrier fibers or
non-biodegradable synthetic fibers. Such conventional methods are
inefficient and produce low quality yam and consequently low
quality fabrics. When high percentages (typically more than 50%) of
virgin fibers are used, raw material costs are substantially higher
and the amount of cloth/ fibers recycled is low because the
resulting yarn/fabric is primarily virgin/fabric.
[0006] Also, the yarn/fabric produced usually must be dyed to a
required color since the large amount of carrier fibers required
dilutes the color of the scrap material being recycled. This
problem is of particular importance when recycling denim because it
must be over coat dyed with indigo, the only accepted organic
natural dye. Because most of the cloth scraps being recycled
already have been dyed, it would be desirable to provide a
recycling process which is capable of using a high percentage of
dyed fibers in the raw material mix. Products derived from such
recycled, dyed fibers or yams would not require any additional
dyeing. This advantageously would eliminate the many costs
associated with dyeing yams and fabrics.
[0007] Although non-biodegradable synthetic fibers are available,
their use implicates serious environmental as well as cost
concerns. The synthetic fibers lack the ability to retain dyes as
efficiently as natural fibers, and they do not bond well with other
fibers because of their slick surfaces. Furthermore, the resulting
fabrics do not have the texture, quality, or acceptance level of
premium natural fibers.
[0008] Therefore, what is needed is a method of recycling natural
or synthetic fibers which can be needle punched and/or provided for
hydroentanglement to produce a superior finished nonwoven product.
What is also needed is a new method to effectively and efficiently
recycle cloth scraps into substantially virgin like fibers which
can be needle punched and/or hydroentangled to produce a superior
fabric and garments using a minimum amount of carrier fibers.
[0009] Recycled fibers also can comprise synthetic fibers, plant
fibers, regenerated cellulose fibers, pulp fibers or the like.
Conventional methods for mechanical recycling of fibers from
nonwoven and textile material are well known.
[0010] U. S. Pat. No. 5,481,864 describes a conventional process
for recycling cloth scraps to produce a yarn from the fibers
contained in the cloth. The process includes moistening the cloth
scraps and maintaining the moisture conditioning at a level of at
least 10 per cent throughout the process. The process of
maintaining fibers in a moist state throughout the shredding
process has disadvantages. The web of moist fibers weighs more and
the fibers tend to progressively agglutinate and clog the cutting
pins of the cylinders in the tearing line. This tends to slow the
process and makes the machines run hotter. The progressive
agglutination of the fibers also reduces the cutting action and
prevents fibers from being fully opened.
[0011] The inability to open the moisture laden fibers results in a
finished nonwoven product which comprises typically weak, soft and
bulky yarn. A web of material comprising such unopened fibers does
not have uniform density and is not suitable for hydroentanglement,
nor for the production of a strong nonwoven material which would be
be capable of use for a wide variety of applications.
[0012] Conventionally, surplus fibers, particularly cotton, are
opened from a bale and cleaned on air carding machines which act to
separate the fibers, ideally to a single fiber state. In order to
open the fibers, it is necessary to extract at least some of the
surface additives such as starches, binders, or other materials
which alter the surface properties of the fibers and prevent fibers
from being easily opened.
[0013] Binders are typically glues or other types of adhesives
which cling to fibers and make them unacceptable for reuse in
applications requiring fiber sterility. Binders especially need to
be removed from recycled fibers in order to enable the fibers to be
opened and reused for other applications U.S. Pat. No. 6,037,282
discloses a conventional process for making a nonwoven material by
hydroentangling a fiber web. The fibers used for forming the web
comprise waste synthetic fibers, plant fibers, regenerated
cellulose fibers or pulp fibers. The fibers are developed by
mechanically tearing or shredding a waste material into small bits
by conventional methods. The fibers are then blown randomly onto
screens and air laid. This creates a random orientation of fibers
on a web. Such a random orientation of fibers, when applied to
hydroentanglement, produces a structurally inferior product
characterized by varying thread density, unopened fibers, neps and
other unconformities which render the finished hydroentangled
product incapable of being cross lapped or laminated, and thus
limits useful applications.
[0014] A further disadvantage of the process taught by U.S. Pat.
No. 6,037,282 is that the tearing action for freeing the fibers
also shreds and stretches the fibers along the longitudinal axis,
resulting in weakened, frayed and distorted fibers which may end up
twisted and difficult to open. U.S. Pat. No. 6,037,282 concedes
that the freeing of the fibers is often incomplete and the fibers
clump together to form flocks. The flocks in turn produce
nonuniformities in the final nonwoven product, resulting in reduced
strength. (See U.S. Pat. No. 6,037,282 at col. 2, lines 54-63;
"notably lower strength," col. 3, lines 58-62.)
[0015] A conventional process such as U.S. Pat. No. 6,037,282 must
compensate for reduced strength of the hydroentangled product by
adding binders such as polyamide-epichlorohydrin, EVA, latex, or
the like. The amount of additive is between 0.1 and 10 percent by
weight, preferably between 1 and 5 percent by weight, calculated as
part of the weight of the material (Column 3, lines 24). However,
this puts surface impurities onto the fibers, making them
unsuitable for many applications requiring medical sterility or
high absorbency. The addition of binders makes the resulting
fibers, which are already weakened, even more difficult to open in
the event the nonwoven product is to be recycled Thus, the addition
of binders limits the finished nonwoven material to a single use
product.
[0016] In addition to adding undesirable binders, a conventional
process such as in U.S. Pat. No. 6,037,282 also results in so many
unopened fibers and threads that the unopened threads cannot be
cleaned of trash such as surface impurities, binders, and other
additives. Thus, a hydroentangled product made from such a large
proportion of unopened fibers is unusable except for limited
applications. such as an industrial wiping or drying material.
[0017] Therefore, what is needed is a system for reconstituting
fibers from waste or surplus materials, wherein the reconstituted
fibers can be applied to a hydroentangling process to produce a
nonwoven product of superior strength and uniformity, thereby
enabling the final product to be used in a wide variety of
applications.
[0018] What is also needed is a method for opening fibers of
recyclable materials and for removing trash, binders, starches, and
other surface impurities from the opened fibers. Such a process
advantageously would provide structurally stronger, cleaner fibers
which would be more amenable to hydroentangling. A nonwoven product
embodying such engineered fibers would be characterized by surface
uniformity, high strength and would be suitable for a wide variety
of household and industrial applications.
[0019] What is also needed is a method for recycling a tightly
woven fabric such as cotton denim and for fully opening those
fibers with minimal distortion and loss of structural integrity due
to tearing and shredding the fibers along their longitudinal axis,
such that the fibers may be reused in making a hydroentangled
product without defects.
[0020] In addition, it would be highly desirable to provide a
process for engineering or structurally reconstituting reclaimed
fibers which would open and remove all surface additives and
impurities from the fibers. Thus, a hydroentangled product
comprising such fibers could be made without the need for binders
and would conform to high standards of medical sterility for
medical, cosmetic, and other applications requiring a contamination
free product. Such a hydroentangled product, made without binders,
also easily could be recycled for other applications, thereby
providing a multi use, resource sustainable product.
SUMMARY
[0021] In order to achieve the foregoing objectives and other
advantages, an aspect of the invention reconstitutes fibers from
recycled or waste fabrics, including cotton denim waste, and forms
the reconstituted fibers into a hydroentangled product
characterized by substantially uniform fiber density, greater
tensile strength and preferential fiber orientation. This enables
the hydroentangled material to be cross lapped or laminated with
other materials for greatly increased strength. For example,
hydroentangled materials comprising directionally oriented fibers
in accordance with an aspect of the invention can be cross lapped
and coated with a polyurethane laminate barrier, which provides an
absolute barrier to blood borne pathogens and has widespread
benefit in medical applications.
[0022] An aspect of the invention provides a means for granulating
the fibers and for conveying fibers through a series of cutting
screens, such that the fibers are cut substantially across their
diameter, thereby minimizing fiber distortion and preserving the
structural integrity of the fibers.
[0023] Another aspect of the invention applies steam in combination
with an enzyme scrubbing process for completely opening fibers of
recycled waste material including cotton denim waste. This
substantially removes all surface impurities from the opened fibers
including starches, adhesives, binders, and other contaminants.
This enables a nonwoven product produced from such fibers to meet
stringent standards of sterility for medical applications.
[0024] In accordance with another aspect of the invention, a
carding I equalization process provides a web of fibers for
hydroentanglement characterized by unidirectional fiber orientation
and uniform fiber density. The resulting hydroentangled product is
structurally different from one produced by a conventional
hydroentangled fiber web, in that it is characterized by a
preferential fiber orientation and can be cross lapped or laminated
with other materials.
[0025] The foregoing aspects of the invention also eliminate the
need for adding binders and adhesives to the recycled fibers in
order to provide material strength. Thus, a nonwoven product
produced in accordance with the invention is amenable to further
recycling, thereby providing a sustainable, multiple use
product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] These and other features, aspects and advantages of the
invention will become better understood with regard to the
following descriptions, appended claims and accompanying drawings
in which:
[0027] FIG. 1 is a block diagram showing a conventional tearing and
carding process prior to hydroentanglement.
[0028] FIG. 2 is a block diagram of a process for engineering
fibers and for producing a finished product by hydroentanglement in
accordance with an aspect of the present invention.
[0029] FIG. 3 is a block diagram of an alternative process for
engineering fibers and producing a finished product by
hydroentanglement in accordance with an aspect of the present
invention.
[0030] FIG. 4 is a block diagram of another process for engineering
fibers and for producing a finished product by hydroentanglement in
accordance with an aspect of the present invention.
[0031] FIG. 5 is a block diagram of another process for engineering
fibers for hydroentanglement in accordance with an aspect of the
invention.
DETAILED DESCRIPTION
[0032] FIG. 1 shows a conventional process for recycling fibers and
for preparing the fibers for hydroentangling. Raw material 100
comprises recycled waste textiles or unused, surplus scrap material
comprising natural or synthetic fibers. Raw material 100 is
provided on a conveyor or cutting line to a conventional system of
rotary cutters 102. Rotary cutters 102 successively shred the
recycled material in a substantially random manner. From rotary
cutters 102 the shredded material is conveyed to a conventional
tearing line 106 comprising a series of rotary cutters or rotary
pins, wherein the fabric is successively torn and shredded. Such a
conventional tearing line is incapable of opening woven cotton
denim. Woven cotton denim is one of the toughest of fabric
materials and is woven so tightly that it cannot be opened
sufficiently for reuse in needle punched or hydroentangled product.
Thus, a conventional process cannot accept denim scrap for
recycling.
[0033] Referring again to FIG. 1, the tearing line typically aligns
the fibers in parallel along the longitudinal axis of the fiber.
Each subsequent tearing step tears and shreds the fibers along the
same longitudinal axis causing stretching, fraying, distortion and
twisting of the fibers, resulting in general loss of integrity and
weakening of the fibers. In addition, twisting of the fibers makes
the fibers difficult to open.
[0034] Subsequent to the tearing line 106, the torn and separated
fibers are conveyed to a web forming process 108 wherein the fibers
may be wet laid, air laid, dry laid, or foam laid. In a dry-laid
system, the web is formed by having the fibers blown onto a screen
in a random manner while in a dry state. With the wet laid system,
the web structure is formed by manipulating the fibers while in a
wet state. In a foam-laid system, the web structure is formed by
blowing thermoplastic fibers onto a collection surface as the
fibers are being extruded. In all cases, the web forming fibers are
oriented in a substantially random manner.
[0035] The resulting web of fibers is then sent to a conventional
hydroentanglement process 110. A disadvantage of this conventional
process is that the tearing line and web forming process are
insufficient to open the fibers that have been delivered from the
tearing line. That is, a multitude of unopened, twisted or weakened
fibers will be put through the hydroentangling process. This
results in a finished nonwoven product which is characterized by
surface discontinuities, neps, unopened threads, and a generally
unaesthetic appearance. Such a nonwoven product is typically usable
for only limited applications such as for industrial wipes or
carpet underlayment. In addition, the fibers comprising such a
product must be held together by the addition of binders or glues.
Basically, this conventional process results in a single use
product which again creates more waste after only a single
application.
[0036] FIG. 2 shows a fiber balancing process 200 according an
aspect of the invention in which waste synthetic or natural fibers
derived from raw materials, including cotton denim, are opened and
provided in a preferential directional orientation on a web for
hydroentanglement.
[0037] Referring to FIG. 3, opened fibers from a series of rotary
pin or wired cylinders 314 are provided to a willow cleaner 316 and
condenser 318, respectively. The willow cleaner 316 air lofts and
cleans the fibers in accordance with standard techniques. The
fibers are then collected in the condenser 318 and condensed into
the form of a lap or bating. The condensed fibers are delivered to
a conveyor for transporting to baler 320 where fibers are laid down
into open bales in a standard manner for further processing.
[0038] Referring again to FIG. 2, bales of fibers from baler 320
are provided to a fiber balancing/equalization process 200. Fiber
balancing process 200 separates bales of fibers in accordance with
known techniques for picking and balancing fibers according to
measurable characteristics such as size and weight or by the
composition of fiber. In the example shown, natural fibers are
output to a plurality of bales B1, B2 . . . Bn. The bales represent
successive "runs" or applications of natural fibers through rotary
pin or wired cylinders 314 (FIG. 3) or a granulating process (such
as 406 in FIG. 4) which cuts the fibers to a predetermined
size.
[0039] Successive "runs" of synthetic fibers through the
granulating process also result in synthetic fibers being sorted
into a series of bales, SYN1, SYN 2 . . . SYN n. Fiber balancing
process 200 enables multiple bales of engineered fibers of known
lengths and characteristics to be sorted according to known
characteristics for subsequent processing and blending.
[0040] In accordance with this aspect of the invention, fiber
finishing 322 comprises an equalization process which is applied
selectively to the plurality of bales in 200. Fiber finishing
includes a picker or other means for sequentially removing a layer
of fibers from each bale or selected bales B1 . . . Bn or SYN1 . .
. SYN n. Alternatively, bales of natural fibers B1 . . . Bn can be
balanced in any desired proportion with bales of synthetic fiber
SYN 1 . . . SYN n. In addition, layers of fibers can be balanced
selectively from each of the bales B1 . . . Bn or SYN 1 . . . SYN
n. The thickness of each layer selected can be the same or may be
varied in accordance with the needs of the material which is to
comprise the final product. The purpose of this process is to
ensure uniformity of fiber characteristics such as density or
preferential fiber orientation. By picking a layer of fibers from
selected bales a web of material is successively built up of layers
wherein the resulting fibers are equalized. That is, a web of
material can be made uniform because fibers can be sorted by their
properties to build in uniformity to an extent which was not
previously possible.
[0041] In addition, equalized layers from natural fibers, (for
example B1, B2) can be matched with other selected layers from
synthetic bales SYN 1, SYN 2, . . . SYN n, etc. This also enables
fibers of selected lengths and characteristics to be blended with a
high degree of uniformity in the resulting hydroentangled
material.
[0042] After blending of fibers at 200, blended fibers are conveyed
through a station 201 which applies a warm mist comprising a
glycerine based lubricant to the fibers. The warm mist is at a
temperature in a range sufficient to enable the fibers to be
expanded, but does not agglutinate the fibers. The mist applies a
glycerine based oil to the fibers which softens and untwists the
fibers. The adhesion of the glycerin based oil to the fibers also
eliminates untwisted fibers, neps and nonconforming fibers in the
fiber finishing process at 322. Fiber finishing 322 comprises a
series of combing wires. The lubricated fibers from 201 are
completely straightened and untwisted by the combing wires in fiber
finishing 322 such that the resulting blended bales at 208 are free
of any neps and are characterized by uniform density.
[0043] According to this aspect of the invention, fiber balancing
200 in combination with fiber finishing 322 makes possible a more
uniform distribution of fibers by removing in sequence a
predetermined layer from each of a plurality of bales. This also
produces at new blended bales station 208 a blending of synthetic
and natural fibers of desired lengths and other characteristics
such as weight, thickness, color, or the like.
[0044] From the fiber finishing 322 and new blended bales 208, the
fibers are then provided to a blending line 210. At 210 the
finished fibers are formed into a web characterized by their
selected uniform characteristics. For example, fibers may be formed
onto a web with a preferred uniform directional orientation. The
web of directionally oriented fibers is provided selectively to
either a needle punch station 212 or to hydroentanglement 220.
[0045] In needle punched station 212, the fibers are needle punched
in a wide variety of thick nesses in accordance with the
characteristics imparted by fiber balancing 200 and fiber finishing
208. Needle punch station 212 also can perform needle bonding
wherein a fiber web is bonded into sheets by the action of barbed
needles which entangle the fibers. The needle punched fibers from
212 are then conveyed to hydroentanglement station 220 to be
hydroentangled into a finished product.
[0046] In accordance with an aspect of the invention, the foregoing
process results in a web characterized by preferred directional
fiber orientation. This provides a hydroentangled product of
uniform density and selected directional fiber orientation
structurally different from that produced by a conventional web of
randomly oriented fibers.
[0047] The hydroentangled product made from the web according to
this aspect of the invention is substantially uniform in terms of
fiber density, has greater tensile strength, and is free of
unopened fibers. In addition, the ability to form a web of
unidirectionally oriented fibers according to the invention enables
the resulting hydroentangled product to be cross lapped to thereby
provide greatly increased strength and absorbency.
[0048] The crosslapping of directionally oriented fibers also
enables the hydroentangled product to be laminated and coated with
a polyurethane laminate barrier, for example, which would provide
an absolute barrier to blood -borne pathogens. This provides a
clear advantage in using such a hydroentangled product for medical
applications.
[0049] Optionally, the web of material from 210 may be conveyed to
an air laid station 214 wherein layers of fibers are progressively
laid down and may be cross lapped to impart additional strength.
The air laid fibers at 214 have a preferred weight in a range of
about 3 oz. up to 7 or 8 oz. per square yard.
[0050] FIG. 3 shows an aspect of the invention in which bales of
raw material 300 are provided to an entrance conveyor 302. Raw
material 300 comprises either natural or synthetic fibers or a
blend of both. Aspects of the invention provide for substantially
complete opening of the fibers and removal of all surface additives
or "trash". Accordingly, fibers can be derived from waste, surplus
or recycled materials including woven cotton denim. Thus, raw
material 300 may comprise for example, recyclable synthetic
material or natural material such as 100% cotton denim waste,
linen, wool, or the like.
[0051] The following aspects of the invention provide a process for
producing reconstituted fibers from the foregoing materials which
are substantially opened, cleaned of any surface additives
including binders and starches and reengineered to a substantially
virgin state. Furthermore, the reconstituted fibers can be long
enough (0.8-0.9 inches) so that they can be used in a variety of
applications and are delivered to needle punching or
hydroentangling substantially without neps, unopened threads, or
the like.
[0052] From the entrance conveyor 302, bales of raw material are
conveyed to guillotine cutters 304. The guillotine cutters 304 cut
the raw material to a desired manageable size. The cut raw material
is then conveyed to rotary cutters 306. Rotary cutters 306 comprise
one or more rotary cutters which further cut the materials and
impart an initial desired orientation to the scraps of
material.
[0053] The scraps of material from the rotary cutters 306 are then
conveyed to storage/blending boxes 307 for blending with other
scraps. The blended materials in the storage boxes are amenable to
chemical treatment or other chemical manipulation, for example the
application of sterilizing agents or other agents to remove trash
or surface additives from fibers. A conventional pinned inclined
apron picks up material from the storage boxes such that the
material is then air conveyed or air transferred out of
storage/blending boxes 307 to rotary pin cylinders 308.
Alternatively, scraps of material from the rotary cutters 306 may
be conveyed directly in a web to a first series of rotary pin
cylinders 308.
[0054] In a preferred embodiment, rotary pin cylinders 308 comprise
three or more independently controlled cylinders C1, C2, Cn. Thus
the speed of cylinders C1, C2, Cn, can be varied to obtain
different cutting results with respect to different types of
fabrics. The rotary pin cylinders 308 are provided with a plurality
of cutting pins disposed about the circumference of their
respective surfaces. The angle of the cutting pins can be varied so
that the angle at which the pins strike the fibers can be optimized
to increase or decrease the cutting action depending upon the
strength and thickness of the fibers and other variables. When the
web of material having a preferential orientation is passed over
the first rotary pin cylinder C1, the incident angle of the cutting
pins with respect to the fibers can be set according to properties
desired in the output fibers. The fiber web is then passed
sequentially over successive rotary pin cylinders C2, . . . Cn. The
incident angle of the cutting pins of each subsequent rotary pin
cylinders 308 can be adjusted so that the fibers can be gradually
opened without loosing strength or integrity.
[0055] The web of opened fibers from rotary pin cylinders 308 is
then conveyed to one or more storage boxes 310. Alternatively, the
web of fibers may be conveyed directly to an enzyme treatment as
described infra. The storage boxes 310 are filled sequentially in
layers for blending. Blending of fibers of different weights can be
accomplished in the storage boxes by fiber equalization as
described in FIG. 2. In accordance with an aspect of the invention,
storage boxes 310 facilitate the selective incorporation of an
enzyme treatment to the fibers or selected layers of fibers. Steam
and enzyme treatment 312 also can incorporate the application of
reducing agents to thereby remove chemical impurities, and prepare
for subsequent steam removal of surface additives such as starch,
binders, or other so-called trash. The progressive opening of the
fibers accomplished by rotary pin cylinders 308 enhances chemical
manipulation of the fibers.
[0056] The opened fibers are conveyed from storage boxes 310 to a
steam and enzyme application station 312. Steam at 312 is provided
to the fibers through a series of jets which may be disposed above
or below a web containing the fibers. The steam has a temperature
in a range of about 185 degrees F. to 310 degrees F. What is
important is that the steam is applied at a temperature and rate
sufficient to cleanse the fibers of additives and bacteria, yet not
saturate the web. This prevents agglutination or clumping of fibers
and therefore eliminates inconsistencies or density variations in
the web. The steam is applied in a manner so as to not over
saturate the fibers while at the same time further opening the
fibers and removing surface additives such as starch, binders or
other trash from the fibers.
[0057] The steam-opened and cleaned fibers are then conveyed for
the application of enzymes to further remove starch and other
surface additives which may not have been taken out by the steam.
An enzyme treatment is provided to remove starch and binders from
the fibers. Enzymes also may be employed at this point to change
the surface properties of the fibers, making them hydrophilic, if
desired for a high-absorbency application of the hydroentangled
product.
[0058] The enzymes are of a type whose catalytic cleansing ability
is not affected by the temperature of the steam saturated fibers.
The enzymes are typically applied in either a bath or by means of a
high pressure wash. The purpose of the enzyme treatment is to
remove all of the starches, binders, adhesives or any other surface
additives from the material. After the material leaves the enzyme
treatment station 312, steam can be applied to the output fibers in
order to clean the fibers thoroughly so that they could also be
treated with a colorfast chemical at this point. However, these two
steps are optional.
[0059] Preferably, the treatment may be accomplished utilizing a
conventional amylase enzyme which converts starch on the fibers to
sugar, which is water soluble and can be washed out of the fibers.
Such an enzyme treatment is typically about fifteen minutes long at
140 degrees F and comprises adding 1-2% enzyme per pound of fiber.
An example of an enzyme is RAPIDASE-XL, a conventional amylase
enzyme manufactured by International BioSynthetics. Since enzymes
are active within an optimal temperature range of about 45.degree.
C. to 60.degree. C., the enzyme treatment can be deactivated as is
well known by changing the temperature or pH level after the
hydrolysis of fibers to the desired extent. Because the enzymes are
natural proteins, readily biodegradable, they are a favorable
alternative to many finishing chemicals and resins that are
currently used.
[0060] After the enzyme treatment, the fibers are rinsed, typically
for five minutes, or long enough in order to ensure that all
starches and other additives are extracted. The enzyme treatment
also can employ other commercially available amylase enzymes,
penetrants, and wetting agents depending on the desired
characteristics to be engineered into the fibers. A blend of
amylase enzyme, penetrants and wetting agents, such as Blue-J 421,
available from Sybron Tanatex Company, or equivalent, can be used
to rapidly decompose sizing agents from fibers and can improve the
wetting and absorbent properties of synthetic fibers.
[0061] On polyesters, reactions with several lipases can be used to
convert the typically hydrophobic surfaces to hydrophilic ones.
Such enzyme hydrolyzed polyester fibers are well known and can be
chemically engineered in a well known manner to have wetting and
absorbent characteristics much superior to the original fibers. The
surface nature of these reactions has no effect on the strengths of
the materials. With respect to cotton denim, several pectinases,
proteases, and lipases have been shown to be effective in removing
the pectins, proteins, and fatty acids on fiber surfaces, thereby
rendering the fibers hydrophilic.
[0062] Thus, the recycled fibers are structurally reconstituted to
a substantially virgin state. The fibers are completely opened,
sterilized, freed from surface additives, and their surface
structure can be enzymatically engineered to achieve a desired
degree of absorbency.
[0063] The resulting hydroentangled product derived from the
engineered fibers according to this aspect of the invention is
characterized by superior strength due to the unidirectional
properties of the input fibers, exhibits a marked increase in
dimensional stability and can be held together without binders. The
sterile, binderless fibers also can be cross-lapped such that the
hydroentangled product surface structure is characterized by a high
hydrophilic state. A hydroentangled product comprising such fibers
thus can be provided with specific therapeutic substances for
medical applications.
[0064] After steam and enzyme treatment 312, the fibers may be
transported to rotary pin or wired cylinders 314 for further
processing or drying.
[0065] At the output end of enzyme station 312, fibers from the
bales of raw materials 300 are now reengineered in the sense that
they have been opened and all surface additives have been removed.
The fibers are then air lofted and conveyed to a second series of
rotary pin cylinders 314. Rotary pin cylinders 314 comprise a one
or more successive rotary pin cylinders. In a preferred embodiment,
three rotary pin cylinders 314 are employed.
[0066] The speed of the rotary pin cylinders 314 can be varied to
provide additional refinements to the fibers. For example, the
speed of the rotary pin cylinders 314 can be optimized to cool the
fibers such as cotton. This aids in keeping the cotton fibers at a
specific temperature in order to further open the fibers without
breaking them. In addition, the angles of the cutting means or pins
on the rotary pin cylinders 314 also can be varied to a specific
angle which optimizes opening of the fibers without breaking.
[0067] It will be appreciated that fibers from the output end of
rotary pin cylinders 314 are now engineered in the sense that they
are substantially completely opened and are free of all surface
additives. That is, recycled fibers including woven cotton denim
have been opened, and reengineered to a substantially virgin state.
Unopened fibers are kept to a range of less than 10% and preferably
to range of about 0% to 1%. Such fibers now can be reused in either
a needle punched product or can be delivered to hydroentanglement
to provide a more uniform hydroentangled product without neps,
unopened threads, or other nonconformities.
[0068] Fibers from the output end of rotary pin cylinders 314 are
provided to willow cleaner 316 where they are cleaned and air
lofted in accordance with standard techniques. From willow cleaner
316, the fiber s are conveyed into a condenser 318. The condenser
318 removes air from the fiber web thereby enabling the fibers to
fall by gravity into boxes to be compressed into bales a t 320.
[0069] Bales are then provided to fiber balancing station 200.
Balanced fibers are then misted with warm glycerine based lubricant
at station 201 as explained with reference to FIG. 2; and conveyed
for fiber finishing at 322: Fiber finishing creates a preferential,
unidirectional orientation of the fibers. The resulting
hydroentangled product employing these fibers is characterized by a
finish free of twisted yarn and nonconformities. The hydroentangled
product made by this process can result in a high-grade material of
medical purity for reception of anti-microbial agents for medical
and cosmetic applications. In addition, the preferential
orientation enables the hydroentangled product to be cross lapped
and laminated for superior strength.
[0070] FIG. 4 shows another embodiment of the present invention for
opening fibers from waste or surplus material. In particular, this
aspect of the invention also can be used to open fibers from 100%
cotton denim. Referring to FIG. 4, bales of cotton denim or other
raw material 400 are provided to entrance conveyor 402 and then
conveyed to Piret cutters 404.
[0071] Piret cutters 404 cut the fabric from the entrance conveyor
and perform an initial fiber orientation across the web of fabric.
Piret cutters 404 cause the fiber orientation to be in the
lengthwise direction parallel to the direction of travel of the
web. The fiber orientation can be achieved by preferential
placement of the Piret cutters. The Piret cutters influence the
elongation properties of the fibers and thereby prepare the fibers
for the engineering process 406.
[0072] Materials are conveyed from the Piret cutters 404 to
storage/blending boxes 407. These have the same function as
storage/blending boxes 307 described with reference to FIG. 3.
Engineering process 406 comprises a first set of rotary screen
cutters 408 which receive the fibers in a preferred orientation
from Piret cutters 404. Rotary screen cutters 408 comprise a series
of preferably two to four or more serially disposed rotary screen
cutters 408 which are arranged to cut the fibers substantially
across their diameters, thereby minimizing the fraying, stretching,
twisting, distortion and general weakening of the fibers
characterized by a conventional tearing process.
[0073] In accordance with an aspect of the invention, the
engineering process 406 also comprises a series of multiple cutting
screens 410 which cut the fibers across their diameters. The
purpose of sequential cutting by a series of multiple cutting
screens 410 is to create fibers of consistent length and denier
quality. The series of multiple cutting screens 410 can selectively
cut the fibers to specified lengths as short as {fraction (1/32)}
of an inch. Thus, the engineering process creates fibers of uniform
sizes such as, for example: {fraction (1/32)}, 1/8, {fraction
(3/16)}, 1/4, 3/8, 1/2, or 3/4 inches by successive applications of
fibers through each of the granulating or multiple cutting screens
410. Thus, if a shorter fiber is required, multiple screens are
used. This results in an engineered fiber characterized by superior
structural integrity, wherein neps, twisted fibers and any
nonconforming fibers can be eliminated. The engineered fibers are
now consistent in length and diameter.
[0074] The engineered fibers are then optionally conveyed to willow
cleaner 316 which operates as described with reference to FIG. 3.
From the willow cleaner 316, fibers are conveyed to condenser 318
and baler 320 which also operate as explained with reference to
FIG. 3. The output fibers from baler 320 are then conveyed to an
air laid process 414. Air laid process 414 then blows the
engineered fibers onto a web. All fibers are consistent in length
and diameter. The air laid process 414 results in a web
characterized by uniform density and the absence of unopened
fibers, twisted fibers, nonconforming fibers, or other
nonconformities which would result in neps or unevenness. The web
of uniform density is then conveyed to hydroentanglement 420. The
resulting hydroentangled product is characterized by uniform
density, increased strength and absorbency.
[0075] In accordance with an aspect of the invention, the
engineering process shown in FIG. 4 enables the fibers to be cut
across their diameters. This substantially eliminates unopened
threads, twisted and frayed fibers and inconsistent or uneven
disbursement of fibers. Thus, the finished hydroentangled product
according to the present process is highly uniform in structure and
appearance. The consistent disbursement of fibers also increases
absorbency and the capacity to retain fluids for subsequent
applications without waste, such as hydroentangled pads saturated
with fine lubricants.
[0076] FIG. 5 shows a process for engineering fibers, including
fibers derived from woven cotton denim waste, such that the fibers
are reconstituted to a substantially virgin state. Bales of raw
material including surplus cotton denim fabric 500 are provided to
entrance conveyor 502. The material is then conveyed to guillotine
cutters 504. Guillotine cutters 504 cut the bales of fabric in a
controlled manner and impart a fiber orientation in the
longitudinal direction. The web of cut fibers is then applied to a
tearing line comprising a series of rotary cutters 506. Rotary
cutters 506 preferably comprise three or more independently
controlled rotary cutters, R1, R2, Rn . . . In accordance with an
aspect of the invention, the rotary cutters are independently
controlled and the speed of each cutter can be optimized to
maintain a constant temperature for cotton fibers.
[0077] As the fibers are opened by rotary cutters 506, a web is
elongated and successive cutters must rotate faster than initial
cutters. In accordance with an aspect of the invention, steam may
be added anywhere in the tearing line comprising rotary cutters
506. However, it has been found that best results are obtained when
steam and enzymes 508 are added after the third or subsequent
rotary cutter.
[0078] From rotary cutters 506, shredded material is conveyed to
blending ans storage boxes 507 for chemical manipulation as
explained with reference to storage boxes 307 in FIG. 3. The
material is then air conveyed to steam and enzyme application
station 508.
[0079] Steam and enzymes 508 are added in accordance with the
description set forth with reference to FIG. 3, and provide many
advantages not previously attainable. For example, the addition of
steam in the tearing line has been found to open denim without
breaking the fibers. The steam additionally untwists the fibers and
adds strength during the subsequent opening of the fibers by the
series of rotary cutters. The addition of steam at 508 also has
been found to advantageously cool the web of material and the
rotary cutters, thereby enabling the entire process to run cooler.
This occurs due to the fact that the steam condenses quickly onto
the fibers on the moving web. This also adds an additional
disinfecting step so that the output fibers are sufficiently clean
to meet standards of medical purity.
[0080] After the application of steam and enzymes at 508, The web
of opened and sterilized fibers is sent to a series of rotary pin
cylinders 509 which are used to further refine the lengths of the
fibers according to the needs of the final product. It will be
appreciated that the fibers from the output of steam and enzyme
treatment 508 are substantially opened and have a preferential
lengthwise orientation on the fiber web. This is also true for the
engineered fibers from the output of the series of rotary pin
cylinders 509.
[0081] In addition to the cleaning and strengthening action of the
steam, the enzyme process at 508 removes all of the surface
additives from the fibers. Thus, denim or other fibers exiting the
rotary pin cylinders 509 are completely cleaned and opened, and are
reconstituted to a state substantially equivalent to virgin fibers.
For this reason, the output fibers in accordance with this aspect
of the invention are defined herein as engineered fibers.
[0082] The cleaned and opened fibers now have a lengthwise
orientation on a fiber web. The opened fibers are then conveyed to
engineering process 510 comprising a series of multiple cutting
screens which create a specified fiber length. The multiple cutting
screens are disposed for cutting the lengthwise oriented fibers cut
the fibers substantially across their diameters and can create
fibers in selected lengths as short as {fraction (1/32)} of an
inch. This eliminates neps, unconformities and twisted fibers. The
fibers are then air laid at 512 and conveyed to hydroentanglement
or paper conversion 516.
[0083] Alternatively, the air laid fibers can be conveyed to
finishing cards at finished fiber station 514. The finishing cards
align the fibers in a substantially uniform, preferential direction
or orientation for subsequent hydroentanglement. The carding
process at 514 results in a web characterized by uniform density
and unidirectional fiber orientation. The hydroentangled product
made from the web according to this aspect of the invention is
substantially uniform in terms of fiber density, has greater
tensile strength, and is free of unopened fibers.
[0084] Since the fibers are cleaned of surface additives,
disinfected by superheated steam and fully opened, they provide a
superior product capable of meeting standards of medical purity.
Such fibers can be used for many medical applications and can be
used as an applicator base for the superficial application of
liquid medications, salves, ointments, or the like.
[0085] The finished hydroentangled product, according to this
process also has many advantageous cosmetic applications. For
example, the hydroentangled finished product produced by the
process described herein actually has higher absorbency
characteristics than can be achieved by a conventional
hydroentanglement process. The substantially complete cleaning ad
disinfecting of the opened fibers from the output of tearing line
406 makes the fibers more amenable to hydroentanglement.
[0086] Also, since the fibers are finished to attain a preferential
orientation on a web, the hydroentangled product made from the web
carries over and incorporates a preferential alignment of fibers.
This enables the hydroentangled product to be cross lapped and
laminated with a barrier film such as polyurethane, to provide an
absolute barrier to blood borne pathogens in medical applications.
The crosslapping of directionally aligned fibers of a finished
hydroentangled product also results in greatly increased absorbency
or the capacity to hold and apply medication or cosmetics for a
prescribed duration of time.
[0087] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiments, it is to be understood that the invention is not
limited to the disclosed embodiments and alternatives as set forth
above, but on the contrary is intended to cover various
modifications and equivalent arrangements included within the
spirit and scope of the appended claims.
[0088] For example, one skilled in the art will recognize that
tearing lines may be replaced with one or more granulators for
cutting material and opening fibers. Also, steam can be added at
any point in the tearing line or prior to air lofting.
Additionally, many equivalent classes of enzymes can be utilized to
hydrolyze starches or alter surface properties of fibers. The
enzyme process also can be added prior to or subsequent to the step
of adding steam. Other chemical reagents for removing surface
impurities may be substituted for the application of enzymes.
[0089] Therefore, persons of ordinary skill in this field are to
understand that all such equivalent arrangements and modifications
are to be included within the scope if the following claims.
* * * * *