U.S. patent application number 10/827129 was filed with the patent office on 2004-10-28 for process for the conversion of cellulose acetate waste fibers into a suitable form for paper production and the resultant paper products.
Invention is credited to Mitchell, Melvin G., Stroud, Herbert D. JR..
Application Number | 20040214702 10/827129 |
Document ID | / |
Family ID | 33303280 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040214702 |
Kind Code |
A1 |
Stroud, Herbert D. JR. ; et
al. |
October 28, 2004 |
Process for the conversion of cellulose acetate waste fibers into a
suitable form for paper production and the resultant paper
products
Abstract
A process for producing artificial fibers without significant
fiber surface hydrolysis from waste cellulose acetate continuous
filament or filter rods which can then be used in the manufacture
of specific paper products. Waste cellulose acetate fibers
generated during filament manufacture or cigarette manufacture as
off quality production is used for rendering the into a form
suitable for specific paper manufacture. Paper products which
comprise 1-10% of the subject fiber as part of the pulp furnish is
also disclosed.
Inventors: |
Stroud, Herbert D. JR.;
(Rutherfordton, NC) ; Mitchell, Melvin G.;
(Penrose, NC) |
Correspondence
Address: |
Adams Evans P.A.
2180 Two Wachovia center
301 S. Tryon Street
Charlotte
NC
28282
US
|
Family ID: |
33303280 |
Appl. No.: |
10/827129 |
Filed: |
April 19, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60465743 |
Apr 25, 2003 |
|
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|
Current U.S.
Class: |
493/39 ; 162/139;
162/4 |
Current CPC
Class: |
D21H 13/06 20130101;
D21B 1/12 20130101 |
Class at
Publication: |
493/039 ;
162/004; 162/139 |
International
Class: |
D21B 001/08; D21B
001/32; A24F 007/00 |
Claims
We claim:
1. A process for producing paper with mechanically processed waste
cellulose acetate fiber, comprising the steps of: (a) providing a
raw material in the form of waste long staple or continuous
filament cellulose acetate fibers; (b) mechanically shredding the
waste cellulose acetate to a fiber length of less than about 14 mm;
(c) mixing the shredded waste cellulose acetate with cellulose to
form a slurry; and (d) making paper from the slurry.
2. The process of claim 1 wherein the waste cellulose acetate fiber
contains substantial crimp.
3. The process of claim 2 wherein the crimp is produced by
mechanical interfiber plasticizer bond separation due to
shredding.
4. The process of claim 3, and further comprising the step of
repulping the mechanically shredded cellulose acetate and cellulose
with water.
5. The process of claim 4, and further comprising the step of
repulping is conducted with periodic or continuous high shear
agitation.
6. The process of claim 5, and further comprising the step of
confricating or mechanically refining the aqueous mixture of
cellulose acetate and cellulose.
7. The process of claim 6, and further comprising the step of
blending the aqueous mixture of cellulose acetate and cellulose
with paper manufacturing fillers and sizes.
8. The process of claim 7 wherein the paper comprises between about
90 and about 99% by weight of cellulose and between about 1 and
about 10% percent by weight of cellulose acetate fiber having a
length of less than about 14 mm.
9. The process of claim 1 or 8, and including the steps of: (a)
forming the paper product into a continuous paper web with a weight
of about 15-40 grams/meter.sup.2; and (b) fabricating the paper web
into cigarette filter tips.
10. A process of claim 1 or 8, and including the steps of: (a)
forming the paper product into a continuous paper web weighing
200-800 grams/meter.sup.2; and (b) fabricating the paper web into
absorbent paper products selected from the group consisting of
feminine hygiene articles, adult incontinent diapers and infant
diapers.
11. The product formed according to the process of claim 9.
12. The product formed according to the process of claim 10.
Description
[0001] This application is based on and claims priority from
Provisional Application No. 60/465,743, filed Apr. 25, 2003.
TECHNICAL FIELD AND BACKGROUND OF THE INVENTION
[0002] This invention relates to a process for the conversion of
cellulose acetate waste fibers into a suitable form for paper
production, and resultant paper products.
[0003] The majority of cigarettes manufactured today have a filter
composed of cellulose acetate fibers. Cigarettes having a cellulose
acetate filter are typically prepared by using a continuous length
of cellulose acetate fiber to prepare a long filter rod, then
cutting the long filter rod into a multiplicity of shore lengths,
or plugs, to form individual cigarette filters. The cigarette is
then prepared by attaching these filters to an elongate column of
tobacco contained in cigarette paper.
[0004] The above described process for preparation of cigarettes
results in three waste streams of cellulose acetate fiber. The
first waste stream results from the manufacture of the continuous
cellulose acetate filament which is used in filter rod manufacture.
Filament waste typically comes from off-specification filament
bands, damaged gaylords or aged inventory. Although these filaments
can be redissolved and recycled back into an acetate dope filament
production process, this recycling method is sometimes
undesirable.
[0005] The second waste stream results from preparing the cellulose
acetate fiber into filter rods and individual filters and is often
referred to in the tobacco industry as "plug room waste". Plug room
waste typically comes from off-specification filters and filters
used for quality control. In addition to the cellulose acetate
fiber, this material typically contains plasticizer, paper and
other materials.
[0006] The third waste stream results from improperly manufactured
cigarettes and is often referred to in the tobacco industry as "rip
room waste". In addition to the cellulose acetate fiber, this
material typically contains tobacco, plasticizer, paper and other
materials.
[0007] These waste materials are currently being land-filled.
However, because of the increasing cost of disposal and decreasing
landfill space, cigarette filter tow suppliers and cigarette
manufacturers are looking for alternatives to disposal.
[0008] The addition of cellulose acetate fibers to paper is well
known in the art. U.S. Pat. No.4,040,856 to Litzinger discloses an
extrusion process for making cellulose acetate fibers for
papermaking. The fibers are suitable for direct addition to
conventional papermaking methods. Two related patents, U.S. Pat.
Nos. 4,047,862 and 4,460,647 to Keith disclose a cellulose acetate
fiber for use in paper applications which is produced by
precipitation of cellulose acetate from a dope under high shear
conditions. In U.S. Pat. No. 5,213,883 to Mehta, a decorative sheet
is disclosed having 1 to 20 weight percent cellulose acetate fibers
added to cellulose pulp and TiO.sub.2. However, the amount of
cellulose acetate fibers that can be added to paper without
substantial Tinting during the printing process is typically below
10 percent by weight, thus limiting the extent of the addition of
this artificial fiber to the paper. With binders the cellulose
acetate fiber content may be doubled, however this technology is
not desirous because of the expense and difficulty in processing
binders.
[0009] Thus, there is a need in the art to obtain a paper product
with enhanced bonding to cellulosic fibers therefore allowing the
addition of greater quantities of cellulose acetate fibers without
the problems associated with linting and using binders, such as is
disclosed in two related patents, U.S. Pat. Nos. 5,573,640 and
5,662,773 to Frederick. These patents disclose a process for
producing a cellulose acetate fiber which has been treated with an
aqueous base until at least 5% of the acetyl groups on the said
cellulose acetate has been hydrolyzed for use in paper applications
and the resultant paper produced.
SUMMARY OF THE INVENTION
[0010] Therefore, it is an object of the invention to provide a
process for treating waste cellulose acetate into a form suitable
for incorporation into paper products.
[0011] It is another object of the invention to provide a process
for treating waste cellulose acetate that makes use of several
types of typical cellulose acetate waste that is currently disposed
of by landfilling.
[0012] It is another object of the invention to provide paper
products that contain specified percentages of processed waste
cellulose acetate.
[0013] These and other objects of the present invention are
achieved in the preferred embodiments disclosed below by providing
a process for producing paper with mechanically processed waste
cellulose acetate fiber, comprising the steps of providing a raw
material in the form of waste long staple or continuous filament
cellulose acetate fibers, and mechanically shredding the waste
cellulose acetate to a fiber length of less than about 14 mm. The
shredded waste cellulose acetate is mixed with cellulose to form a
slurry, and paper is made from the slurry.
[0014] According to one preferred embodiment of the invention, the
waste cellulose acetate fiber contains substantial crimp.
[0015] According to another preferred embodiment of the invention,
the crimp is produced by mechanical interfiber plasticizer bond
separation due to shredding.
[0016] According to yet another preferred embodiment of the
invention, the process includes the step of repulping the
mechanically shredded cellulose acetate and cellulose with
water.
[0017] According to yet another preferred embodiment of the
invention, the step of repulping is conducted with periodic or
continuous high shear agitation.
[0018] According to yet another preferred embodiment of the
invention, the process further comprises the step of confricating
or mechanically refining the aqueous mixture of cellulose acetate
and cellulose.
[0019] According to yet another preferred embodiment of the
invention, the process comprises the step of blending the aqueous
mixture of cellulose acetate and cellulose with paper manufacturing
fillers and sizes.
[0020] According to yet another preferred embodiment of the
invention, the paper comprises between about 90 and about 99% by
weight of cellulose and between about 1 and about 10% percent by
weight of cellulose acetate fiber having a length of less than
about 14 mm.
[0021] According to yet another preferred embodiment of the
invention, the process includes the steps of forming the paper
product into a continuous paper web with a weight of about 15-40
grams/meter.sup.2, and fabricating the paper web into cigarette
filter tips.
[0022] According to yet another preferred embodiment of the
invention, the process includes the steps of forming the paper
product into a continuous paper web weighing 200-800
grams/meter.sup.2, and fabricating the paper web into absorbent
paper products selected from the group consisting of feminine
hygiene articles, adult incontinent diapers and infant diapers.
[0023] Other preferred embodiments of the invention comprise paper
products formed according to the process, including cigarette
filter tips, feminine hygiene articles, adult incontinent diapers
and infant diapers.
DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE
[0024] The paper products produced from cellulose acetate fibers in
accordance with to the invention benefit from reduced bulk or more
open sheet porosity, with usage levels typically below 10% of the
fiber furnish.
[0025] Waste cellulose acetate fibers processed according to the
invention are shredded to cut the very long continuous filament
fibers down to a length usable in paper manufacture. A
cutting/shredding device is utilized which consists of a high speed
rotary cutter head which processes the waste cellulose acetate
fibers against a stationary cutter blade. A screen in the rotary
cutter retains the waste cellulose acetate fibers until the desired
reduction in fiber length is achieved. The screen in the rotary
cutter will typically contain openings of approximately 10 mm or
less. Multiple cutters or a single cutter with a screen retention
basket can be used. The fibers produced from the cutting/shredding
process preferably have an average length in the range of 0.1 to 14
mm. The fibers have a denier in the range of 1-30 grams per 9000
meters and contain substantial crimp in the range of 1 to 20 crimps
per centimeter resulting from crimp inserted during initial
manufacture of the cellulose acetate, produced by mechanical
interfiber plasticizer bonding, and resulting from impact on the
fibers during shredding.
[0026] Waste cellulose acetate fibers altered in this manner are
suitable for use in various paper products. The paper of the
present invention is produced by a specific process. This process
is comprised of the steps of forming a slurry of cellulose and
mechanically altered waste cellulose acetate fibers, and
confricating the slurry. The confricated slurry is diluted and then
blended with paper manufacturing fillers and sizes. A paper is then
prepared from the diluted confricated slurry. The paper is
dewatered and dried.
[0027] The cellulose fiber used to prepare the paper of this
invention is conventional paper making cellulose fiber obtained
from wood, cotton, hemp, bagasse, straw, flax and other plant
sources. Both hardwood and softwood may be used. The paper products
produced from these fibers with the addition of cellulose acetate
as described above benefit from reduced bulk and more open sheet
porosity. The cellulose acetate is added at levels typically below
10% of the fiber furnish.
[0028] In other paper product applications, the waste cellulose
acetate fiber can be used to enhance product performance. One
specific product is cigarette filter tips. At least 10% of the
world's cigarette filter tips are manufactured using continuous
paper in bobbin form which contains approximately 25
grams/meter.sup.2 of essentially 100% cellulose fibers. Addition of
1-90% waste cellulose acetate fiber to this existing type paper
filter will provide enhanced porosity, reduced yellowing, selective
smoke stream component filtration, reduced wet collapse and
improved cigarette butt environmental dispersion for cigarette
filter tips manufactured in this manner.
[0029] Waste cellulose acetate fibers can also be used as a binder
fiber for absorbent products. The addition of 1-90% waste cellulose
acetate fiber into fluff pulp during manufacture of commercial 750
grams/meter.sup.2 rolls will allow the fluff pulp rolls to contain
the acetate fibers prior to use for the manufacture of absorbent
products. Absorbent products, defined as feminine hygiene, adult
incontinent and baby diapers, can then be manufactured from this
fluff pulp and waste cellulose acetate blend. During manufacture,
the continuous web of fluff pulp and waste cellulose acetate blend
is hammer milled and pneumatically blended with super absorbent
polymer. Addition of 5-15% plasticizer to this mixture will cause
the acetate to become a binder fiber for the absorbent pad upon
drying.
[0030] The following example sets forth one embodiment of the
method by which the formulation of the present invention can be
produced.
EXAMPLE 1
[0031] Waste cellulose acetate fibers (filter rods) were shredded
using a high speed rotary cutter which included a screen retention
basket with openings (holes) of 0.375 inch diameter. The fibers
produced from the cutting/shredding process contained substantial
crimp. The average length of the fibers was approximately 7mm. The
fibers had a denier of 3 grams per 9,000 meters.
[0032] Papers containing the mechanically altered plug room waste
fibers were produced using lab-scale Canadian Standard Handsheet
equipment owned by Herty Foundation located in Savannah, Ga.
Batches with a furnish ratio of Hardwood, % Astracel=50% of wood,
Softwood, % Albacel=50% of wood were prepared, confricated and
papered out. The processed cellulose acetate waste fibers were
added to the furnish prior to confrication a various desired
levels. Handsheets with the various levels of processed waste
cellulose acetate were prepared for physical property comparison.
Test results follow:
Table No. 1.
Processed Waste Fiber Impact on Properties of 108 Grams/Meter.sup.2
Unfilled Sheet
[0033]
1TABLE 1 CDAP Impact on 108 gsm Unfilled Sheet Properties Hardwood,
% Astracel = 50% of wood Softwood, % Albacel = 50% of wood CDAP =
plugroom waste ground to .about.7 mm which contains .about.7%
triacetin Porosity Caliper Density Gurley Tensile CDAP mils
g/cm.sup.3 sec/100 cc kN/m 0 6.1 0.7 43.9 10.2 5 7.5 0.6 30.3 9.4
10 8.5 0.52 13.2 8.5 25 10.8 0.4 2.8 6.3 60 15.5 0.19 0 1.2 Caliper
CDAP Increase % 0 0 1 6 2 11 3 16 4 19 5 23 6 27 7 30 8 33 9 36 10
39
[0034]
[0035] A process for converting cellulose acetate into processed
waste fibers in suitable form for paper production and the
resulting paper product is described above. Various details of the
invention may be changed without departing from its scope.
Furthermore, the foregoing description of the preferred embodiment
of the invention and the best mode for practicing the invention are
provided for the purpose of illustration only and not for the
purpose of limitation--the invention being defined by the
claims.
* * * * *