U.S. patent application number 14/146475 was filed with the patent office on 2014-08-28 for teabags and coffee/beverage pouches made from mono-component, mono-constituent polylactic acid (pla) fibers.
The applicant listed for this patent is Nonwoven Network LLC. Invention is credited to Stephen W. Foss, Jean-Marie Turra.
Application Number | 20140242309 14/146475 |
Document ID | / |
Family ID | 51388431 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140242309 |
Kind Code |
A1 |
Foss; Stephen W. ; et
al. |
August 28, 2014 |
Teabags and Coffee/Beverage Pouches Made From Mono-component,
Mono-constituent Polylactic Acid (PLA) Fibers
Abstract
A non-woven mono-component, mono-constituent poly lactic acid
(PLA) web is disclosed. The web material is useful for production
of tea bags and other infusion beverages. The nonwoven network of
PLA fibers in mono-component, mono-constituent configuration
provides infusion properties, strength and weight properties that
surpass current beverage bags and pouches because of its unique
composition and structure.
Inventors: |
Foss; Stephen W.; (Naples,
FL) ; Turra; Jean-Marie; (Greer, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nonwoven Network LLC |
Naples |
FL |
US |
|
|
Family ID: |
51388431 |
Appl. No.: |
14/146475 |
Filed: |
January 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12971505 |
Dec 17, 2010 |
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14146475 |
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Current U.S.
Class: |
428/35.2 ;
428/219; 442/333; 442/334; 442/337; 442/359; 442/361; 442/392 |
Current CPC
Class: |
D04H 1/54 20130101; Y10T
442/611 20150401; Y10T 442/671 20150401; B65D 85/808 20130101; D04H
1/55 20130101; Y10T 442/608 20150401; Y10T 428/1334 20150115; Y10T
442/635 20150401; Y10T 442/637 20150401; D04H 1/541 20130101; D04H
1/435 20130101; Y10T 442/607 20150401 |
Class at
Publication: |
428/35.2 ;
442/392; 428/219; 442/337; 442/359; 442/333; 442/334; 442/361 |
International
Class: |
B65D 85/808 20060101
B65D085/808; D04H 1/435 20060101 D04H001/435 |
Claims
1. A non-woven fabric composition web of mono-component,
mono-constituent PLA fiber composition consisting of: a plurality
of fiber layers made from a plurality of individual fibers that are
blends of a mono-component, mono-constituent polylactic acid (PLA)
fiber; said polylactic acid (PLA) fiber having different deniers
and blend percentages of high and low fibers having a melt flow
temperature in a range of 145-175.degree. C. and 105-165.degree.
C., respectively.
2. The non-woven fabric composition web composition in claim 1,
wherein the plurality of layers are sequenced by at least one of
the following layer configurations: ABA, AAB, ABB, BAB, ABC, CBA,
CAB, CCA, CCB, BBC, BBA, BCB, and BAC, wherein layer A is a first
fiber blend layer, layer B is a second fiber blend layer, and layer
C is a third fiber blend layer.
3. The non-woven web composition in claim 2, wherein the layer
configuration is made up of layers up to 7 layers.
4. The non-woven web composition in claim 3, wherein the plurality
of layers are sequenced by at least one of the following layer
configurations: ABCDEFG; BCDEFGA; CDEFGAB; DEFGABC; EFGABCD;
FGABCDE; GABCDEF and any combination thereof, wherein layer A is a
first fiber blend layer, layer B is a second fiber blend layer, and
layer C is a third fiber blend layer, layer D is a fourth fiber
blend layer, layer E is a fifth fiber blend layer, and layer F is a
sixth fiber blend layer and layer G is a seventh fiber blend
layer.
5. The non-woven fabric web composition in claim 1, wherein the
non-woven fabric web has a weight from 10 gsm to 125 gsm.
6. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a cross section, said cross-section is in
a non-circular shape, and more particularly said cross-section is
in a shape selected from the group consisting of: a triangle, a
mock hollow or "C" shape, a flat shape, a rectangular shape, a
ribbon shape, a spiral shape, a helix shape, a square shape, an
oval shape, a polygon shape, and a multi-dimensional shape.
7. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers further consists of a permanent hydrophilic
fiber finish to enhance rapid infusion of water.
8. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a unit of weight that describes thickness
in the range from 0.8 to 26 deniers.
9. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a unit of weight that describes thickness
in the range from 1.0 to 6.0 deniers.
10. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a length in the range from 0.75 to 6
inches.
11. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a length in the range from 1.5 to 3
inches.
12. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a weight in the range from 12 to 120 grams
per square meter (gsm).
13. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a weight in the range from 16 to 100 grams
per square meter (gsm).
13. The non-woven fabric web composition in claim 1, wherein the
plurality of fibers have a weight in the range from 90 to 100 grams
per square meter (gsm).
14. The non-woven fabric web composition in claim 1, wherein the
PLA fibers are blended with synthetic cellulose fibers selected
from a group consisting of Rayon, Lyocell (Tencel.RTM.),
regenerated cellulose, acetate or any combination thereof to make a
blend.
15. The non-woven fabric web composition in claim 14, wherein the
blend consists of 40% to 95% PLA or CoPLA, and 5% to 60% synthetic
cellulose fibers with deniers from 0.5 to 7.0 denier and a fiber
length of 0.25 to 7'' in length.
16. The non-woven fabric web composition in claim 1, wherein the
nonwoven fabric web further includes a food grade and FDA compliant
hydrophilic fiber finish.
17. A nonwoven web for use in producing beverage infusion pouches
and bags, said web consisting of: a plurality of mono-component
mono-constituent Polylactic Acid (PLA) fibers forming said web by
dry thermo-bonding without the use of plasticizers and other
surface treatments, wherein said web provides for biodegradability
after usage and recyclability of waste materials during each step
of a manufacturing process of said web; the mono-component
mono-constituent Polylactic Acid (PLA) fibers having an amorphous
portion and a crystalline portion; said mono-component
mono-constituent Polylactic Acid (PLA) fibers form pore sizes of
the web that are maintained if infused with hot liquids to enhance
flow; and. the PLA fibers are blended with synthetic cellulose
fibers selected from a group consisting of Rayon, Lyocell
(Tencel.RTM.), regenerated cellulose, acetate or any combination
thereof to make a blend.
18. A web as in claim 17 wherein the web fibers have a fiber length
of between about 20 mm to 90 mm.
19. A web as in claim 17 wherein the web fibers have a length of 38
mm.
20. A web as in claim 17 wherein the web fibers are from between
about 0.6 denier to 6.0 denier.
21. A web as in claim 17 wherein the web fibers are 3.0 denier.
22. A web as in claim 17 wherein the web fibers are 1.5 denier.
23. A web as in claim 17 wherein the web fibers are 1.2 denier.
24. A web as in claim 17 having a dry basis weight from between
about 8 to 50 grams per square meter.
25. A web as in claim 17 wherein the PLA mono-component
mono-constituent fibers have two different melting points for a
crystalline portion and an amorphous portion that is
145-175.degree. C. and 105-165.degree. C. respectively.
26. A web as in claim 17 wherein the fibers are 100% of PLA fibers
that melt at a temperature of between about 135.degree. to
175.degree. C.
27. A web as in claim 17 where a proportion of fibers are PLA
fibers are between 0.8 to 26 Denier.
28. A web as in claim 27 wherein the web fibers consist of
mono-component mono-constituent fibers having a melting point of
145.degree. to 175.degree. C. and the Co PLA fiber portion of the
mono-component mono-constituent fiber is CoPLA with a melt
temperature from 105.degree. to 165.degree. C. having a lower
melting temperature than the melting temperature of other
mono-component mono-constituent fibers.
29. A web as in claim 17 wherein the mono-component
mono-constituent fibers further include a thermally active
component that is 5% to 50% by weight, wherein percentages are
based on weight of the web.
30. A web as in claim 17 usable as material for bags or pouches
for: Lemonade, herbal sachets, coffee, tea, hot chocolate, soap
powder, chemicals and chlorine for pools and spas, decontaminating
liquids, coloring of liquids, dehumidifying chemicals, carriers for
phase-change materials for heating or cooling, tobacco pouches, and
all materials that can be placed in a heat and/or ultra sound
activated sealable container.
31. A bag or pouch formed at least in part from the web of claim
17.
32. A bag or pouch as formed essentially entirely from the web of
claim 17.
33. A bag or pouch using a web as in claim 17, but made using
randomizing rolls so that the fibers in the web are randomized.
34. A web as in claim 17 wherein the fibers are at least two
mono-component mono-constituent fibers of PLA fibers, a first fiber
and a second fiber, with different melting points for forming the
web such that the first fiber melts at a higher temperature than
the second fiber.
35. A web as in claim 17 wherein the web is a beverage infusion
package for providing biodegradability after usage and
recyclability of waste materials during each step of the
manufacturing process from polymer to finished web.
36. A web as in claim 35 usable in bags or pouches for materials
selected from the group consisting of: lemonade, herbal sachets,
coffee, tea, hot chocolate, soap powder, chemicals and chlorine for
pools and spas, decontaminating liquids, coloring of liquids,
dehumidifying chemicals, carriers for phase-change materials for
heating or cooling, tobacco pouches, and wherein said bags or
pouches are sealable by heat or ultra sound.
37. A web as in claim 36 further including a string attached to
each one of the bags, said string also made of the mono-component
mono-constituent Polylactic Acid (PLA) fibers.
38. A web as in claim 35 wherein the crystallinity of the
mono-component mono-constituent Polylactic Acid (PLA) fibers are
controlled by drawing.
39. A web as in claim 35 further including a dry basis weight from
between about 8 to 50 grams per square meter.
40. A web as in claim 35 wherein the pore size of the web if
infused with hot liquids is substantially maintained to enhance
flow.
Description
[0001] The present application claims priority from U.S.
provisional patent application 61/376,845 filed Aug. 25, 2010 and
non-provisional patent application Ser. No. 12/971,505 filed Dec.
17, 2010.
BACKGROUND
Field
[0002] The present invention relates to a melt-extrudable
thermoplastic composition and to the preparation of nonwoven webs.
The composition described is a non-woven fiber web made of a
mono-component, mono-constituent polylactic acid (PLA) and more
particularly made of PLA of a plurality of layers and having fibers
with cross-sections in various structural configurations.
[0003] As beverage fabrics presented in Noda (2002/0143116), Rose
(203/0113411), Jordan (2005/0136155) as well as Ser. No. 12/971,505
have been produced there is still a need for improvement.
[0004] In the United States, a cup of coffee is generally produced
under atmospheric pressure with hot water flowing through the
coffee grounds and through a filter. The resultant coffee is
coloring the water from light grey to black, but still maintains a
clarity. In Europe as well as most of the rest of the world, coffee
is generally produced under a pressure greater than 1 atmosphere
and the coffee is generally ground to finer particles. As a result,
coffee is cloudy, stronger and has a "crema" or foam on the
surface. Such coffee is sipped slowly to enjoy the enhanced
flavor.
[0005] In all cases, there is a need for a tortuous path for the
water to flow through a filter that will allow a fast flow, but
preventing any particles from flowing into the cup. It is believed
that a tortuous path will allow more complete transfer of the
coffee essence from the grounds to the liquid, while at the same
time increasing the "crema".
[0006] Cellulosic "paper" products have an inverse relationship of
weight with porosity. As cellulosic papers get higher than 30 gsm
in weight, there porosity goes to zero and become impermeable.
Further cellulose fibers swell on contact with water, further
closing the pores of the paper.
[0007] Therefore a need exists for improvement to the Ser. No.
12/971,505 invention.
[0008] There is also a need for an infusion substrate, particularly
for tea and coffee, which provides rapid infusion of hot water into
the tea or coffee particles, while being strong enough to keep the
particles within a bag or pouch made up in substantial part or
wholly of such substrate. There is also a need for heat-sealable
pouch for tobacco and tobacco products (i.e. snuff and chewing
tobacco).
[0009] Further, it is highly desirable that the substrate media be
100% bio-degradable and not contain any inert or non-biodegradable
components.
[0010] Further, it is highly desirable that the media, including
all of the production scrap, be recyclable into itself.
[0011] Significant development of Polylactic Acid (PLA) fiber was
conducted by Cargill Inc. to make fibers from natural raw materials
and resultant process and products are described in U.S. Pat. No.
6,506,873.
[0012] Kimberly Clark mentions PLA in its U.S. Pat. No. 7,700,500,
"Durable hydrophilic treatment for biodegradable polymer
substrate."
[0013] U.S. Pat. No. 6,510,949 by Grauer et al teaches that
hydrophilic substances may be impregnated, into filter paper to
improve the water-wet ability and water absorption.
[0014] Tea bags and coffee pouches traditionally have been made of
paper and teabags suffer from slow infusion times and tend to float
on the liquid surface.
[0015] A new tea bag fabric from Japan has been made using a nylon
knitted mesh, which provides rapid infusion, but requires a
non-traditional sealing method, are expensive and are not
biodegradable.
[0016] Attempts have been made to produce a spun melt nonwoven from
PL A, but it suffers from poor sealability and performance in
automated packing machines.
SUMMARY
[0017] The present invention provides a highly porous media of web
form, divisible and fabricated into end product components (e.g.
bags, pouches) or portions of the same that is produced from PLA,
alone or with Co-PLA fibers, using a thermo bonded nonwoven
manufacturing method. The media exhibits high efficiency for
infusion of hot water into the coffee or tea (or other liquid as
more broadly indicated above). The use of Synthetic Cellulosic
fibers blended with proprietary PLA formula is disclosed.
[0018] The fibers self bond at many cross over points through web
heating and/or pressure applications in initial web production
and/or subsequent steps. Disclosed is a melt-extruded thermoplastic
non-woven web composition consisting of: a plurality of fiber
layers made from a plurality of fibers that are blends of
mono-component, mono-constituent polylactic acid (PLA) fibers.
[0019] The polylactic acid (PLA) fiber have different deniers and
blend percentages of high and low fibers having a melt flow
temperature in a range of 145-175.degree. C. and 105-165.degree.
C., respectively. Various layer combinations and sequences are also
provided for within the purview of the invention.
[0020] The present invention also provides a highly porous media of
web form, divisible and fabricatable into end product components
(e.g. bags, pouches) or portions of the same that is produced from
PLA, alone or with Co-PLA fibers, using a thermo bonded nonwoven
manufacturing method. The media exhibits high efficiency for
infusion of hot water into the coffee or tea (or other liquid as
more broadly indicated above). The fibers self bond at many cross
over points through web heating and/or pressure applications in
initial web production and/or subsequent steps.
[0021] The web material of the invention is produced in a continual
process that provides for controllable machine processing direction
and cross machine direction properties that enhance the performance
of the media. By controlling the % of the lower melt Co-PLA in an
intimate blend of PLA and Co-PLA fibers, the thermo bonding
strength can be controlled during web manufacture by fiber
orientation, temperature setting, and time of exposure to heat.
During bag or pouch manufacture, the strength of the sealing bond
can be controlled by temperature, dwell time, and knife
pressure.
[0022] PLA and Co-PLA have specific gravity of 1.25, i.e. greater
than water, which causes the bag or pouch to sink and to be
submerged and be totally engulfed in the hot water. Further, PLA is
naturally hydrophilic, without special treatment, which allows the
water to flow quickly into the tea or coffee.
[0023] The Co-PLA can be chosen with a melt point from 125.degree.
C. to 160.degree. C. by varying the isomer content of the polymer.
Thus it is possible to address the sealing requirements of various
automated packaging machines.
[0024] Not only is the media made from a renewable raw material,
but the scrap fiber, nonwoven trim scrap, and the bag making scrap
can be remelted, extruded into a pellet, and blended into the
extrusion operation to make more fiber. It is from 100% renewable
source and it is 100% recyclable. During the fiber manufacturing
process, any "waste" fiber may be re-extruded into pellets and put
back into the fiber process. During the nonwoven web production
process, any startup or trim "waste" may be re-extruded into
pellets and put back into the fiber process. During the infusion
package manufacturing process, any trim, start-up, or other web
"waste" may be re-extruded and put back into the fiber manufacture
process.
[0025] Unlike PET, nylon, and most papers, which contain latexes
and synthetic fillers, the media of the present invention is 100%
compostable. After hydrolysis at 98% humidity and 60 C or higher,
PLA is readily consumed by microbes and its component atoms are
converted for possible re-use in growing more corn, beets, rice or
etc. for future conversion to PLA.
[0026] The invention was produced in three weights: 16, 18 and 20
gsm (grams per square meter, but could be produced in a lighter or
heavier weight).
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIGS. 1A-1I illustrate embodiments of fiber shapes that
utilize the teachings of the present invention;
[0028] FIGS. 2A-2I illustrate one embodiments of layers;
[0029] FIG. 3 illustrates three different fibers. Large diameter,
smaller diameter and low melt forming fused bond points at 4.times.
magnification;
[0030] FIG. 4 illustrates another view of FIG. 3 at 10.times.
magnification showing low melt bond points and that the low melt
fiber ceases to be a fiber;
[0031] FIG. 5 is photomicroscope slide (1) at 40.times.
magnification power showing an 18 gsm web with 30% (by weight)
co-PLA/70% PLA which exhibited excellent strength and superb
sealing characteristics. It should perform equally well at lighter
weights from 12 to 20 gram per square meter (gsm);
[0032] FIG. 6 is photomicroscope slide (2) showing an 16 gsm web
with 10% co-PLA/90% PLA blend, which exhibited adequate strength
but did not have enough low melt fiber to seal effectively;
[0033] FIG. 7 is a drawing of a bi-component fiber with a high melt
core (PLA @ 175.degree. CM) and a low-melt sheath (Co-PLA @
135.degree. C.);
[0034] FIG. 8 is a Microscope slide of 85/15% blend at 18 gsm-40
power;
[0035] FIG. 9 is a Microscope slide of 80/20% blend at 18 gsm-40
power;
[0036] FIG. 10 is a microscope slide of 80/20% blend at 18 gsm-100
power;
[0037] FIG. 11 is a microscope slide of standard paper; and;
[0038] FIG. 12 is a microscope slide of a Japanese made nylon
fabric, and FIG. 13 is Table I showing a comparison of paper
airflow with PLA airflow and Graph A showing the relationship of
breathability properties to GSM.
DETAILED DESCRIPTION
[0039] Nonwoven webs are porous, textile-like materials which are
composed primarily or entirely of fibers assembled in flat sheet
form. The tensile properties of such webs may depend on frictional
forces or on a film-forming polymeric additive functioning as a
binder. All or some of the fibers may be welded to adjacent fibers
by a solvent or by the application of heat and pressure.
[0040] Nonwoven webs currently are employed in a variety of
products such as diapers, napkins, sterilization wraps; medical
drapes, such as surgical drapes and related items; medical
garments, such as hospital gowns, shoe covers, and the like to name
but a few. The nonwoven webs can be utilized as a single layer or
as a component of a multilayered laminate or composite. When a
multilayered laminate or composite is present, often each layer is
a nonwoven web. Such multilayered structures are particularly
useful for providing improved performance in strength
properties.
[0041] In order to improve the performance of a nonwoven-containing
product, it sometimes is necessary to modify certain
characteristics of the fibers of which the web is composed. A
classic example is the modification of the hydrophobicity of fibers
by a topical treatment of the web with a surfactant or through the
use of a melt additive.
[0042] The use of a topical treatment or melt additive has the draw
back when the non-woven is used in the food industry or related to
contact with human skin or human digestion. The present invention
avoids the use of such surfactants and topical treatments and
provides additional unexpected results.
[0043] The diameter of fibers will affect the nesting or stacking
of the fibers during web formation. Further, the percentage of low
melt fibers will affect the density and porosity of the web.
[0044] The ability to produce a web with multiple layers presents
the ability to create webs of different porosity, thickness, and
stiffness. Webs were produced with three layers A B A. All fibers
were mono-component, mono-constituent PLA.
[0045] It is within the purview of this invention that different
layers, depending on the embodiment, contain different diameters,
different ratios of high & low melt, and different shapes as
well as the weight of each layer.
[0046] The A layers were produced with 50% 1.5 d.times.2'' High
Melt (170.degree. C.) PLA (PS 2650) and 50% 2.5 d.times.2'' Low
Melt (130.degree. C.) co-PLA (PS1801).
[0047] The B layer (in the center) was produced with 75% 2.5
d.times.2'' High melt (170.degree. C.) PLA (PS2650) and 25% 2.5
d.times.2'' Low melt (130.degree. C.) Co-PLA (PS1801). Note that B
has 2.5 d vs. 1.5 d high melt fibers which are about 2.5.times.
greater in diameter and only 25% vs. 50% of the low melt.
[0048] The fibers were blended separately and then fed into the
card feeders. All cards were Hergerth 3 m wide roller cards with
randomizing rolls. The first two cards produced the A layer and fed
the layer onto a collecting apron. The next two cards produced the
B layer and it onto the apron on top of the A layer. The final 2
cards produced the A layer and fed it onto the same apron on top of
the B layer, creating a single web of A B A layers.
[0049] The collective web was then delivered to a heated two roll
calendar machine with the rolls heated by Hot Oil to a temperature
of 150.degree. C.
[0050] The fabric weight was adjusted between 80 to 120 grams per
square meter and a weight of 90 grams per square meter was chosen
as having the best properties.
[0051] The stiffness improved to fit the Senseo.RTM. brewing
machines and produce an excellent cup of coffee without leaking
around the edges.
[0052] The porosity of the 90 gsm ABA web was tested against other
weights of mono-component, mono-constituent PLA webs ranging from
16 to 90 gsm. The porosity was measured with a Frazer.RTM.
air-permeometer and measured in liters/m.sup.2/second. Industry
standard webs made from cellulose with either a Polyethylene or PLA
bi-component fiber at 30% were compared by weight in the following
table and graph:
[0053] The net effect is that a 90 gsm web was obtained with
excellent airflow or permeability, but the cellulosic web had
virtually no airflow.
[0054] Up to this point, only round, solid fibers of
mono-component, mono-constituent PLA fibers were used.
[0055] Fibers made in other shapes were investigated. The shapes
included a triangle, mock hollow or "C" shaped, and ribbon or flat.
(See FIGS. 2A-2I).
[0056] These fibers were produced in the same manner as round. The
molten polymer (PLA) was pumped by a metering pump through a metal
spinneret. (Note: The low melt Co-PLA was not produced (but could
be in the future) as they would melt, flow, and lose their shape).
The fibers were air quenched and then drawn at their Tg of
60.degree. C. at a ratio of 3.5:1 to obtain desired crystallinity.
The fibers were crimped, heat set and cut to length.
[0057] It was found that these shaped fibers do not affect the air
flow, but improve the "crema" or foam in the finished cup of
coffee.
[0058] It was also learned that blending in synthetic cellulosic
fibers, such as rayon, acetate, or Lyocell (Tencel.RTM.) solved a
problem of heat effect on coffee and tea bag formation. Tencel.RTM.
(generic name Lyocell) is a sustainable fabric regenerated from
wood cellulose. Lyocell regenerated cellulose fiber is made from
dissolving pulp (bleached wood pulp). It was developed and first
manufactured for market development as Tencel.RTM. in the 1980s by
Courtaulds Fibres. Standard forming machines (such as IMA or Cloud)
do not have adequate heat controls to maintain a precise
temperature over a wide range of running speeds. Hence, there were
times when the mono-component, mono-constituent PLA fibers would
melt, creating flaws in the pouch or pad.
[0059] By blending in from 5 to 60% of the synthetic cellulosic
fibers with the high and low melt PLA, there was a greater
temperature range for pad formation available. Tencel.RTM. was
found to be the easiest to blend with the PLA fibers. The net
result was a fabric with higher strength at the melting point of
the high melt PLA. While blending in the synthetic cellulose fibers
negated the recyclability attribute, the end product was still
suitable for tea and coffee pads, bags, or pouches. The fabric was
still biodegradable and since Tencel.RTM. has a specific gravity
compared to 1.24 for PLA, the blended fabric had equal or better
ability to sink in the cup rather than float.
[0060] Finally, hydrophilic finishes or lubricants were applied to
the fibers during fiber production. These finishes were provided by
Goulston Technologies, Inc. of Monroe N.C. These finishes were
designed to meet FDA and German BfR requirements for food quality.
Goulston finishes such as PS-11473, PS-10832, and PS 12062 were
tried. All were heat set at 130.degree. C. during the fiber
production process to thoroughly bond them to the fibers. The
heat-setting bonded the finishes so that they were not released
into the boiling water (100-110.degree. C.) used for Tea Bags,
coffee pads, or other pouches.
[0061] The water flow appeared to improve as the color of the water
darkened at a much faster rate than PLA fibers made only with an
anti-stat such as Goulston AS-23. These finishes were totally
compatible to provide excellent carding and fabric formation. The
hydrophilic properties and the 1.24 specific gravity of PLA,
resulted in bags that would sink and wet out easily, resulting in a
faster brew cycle.
[0062] Another advantage of the invention is that since the pouch
or bag is hydrophilic it sinks. This advantage is seen in a tea or
coffee bag where most paper or other bags float on the top and give
minimal diffusion of the coffee or tea contents. By having the bag
sink diffusion of the contents is further given. Another advantage
is as the non-woven web is exposed to water, it becomes clearer
showing the contents of the bag or pouch. The bag or pouch has the
benefits of using less contents such as coffee or tea leafs to
accomplish the same strength of beverage. In addition diffusion
time is decreased since the pore size is relatively maintained
using the mono-component fiber. This invention is not limited to
beverage pouches and can be utilized in any application that
requires diffusion of contents through a pouch or bag. The
advantages of biodegradation, recyclability, decreased amount of
contents needed, decreased diffusion time, and clarity of the pouch
is all realized in the present invention.
[0063] In view of the disclosed description, it will now be
apparent to those skilled in the art that other embodiments,
improvements, details, and uses can be made consistent with the
letter and spirit of the foregoing disclosure and within the scope
of this patent, which is limited only by the following claims,
construed in accordance with the patent law, including the doctrine
of equivalents.
[0064] A preferred embodiment of the invention was made, and is
explained as follows, including all or most of its fibers in
bi-component form and its production of mono-component PLA fiber
made from Fiber Innovation Technologies (Type T811) was blended
with core/sheath bi-component (BiCo) fibers with PLA in the Core
and Co-PLA in the sheath. The core/sheath area ratio was 50/50%.
Fibers were produced with a ratio between 80/20% and 20/80%. Other
fiber producers such as Palmetto Synthetics and Foss Manufacturing
Company can make these fibers. PLA fibers typically are made using
lactic acid as the starting material for polymer manufacture. The
lactic acid comes from fermenting various sources of natural
sugars. These sugars can come from annually renewable agricultural
crops such as corn or sugar beets. The polymer must be completely
dried prior to extrusion to avoid hydrolysis. PLA is an aliphatic
polyester and the helical nature of the PLA molecule makes it
easier to crystallize than PET. The PLA can be extruded into a
fiber using standard PET fiber equipment.
[0065] In the case of the mono-component PLA fiber, the high
temperature variant with a melt temperature of 175.degree. C. is
extruded into a fiber. The initial fiber is then drawn 3.5 times
its length to get to the required 1.5 denier. It is then crimped
and heat set to 140.degree. C. to improve the crystallinity and
stabilize the crimp. It is then cut to 1.5'' (38 mm). In the case
of the Bi-CO fiber, a melt spinning line using the co-extrusion
spinerettes made by Hills Inc, of Melbourne Fla. was used. The
spinerettes of the line produced a fiber similar to FIG. 3. The
higher melting (175.degree. C.) PLA is in the core, while the lower
melting Co-PLA (135.degree. C.) is in the sheath. Generally, the
low melt Co-PLA is fully amorphous, which makes it easier to melt
and flow around the crystalline mono-component PLA fibers. The core
PLA fiber remains and combines with (bonds to) the mono-PLA fiber
at many cross-over points in the web for strength. A web comprising
PLA fibers has two different melting points, 145 C-175 C and 105
C-165 C, respectively. The PLA fibers have a melting (softening)
point of 145 C to 175 C and the Co-PLA fiber, mono-component is
CoPLA with a melt temperature from 105 C to 165 C.
[0066] The blend percentages were varied from 90% PLA/10% BiCo to
60% PLA/40% BiCo. The 70/30% produced the best fabric for strength
and sealability. It is also possible to make a blend of crystalline
PLA (175.degree. C. melt point) and a mono-component fiber made
from 100% Co-PLA (melt point between 135.degree. and 165.degree.
C.) Blending is performed by weighing out the desired percentages
of PLA and BiCo fibers either manually or with automated weigh
feeders. The two fibers are layered on top of each other and fed
into an opener which has feed rolls, feeding the fibers into a
cylinder with teeth that pulls the clumps into individual fibers.
The fibers are then blown into a blending bin to create a
homogeneous mixture by first layering the fibers uniformly in the
bin and then cross-cutting the layers with a spiked apron which
feeds the fibers to a carding system.
[0067] The carding system consists of two feeding hoppers. The
first acts as a reserve holding bin to ensure continuous supply.
The second feeding hopper has a continuous scale with a load cell
that provides a set weight feed to the card. The card is a series
of interacting cylinders covered with toothed wire that tears and
combs the fibers into a parallel web.
[0068] The fabric weights were varied from 12 to 20 gsm, with the
18 gsm chosen for testing. It is believed that the 16 gsm (not run)
will provide the best characteristics.
[0069] The production line was a Asselin-Thibeau line with 3
carding machines, each 2.3 meters wide. The web was run in a
straight line and fed into a calendar with 460 mm diameter rolls
heat with thermal oil at a temperature of 130.degree. C. to
152.degree. C. Line speeds were 40 meters per minute at a finished
width of 2.0 meters.
[0070] If a parallel web is desired, the fibers coming straight out
of the carding system are combined with the other two cards and
thermo-bonded. This generally results in a Machine Direction
(MD)/Cross Machine Direction (CMD) strength ratio of 4:1. If a more
balanced strength ratio is desired then a "randomizer" roll system
may be added to one or more cards. The result can be MD/CMD
strength ratio up to 1.5:1.
[0071] By controlling the carding system and fiber orientation, the
fibers can be aligned in a manner to control the apertures or
openings in the web to enhance rapid infusion of the hot water.
[0072] The rolls were slit to a width of 156 mm (6.14'') for the
Tea Bag machine.
[0073] The tea bag machine was a model ASK020 made by Miflex Masz.
Two rolls were placed on the machine and centered on the mold. The
correct amount of tea was deposited and the top and bottom sheet
sealed automatically at a temperature of 135 C with a dwell time
between 0.5 and 0.8 seconds,
[0074] The present invention cuts easily on standard tea/coffee
packaging machines with a simple knife device and creates minimal
amount of lint or loose fibers.
[0075] The web maintains its pore size during the infusion with hot
liquids because the fibers do not swell. This enhances to flow of
water into the tea or coffee, reducing the brewing time.
[0076] Because the web fibers do not swell, the risk of gas
pressure build up is eliminated and thus the risk of bag breakage
and particle dispersion is eliminated.
[0077] Using boiling water, the infusion time is reduced to one (1)
minute
[0078] When pressed, the infusion liquid completely leaves the
container (bag or pouch), leaving a silky, translucent surface.
[0079] Recycling of PLA is very easy, a depend on the place in the
process. During fiber manufacture, all of the fibers from both
spinning and drawing can be re-extruded to pellets by densifying
the fiber scrap using an "Erema" or "Mechanic Moderne" recycling
line (There are many others that will also work). The equipment
will density the fibers and partially melt them to pre-dry to drive
off any moisture. The dense particles are forced into a vented
extruded to remove all of the moisture. The PLA is then fully
melted and extruded and filtered to form pure amorphous pellets.
The pellets can then be blended with virgin pellets to make new
fiber. During the Thermo-Bond process, scrap fiber, edge trim, and
defective fabric can be baled and shipped back to the recycling
system described above. During the Tea-Bag process, the trimming
scrap and "skeleton" scrap, especially from making round pouches,
can be baled and reprocessed as described above. Finally, the tea
bags can be composted after use and the PLA will turn back into
sugars which can be used to make more PLA.
[0080] The present invention may also be used as pouches for:
lemonade, herbal sachets, soap powder, chemicals and chlorine for
pools and spas, decontaminating liquids, coloring of liquids,
dehumidifying chemicals, carriers for phase-change materials for
heating or cooling, tobacco pouches, and all materials that can be
placed in a heat/ultra sound activated scalable container,
[0081] A further preferred embodiment comprises a tea bag material
and end product made in whole or in part of a mono-component fiber
with self bonding property to similar fibers or other to produce
effective web material and effective end product.
[0082] A preferred mono-component is co-PLA with a melt temperature
of 135.degree. C. Such a fiber was produced in a 1.3
denier.times.38 mm fiber. This produced a fiber which is 100%
binder as opposed to a bi-component fiber, generally consisting of
50/50 PLA/Co-PLA. The Mono-component fiber was blended with
standard PLA fiber in a ratio of 85% PLA/15% CoPLA. The blend was
processed on a carded web line at 18 and 20 gsm. The result was a
significantly stronger web than that produced with the bi-component
fiber. The web was clearer and less opaque than the one with the
Bi-co fiber. This is a very desirable attribute.
[0083] In a second trial, the mono-component Co-PLA fiber was
blended with the type 811 PLA fibers in a ratio of 80/20%. The web
was produced in a weight of 18 and 20 gsm. The strength increased
and the fabric was less opaque or more translucent. Rolls of both
of the types were then slit to appropriate widths and processed on
tea bag machines. A further advantage was that the PLA/CoPLA blend
absorbed less water that the standard paper. While both the PLA and
Standard paper weighed 18 gsm dry, the PLA reached 90 gsm when
fully saturated with water, while the standard paper reached 200
gsm.
[0084] A first trial was on a Fuso machine replacing an expensive
nylon fabric. The tea bags formed well and the seams were stronger
than those made with the nylon fabric. The 18 gsm with the 80/20
blend provided the best results.
[0085] To improve strength, uniformity, and fiber distribution, one
of the carding machines (out of 5) was modified by placing a
randomizing unit on the doffer or take off rolls. On a standard
card machine, the fiber orientation is generally 5:1 in the machine
versus cross machine direction and can be optimized to 3.5:1. With
the randomizing rolls, the orientation is about 1.5:1 for the card
with the randomizer. The resultant composite web had an orientation
of between 2:1 and 3:1. This was a significant improvement. The
resultant webs showed no degradation of strength during wet
conditions that standard tea bag paper exhibits.
[0086] It will now be apparent to those skilled in the art that
other embodiments, improvements, details, and uses can be made
consistent with the letter and spirit of the foregoing disclosure
and within the scope of this patent, which is limited only by the
following claims, construed in accordance with the patent law,
including the doctrine of equivalents.
* * * * *