U.S. patent application number 10/744460 was filed with the patent office on 2005-06-23 for specialty beverage infusion package.
Invention is credited to Jordan, Joy Francine, McClellan, Rowland Jaynes JR., Potts, David Charles, Seters, Anne van, Strack, David Craige.
Application Number | 20050136155 10/744460 |
Document ID | / |
Family ID | 34678867 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050136155 |
Kind Code |
A1 |
Jordan, Joy Francine ; et
al. |
June 23, 2005 |
Specialty beverage infusion package
Abstract
The present invention provides an infusion beverage package
having a good balance of properties including, being biodegradable,
good tensile strength and a short infusion times, while being
transparent enough so as to enable a user of the package to see the
contained infusion beverage precursor within the package before
infusing the package into water. The infusion beverage package of
the present invention is prepared from a porous web derived from a
biodegradable thermoplastic polymer, wherein the package has a
transparency of at least about 30%, a tensile strength of at least
about 2N/15 mm, and an infusion time of less than about 20 seconds.
In addition, the seal strength of the package is at least 2N/15
mm.
Inventors: |
Jordan, Joy Francine;
(Marietta, GA) ; Strack, David Craige; (Canton,
GA) ; Seters, Anne van; (Utrecht, NL) ; Potts,
David Charles; (Dunwoody, GA) ; McClellan, Rowland
Jaynes JR.; (Alpharetta, GA) |
Correspondence
Address: |
KIMBERLY-CLARK WORLDWIDE, INC.
401 NORTH LAKE STREET
NEENAH
WI
54956
|
Family ID: |
34678867 |
Appl. No.: |
10/744460 |
Filed: |
December 22, 2003 |
Current U.S.
Class: |
426/77 |
Current CPC
Class: |
B65D 85/808 20130101;
D04H 3/16 20130101; D04H 1/70 20130101; B65D 65/466 20130101; Y02W
90/13 20150501; Y02W 90/10 20150501; D04H 1/56 20130101 |
Class at
Publication: |
426/077 |
International
Class: |
B65B 029/02 |
Claims
We claim:
1. An infusion beverage package comprising a porous web comprising
a biodegradable thermoplastic polymer, wherein said package has a
transparency of at least about 30%, a tensile strength of at least
about 2N/15 mm , and a sink time of less than about 20 seconds.
2. The package of claim 1, wherein the web comprises a nonwoven
web.
3. The package of claim 1, wherein the biodegradable thermoplastic
polymer comprises an aliphatic polyester.
4. The package of claim 3, wherein the aliphatic polyester
comprises at least one member selected from polyhydroxy butyrate
(PHP), polyhydroxy butyrate-co-valerate (PHBV), polycaprolactane,
polybutylene succinate, polybutylene succinate-co-adipate,
polyglycolic acid (PGA), polylactide or polylactic acid (PLA),
polybutylene oxalate, polyethylene adipate, polyparadioxanone,
polymorpholineviones, and polydioxipane-2-one.
5. The package of claim 4, wherein the aliphatic polyester
comprises polylactide.
6. The package of claim 2, wherein the nonwoven web comprises a
spunbond nonwoven web, an airlaid nonwoven web, a bonded carded web
or a meltblown nonwoven web.
7. The package of claim 6, wherein the nonwoven web comprises a
spunbond nonwoven web.
8. The package of claim 2, wherein fibers of the nonwoven web
comprise monocomponent fibers, multicomponent fibers,
multiconstituent fibers or a mixture thereof.
9. The package of claim 8, wherein the fiber comprises
monocomponent fibers and the fibers comprise an aliphatic
polyester.
10. The package of claim 8, wherein the fibers comprise
multiconstituent fibers and comprises an aliphatic polyester as a
constituent of the multiconstituent fibers.
11. The package of claim 8, wherein the fiber multicomponent fibers
and one of the components of the multicomponent fibers comprises an
aliphatic polyester.
12. The infusion beverage package of claim 1, further comprising an
infusion beverage precursor contained within the package.
13. The package of claim 1, where the porous web comprises a
hydrophilic treatment.
14. The package of claim 13, wherein the hydrophilic treatment
comprises a corona glow discharge, a hydrophilic polymeric
material, a plant extract, or a combination thereof.
15. The package of claim 1, wherein the sink time is less than
about 10 seconds.
16. The package of claim 15, wherein the transparency is between
30% and 70%, the tensile strength is approximately 2 to 5 N/15
mm.
17. The package of claim 1, wherein the heat seal strength is
approximately 2 to 15 N/15 mm.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a porous infusion beverage
package, which holds an infusion beverage precursor material.
BACKGROUND OF THE INVENTION
[0002] Infusion beverage packages are known in the art and
typically contain a beverage precursor material, such as tea or
coffee. To produce a beverage, the package containing the beverage
precursor is typically infused into hot water, by placing the
package into hot water, pouring hot water onto or through the
package, or heating water to desired temperature while the package
is immersed in the water. Alternatively, the beverage infusion
package may be placed in cold water to form the beverage.
[0003] These packages are generally in the form of a pouch, a bag
or a sachet and are generally prepared from a very thin and light
weight paper product. Typically, these packages are translucent
when wet, and the contents of the package can only be seen after
the package has been infused or while the package is infused in
water.
[0004] Recently, tea bags have been produced form biodegradable
thermoplastic polymers such as polylactic acids. See, for example,
Japan published patent applications 2001-063757 A2 and 2002-101506
A2. In addition, polylactic acid binder fibers have been added to
the paper making process to produce beverage infusion package, as
is taught in WO 02/02871 A1.
[0005] Over the last couple of years, the infusion beverage
industry has gone to more specialty products, such as long leaf tea
leaves. However, with the current infusion beverage packages, the
customer is unable to see the specialty beverage precursor due to
the translucent nature of the current packages available and is
unable to appreciate the nature and quality of the product. The
customer is often unsure whether or not they are receiving a
premium product. One method of preparing infusion type beverage
with the premium precursors is to place the precursor directly in
the beverage container. However, this method runs the risk that the
beverage precursor will be ingested by the user.
[0006] With this in mind, there is a need in the art to have an
infusion beverage package that will enable the user of the package
to see the quality of the infusion beverage precursor, wherein the
package also has sufficient strength, a quick infusion time and is
biodegradable after use.
SUMMARY OF THE INVENTION
[0007] The present invention provides an infusion beverage package
having a good balance of properties including, being biodegradable,
good tensile strength and a short sink times, while being
transparent enough so as to enable a user of the package to see the
contained infusion beverage precursor within the package before
infusing the package into water. The infusion beverage package of
the present invention is prepared from a porous web derived from a
biodegradable thermoplastic polymer, wherein the package has a
transparency of at least about 30%, a tensile strength of at least
about 2N/15 mm, and an infusion time of less than about 20 seconds.
In addition, the seal strength of the package is at least 2N/15
mm.
[0008] The infusion beverage package of the present invention may
be made hydrophilic by treating the package material with a
hydrophilic treatment. Rendering the infusion beverage package
hydrophilic reduces the sink time of the package and contents in
water. Examples of hydrophilic treatments which can be used in this
invention include, a corona treatment, coating with package
material with a durable hydrophilic polymeric coating and treating
the package material with a plant-based extract.
BRIEF DESCRIPTION OF DRAWINGS
[0009] FIG. 1 shows the apparatus used to measure the transparency
of the infusion beverage package.
DEFINITIONS
[0010] As used herein, the term "comprising" is inclusive or
open-ended and does not exclude additional unrecited elements,
compositional components, or method steps.
[0011] As used herein, "biodegradable" is meant to represent that a
material degrades from the action of naturally occurring
microorganisms such as bacteria, fungi, algae and the like.
"Biodegradable" also includes a material which degrades in the
presence of oxygen over an extended period of time.
[0012] As used herein, the term "polymer" generally includes, but
is not limited to, homopolymers, copolymers, such as for example,
block, graft, random and alternating copolymers, terpolymers, etc.
and blends and modifications thereof. Furthermore, unless otherwise
specifically limited, the term "polymer" shall include all possible
geometrical configurations of the molecule. These configurations
include, but are not limited to isotactic, syndiotactic and random
symmetries.
[0013] As used herein, the term "fiber" includes both staple
fibers, i.e., fibers which have a defined length between about 19
mm and about 60 mm, fibers longer than staple fiber but are not
continuous, and continuous fibers, which are sometimes called
"substantially continuous filaments" or-simply "filaments". The
method in which the fiber is prepared will determine if the fiber
is a staple fiber or a continuous filament.
[0014] As used herein, the term "nonwoven web" means a web having a
structure of individual fibers or threads which are interlaid, but
not in an identifiable manner as in a knitted web. Nonwoven webs
have been formed from many processes, such as, for example,
meltblowing processes, spunbonding processes, air-laying processes,
coforming processes and bonded carded web processes. The basis
weight of nonwoven webs is usually expressed in ounces of material
per square yard (osy) or grams per square meter (gsm) and the fiber
diameters useful are usually expressed in microns, or in the case
of staple fibers, denier. It is noted that to convert from osy to
gsm, multiply osy by 33.91.
[0015] As used herein the term "spunbond fibers" refers to small
diameter fibers of a drawn polymeric material. Spunbond fibers may
be formed by extruding molten thermoplastic material as filaments
from a plurality of fine, usually circular capillaries of a
spinneret with the diameter of the extruded filaments then being
rapidly reduced as in, for example, U.S. Pat. No.4,340,563 to Appel
et al., and U.S. Pat. No. 3,692,618 to Dorschner et al., U.S. Pat.
No. 3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992 and
3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, U.S. Pat.
No. 3,542,615 to Dobo et al, and U.S. Pat. No. 5,382,400 to Pike et
al., each herein incorporated by reference. Spunbond fibers are
generally not tacky when they are deposited onto a collecting
surface and are generally continuous. Spunbond fibers are often
about 10 microns or greater in diameter. However, fine fiber
spunbond webs (having an average fiber diameter less than about 10
microns) may be achieved by various methods including, but not
limited to, those described in commonly assigned U.S. Pat. No.
6,200,669 to Marmon et al. and U.S. Pat. No. 5,759,926 to Pike et
al., each is hereby incorporated by reference in its entirety.
[0016] As used herein, the term "meltblown fibers" means fibers
formed by extruding a molten thermoplastic material through a
plurality of fine, usually circular, die capillaries as molten
threads or filaments into converging high velocity, usually hot,
gas (e.g. air) streams which attenuate the filaments of molten
thermoplastic material to reduce their diameter, which may be to
microfiber diameter. Thereafter, the meltblown fibers are carried
by the high velocity gas stream and are deposited on a collecting
surface to form a web of randomly dispersed meltblown fibers. Such
a process is disclosed, for example, in U.S. Pat. No. 3,849,241 to
Butin, which is hereby incorporated by reference in its entirety.
Meltblown fibers are microfibers, which may be continuous or
discontinuous, and are generally smaller than 10 microns in average
diameter The term "meltblown" is also intended to cover other
processes in which a high velocity gas, (usually air) is used to
aid in the formation of the filaments, such as melt spraying or
centrifugal spinning.
[0017] "Bonded carded web" refers to webs that are made from staple
fibers which are sent through a combing or carding unit, which
separates or breaks apart and aligns the staple fibers in the
machine direction to form a generally machine direction-oriented
fibrous nonwoven web. Such fibers are usually purchased in bales
which are placed in an opener/blender or picker which separates the
fibers prior to the carding unit. Once the web is formed, it then
is bonded by one or more of several known bonding methods. One such
bonding method is powder bonding, wherein a powdered adhesive is
distributed through the web and then activated, usually by heating
the web and adhesive with hot air. Another suitable bonding method
is pattern bonding, wherein heated calender rolls or ultrasonic
bonding equipment are used to bond the fibers together, usually in
a localized bond pattern, though the web can be bonded across its
entire surface if so desired. Another suitable and well-known
bonding method, particularly when using bicomponent staple fibers,
is through-air bonding.
[0018] "Airlaying" or "airlaid" is a well known process by which a
fibrous nonwoven layer can be formed. In the airlaying process,
bundles of small fibers having typical lengths ranging from about 3
to about 19 millimeters (mm) are separated and entrained in an air
supply and then deposited onto a forming screen, usually with the
assistance of a vacuum supply. The randomly deposited fibers then
are bonded to one another using, for example, hot air or a spray
adhesive.
[0019] As used herein, the term "multicomponent fibers" refers to
fibers or filaments which have been formed from at least two
polymers extruded from separate extruders but spun together to form
one fiber. Multicomponent fibers are also sometimes referred to as
"conjugate" or "bicomponent" fibers or filaments. The term
"bicomponenr" means that there are two polymeric components making
up the fibers. The polymers are usually different from each other,
although conjugate fibers may be prepared from the same polymer, if
the polymer in each component is different from one another in some
physical property, such as, for example, melting point or the
softening point. In all cases, the polymers are arranged in
substantially constantly positioned distinct zones across the
cross-section of the multicomponent fibers or filaments and extend
continuously along the length of the multicomponent fibers or
filaments. The configuration of such a multicomponent fiber may be,
for example, a sheath/core arrangement, wherein one polymer is
surrounded by another, a side-by-side arrangement, a pie
arrangement or an "islands-in-the-sea" arrangement. Multicomponent
fibers are taught in U.S. Pat. No. 5,108,820 to Kaneko et al.; U.S.
Pat. No. 5,336,552 to Strack et al.; and U.S. Pat. No. 5,382,400 to
Pike et al.; the entire content of each is incorporated herein by
reference. For two component fibers or filaments, the polymers may
be present in ratios of 75/25, 50/50, 25/75 or any other desired
ratios.
[0020] As used herein, the term "multiconstituent fibers" refers to
fibers which have been formed from at least two polymers extruded
from the same extruder as a blend or mixture. Multiconstituent
fibers do not have the various polymer components arranged in
relatively constantly positioned distinct zones across the
cross-sectional area of the fiber and the various polymers are
usually not continuous along the entire length of the fiber,
instead usually forming fibrils or protofibrils which start and end
at random. Fibers of this general type are discussed in, for
example, U.S. Pat. Nos. 5,108,827 and 5,294,482 to Gessner.
[0021] As used herein, the term "pattern bonded" refers to a
process of bonding a nonwoven web in a pattern by the application
of heat and pressure or other methods, such as ultrasonic bonding.
Thermal pattern bonding typically is carried out at a temperature
in a range of from about 80.degree. C. to about 180.degree. C. and
a pressure in a range of from about 150 to about 1,000 pounds per
linear inch (59-178 kg/cm). The pattern employed typically will
have from about 10 to about 250 bonds/inch.sup.2 (1-40
bonds/cm.sup.2) covering from about 5 to about 30 percent of the
surface area. Such pattern bonding is accomplished in accordance
with known procedures. See, for example, U.S. Pat. No. 239,566 to
Vogt, U.S. Pat. No. 264,512 to Rogers, U.S. Pat. No. 3,855,046 to
Hansen et al., and U.S. Pat. No. 4,493,868, supra, for
illustrations of bonding patterns and a discussion of bonding
procedures, which patents are incorporated herein by reference.
Ultrasonic bonding is performed, for example, by passing the
multilayer nonwoven web laminate between a sonic horn and anvil
roll as illustrated in U.S. Pat. No. 4,374,888 to Bornslaeger,
which is hereby incorporated by reference in its entirety.
[0022] As used herein the term "denier" refers to a commonly used
expression of fiber thickness which is defined as grams per 9000
meters. A lower denier indicates a finer fiber and a higher denier
indicates a thicker or heavier fiber. Denier can be converted to
the international measurement "dtex", which is defined as grams per
10,000 meters, by dividing denier by 0.9.
[0023] Description of the Test Methods
[0024] Sink time is measured by a test where a 5 gram sample of
material is placed in a 8 cm high, 5 cm in diameter wire cage
cylinder prepared from a wire of suitable gauge so that the
cylinder weighs 3 grams. The cage and the material are dropped into
room temperature water and the time of the basket to sink is
measured. The full test procedure is outlined in ISO-9073, which is
incorporated by reference.
[0025] Transparency is measure using a spectrophotometer, a light
source and a filter holder. Any spectrophotometer may be used. For
a better understanding of the set-up used attention is directed to
FIG. 1. The set-up 10 includes a sample holder 12. The sample 14 is
placed between two glass plates 16 and the glass plates 16 are held
against an upright portion of the holder 12', using a spring clip
18. The spring clip and upright portion of the holder 12' are
configured such that light is uninhibited from the light source 20
and the detector 22. The light from the light source 20 is focused
through a lens 24 and reflected from a mirror 26 towards the sample
14 and the detector 22. Samples of the material to be tested are
cut to a minimum of 16 mm (wide).times.32 mm (long) to a maximum of
25 mm (wide).times.55 mm (long), depending on the size of the
sample holder. For a given material, twelve samples of the material
were tested at a wavelength of 445 nm. The highest and lowest
values were discarded and the average transparency for the ten
remaining data points is reported. The transparency is reported as
a percentage of the light at 445 nm being detected by the detector.
A transparency of 100% means that all or nearly all of the light is
transmitted through the sample and is being detected by the
detector. A transparency of 0% means that none of the light is
transmitted through the sample.
[0026] Tensile strength is measured in accordance with
ASTM-ISO-1924-2. The material to be tested is cut into strips 25 mm
in width. The clamps, which are 15 mm in width, of the tensile
tester were set at 180 mm apart and the clamps are separated at a
rate of 20 mm/min.+-.5 mm/min. The force at failure is
reported.
[0027] The following process measures heat seal strength. Ten
sample of 100 mm.times.100 mm are cleanly cut. Two pieces of the
samples are placed in face to face contact with one another. About
a 2 mm wide seam is formed by sealing the pieces with a bar at a
pressure of 70-100 N/cm.sup.2, at a temperature of 230.degree.
(110.degree. C.)-300+ (149.degree. C.) for 0.5 to 2.0 seconds
depending on the polymers used. The seam is formed approximately
2/3 from one of the edges of the material. Next the samples are cut
into strips 25 mm wide such that the cuts are perpendicular to the
seam formed across the sample. In addition, the samples were cut
into 100 mm long strips such that the seam is in the middle of the
strips. The samples are allowed to stand at standard conditions
(23.degree. C. and 50% Relative humidity) for 5. minutes before
testing. The samples are placed in the tensile tester and the seam
placed in the middle of the upper and lower gripping jaws. The
upper and lower jaws are set at 100 mm apart. The samples were
tested at a rate of 100 mm/min. After testing, the value at failure
is recorded and it is noted if the seam failed or if the material
failed.
[0028] Sift out test is completed to determine the ability of the
material being tested to retain the infusion beverage. In this
test, seven grades of sand are used to determine the ability of the
material to retain particles. The seven grades, referred to as
grade 1, grade 2, grade 3, grade 4, grade 5, grade 6 and grade 7
have diameters of 75-106 .mu.m, 106-150 .mu.m, 150-250 .mu.m,
250-355 .mu.m, 355-500 .mu.m, 500-710 .mu.m and 710-1000 .mu.m,
respectively. A sample is cut to the shape and size of the
particular horizontal shaker and/or Kilner jar used in the test. 10
g of each grade of sand are placed in three different Kilner jars.
The ring of the Kilner jar is place on the jar with an appropriate
size and shaped material sample being tested. A container, which is
weighed before testing, is place over the Kilner jar. Each assembly
of the jar, sand, ring, container and sample is inverted and placed
on the shaker. Any type of shaker can be used. The shaker is
operated at 3.55 Hz with a stroke of 37 mm for 14 minutes. After
the shaker stops, the Kilner jar and sample are remove from the
container. The weight of the sand in each of the three containers
is measured and the weight percentage of sand which penetrated the
sample is calculated, using the following equation: 1 % sand =
weightofcontainerandsandaftertest - weightofcontainerbeforetest
weightofsandplacedin Kilnerjar
[0029] Detailed Description of the Invention
[0030] The present invention provides an infusion beverage package
having a good balance of properties including, being biodegradable,
having good tensile strength and short infusion times, while being
transparent enough so as to enable a user of the package to see the
contained infusion beverage precursor within the package before
infusion. The infusion beverage package of the present invention is
prepared from a porous web comprising a biodegradable thermoplastic
polymer, wherein the package has a transparency of at least about
30%, a tensile strength of at least about 2N/15 mm, and an infusion
time of less than about 20 seconds. In addition, it is desirable
that the package has a heat seal strength of at least 2N/15 mm. The
package needs to also have the ability to contain the infusion
beverage precursor.
[0031] The package material may be prepared from a porous substrate
which has a sheet-like structure, such as a web or a film. The
sheet-like material also may be a fibrous web, such as a woven or
nonwoven fabric or web. The substrate also may include polymer
fibers, per se, or polymer fibers which have been formed into a
fibrous web. The fibrous web desirably will be a nonwoven web, such
as, but not limited to, a meltblown web, a spunbond web, a bonded
carded web, or an air-laid web. The substrate also may be a
laminate of two or more layers of a sheet-like material. For
example, the layers may be independently selected from the group
consisting of meltblown webs, spunbond webs, bonded carded webs,
and air-laid webs. However, other sheet-like materials may be used
in addition to, or instead of, meltblown webs, spunbond webs,
bonded carded webs, or air-laid webs. Other porous sheet like
materials include, for example, a perforated film or a fiberated
film. In addition, the layers of a laminate may be prepared from
the same biodegradable polymer or different biodegradable
polymers.
[0032] In the present invention, any biodegradable polymers may be
used provided that they do not lose their strength when immersed in
water under conditions of use. The biodegradable polymers used to
produce the porous web include biodegradable aliphatic polyester
polymers. Examples of biodegradable aliphatic polyesters usable in
the present invention include, but are not limited to polyhydroxy
butyrate (PHP), polyhydroxy butyrate-co-valerate (PHBV),
polycaprolactane, polybutylene succinate, polybutylene
succinate-co-adipate, polyglycolic acid (PGA), polylactide or
polylactic acid (PLA), polybutylene oxalate, polyethylene adipate,
polyparadioxanone, polymorpholineviones, and polydioxipane-2-one.
Of these aliphatic polyesters, polyglycolic acid and polylactide
(polylactic acid) are desirable due to the availability and recent
manufacturing advances. Due to current cost considerations,
polylactide (polylactic acid) is most desired.
[0033] Polylactides are sometimes referred to as polylactic acid.
As used herein, the term polylactide is intended to cover both
polylactides and polylactic acid. Polylactides are often
abbreviated "PLA". Polylactide polymers are commercially available
from Cargill-Dow LLC, Minnetonka, Minn., for example, 6200 D grade
as described by EP 1 312 702 A1, from PURAC America, Lincolnshire,
Ill. and from Biomer, Krailling Germany. Polylactides are also
described in U.S. Pat. No. 5,338,822 to Gruber et al.; U.S. Pat.
No. 6,111,060 to Gruber et al.; U.S. Pat. No. 5,556,895 to Lipinsky
et al.; U.S. Pat. No. 5,801,223 to Lipinsky et al.; U.S. Pat. No.
6,353,086 to Kolstad et al.; and U.S. Pat. No. 6,506,873 to Ryan et
al., each hereby incorporated by reference in its entirety.
[0034] The material used to produce the infusion beverage package
must have sufficient tensile strength so as not to tear or rip
during handing or use. In addition, the material must be able to be
sealed desirably with heat with a sufficient strength so that the
seam formed to contain the infusion beverage precursor will be
retained in the package during handling and use. The material of
the package should have a tensile strength of at least 2N/15 mm, as
measured by the method described above, and the heat seal strength
should also be at least 2N/15 mm as measured by the test described
above. Generally, the tear strength is in the range of about 2 N/15
mm and about 10 N/15 mm and usually in the range of about 2 N/15 mm
to about 5 N/15 mm. Similarly, the heat seal strength should be
between about 2 N/15 mm and about 10 N/15 mm and usually in the
range of about 2 N/15 mm to about 5 N/15 mm.
[0035] The material used for the infusion beverage package also has
a transparency of at least 30%. Transparency is measured by the
test describe above. The transparency is generally in the range of
about 30 to about 70%. Transparency results from using lightweight
materials to form the web. For example, the material used to
produce the infusion beverage package should have a basis weight
less than about 68 gsm, desirably less than about 51 gsm, most
desirably between about 10 to 20 gsm. Higher basis weight materials
may be used; however, the transparency tends to be reduced as the
basis weight increases.
[0036] When the substrate is a nonwoven web, the fibers of the
nonwoven web layer may be monocomponent fibers, multiconstituent
fibers, or multicomponent fibers. The multicomponent fibers may,
for example, have either of an A/B or ANB/A side-by-side
cross-sectional configuration, a sheath-core cross-sectional
configuration, wherein one polymer component surrounds another
polymer component, a pie cross-sectional arrangement or an
island-in sea arrangement. Each of the polymers of the
multicomponent fibers may be biodegradable, or one may be
biodegradable and the other may not be biodegradable. More than two
components may be used as well. Desirably, the fiber configuration
of the multicomponent fiber is a sheath-core configuration.
[0037] When the polymer fibers are sheath/core fibers, it is
desirable that the sheath component have a lower melting point than
the core component. It is also desirable that the sheath component
of the multicomponent fiber comprise a biodegradable polymer
described above. The fiber may be continuous fiber or staple
fibers. From a standpoint of production, it is preferable that the
fibers are continuous and that the fibers are spunbond fibers.
[0038] When the material used to make the infusion beverage package
is fibrous, it is desirable that the fibers have a small fiber
diameter. In the present invention, it is preferable that the
fibers have a fiber denier less than about 6 dpf (6.66 dtex),
preferable below 5 dpf (5.55 dtex) and generally in the range of
about 0.5 dpf (0.55 dtex) to about 4 dpf (4.44 dtex). Typically,
the desirable denier of the fibers is about 1.5 dpf to about 3 dpf.
As the fiber diameter increases, the transparency of the material
tends to decrease.
[0039] A second polymer may be blended with the biodegradable
polymer, in particular the aliphatic polyester polymer prior to
film, fiber and/or nonwoven web formation to improve the tensile
strength and heat seal strength of the package material. The second
polymer may be added to the biodegradable in an amount up to about
35% by weight based on the weight of the biodegradable polymer. The
amount added depends on a number of factors, such as the percentage
of D isomer units in the biodegradable polymer.
[0040] The selection of the second polymer is such that the second
polymer is thermoplastic and it has a lower melting point and/or a
lower molecular weight than the biodegradable aliphatic polyester
polymer. The second polymer is generally an amorphous polymer.
Addition of the second polymer would favorably influence the melt
rheology of the blend and improve bonding under the process
conditions used. Further, the second polymer is desirably
compatible with the first polymer. Examples of such polymers
include hydrogenated hydrocarbon resins, such as REGALREZ.RTM.
series tackifiers and ARKON.RTM. P series tackifiers. REGALREZ.RTM.
tackifiers are available from Hercules, Incorporated of Wilmington,
Del. REGALREZ.RTM. tackifiers are highly stable, light-colored, low
molecular weight, nonpolar resins. Grade 3102 is said to have a
softening point of 102 R&B.degree. C., a specific gravity at
21.degree. C. of 1.04, a melt viscosity of 100 poise at 149.degree.
C. and a glass transition temperature, Tg, of 51.degree. C.
REGALREZ.RTM. 1094 tackifier is said to have a softening point of
94.degree. C., a specific gravity at 21.degree. C. of 0.99, a melt
viscosity of 100 poise at 126.degree. C. and a glass transition
temperature, Tg, of 33.degree. C. Grade 1126 is said to have a
softening point of 126.degree. C., a specific gravity at 21.degree.
C. of 0.97, a melt viscosity of 100 poise at 159.degree. C. and a
glass transition temperature, Tg, of 65"C. ARKON.RTM.P series
resins are synthetic tackifying resins made by Arakawa Chemical
(U.S.A.), Incorporated of Chicago, Ill. from petroleum hydrocarbon
resins. Grade P-70, for example, has a softening point of
70.degree. C., while grade P-100 has a softening point of
100.degree. C. and Grade P125 has a softening point of 125.degree.
C. ZONATEC.RTM. 501 lite resin is another tackifier which is a
terpene hydrocarbon with a softening point of 105.degree. C. made
by Arizona Chemical Company of Panama City, Fla. EASTMAN.RTM.
1023PL resin is an amorphous polypropylene tackifying agent with a
softening point of 150-155.degree. C. available from Eastman
Chemical Company Longview, Tex.
[0041] Generally, other examples the second polymer include, but
are not limited to, polyamides, ethylene copolymers derived from
ethylene and a non-hydrocarbon monomer such as ethylene vinyl
acetate (EVA), ethylene ethyl acrylate (EEA), ethylene acrylic acid
(EM), ethylene methyl acrylate (EMA) and ethylene normal-butyl
acrylate (ENBA), wood rosin and its derivatives, hydrocarbon
resins, polyterpene resins, atactic polypropylene and amorphous
polypropylene. Also included are predominately amorphous ethylene
propylene copolymers commonly known as ethylene-propylene rubber
(EPR) and a class of materials referred to as toughened
polypropylene (TPP) and olefinic thermoplastic polymers where EPR
is mechanically dispersed or molecularly dispersed via in-reactor
multistage polymerization in polypropylene or
polypropylene/polyethylene blends. Other polymers useable as the
second polymer component hetrophasic polyproplyene available under
the trade designation Catalloy KS 357 P available from Montell.
[0042] In addition, polyalphaolefin resins can also be used as the
second polymer. Polyalphaolefins usable in the present invention
desirably have a melt viscosity of 100,000 mPa sec or greater.
Commercially available amorphous polyalphaolefins, such as those
used in hot melt adhesives, are suitable for use with the present
invention and include, but are not limited to, REXTAC.RTM.
ethylene-propylene APAOE-4 and E-5 and butylene-propylene BM-4 and
BH-5, and REXTAC.RTM. 2301 from Rexene Corporation of Odessa, Tex.,
and VESTOPLAST.RTM. 792, VESTOPLAST.RTM. 520, or VESTOPLAST.RTM.
608 from Huls AG of Marl, Germany. These amorphous polyolefins are
commonly synthesized on a Ziegler-Natta supported catalyst and an
alkyl aluminum co-catalyst, and the olefin, such as propylene, is
polymerized in combination with varied amounts of ethylene,
1-butene, 1-hexane or other materials to produce a predominantly
atactic hydrocarbon chain.
[0043] Other biodegradable polymers having a molecular weight less
than the first biodegradable polymer may also be used. Blending of
the second biodegradable polymer should result in a polymer blend
with improved polymer melt rheology and provide an improvement in
bonding under the process conditions used. It has been discovered
that the tear strength of a nonwoven fabric produced from a mixture
of a crystalline polylactide and a second polylactide which has a
lower melting point as compared to the crystalline polylactide is
vastly improved over the tear strength of a nonwoven from the
crystalline polylactide alone.
[0044] Although other aliphatic polyesters may be used in the
present invention, as is noted above, polylactides are the desired
biodegradable polymer due to cost and availability. However, in
order to form a nonwoven web from polylactides several
considerations must be taken into account. For example, many
polylactides are known to have poor melt stability and tend to
rapidly degrade at elevated temperatures, typically in excess of
210.degree. C. and may generate by-products in sufficient quantity
to foul or coat processing equipment. Desirably, the polylactide
should be sufficiently melt-processable in melt-processing
equipment such as that available commercially. Further, the
polylactide should desirably retain adequate molecular weight and
viscosity. The polymer should have a sufficiently low viscosity at
the temperature of melt-processing so that the extrusion equipment
may create an acceptable nonwoven fabric. The temperature at which
this viscosity is sufficiently low will preferably also be below a
temperature at which substantial degradation occurs.
[0045] In the practice of the present invention in producing a
nonwoven web, the polylactides, as described by U.S. Pat. No.
6,506,873 to Ryan et al. desirably has a number average molecular
weight from about 10,000 to about 300,000, depending on the type of
nonwoven web being formed. For example, in a composition for a
meltblown nonwoven, a polylactide having a number average molecular
weight ranges from about 15,000 to about 100,000 should be used.
Desirably, the number average molecular weight should be in the
range from about 20,000 to about 80,000 for a meltblown web. In
contrast, for a spunbond nonwoven fabric, the desired number
average molecular weight range is from about 50,000 to about
250,000, and more desirably, the number average molecular weight
range is from about 75,000 to about 200,000.
[0046] The lower limit of molecular weight of the polymer
compositions of the present invention is set at a point above the
threshold of which a fiber has sufficient diameter and density. In
other words, the molecular weight cannot be lower than is necessary
to achieve a targeted fiber diameter and density. The practical
upper limit on molecular weight is based on increased viscosity
with increased molecular weight. In order to melt-process a high
molecular weight polylactide, the melt-processing temperature must
be increased to reduce the viscosity of the polymer. The exact
upper limit on molecular weight can be determined for each
melt-processing application in that required viscosities vary and
residence time within the melt-processing equipment will also vary.
Thus, the degree of degradation in each type of processing system
will also vary. One skilled in the art could determine the suitable
molecular weight upper limit for meeting the viscosity and
degradation requirements in any application and the equipment being
used.
[0047] The polylactides used as the biodegradable aliphatic
polyester are desirably crystalline. Polylactides with a
predominate L-lactide configuration are more crystalline than
polylactides having a portion of D-lactide configuration. The
D-lactide configuration isomer is an impurity which is naturally
formed during the production of the poly(l-lactide). The larger the
percentage of the D-isomer present in the polylactide, the slower
the rate of crystallization. Ideally, in the present invention it
is desirable the polylactide have less than about 4.5% by weight of
the D-isomer. Desirably, the D-isomer should make-up less than
about 3.0% by weight and more desirable less than about 2.0% by
weight of the poly(L-lactide).
[0048] Lactide polymers may also be in either an essentially
amorphous form or in a semi-crystalline form. Generally, the
desired range of compositions for semi-crystalline poly(lactide) is
less than about 6% by weight D-isomer lactide and the remaining
percent by weight either L-lactide or D-lactide, with L-lactide
being more readily available. A more preferred composition contains
less than about 4.5% by weight D-lactide with the remainder being
substantially all L-lactide.
[0049] In polylactides which are amorphous polymers, the preferred
composition of the reaction mixture is above 4.5% by weight
D-lactide and a more desirably above 6.0% by weight D-lactide with
the remaining lactide being substantially all L-lactide mixture.
Stated another way, the more D-lactide present in a given
polylactide, the less crystalline the polylactide. The D-lactide
isomer can be used to control the crystallinity in a predominantly
L-lactide polylactide polymer.
[0050] Even small amounts of D-lactide in a polymer will be slower
to crystallize than polymerization mixtures having lesser amounts
of D-lactide. Beyond about 6.0% by weight of the D-lactide content,
the polymer remains essentially amorphous following a typical
annealing procedure.
[0051] The polydispersity index (PDI) of the polylactide polymer is
generally a function of branching or crosslinking and is a measure
of the breadth of the molecular weight distribution. In most
applications where crystalline polylactide is desired, the PDI of
the polylactide polymer should be between about. 1.5 and about 3.5,
and preferably between about 2.0 and about 3.0. Of course,
increased bridging or crosslinking may increase the PDI
Furthermore, the melt flow index of the polylactide polymer should
be in the ranges measured at 210.degree. C. with a 2.16 Kg weight.
For meltblown fibers the melt flow index should be between about 50
and 5000, and preferably between about 100 and 2000. For spunbond
fibers the melt flow index should be between about 10 and 100, and
more preferably between about 25 and about 75.
[0052] The biodegradable polymeric porous web may be rendered
hydrophilic with a durable hydrophilic treatment by one of two
methods. In a first method of the present invention, the
biodegradable polymeric substrate is rendered hydrophilic by
subjecting the substrate to a corona glow discharge. In this
method, the biodegradable polymeric substrate having a surface is
subjected to a corona glow discharge to render the surface
hydrophilic.
[0053] Corona glow discharge treatments of polymeric films are
known in the art and result in a chemical modification of the
polymers in the surface of the polymeric material. See for example
U.S. Pat. No. 3,880,966 to Zimmerman et al., U.S. Pat. No.
3,471,597 to Schirmer Corona discharge treatment of films is also
old in the art and it is known that corona discharge treatment of a
polymer film in the presence of air entails substantial
morphological and chemical modifications in the polymer film's
surface region. See Catoire et al, "Physicochemical modifications
of superficial regions of low-density polyethylene (LDPE) film
under corona discharge," Polymer, vol. 25, p. 766, et. seq, June,
1984.
[0054] Generally speaking, corona treatment has been utilized to
either (1) improve the print fastness on the film, or (2) to
perforate the film. For example, U.S. Pat. No. 4,283,291 to Lowther
describes an apparatus for providing a corona discharge, and U.S.
Pat. No. 3,880,966 to Zimmerman et al discloses a method of using a
corona discharge to perforate a crystalline elastic polymer film
and thus increase its permeability. U.S. Pat. No. 3,471,597 to
Schirmer also discloses a method for perforating a film by corona
discharge. U.S. Pat. No. 3,754,117 to Walter discloses an apparatus
and method for corona discharge treatment for modifying the surface
properties of thin layers or fibers which improve the adhesion of
subsequently applied inks or paints or of subsequent bonding.
[0055] In the present invention, the biodegradable polymeric
substrate is exposed to a corona field. As used herein, the term
"corona field" means a corona field of ionized gas. In general, the
generation of a corona field and exposure of the fibers are
accomplished in accordance with procedures which are well known to
those having ordinary skill in the art. The dose or energy density
to which the fibers are exposed can range from about 1 to about 500
watt-minute per square foot (w-min/ft.sup.2), which is
approximately equivalent to a range of from about 0.6 to about 323
kilojoules per square meter (kJ/m.sup.2). Desirably, such dose will
be in a range of from about 15 to about 350 w-min/ft.sup.2 (from
about 10 to about 226 kJ/m.sup.2). Most desirably, the dose will be
in a range of from about 20 to about 80 W-min/ft.sup.min/ft.sup.2
(from about 13 to about 52 kJ/m.sup.2). Desirably, the corona glow
discharge treatment is applied to the substrate under ambient
temperature and pressure; however, higher or lower temperature and
pressures may be used.
[0056] In a second method of the present invention, the
biodegradable polymeric substrate is rendered hydrophilic with a
durable hydrophilic treatment by coating onto the substrate, a
hydrophilic polymeric material which is durable to an aqueous
medium at a temperature in a range of from about 10.degree. C. to
about 90.degree. C. and does not significantly suppress the surface
tension of an aqueous medium with which the fibrous web may come in
contact. For example, the surface tension of the aqueous medium may
not be suppressed or lowered more than about 10 percent.
[0057] By way of illustration only, the hydrophilic polymeric
material may be a polysaccharide. The polysaccharide may have a
plurality of hydrophobic groups and a plurality of hydrophilic
groups. The hydrophobic groups may be .dbd.CH-- and --CH2-- groups
in the polysaccharide backbone. The hydrophobic groups may be
adapted to provide an affinity of the polymeric coating material
for biodegradable polymeric substrate and the hydrophilic groups
may be adapted to render the polymeric material hydrophilic.
Examples of polysaccharides include, for example, natural gums,
such as agar, agarose, carrageenans, furcelleran, aiginates, locust
bean gum, gum arabic, guar gum, gum konjac, and gum karaya;
microbial fermentation products, such as gellan gum, xanthan gum,
and dextran gum; cellulose, such as microcrystalline cellulose; and
animal products, such as hyaluronic acid, heparin, chitin, and
chitosan.
[0058] Again by way of illustration only, the hydrophilic polymeric
material may be a modified polysaccharide. A modified
polysaccharide also may have a plurality of hydrophobic groups and
a plurality of hydrophilic groups. The hydrophobic groups may be
.dbd.CH-- and --CH2-- groups in the polysaccharide backbone, or
pendant groups. The hydrophilic groups also may be pendant groups.
Again, the hydrophobic groups may be adapted to provide an affinity
of the biodegradable polymeric substrate and the hydrophilic groups
may be adapted to render the polymeric material hydrophilic. By way
of illustration only, examples of modified polysaccharides include
modified celluloses or cellulose derivatives, such as hydroxyethyl
cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl
cellulose, methyl hydroxypropyl cellulose, ethyl hydroxyethyl
cellulose, and carboxymethyl cellulose; starch and pectin
derivatives, such as carboxymethyl starch, starch aldehyde, and
pectates; and animal product derivatives, such as carboxymethyl
chitin and carboxymethyl chitosan.
[0059] Particularly useful types of polysaccharides and modified
polysaccharides include, by way of illustration, agar; alginates;
and modified celluloses, such as ethyl hydroxyethyl cellulose. In
modified polysaccharides, particularly in the useful type of
modified polysaccharides just noted, the hydrophobic groups may be
pendant monovalent alkyl groups. For example, such hydrophobic
groups may be methyl or ethyl groups. As a further example, the
hydrophilic groups may be pendant monovalent hydroxyalkyl groups.
As yet another example, such hydrophilic groups may be hydroxyethyl
groups.
[0060] Turning now to the method for preparing a coated substrate,
the method involves providing a biodegradable polymeric substrate
and optionally exposing at least a portion or all of the substrate
to a field of reactive species. At least a portion of the
substrate, including any portion exposed to the field of reactive
species, then is treated with a mixture which includes water and a
hydrophilic polymeric material as described above under conditions
sufficient to substantially uniformly coat the surfaces of the
substrate with the hydrophilic polymeric material. Any conventional
treating method, for example, spraying, applying a foam, printing,
dipping and the like, may be used to coat the substrate. The
coating of the hydrophilic polymeric material is durable to an
aqueous medium at a temperature in a range of from about 10.degree.
C. to about 90.degree. C. and the coating does not significantly
depress the surface tension of an aqueous medium with which the
coated substrate may come in contact. For example, the surface
tension depression of such an aqueous medium may be less than about
10 percent. In some instances, it may be either helpful or
necessary to crosslink the coating on the substrate to impart a
desired level of durability.
[0061] The field of reactive species serves to increase the
affinity of the hydrophilic polymeric material for the
biodegradable polymeric substrate. The field of reactive species
may be, by way of example, a corona field. As another example, the
field of reactive species may be a plasma field.
[0062] As an alternative method, the coating may first be applied
to the substrate and then the substrate may be subjected to a
reactive species field.
[0063] Without wishing to be bound by theory, it is believed that
exposure of the biodegradable polymer substrate to a field of
reactive species results in alterations of the surfaces of the
substrate, thereby temporarily raising the surface energy of the
substrate. This, in turn, allows the penetration of the treating
solution into the substrate; that is, the substrate may be
saturated with the treating solution. It is also believed that the
durability of the treatment is due to surface oxidation and
enhanced secondary bonding of a hydrophilic coating which may be
applied to the substrate.
[0064] Although exposure of the substrate to a field of reactive
species is a desired method of temporarily raising the surface
energy of the substrate, other procedures may be employed. For
example, the substrate may be treated with ozone or passed through
an oxidizing solution, such as an aqueous medium containing
chromium trioxide and sulfuric acid. Care should be taken with such
other procedures, however, to either prevent or minimize
degradation of the substrate.
[0065] The strength of the field of reactive species may be varied
in a controlled manner across at least one dimension of the fibrous
web. Upon coating the substrate with the hydrophilic polymeric
material, the extent or degree of hydrophilicity of the coating is
directly proportional to the strength of the field. Thus, the
hydrophilicity of the coating of polymeric material will vary in a
controlled manner across at least one dimension of the fibrous
web.
[0066] The strength of the field of reactive species is readily
varied in a controlled manner by known means. For example, a corona
apparatus having a segmented electrode may be employed, in which
the distance of each segment from the sample to be treated may be
varied independently. As another example, a corona apparatus having
a gap-gradient electrode system may be utilized; in this case, one
electrode may be rotated about an axis which is normal to the
length of the electrode. Other methods also may be employed; see,
for example, "Fabrication of a Continuous Wettability Gradient by
Radio Frequency Plasma Discharge", W. G. Pitt, J. Colloid Interface
Sci., 133, No. 1, 223 (1989); and "Wettability Gradient Surfaces
Prepared by Corona Discharge Treatment", J. H. Lee, et al.,
Transactions of the 17th Annual Meeting of the Society for
Biomaterials, May 1-5, 1991, page 133, Scottsdale, Ariz.
[0067] If desired, at least a portion of the biodegradable
polymeric substrate may be exposed to a field of reactive species
subsequent to treating at least a portion of the substrate with a
mixture comprising water and a polymeric material. Such
post-exposure typically increases the hydrophilicity of the coated
substrate. Moreover, the strength of the field of reactive species
in such post-exposure also may vary in a controlled manner across
at least one dimension of the fibrous web as already described.
Such post-exposure may even enhance the durability of the coating
through crosslinking.
[0068] Typically, the add-on amount of the hydrophilic polymer in
the coating applied to the substrate is generally in the range of
about 0.01 wt % to about 2.0 wt %, and desirably between 0.05 wt %
and 1.0 wt %, most desirably between about 0.1 wt % and about 0.5
wt %, each based on the dry weight of the substrate and hydrophilic
polymer in the coating.
[0069] The hydrophilic treatment renders the package material
wettable. As the degree of wettability increases, the sink time for
the package material tends to decrease. In the present invention,
it is desirable that the sink time for the package material is less
than 20 seconds, and preferably as quick as possible so that the
user of the package can infuse the infusion beverage package in
water in a very short period of time. Typically, the package will
sink in under 10 seconds, in many cases under 5 seconds, and
desirably immediately.
[0070] The fiber or filaments of the nonwoven web may be generally
bonded in some manner as they are produced in order to give them
sufficient structural integrity to withstand the rigors of further
processing into a finished product. Bonding can be accomplished in
a number of ways such as ultrasonic bonding, adhesive bonding and
thermal bonding. Ultrasonic bonding is performed, for example, by
passing the nonwoven web between a sonic horn and anvil roll as
illustrated in U.S. Pat. No. 4,374,888 to Bornslaeger, which is
hereby incorporated by reference in its entirety.
[0071] Thermal bonding of a nonwoven web may be accomplished by
passing the web between the rolls of a calendering machine. At
least one of the rollers of the calender is heated and at least one
of the rollers, not necessarily the same one as the heated one, has
a pattern which is imprinted upon the nonwoven web as it passes
between the rollers. As the material passes between the rollers,
the nonwoven web is subjected to pressure as well as heat. The
combination of heat and pressure applied in a particular pattern
results in the creation of fused bond areas in the nonwoven web
where the bonds thereon correspond to the pattern of bond points on
the calender roll.
[0072] Various patterns for calender rolls have been developed. One
example is the Hansen-Pennings pattern with between about 10 to 25%
bond area with about 100 to 500 bonds/square inch as taught in U.S.
Pat. No. 3,855,046 to Hansen and Pennings. Another common pattern
is a diamond pattern with repeating and slightly offset diamonds.
The particular bond pattern can be selected from widely varying
patterns known to those skilled in the art. The bond pattern is not
critical for imparting the properties to the present invention.
[0073] The exact calender temperature and pressure for bonding the
nonwoven web depend on the polymers from which the nonwoven webs
are formed. Generally for nonwoven web formed from polylactides,
the preferred temperatures are between 250.degree. and 350.degree.
F. (121.degree. and 177.degree. C.) and the pressure between 100
and 1000 pounds per linear inch. More particularly, for polylactic
acid, the preferred temperatures are between 270.degree. and
320.degree. F. (132.degree. and 160.degree. C.) and the pressure
between 150 and 500 pounds per linear inch. However, the actual
temperature and pressures need are highly dependent of the
particular polymers used. The actual temperature and pressure used
to bond the fibers of the nonwoven together will be readily
determined by those skilled in the art. Of the available methods
for bonding the layer of the nonwoven web usable in the present
invention, thermal and ultrasonic bonding are preferred due to
factors such as materials cost and ease of processing.
[0074] The methods described above may be used to render the
biodegradable polymer hydrophilic. In addition to being
hydrophilic, the methods may provide a coating which is food safe
and can be used in food storage products as well as in medical
devices which are used on and in the human body, although this has
not been confirmed. The treatments of the present invention impart
fast wettability, durability during storage, durability during use
which allows for rewetting of the surface after a first insult,
have efficacy at elevated temperatures, are tasteless, are
non-foaming and are food safe, such as in the case for ethyl
hydroxyl cellulose coatings. Surprisingly, it has been discovered
that the corona treatment of the biodegradable polymeric substrate
results in a substrate which retains its imparted hydrophilic
properties even after storage for an extended period of time.
[0075] Other methods of making the material hydrophilic which may
be used to produce the infusion beverage bag include preparing an
extract of a plant based material. Examples of extracts include,
but are not limited to, tea, coffee and other plant based
materials. The extracts are formed into solutions which generally
contain from about 0.01% to about 50% of the plant material
extract. Typically, the amount of the extract in the solution used
to treat the infusion beverage is between about 0.1 and 1.0% by
weight of the solution.
[0076] Advantages of using the extracts include, they tend to be
naturally food safe, in the case of edible or digestible materials.
Further, extracts from similar materials as the infusion beverage
will not change the taste of the infusion beverage, since the
extract flavor will be similar to that of the infusion
beverage.
[0077] Typically, the add-on amount of the plant based extract in
the coating applied to the material used for the infusion beverage
package is generally in the range of about 0.01 wt % to about 2.0
wt %, and desirably between 0.05 wt % and 1.0 wt %, most desirably
between about 0.1 wt % and about 0.5 wt %, each based on the dry
weight of the substrate and extract in the coating.
[0078] In the present invention, it is desirable that the material
for the infusion beverage package is a nonwoven material prepared
from multicomponent fibers. The nonwoven is generally preferred to
be a spunbond nonwoven web or a bonded carded web.
[0079] Once formed, the nonwoven material can be formed into an
infusion beverage package using known techniques. The infusion
beverage precursor is placed into the material and the material is
sealed using the bonding techniques described herein such that the
infusion beverage is contained within.
[0080] The present invention is further described by the examples
which follow. Such examples, however, are not to be construed as
limiting in any way either the spirit or the scope of the present
invention.
EXAMPLES
[0081] Bicomponent spunbond samples were prepared using the process
described in U.S. Pat. No. 5,382,400 which is hereby incorporated.
The bicomponent spunbond has a sheath/core configuration and
contains as the sheath component, a polyactide available from
Cargill Dow, LLC under the designation Ingeo.TM. 6350 D. The core
component is a polyactide available from Cargill Dow, LLC under the
designation Ingeo.TM. 6250 D. The ratio of the sheath component to
the core component is 1:1 in each of the Examples below.
[0082] The fibers were prepared by extruding about 0.7 grams per
hole/min of the total polymer at a temperature of about
410.degree.-430.degree. F. (210.degree.-221.degree. C.) and the
resulting fibers were quenched with air. The fibers were drawn at a
FDU pressure of 12 psi. The fibers were laid down on a forming wire
moving at about 135 feet per minute (41.2 meters per minute). The
fibers had a denier of about 3 dpf (3.3 dtex). The fibers deposited
on the forming wire were preliminarily bonded with a hot air knife
at a temperature of 250.degree. F. (121.degree. C.). Next the
fibers were bonded using HDD pattern bond roll, which has point
bonds having about 460 pins/in.2 for a bond area of about 15% to
about 23%, heated to a temperature of about 250.degree. F.
(121.degree. C.) with an anvil having a temperature of 240.degree.
F. (115.degree. C.). The material had a basis weight of about 25.3
gsm) and is referred to as Example 1 material. The process
conditions are also summarized in Table 1.
[0083] Additional samples were prepared in the same manner except
using the conditions in Table 1.
1 TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Extrusion rate 0.7
0.5 0.7 0.3 0.5 0.5 (g per hole/min) Extrusion temperature 410-430
410-430 410-430 410-430 410-430 410-430 (.degree. F.) FDU Pressure
12 16 12 8 16 16 (inches of water) Forming wire rate 135 205 135
135 390 290 (feet/min.) Hot air knife 250 215 212 221 213 213
temperature (.degree. F.) Bonding temperature 265/240 270/220
275/240 275/240 275/270 275/270 (.degree. F.) Fiber denier (dpf) 3
2 3 1 2 2 Basis weight (gsm) 25.3 24.3 19.1 16.8 12.9 16.7
[0084] Each sample was dipped into an aqueous solutions containing
0.2 wt % of ethyl hydroxyethyl cellulose (Bermocol E481, Akzo
Nobel). After complete saturation of the fabric, indicated by a
change in color from white to translucent, the fabric was nipped
between two rubber rollers in an Atlas laboratory wringer at 10 lbs
(about 4.5 kg) nip pressure. The coated fabric then was dried in an
oven at 60.degree. C. for about 30 minutes. The results of each of
the above described test are show in Table 2.
2 TABLE 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example
6 TENSILE/ELONGATION/ E-MOLULUS F max (N/15 mm) Machine direction
6.4 14.6 4.4 7.9 7.1 12.1 Cross direction 1.2 3.5 0.7 2.4 1.0 2.3
SIFT OUT - large particle (%) Sand 1 100 100 100 100 100 100 Sand 2
100 87.4 100 100 100 100 Sand 3 92.8 14.3 100 93.2 100 88.5 Sand 4
76.5 1.0 99.4 8.6 99.6 48.8 Sand 5 37.8 0 89.9 0.5 3.6 4.4 Sand 6
0.8 0 35.5 0 0 0 Sand 7 0 0 0.2 0 0 0 Transparency (%) 34.3 22.2
50.8 33.1 47.3 37.0 Sink Time (with E481 <10 sec <10 sec
<10 sec <10 sec <10 sec <10 sec treatment)
[0085] As can be seen in Table 2, the material of the present
invention has a good balance of properties which makes it
acceptable as an infusion beverage.
[0086] While the specification has been described in detail with
respect to specific embodiments thereof, it will be appreciated
that those skilled in the art, upon attaining an understanding of
the foregoing, may readily conceive of alterations to, variations
of, and equivalents to these embodiments.
* * * * *