U.S. patent application number 16/879516 was filed with the patent office on 2020-11-26 for apparatus and methods for manufacturing biodegradable, compostable, drink straws from polyhydroxyalkanoate material.
This patent application is currently assigned to New WinCup Holdings, Inc.. The applicant listed for this patent is MEREDIAN BIOPLASTICS, INC., New WinCup Holdings, Inc.. Invention is credited to Paul Daniel George, JR., Adam Johnson, Bradley Keith Laporte, Billy Poindexter, II, William Lloyd Prickett.
Application Number | 20200367682 16/879516 |
Document ID | / |
Family ID | 1000005000233 |
Filed Date | 2020-11-26 |
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United States Patent
Application |
20200367682 |
Kind Code |
A1 |
Laporte; Bradley Keith ; et
al. |
November 26, 2020 |
APPARATUS AND METHODS FOR MANUFACTURING BIODEGRADABLE, COMPOSTABLE,
DRINK STRAWS FROM POLYHYDROXYALKANOATE MATERIAL
Abstract
Apparatus and methods for manufacturing compostable,
biodegradable drink straws from polyhydroxyalkanoate (PHA) material
are disclosed herein. Such apparatus may include a hopper that
contains raw PHA material, an extruder that receives the raw PHA
material from the hopper and produces extruded PHA material, one or
more waters baths that cool the extruded PHA material, a puller
that pulls a tubular stream of PHA material through the system, and
a cutter that is configured to cut the stream of PHA material into
finished straws. The finished straws may be soil- and
marine-biodegradable, as well as home- and
industrial-compostable.
Inventors: |
Laporte; Bradley Keith;
(Newman, GA) ; George, JR.; Paul Daniel;
(Jacksonville, FL) ; Prickett; William Lloyd;
(Buford, GA) ; Poindexter, II; Billy; (Newnan,
GA) ; Johnson; Adam; (Bainbridge, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
New WinCup Holdings, Inc.
MEREDIAN BIOPLASTICS, INC. |
Stone Mountain
Bainbridge |
GA
GA |
US
US |
|
|
Assignee: |
New WinCup Holdings, Inc.
Stone Mountain
GA
MEREDIAN BIOPLASTICS, INC.
Bainbridge
GA
|
Family ID: |
1000005000233 |
Appl. No.: |
16/879516 |
Filed: |
May 20, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62850520 |
May 20, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L 67/04 20130101;
C08J 5/18 20130101; C08L 2201/06 20130101; B29C 48/09 20190201;
A47G 21/181 20130101; C08J 2367/04 20130101 |
International
Class: |
A47G 21/18 20060101
A47G021/18; C08L 67/04 20060101 C08L067/04; C08J 5/18 20060101
C08J005/18; B29C 48/09 20060101 B29C048/09 |
Claims
1. A drink straw, comprising: a tubular body, wherein the tubular
body is made of a material comprising at least 50%
polyhydroxyalkanoate (PHA).
2. The drink straw of claim 1, wherein the tubular body has a
length, and wherein the length of the tubular body is in a range of
about five inches to about 10.25 inches.
3. The drink straw of claim 2, wherein the length of the tubular
body is in a range of about 7.75 inches to about 10.25 inches.
4. The drink straw of claim 1, wherein the tubular body has an
outer cross-sectional diameter, an inner cross-sectional diameter,
and a material thickness defined by the outer cross-sectional
diameter and the inner cross-sectional diameter, and wherein the
material thickness is in a range of about five mils to about ten
mils.
5. The drink straw of claim 4, wherein the material thickness of
the tubular body is in a range of about six mils to about seven
mils.
6. The drink straw of claim 5, wherein the tubular body has a
length, wherein the length of the tubular body is in a range of
about five inches to about 10.25 inches.
7. The drink straw of claim 1, wherein the drink straw is
marine-biodegradable, soil-biodegradable, and compostable.
8. The drink straw of claim 7, wherein the drink straw degrades by
about 80% in a marine environment in less than two years.
9. The drink straw of claim 7, wherein the drink straw degrades by
about 88% in a marine environment within about 97 days.
10. The drink straw of claim 1, wherein the drink straw defines a
shovel-shaped end portion thereof.
11. An extruder for use in apparatus for manufacturing a drink
straw, the extruder comprising: a cylindrical barrel; and an
extruder screw that extends through the barrel, wherein the
extruder screw is configured to draw a raw material comprising at
least 50% polyhydroxyalkanoate (PHA) from a hopper into a first end
of the extruder barrel and to push molten PHA material out of a
second end of the extruder barrel toward a die; and wherein the
extruder is configured to melt the raw PHA material to form the
molten PHA material, and wherein the extruder to have a temperature
profile such that the first end of the extruder barrel is at a
first temperature and the second end of the extruder barrel is at a
second temperature that is greater than the first temperature.
12. The extruder of claim 11, wherein the extruder is configured
such that temperature within the extruder increases from the first
end of the extruder barrel to the second end of the extruder
barrel.
13. The extruder of claim 11, wherein the first temperature is in a
range from about 290.degree. F. to about 340.degree. F., and the
second temperature is in a range from about 340.degree. F. to about
390.degree. F.
14. The extruder of claim 13, wherein the first temperature is
about 300.degree. F., and the second temperature is about
350.degree. F.
15. The extruder of claim 11, wherein the extruder screw is a
low-shear, low-volume, non-mixing screw that is configured to meter
the molten PHA material toward the die.
16. A two-stage water bath for use in apparatus for manufacturing a
drink straw, the water bath comprising: a housing; a wall disposed
within the housing, wherein the wall and the housing cooperate to
define a first chamber within the housing and a second chamber
within the housing, wherein the wall is disposed between the first
chamber and the second chamber, wherein the wall separates the
first chamber and the second chamber; wherein the first chamber
contains water having a first temperature and is configured to
receive extruded PHA material from an extruder, and wherein the
second chamber contains water having a second temperature that is
lower than the first temperature and is configured to receive first
cooled PHA material from the first chamber and to produce second
cooled PHA material.
17. The two-stage water bath of claim 16, wherein the water
contained by the first chamber has a temperature of between about
125.degree. F. and 175.degree. F., and wherein the water contained
by the second chamber has a temperature of between about 70.degree.
F. and 90.degree. F.
18. The two-stage water bath of claim 17, further comprising: a
sizing tube that controls an inner diameter and wall thickness of
the straw, wherein the sizing tube has an outer diameter that
corresponds to the inner diameter of the straw, and a plurality of
holes through which the extruded PHA material is pulled to an outer
surface of the sizing tube.
19. The two-stage water bath of claim 18, further comprising a
gasket in the wall that separates the first chamber from the second
chamber, wherein the first cooled PHA material is pulled through
the gasket into the second chamber.
20. The two-stage water bath of claim 16, wherein the extruded PHA
material is pulled through the first chamber at a rate that allows
for the extruded PHA material to remain in the first chamber for a
period of time ranging from 1.5-2.0 seconds to produce the first
cooled PHA material, and wherein the first cooled PHA material is
pulled through the second chamber at a rate that allows for the
first cooled PHA material to remain in the second chamber for a
period of time ranging from 1.5-2.0 seconds to produce the second
cooled PHA material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of provisional U.S. patent
application No. 62/850,520, filed on May 20, 2019, the disclosure
of which is incorporated herein by reference.
[0002] This application is related to U.S. patent application Ser.
No. [attorney docket WINC_PHA_US01], filed on even date herewith,
the disclosure of which is incorporated herein by reference.
BACKGROUND
[0003] Traditional drink straws may be made of a plastic or
thermoplastic polymer material, such as polypropylene, for example.
Typically, such materials, and consequently, straws made of such
materials, are usually neither biodegradable nor compostable.
[0004] Efforts are being made to produce straws that are
soil-biodegradable, marine-biodegradable, home-compostable, and
industrial-compostable. A challenge has been to produce a
biodegradable and compostable straw that also has thermoplastic and
mechanical properties that are acceptable for consumer use.
[0005] Polyhydroxyalkanoate (PHA) is an example of a material that
has better compostable and biodegradable properties than other
polymer materials from which straws are typically made. However,
there have been challenges associated with processing PHA material
into straws, as the PHA material has thermoplastic and mechanical
properties that are different from those of the polymer materials
that are typically used to produce straws. Thus, there is a need in
the art for apparatus and methods for manufacturing compostable,
biodegradable straws from PHA material.
SUMMARY
[0006] Apparatus and methods for manufacturing drink straws from
polyhydroxyalkanoate (PHA) material are disclosed herein. An
example of such apparatus may include a hopper that contains raw
PHA material, and an extruder that receives the raw PHA material
from the hopper and produces extruded PHA material. The extruder
may have a temperature profile, such that the temperature within
the extruder increases from the end of the extruder that receives
the raw PHA material from the hopper to the end of the extruder
that provides the extruded PHA material to a die.
[0007] Such apparatus may also include a two-stage water bath. An
example of such a two-stage water bath may include a first chamber
that receives the extruded PHA material and produces first cooled
PHA material, and a second chamber that receives the first cooled
PHA material from the first chamber and produces second cooled PHA
material. A puller draws the PHA material through the two-stage
water bath.
[0008] As disclosed herein, the first chamber may contain water
having a first temperature, while the second chamber contains water
having a second temperature that is lower than the first
temperature. For example, the water in the first chamber may be
kept at a temperature in a range of about 125.degree. F. to about
175.degree. F. The water in the second chamber may be kept at a
temperature in a range of about 70.degree. F. to about 90.degree.
F.
[0009] A drink straw produced by such an apparatus may have a
tubular body that is made of a PHA material. Such a straw may be
marine-biodegradable, soil-biodegradable, home-compostable, and
industrial-compostable. For example, such a straw may degrade by as
much as 80% in a marine environment within one to two years.
Testing has shown that such straws may degrade by as much as 88% in
a marine environment in as few as 97 days.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a system diagram illustrating example apparatus
and methods as disclosed herein for manufacturing PHA straws.
[0011] FIG. 2A depicts a typical extruder screw for use in
manufacturing prior art drink straws. FIG. 2B depicts an example
extruder screw for use in manufacturing PHA drink straws in
accordance with the methods disclosed herein.
[0012] FIG. 3 depicts an example extrusion die for use in
manufacturing PHA drink straws in accordance with the methods
disclosed herein.
[0013] FIG. 4 depicts an example pre-sizing water bath and an
example two-stage water bath for use in manufacturing PHA drink
straws in accordance with the methods disclosed herein.
[0014] FIGS. 5A and 5B depict an example water removal system for
use in manufacturing PHA drink straws in accordance with the
methods disclosed herein.
[0015] FIG. 6 depicts an example cutter for use in manufacturing
PHA drink straws in accordance with the methods disclosed
herein.
[0016] FIG. 7 depicts an example vision system for use in
manufacturing PHA drink straws in accordance with the methods
disclosed herein.
[0017] FIG. 8A depicts an example drink straw; FIG. 8B is a side
plan view of the drink straw depicted in FIG. 8A; FIG. 8C is a
cross-sectional view of the drink straw depicted in FIG. 8A.
[0018] FIG. 9A depicts an example drink straw having a shovel end
portion; FIG. 9B is a side plan view of the drink straw depicted in
FIG. 9A; FIG. 9C is a cross-sectional view of the drink straw
depicted in FIG. 9A.
DETAILED DESCRIPTION
[0019] FIG. 1 is a system diagram illustrating an example system
100 for manufacturing drink straws from polyhydroxyalkanoate (PHA)
materials. As shown in FIG. 1, the system 100 may include a hopper
102. The hopper 102 may receive raw PHA material 108A. As used
herein, the term PHA material refers to any material that is made
of at least 30% PHA by weight. Accordingly, the raw PHA material
108A may be a raw material that contains at least 30% PHA,
preferably at least 50% PHA, and more preferably about 80-85% PHA.
The raw PHA material 108 may be provided to the hopper in pellet
form. Thus, the raw PHA material 108A may include pellets that are
made of a material that contains at least 30% PHA, i.e., PHA
pellets. The hopper 102 may also receive color additives for
changing the color of the raw materials. The color additives may be
mixed into the raw PHA material 108A.
[0020] The raw PHA material 108A may be transferred from the hopper
102 to an extruder 104. The extruder 104 may melt the raw PHA
material 108A to form molten PHA material 108B. That is, the PHA
pellets may be transferred to the extruder 104, where the PHA
pellets may be melted to form a fluid. The extruder 104 may be a
screw-and-barrel extruder. A screw-and-barrel extruder may have an
auditor compression-type screw 105 inside a cylindrical barrel 107.
The extruder screw 105 may push the molten PHA material 108B
through the cylindrical extruder barrel 107. The extruder screw 105
may draw the raw PHA material 108A from the hopper 102 and meter
the molten PHA material 108B toward a die 106.
[0021] To melt the raw PHA material 108A, the extruder 104 may be
configured to have a temperature profile. That is, the extruder 104
may be configured such that the temperature within the extruder is
lower at the end 104A of the extruder 104 that receives the raw PHA
material 108A from the hopper 102, than it is at the end 104B of
the extruder 104 that provides the molten PHA material 108B to the
die 106. In other words, the temperature within the extruder barrel
105 may increase from one end 104A of the extruder 104 to the other
end 104B.
[0022] For example, the temperature profile of the extruder 104 may
range from about 290.degree. F. at the end 104A of the extruder 104
that receives the raw PHA material 108A from the hopper 102, to
about 390.degree. F. at the end 104B of the extruder 104 that
provides the molten PHA material 108B to the die 106. The
temperature at the end 104A of the extruder 104 may be between
about 290.degree. F. and 340.degree. F. The temperature at the end
104B of the extruder 104 may be between about 340.degree. F. and
390.degree. F. The length of the extruder 104 in the direction
along which the molten PHA material 108B is being pushed may be
about 90 to about 145 inches.
[0023] Before using the extruder 104 for manufacturing PHA drink
straws in accordance with the methods disclosed herein, it may be
desirable to purge the extruder 104. That is, it may be desirable
to remove any raw materials that might have been used in a previous
straw-making process in order to prepare the extruder 104 for use
with PHA material. For example, an extruder that is to be used to
manufacture PHA drink straws may have been used previously for
extruding a different material, such as a polypropylene material,
for example. In such event, any residual polypropylene material may
be purged from the extruder 104 using a chemical, such as an
ethylene (e.g., polyethylene). Purging the extruder as such allows
for bridging the transition from a first temperature profile used
for melting and extruding a first material, such as a
polypropylene-based material, for example, to a second temperature
profile used for melting and extruding a second material, such as a
PHA-based material, for example. Such a purging process enables
clean use of PHA material for making drink straws.
[0024] FIGS. 2A and 2B depict example extruder screws. FIG. 2A
depicts a typical high-shear, high-volume, mixing screw 15 that
might be commonly used in manufacturing prior art drink straws from
polymer materials that are not PHA materials. Polypropylene is an
example of such a material. FIG. 2B depicts an example low-shear,
low-volume, non-mixing screw 105 that has been developed for use in
manufacturing PHA drink straws in accordance with the methods
disclosed herein. Such a low-shear, low-volume, non-mixing screw is
desirable to prevent overworking the PHA material in the extruder
104.
[0025] As shown, screw 15 includes a mixing section 17. Screw 105
has no such mixing section. Also, the thread pitch P2 of screw 105
is greater than the thread pitch P1 of screw 15, and the
crest-to-crest diameter D2 of screw 105 is smaller than the
crest-to-crest diameter D1 of screw 15. The greater thread pitch P2
and smaller crest-to-crest diameter D2 of screw 105 conspire to
reduce the amount of shear within the extruder 104. The greater
thread pitch P2 and smaller crest-to-crest diameter D2 also
conspire to reduce the flow rate of the molten material 108B
through the extruder 104. The flow rate at which the molten
material 108B is pushed through the extruder 104 is reduced by
reducing the volume of molten material 108B produced in the
extruder 104 in a given amount of time.
[0026] As mentioned above, the extruder screw 105 pushes the molten
PHA material 108B through a die 106. The die 106 may receive the
molten PHA material 108B from the extruder 104 and form the molten
PHA material 108B into a tube.
[0027] FIG. 3 is a cross-sectional view of an example extrusion die
106 for use in manufacturing PHA drink straws in accordance with
the methods disclosed herein. As shown, an end portion 106E of the
die 106 may be generally tubular in shape. The die 106 may have a
body portion 183 and a pin 181. The pin 181 may be disposed within
a bore defined by the body portion 183. A material channel 182 may
be defined between the pin 181 and the body portion 183. The molten
PHA material 108B may be received into the material channel 182 and
pushed through the die by the extruder screw 105 (not shown in FIG.
3).
[0028] At the end 106E of the die 106 opposite the extruder 104
(i.e., where the extruded PHA material 108C exits the die 106), the
material channel 182 may be defined by the inner surface of the
body portion 183 and the tip 181T of the pin 181. For manufacturing
a PHA straw having an inner diameter of about 200 mils, the
clearance, C, between the outer surface of the pin tip 181T and the
inner surface of the body portion 183 at the end 106E of the
material channel 182 may be about 104 mils. The inner diameter of
the body portion 183 may be about 734 mils, while the outer
diameter of the pin tip 181T may be about 630 mils. Thus, the "draw
down" from the outer diameter of the pin tip 181T to the inner
diameter of the straw would be about 430 mils. In another example,
for manufacturing a PHA straw having an inner diameter of about 98
mils, the clearance, C, between the outer surface of the pin tip
181T and the inner surface of the body portion 183 at the end 106E
of the material channel 182 may be about 90 mils. The inner
diameter of the body portion 183 may be about 535 mils, while the
outer diameter of the pin tip 181T may be about 445 mils. Thus, the
"draw down" from the outer diameter of the pin tip 181T to the
inner diameter of the straw would be about 347 mils.
[0029] The die 106 may also include an air channel 187 that runs
along the longitudinal axis of the die 106. Compressed air 185 may
be forced down the air channel 187 from an air compressor (not
shown) and into the center portion of the extruded PHA material
108C as it exits the die 106 to help the extruded PHA material 108C
maintain its tubular shape.
[0030] The extruded PHA material 108C may be pulled from the die
106 by a puller 116. The extruded PHA material 108C may be pulled
through a two-stage water bath 114 after having been fed through a
sizing ring 112. Additionally, the extruded PHA material 108C may
be pulled through a pre-sizing water bath 110 prior to being fed
through the sizing ring 112.
[0031] FIG. 4 depicts an example pre-sizing water bath 110 for use
in manufacturing PHA drink straws in accordance with the methods
disclosed herein. The pre-sizing water bath 110 may include a water
containment tank 111. The top 111T of the tank 111 may be open or
closed.
[0032] The water 113 contained in the pre-sizing water bath 110 may
have a depth that is sufficient to cover the PHA material 108D that
is being pulled through the water bath 110. For example, the water
113 contained in the pre-sizing water bath 110 may have a depth
that is at least the diameter of the extruded PHA material 108C.
Consequently, the pre-sizing water bath 110 may have a height that
is at least the diameter of the extruded PHA material 108C. The
length of the pre-sizing water bath 110 (i.e., in the direction
along which the extruded PHA material 108C is being pulled) may be
at least about 4 inches, preferably within a range of about 4 to 5
inches.
[0033] The pre-sizing water bath 110 may be a hot water bath. That
is, the pre-sizing water bath 110 may contain water that has been
heated to a temperature that is greater than about 125.degree. F.
For example, the pre-sizing water bath 110 may contain water at a
temperature that is within a range of about 125.degree. F. to about
150.degree. F. Preferably, the temperature of the water contained
in the pre-sizing water bath 110 is within a range of about
125.degree. F. to 135.degree. F.
[0034] As described above, the end 104B of the extruder 104 from
which the molten PHA material 108B is provided to the die 106 may
be at a temperature of about 355.degree. F. A threshold temperature
for crystallization of the extruded PHA material 108C may be in the
range of 125.degree. F. to 135.degree. F. Consequently, it may be
desirable for the water contained in the pre-sizing water bath 110
to have a minimum temperature of at least about 125.degree. F. to
135.degree. F. The change in temperature from the 355.degree. F. at
the die-end 104B of the extruder 104, to the 125-135 .degree. F.
water bath 110, may shock the extruded PHA material 108C into
beginning a crystallization process. This change in temperatures
may speed up the crystallization process by changing the rate of
crystallization of the extruded PHA material 108C. The tank of the
pre-sizing water bath 110 may be a non-vacuum container (e.g., open
at the top) to allow for the extruded PHA material 108C to begin to
crystallize without being affected by a vacuum-sealed
environment.
[0035] The rate of crystallization of the crystallizing PHA
material 108D in the pre-sizing water bath 110 was tested as
follows. Extruded PHA material 108C was forced out of the extruder
104, the die-end 104B of which was at a temperature of about
355.degree. F., and pulled into the pre-sizing water bath 110.
Tests were conducted with the temperature of the water contained in
the pre-sizing water bath 110 at various temperatures from about
60.degree. F. up to about 135.degree. F. Initial tests were
conducted with the water contained in the pre-sizing water bath 110
having a temperature at about 60.degree. F., as it was hypothesized
that the initial temperature change to cooler temperatures would
trigger a faster change in the crystallization rate of the extruded
PHA material 108C. However, the faster changes in crystallization
rate desired for the process were triggered when the water
contained in the pre-sizing water bath 110 was at a temperature in
the range of about 125.degree. F. to 135.degree. F. Thus, it was
observed that the extruded PHA material 108C crystalizes faster
when surrounded by hotter water temperatures in the water bath 110.
The faster crystallization causes the crystallizing PHA material
108D to become harder faster to allow for the PHA material to be
processed more quickly through the straw making process.
Consequently, the crystallizing PHA material 108D may enter into
the sizing ring 112 and/or a sizing tube (described below) with a
greater tensile strength for processing due to the crystallization
being triggered by the temperature of the pre-sizing water bath
110.
[0036] Thus, extruded PHA material 108C may be lubricated and/or
crystalized as it is pulled through the pre-sizing water bath 110.
Being pulled through the water bath 110 may strengthen the PHA
material for being pulled by the puller 116 and/or through the
sizing ring 112. The PHA material being lubricated and/or
crystalized may give the PHA material the physical characteristics
to be pulled through the sizing ring 112 without breaking or
becoming inconsistent.
[0037] As mentioned above, the extruded PHA material 108C may be
pulled from the die 106 and eventually through a sizing ring 112 by
a puller 116. The sizing ring 112 may be circular in shape and may
have an opening that corresponds to a diameter of the straw being
manufactured from the PHA material 108. It has been discovered that
the PHA material may be too soft to be fed through traditional
baffles that are typically used when making drink straws from other
materials, such as polypropylene, for example.
[0038] As shown in FIG. 1, and in detail in FIG. 4, the extruded
PHA material 108C may be pulled through a two-stage water bath 114
after having been fed through the sizing ring 112. The two-stage
water bath 114 may include a vacuum-sealed tank or housing 147. The
sizing ring 112 may be external to the two-stage water bath 114, as
shown in FIG. 1, or internal to the tank 147, as shown in FIG.
4.
[0039] A sizing tube 123 may be connected to the sizing ring 112.
The sizing tube 123 may extend a distance from the sizing ring 112
into the water bath 114. For example, the sizing tube 123 may
extend about three to five inches into the water bath 114. The
sizing tube 123 may be configured to control the diameter and wall
thickness of the straw. For example, the sizing tube 123 may define
a bore that extends longitudinally therethrough. The bore may have
a diameter that corresponds to the diameter of the straw being
manufactured. That is, the sizing tube may have an inner diameter
that corresponds to the outer diameter of the straw being
manufactured. The sizing tube may have an inner diameter that is
about 40% bigger than the desired outer diameter of the straw. For
example, if the desired outer diameter of the finished straw
product is about 286 mils, the inner diameter of the sizing tube
may be about 396 mils. The outer diameter of the sizing tube may be
about 492 mils. Due to differences in material characteristics, the
sizing tube 123 may be about twenty-five thousandths of an inch
larger than a comparable sizing tube that may be used for making
straws of other material (e.g., polypropylene) to obtain a proper
straw diameter.
[0040] The sizing tube 123 may define a plurality of holes through
the outer surface thereof. Water may be pulled through the holes by
the vacuum in the tank to lubricate and cool the PHA material 108E
as it is being pulled into the two-stage water bath 114. The straws
may be defined at half-inch intervals along the tubular walls of
the sizing ring. The size of the sizing tube 123, and the
configuration of the holes, affects the amount of water that is
pulled into the interior of the sizing ring. This, for its part,
controls the material thickness of the PHA material 108E being
pulled through the sizing tube 123.
[0041] As shown in FIG. 4, the two-stage water bath 114 may include
a housing 147. A wall 119 may be disposed within the housing 147.
The wall 119 and the housing 147 may cooperate to define a first
chamber 115 within the housing and a second chamber 117 within the
housing. Thus, the wall may be disposed between the first chamber
115 and the second chamber 117, and thereby separate the first
chamber 115 and the second chamber 117. The first chamber 115 may
be configured to receive extruded PHA material 108C from the
extruder or crystallizing PHA material 108D from the pre-sizing
water bath 110. The first chamber 115 may be a relatively
warm-water bath that contains water having a first temperature. The
second chamber 117 may be a relatively cool-water bath that
contains water having a second temperature that is lower than the
first temperature. The second chamber 117 may be configured to
receive first cooled PHA material 108E from the first chamber and
to produce second cooled PHA material 108F.
[0042] The water in the first chamber 115 of the water bath 114 may
be at the same or a similar temperature as the water bath 110. For
example, the water in the first chamber 115 of the water bath 114
may be kept at a temperature within a range of about 125.degree. F.
to about 175.degree. F. In another example, the water in the first
chamber 115 of the water bath 114 may be kept at a temperature
within a range of about 130.degree. F. to 140.degree. F., or within
a range of about 135.degree. F. to 145.degree. F. As an example,
the water in the first chamber 115 of the water bath 114 may be
kept at a temperature of about 140.degree. F. The first chamber 115
of the water bath 114 may be about 7 to 10 feet long. A first
temperature control system H1 may be provided to maintain the
desired temperature of the water in the first chamber 115. For
example, the first temperature control system H1 may be a heater,
as the desired temperature of the water in the first chamber 115
will typically be above room temperature.
[0043] The water in the second chamber 117 of the water bath 114
may be kept at a temperature within 70.degree. F. to 90.degree. F.
The water in the second chamber 117 of the water bath 114 may cool
the PHA material 108F over a period of time to solidify the PHA
material 108F and/or strengthen the PHA material 108F. The water in
the second chamber 117 of the water bath 114 may cool the PHA
material 108F to solidify the PHA material 108F and/or strengthen
the PHA material 108F more quickly than pulling the PHA material
108F through warmer temperatures. However, the water bath 114 may
include water at warmer temperatures (e.g., temperatures indicated
for the first chamber 115 of the water bath 114) throughout and the
PHA material 108E/108F may be pulled through the water bath 114
more slowly to allow for the PHA material 108F to strengthen. A
second temperature control system H2 may be provided to maintain
the desired temperature of the water in the second chamber 117. For
example, the second temperature control system H2 may be a
heater/cooler system, as the desired temperature of the water in
the second chamber 117 may be above or below room temperature.
[0044] Crystallization of the PHA material 108E may be expedited in
the warmer chamber 115 of the water bath 114, so the second chamber
117 of the water bath 114 may make the PHA material 108F colder to
make the PHA material 108F firmer for additional processing. The
PHA material 108E/108F may be in each of the chambers 115, 117,
respectively, for a period of time within a range of about one to
three seconds. For example, the PHA material 108E may be in the
first chamber 115 of the water bath 114 for a period of time within
a range of about 1.5 to 2 seconds, or for about 1.8 to 2 seconds.
In an example process, the first chamber 115 of the water bath 114
may be about 10 feet long, and the second chamber 117 of the water
bath 114 may be about 10 feet long. The PHA material 108E/108F may
be processed at a speed of about 330 feet per minute, such that the
PHA material 108E/108F may be in each of the chambers 115, 117 of
the water bath 114 for about 1.8 seconds.
[0045] The wall 119 may include a gasket 121 through which the PHA
material 108E may be pulled into the second chamber 117 by the
puller 116. The cooled PHA material 108G may not be fully hardened
once it is received at the puller 116, as PHA material may harden
more slowly than other materials that may be used for straws, such
as polypropylene, for example. Accordingly, the two-stage water
bath 114 may be longer than typical single-stage water baths used
for making straws out of other material in order to allow for the
PHA material 108E/108F to have more time in the water bath 114 to
strengthen. For example, the water bath 114 may be between 20 and
30 feet in length. In an example, the water bath 114 may be 20 to
22 feet long.
[0046] As shown in FIG. 1, a water removal system 150 may be
provided to remove excess water that may remain on the PHA material
108G after the PHA material 108G is pulled out of the two-stage
water bath 114. FIG. 5A depicts an example water removal system 150
for use in manufacturing PHA drink straws in accordance with the
methods disclosed herein.
[0047] As shown in FIG. 5A, the second chamber 117 of the two-stage
water bath 114 may be fitted with a gasket 129 through which the
PHA material 108G may be pulled. The gasket 129 may be made of a
rubber material, and may have an inner diameter that corresponds to
the diameter of the PHA material 108G. Thus, the gasket 129 may
function to remove excess water from the outer surface of the PHA
material 108G as it is pulled through the gasket 129.
[0048] The water removal system 150 may include one or more air
rings 152. Each of the air rings 152 may be fed by a respective
incoming compressed air line 154. Regulators (not shown) may be
attached to the compressed air lines 154 to control the air
pressure that is delivered to the air rings 152. The air pressure
may be in a range of about 40 to about 60 psi. As the PHA material
108G is pulled through the air rings, the compressed air is
delivered to the PHA material 108G. The compressed air may function
to blow away excess water from the surface of the PHA material
108G.
[0049] FIG. 5B provides a detailed view of an air ring 152. As
shown, the air ring 152 may have a cover portion 155 and a guide
portion 151. As the PHA material 108G is pulled through the guide
portion of the air ring 152, compressed air may delivered to the
PHA material 108G in an inner region 153 defined by the air ring
152. The compressed air may be delivered to the PHA material 108G
via a plurality of air discharge ports 157 defined by the air ring
152. A pulley 156 may be provided to aide movement of the PHA
material 108H out of the water removal system 150 and into the
puller 116.
[0050] As described above, the puller 116 may be configured to pull
the PHA material 108E/108F through the two-stage water bath 114. As
shown in FIG. 1, the puller 116 may include one or more foam belts
127. Each of the belts 127 may be driven by a respective pair of
rollers 125. One belt 127 may be driven to rotate in a clockwise
direction, while the other belt 127 may be driven to rotate in a
counterclockwise direction. The belts 127 may cooperate to grip the
PHA material 108H as it passes through the puller 116. Thus, the
puller 116 may be configured to pull the PHA material in its
various stages from the output of the die 106, through the
two-stage water bath 114, and into the puller 116. And, thus, the
puller 116 may also be configured to push the PHA material 108H
through to a cutter 120.
[0051] The belts 117 may be made entirely or partially of a rubber
material, such as an all-natural gum rubber, for example. The
material of which the belts 117 are made may have a durometer of
30-55, preferably 45. In a typical system for manufacturing
polypropylene straws, the material of which the puller belts are
made may have a durometer of more than 90. It has been discovered
that, as the stream of PHA material 108H is pulled through the
puller 116, grooves form in the belts. The grooves correspond to
the diameter of the PHA material 108H. After the grooves form, the
belts are even better able to grip the material 108H than they are
before the grooves form.
[0052] FIG. 6 depicts an example cutter for use in manufacturing
PHA drink straws in accordance with the methods disclosed herein.
The cutter 120 may be configured to cut the PHA material 108H at
regular intervals to produce PHA straws 206 having a desired straw
length. As shown in FIG. 6, the cutter 120 may receive the PHA
material 108H and feed the PHA material 108H toward a flywheel 202.
The PHA material 108H may be fed toward the flywheel 202 via an
entrance tube 201. The flywheel 202 may be a sixteen-inch flywheel.
The flywheel 202 may include one or more cutting blades 204 for
cutting the PHA material 108H to the desired straw length. The
cutting blades 204 may cut the PHA material 108H between the
entrance tube 201 and an exit tube 203. The inner diameters of the
entrance tube 201 and the exit tube 203 may correspond to the outer
diameter of the PHA material 108H. That is, the cutting tubes may
have inner diameters that correspond to the outer diameter of the
straw being manufactured. The cutting tubes 201 and 203 may have
inner diameters that are about 40% bigger than the desired outer
diameter of the straw. For example, if the desired outer diameter
of the finished straw product is about 286 mils, the inner
diameters of the cutting tubes 201 and 203 may be about 396
mils.
[0053] The cutter 120 may receive the PHA material 108H through a
funnel 122 or other funnel-shaped object. The diameter of the
funnel 122 at the end closer to a cutting blade 204 of the cutter
120 may correspond to the outer diameter of the straw being
produced. The PHA material 108H may be fed through the funnel 122
toward the cutting blade 204 for being cut to the appropriate
length. The funnel 122 may be increased at the end toward the
cutting blade 204 by about twenty-five thousandths of an inch when
processing the PHA material 108H, as compared to when the system is
processing other stronger material, such as polypropylene material.
The increase in size may compensate for the PHA material 108H being
less firm at this stage of the process and in order to feed more
easily through the funnel 122. The PHA material 108H may be fed to
the cutting blade for being cut to a desired length.
[0054] After the PHA material 108D is cut, a resulting straw 206 of
the desired length may be discharged through the exit tube 203 and
onto a conveyor belt 208.
[0055] In some situations, the finished straws 206 may not be
completely dry even after they have been cut to length.
Accordingly, an apparatus for making PHA straws may include an
end-of-line air drying system. With reference once again to FIG. 1,
the end-of-line air drying system may include one or more hot-air
chambers 132, and a drying oven 134. Each of the one or more
hot-air chambers 132 may include a respective electric hot-air fan
133. Each of the one or more hot-air fans 133 may be driven by a
respective blow motor (not shown). The one or more hot-air chambers
132 may be coupled onto the conveyor system such that the fans 133
are situated over the conveyor belt 208. Thus, as the finished
straws 206 are carried along on the conveyor belt 208, hot air
generated by the fans 133 will dry the straws 206 as they pass
through the hot-air chambers 133. The temperature of the hot-air
fans may be set at about 500 F. The conveyor belt 208 may carry the
straws 206 into a drying oven 134 for a final drying before the
finished straws are deposited into an accumulation bin 136. The
temperature of the drying oven may be set at about 190 F. The
finished straws 206 may then be removed from the accumulation bin
136 to be wrapped and bagged.
[0056] A vision system 140 may be provided to monitor certain
characteristics of the PHA material 108H just before it is pulled
into the puller 116. For example, a vision system 140 may be
provided to monitor the diameter and material thickness of the PHA
material 108H.
[0057] FIG. 7 depicts an example vision system 140 for use in
manufacturing PHA drink straws in accordance with the methods
disclosed herein. As shown, the vision system 140 may include a
light projector 142, and a camera 144. The light projector 142 may
project light 145 onto the PHA material 108H as it is being pulled
into the puller 116 (not shown in FIG. 7). The camera 144 may
receive light 147 that has passed through or around the PHA
material 108H. A vertical mounting bracket 143 and a horizontal
mounting bracket 141 may be provided for mounting the vision system
140.
[0058] The camera 144 may be electrically coupled to an analyzer
146, which may be a computer processor. The analyzer 146 determines
from the spatial pattern of the received light 147 whether the
diameter of the PHA material is within acceptable tolerances at
this stage of the process. The spatial pattern of the received
light will be affected by the PHA material 108H blocking some of
the emitted light 145 that is incident on it. The analyzer 146
determines from the intensity of the received light 147 whether the
material thickness of the PHA material 108H is within acceptable
tolerances at this stage of the process. The intensity of the
received light will be affected by the PHA material 108H blocking
some of the emitted light 145 that is incident on it. If the
analyzer 146 determines that either the diameter or the material
thickness is outside of acceptable tolerances, the analyzer may
provide an alarm sound or message to indicate that corrective
action needs to be taken at some point along the system.
[0059] It should be understood that PHA straws produced according
to the systems and methods described herein may have various
lengths, diameters, and material thicknesses. FIG. 8A depicts an
example drink straw 206, which may be made of a PHA material. FIG.
8B is a side plan view of the drink straw 206 depicted in FIG. 8A.
FIG. 8C is a cross-sectional view of the drink straw 206 depicted
in FIG. 8A. As shown, the straw 206 may have a tubular body. The
tubular body may define a hollow tube. The tubular body of the
straw 206 may have a length, L, an inner diameter, ID, and an outer
diameter, OD. The material thickness of the straw 206, that is, the
thickness of the walls of the tubular body of the straw, may be a
function of the inner diameter ID and the outer diameter OD.
Specifically, the material thickness of the straw 206 may be half
the difference between the outer diameter OD and the inner diameter
ID.
[0060] The length of the straw 206 may range from about five inches
to about 10.5 inches. The material thickness of the straw 206 may
range from about five mils to about ten mils, preferably between
six mils and seven mils, and typically around eight mils. In an
example, a drink straw 206 may have a length of about 7.75 inches,
an inner diameter of about 207 mils, an outer diameter of about 219
mils, and a material thickness of about six mils. In another
example, a drink straw 206 may have a length of about 10.25 inches,
an inner diameter of about 270 mils, an outer diameter of about 284
mils, and a material thickness of about seven mils. In yet another
example, a drink straw 206 may have a length of about 8.50 inches,
an inner diameter of about 270 mils, an outer diameter of about 284
mils, and a material thickness of about seven mils. In an example
that may be suitable for use as a drink stirrer, a drink straw 206
may have a length of about 5.00 inches, an inner diameter of about
103 mils, an outer diameter of about 115 mils, and a material
thickness of about six mils.
[0061] It should also be understood that PHA straws produced
according to the systems and methods described herein may have
useful features in addition to a basic hollow tubular body. For
example, a PHA straw produced according to the systems and methods
described herein may have a flexible neck portion. In another
example, a PHA straw produced according to the systems and methods
described herein may have a spiked end portion. Such a straw may be
useful in connection with well-known juice boxes.
[0062] In yet another example, a PHA straw produced according to
the systems and methods described herein may have a shovel-shaped
end portion. Such a straw may be useful in connection with
consuming frozen beverages, such a milkshakes, for example. FIG. 9A
depicts an example drink straw 306, which may be made of a PHA
material. FIG. 9B is a side plan view of the drink straw 306
depicted in FIG. 9A. FIG. 9C is a cross-sectional view of the drink
straw 306 depicted in FIG. 9A. As shown, the straw 306 may have a
tubular body and a shovel-shaped end portion 308. As described
above, the tubular body may define a hollow tube having a length,
L, an inner diameter, ID, and an outer diameter, OD.
[0063] Although features and elements are described herein in
particular combinations, each feature or element can be used alone
or in any combination with the other features and elements.
* * * * *