U.S. patent application number 13/924999 was filed with the patent office on 2014-12-25 for printed foamed film packaging.
The applicant listed for this patent is The Procter & Gamble Company. Invention is credited to Emily Charlotte Boswell, Michael Remus, Neil John Rogers.
Application Number | 20140377512 13/924999 |
Document ID | / |
Family ID | 51063861 |
Filed Date | 2014-12-25 |
United States Patent
Application |
20140377512 |
Kind Code |
A1 |
Rogers; Neil John ; et
al. |
December 25, 2014 |
Printed Foamed Film Packaging
Abstract
A method of constructing a package having printed indicia of
acceptable quality includes providing at least one layer of foamed
thin film and printing the indicia on the printed surface by
applying ink to a printer surface and contacting the printed
surface with the inked printer surface to coat the printed surface
with ink. The layer of foamed thin film comprises a bio-based
content of between about 10% and about 100%, a caliper of between
10 and 250 microns, and between 5% to 50% density reduction as
compared to a non-foamed thin film of substantially the same
caliper and composition, wherein a first surface of the at least
one layer of foamed thin film is the printed surface of the
package.
Inventors: |
Rogers; Neil John; (Vivorde,
BE) ; Remus; Michael; (Heidelberg, DE) ;
Boswell; Emily Charlotte; (Cincinnati, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Procter & Gamble Company |
Cincinnati |
OH |
US |
|
|
Family ID: |
51063861 |
Appl. No.: |
13/924999 |
Filed: |
June 24, 2013 |
Current U.S.
Class: |
428/195.1 ;
493/187 |
Current CPC
Class: |
B65D 33/00 20130101;
B41M 1/10 20130101; B41M 1/30 20130101; Y10T 428/24802 20150115;
B41M 1/04 20130101 |
Class at
Publication: |
428/195.1 ;
493/187 |
International
Class: |
B65D 33/00 20060101
B65D033/00 |
Claims
1. A method of constructing a package having printed indicia of
acceptable quality present on a printed surface, the method
comprising: a. providing at least one layer of foamed thin film,
wherein the layer of foamed thin film comprises: i. a bio-based
content of between about 10% and about 100%; ii. a caliper of
between 10 and 250 microns; and iii. between 5% to 50% density
reduction as compared to a non-foamed thin film of substantially
the same caliper and composition, wherein a first surface of the at
least one layer of foamed thin film is the printed surface of the
package; and b. printing the indicia on the printed surface by
applying ink to a printer surface and contacting the printed
surface with the inked printer surface to coat the printed surface
with ink; wherein the printer surface comprises a plurality of
raised dots, the raised dots having top surfaces configured to
contact the printed surface to imprint the indicia on the printed
surface, and wherein the raised dots have a dot percentage of no
greater than approximately 70%.
2. The method of claim 1, wherein the raised dots have a dot
percentage of between about 50% to about 60%.
3. The method of claim 1, wherein the raised dots have a dot
percentage of approximately 70%.
4. The method of claim 1, wherein the ink is selected to have
approximately a 20 second increased viscosity as compared to ink
that would be selected to print substantially the same indicia on a
print surface of a non-foamed thin film of substantially the same
caliper and composition.
5. The method of claim 1, wherein the ink is selected as having an
intensity that is approximately 30%-50% greater than an intensity
of an ink that would be selected to print substantially the same
indicia on a print surface of a non-foamed thin film of
substantially the same caliper and composition.
6. The method of claim 1 wherein the printed surface is contacted
with the inked printer surface with a pressure that is greater than
a printer pressure that would be used to print substantially the
same indicia on a print surface of a non-foamed thin film of
substantially the same caliper and composition.
7. A method of constructing a package having printed indicia of
acceptable quality present on a printed surface, the method
comprising: a. providing at least one layer of foamed thin film
wherein the layer of foamed thin film comprises: i. a bio-based
content of between about 10% and about 100%; ii. a caliper of
between 10 and 250 microns; and iii. between 5% to 50% density
reduction as compared to a non-foamed thin film of substantially
the same caliper and composition, wherein a first surface of the at
least one layer of foamed thin film is the printed surface of the
package; and b. printing the indicia on the printed surface by
applying ink to a printer surface and contacting the printed
surface with the inked printer surface to coat the printed surface
with ink; wherein the printer surface comprises a half tone
rotogravure print cylinder configured to contact the printed
surface to imprint the indicia on the printed surface, the print
cylinder having a dot percentage of no greater than approximately
70%.
8. The method of claim 7, wherein the print cylinder has a dot
percentage of between about 50% to about 60%.
9. The method of claim 7, wherein the print cylinder has a dot
percentage of approximately 70%.
10. The method of claim 7, wherein the ink is selected to have
approximately a 20 second increased viscosity as compared to ink
that would be selected to print substantially the same indicia on a
print surface of a non-foamed thin film of substantially the same
caliper and composition.
11. The method of claim 7, wherein the ink is selected as having an
intensity that is approximately 30%-50% greater than an intensity
of an ink that would be selected to print substantially the same
indicia on a print surface of a non-foamed thin film of
substantially the same caliper and composition.
12. A package comprising: a. at least one layer of foamed thin
film, wherein the layer of foamed thin film comprises: i. a
bio-based content of between about 10% and about 100%; ii. a
caliper of between 10 and 250 microns; and iii. between 5% to 50%
density reduction as compared to a non-foamed thin film of
substantially the same caliper and composition, wherein a first
surface of the at least one layer of foamed thin film is the
printed surface of the package; and b. printed indicia of
acceptable quality that is printed on a printed surface of the
package, wherein a first surface of the at least one layer of
foamed thin film is the printed surface of the package.
13. The package of claim 12, comprising a foamed thin film
co-extrusion that has a layer comprising a foamed thin film that
includes the printed surface.
14. The package of claim 12, comprising a foamed thin film laminate
that has a layer comprising a foamed thin film that includes the
printed surface.
15. The package of claim 12, wherein the indicia is imprinted on
the printed surface by applying ink to a printer surface and
contacting the printed surface with the inked printer surface to
coat the printed surface with ink and wherein the printer surface
comprises a plurality of raised dots, the raised dots having top
surfaces configured to contact the printed surface to imprint the
indicia on the printed surface, and wherein the raised dots have a
dot percentage of no greater than approximately 70%.
16. The package of claim 15, wherein the raised dots have a dot
percentage of between about 50% to about 60%.
17. The package of claim 15, wherein the raised dots have a dot
percentage of approximately 70%.
18. The package of claim 12, wherein the indicia is imprinted on
the printed surface by applying ink to a printer surface and
contacting the printed surface with the inked printer surface to
coat the printed surface with ink and wherein the printer surface
comprises a halftone rotogravure print cylinder configured to
contact the printed surface to imprint the indicia on the printed
surface, and wherein the print cylinder has a dot percentage of no
greater than approximately 70%.
19. The package of claim 18, wherein the print cylinder has a dot
percentage of between about 50% to about 60%.
20. The package of claim 18, wherein the print cylinder has a dot
percentage of approximately 70%.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the field of packages comprising a
foamed film layer, and more specifically, to the field of packages
that comprise a printed foamed film layer made at least in part of
renewable, recyclable and/or biodegradable materials.
BACKGROUND OF THE INVENTION
[0002] Polyolefin plastic film is used to construct a wide variety
of packages such as bags, pouches, labels and wraps that hold
consumer goods. For example, bags holding stacks of disposable
diapers or hygiene articles, pouches for wet wipes, and bags
containing granular laundry detergent are often made from plastic
film. The plastic film that forms a package may be a single layer
of film (called a monofilm), a combination of layers that are
co-extruded, or a laminate of separately produced layers that are
adhered to one another, or an extrusion lamination whereas one
layer is extruded onto another previously formed layer(s). In
virtually all packages, some sort of indicia is printed on the
plastic film.
[0003] Two types of printing that are often utilized to imprint
plastic film are flexographic printing and rotogravure printing.
Flexographic printing employs a flexible printing plate made of a
flexible, elastomeric material. A raised relief image of the
indicia to be printed on the package is present on the flexible
printer plate. The relief image is coated with ink and then pressed
onto the plastic film. Often, one or more flexographic printer
plates are positioned on a rotating print cylinder that prints on a
sheet of film as the film moves beneath the print wheel. Each plate
may carry a different type or color ink. Rotogravure printing uses
a printer plate that has an engraved relief image. The printer
plate is usually made of metal and is often formed into a
cylindrical print roll. Ink is drawn into the engraved image and
transferred to the plastic film. Because both flexographic and
rotogravure printing involve contacting the surface of the plastic
film with a relief image to transfer the ink to the film,
variations in surface texture of the plastic film will impact print
quality. Rotogravure presses may have multiple print rolls whereas
each print roll can carry a different type or color ink.
[0004] Much of the cost associated with plastic film packages is
the cost of the plastic resin that is used to make the film. Recent
technological developments have made it feasible to produce foamed
polyolefin film of suitable thickness (10-250 microns) and strength
for the types of packages described above. Several exemplary foamed
polyolefin films that are suitable for packages are described in
European Patent No. 1 646 677. The use of foamed thin film allows
for replacement of part of the resin (e.g., 5-50% by weight) with
gaseous bubbles that are formed or incorporated in the film during
a foaming process. Because the voids or cells left by the bubbles
occupy volume that was formerly filled with resin, foamed film
allows for a reduction in resin without a corresponding reduction
in film thickness, commonly referred to as the film's caliper.
[0005] One notable feature of foamed thin films is that they have a
rough surface texture as compared to a non-foamed film of the same
caliper. The rough texture, caused by the presence of the voids in
the film, makes it difficult to print directly on the foamed thin
film using flexographic or rotogravure printing. The rough texture
tends to cause voids in ink coverage due to the recesses in the
surface not contacting the print plate. In addition to detracting
from the appearance of a package and its graphics and text, these
voids in ink coverage may degrade an image of a bar code to such a
degree that a bar code reader could not decode the bar code.
[0006] Most of the materials used in fabrication of consumer
packaging applications are derived from non-renewable resources,
such as petroleum. Often, the components of consumer packages are
made from polyolefins, such as polyethylene, polypropylene, and
polyethylene terephthalate. These polymers are derived from
monomers, such as ethylene, propylene, and terephalic acid, which
are typically obtained directly from petroleum, coal and/or natural
gas via cracking and refining processes. The price and availability
of the petroleum/coal/natural gas feedstock therefore has a
significant impact on the price of consumer packages which utilize
materials derived from petrochemicals. As the worldwide price of
petroleum escalates, so does the price of polyolefin based
packaging. Moreover, many consumers display an aversion to
purchasing products that are packaged in materials derived from
petrochemicals. Other consumers may have adverse perceptions about
products derived from petrochemicals being "unnatural" or not
environmentally friendly.
[0007] Accordingly, it is of continued interest to provide consumer
packages which are at least partially fabricated from renewable or
recycled resources. It may also be desirable to provide renewable
and/or recyclable packaging that is also biodegradable.
SUMMARY OF THE INVENTION
[0008] In one aspect, a method of constructing a package having
printed indicia of acceptable quality includes providing at least
one layer of foamed thin film and printing the indicia on the
printed surface by applying ink to a printer surface and contacting
the printed surface with the inked printer surface to coat the
printed surface with ink. The layer of foamed thin film comprises a
bio-based content of between about 10% and about 100%, a caliper of
between 10 and 250 microns, and between 5% to 50% density reduction
as compared to a non-foamed thin film of substantially the same
caliper and composition, wherein a first surface of the at least
one layer of foamed thin film is the printed surface of the
package. The printer surface comprises a plurality of raised dots,
the raised dots having top surfaces configured to contact the
printed surface to imprint the indicia on the printed surface, and
wherein the raised dots have a dot percentage of no greater than
approximately 70%.
[0009] In another aspect, a method of constructing a package having
printed indicia of acceptable quality includes providing at least
one layer of foamed thin film and printing the indicia on the
printed surface by applying ink to a printer surface and contacting
the printed surface with the inked printer surface to coat the
printed surface with ink. The layer of foamed thin film comprises a
bio-based content of between about 10% and about 100%, a caliper of
between 10 and 250 microns, and between 5% to 50% density reduction
as compared to a non-foamed thin film of substantially the same
caliper and composition, wherein a first surface of the at least
one layer of foamed thin film is the printed surface of the
package. The printer surface comprises a half tone rotogravure
print cylinder configured to contact the printed surface to imprint
the indicia on the printed surface, the print cylinder having a dot
percentage of no greater than approximately 70%.
[0010] In yet another aspect, a package includes at least one layer
of foamed thin film and printed indicia of acceptable quality that
is printed on a printed surface of the package, wherein a first
surface of the at least one layer of foamed thin film is the
printed surface of the package. The layer of foamed thin film
includes a bio-based content of between about 10% and about 100%, a
caliper of between 10 and 250 microns, and between 5% to 50%
density reduction as compared to a non-foamed thin film of
substantially the same caliper and composition, wherein a first
surface of the at least one layer of foamed thin film is the
printed surface of the package.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a top plan view of a foamed thin film with printed
indicia in accordance with one or embodiments of the present
invention.
[0012] FIG. 2 is a cross section view of a printer plate acting on
the foamed thin film of FIG. 1 in accordance with one or
embodiments of the present invention.
[0013] FIG. 3 is a top plan view of the printer plate of FIG.
2.
[0014] FIG. 4 is a cross section view of a prior art printer plate
acting on a non-foamed film with printed indicia.
DETAILED DESCRIPTION OF THE INVENTION
[0015] As used herein, the following terms have the following
meanings:
[0016] "Agricultural product" refers to a renewable resource
resulting from the cultivation of land (e.g., a crop) or the
husbandry of animals (including fish).
[0017] "Bio-based content" refers to the amount of carbon from a
renewable resource in a material as a percent of the mass of the
total organic carbon in the material, as determined by ASTM
D6866-10, Method B. Note that any carbon from inorganic sources
such as calcium carbonate is not included in determining the
bio-based content of the material.
[0018] "Biodegradation" refers to a process of chemical dissolution
of materials by microorganisms or other biological means.
[0019] "Bio-identical polymer" refers to polymers that are made
from monomers where at least one monomer is derived from renewable
resources. For instance, a bio-identical polyolefin is made from
olefins that are derived from renewable resources, whereas a
petro-based polyolefin is made from olefins typically derived from
non renewable oil or gas.
[0020] "Bio-new polymer" refers to polymers that are directly
derived (i.e., no intermediate compound in the derivation process)
from renewable resources. Such renewable resources include
cellulose (e.g. pulp fibers), starch, chitin, polypeptides,
poly(lactic acid), polyhydroxyalkanoates, and the like.
[0021] "Microorganism" is defined as an organism that is too small
to see with the naked eye, such as bacteria, fungi, archaea, and
protists.
[0022] "Monomeric compound" refers to an intermediate compound that
may be polymerized to yield a polymer.
[0023] "Petrochemical" refers to an organic compound derived from
petroleum, natural gas, or coal.
[0024] "Petroleum" refers to crude oil and its components of
paraffinic, cycloparaffinic, and aromatic hydrocarbons. Crude oil
may be obtained from tar sands, bitumen fields, and oil shale.
[0025] "Polymer" refers to a macromolecule comprising repeat units
where the macromolecule has a molecular weight of at least 1000
Daltons. The polymer may be a homopolymer, copolymer, terpoymer,
etc. The polymer may be produced via fee-radical, condensation,
anionic, cationic, Ziegler-Natta, metallocene, or ring-opening
mechanisms. The polymer may be linear, branched and/or
cross-linked.
[0026] "Polyethylene" and "polypropylene" refer to polymers
prepared from ethylene and propylene, respectively. The polymer may
be a homopolymer, or may contain up to about 10 mol % of repeat
units from a co-monomer.
[0027] "Polymers derived directly from renewable resources" refer
to polymers obtained from a renewable resource without
intermediates.
[0028] "Post-consumer recycled polymers" refer to synthetic
polymers recovered after consumer usage and includes recycled
polymers from plastic bottles (e.g., laundry, milk, and soda
bottles).
[0029] "Printed indicia of acceptable quality" means indicia such
as, for example, characters, graphics, and regions of color that
meet industry standards for clarity and density of print on
consumer packaging. One informal way of determining whether the
indicia are of acceptable quality is whether voids in the ink in
the region through which the underlying foamed film can be seen
with the naked eye. Two industry known tests used to measure
whether bar code indicia are of acceptable quality are ISO/IEC
15415 Bar Code Print Quality Test Specification and ISO/IEC 15416
that grades readability of bar codes from "4A" (best) to "OF"
(worst). A bar code readability of 2C as measure by ISO/IEC 15416
is generally considered as acceptable quality in the industry.
Another exemplary way of determining whether graphics and regions
of color are of acceptable quality is to measure the density of the
printed area with a densitometer. In many instances, specific test
patterns can be printed and measured using ASTM F 2036. A density
of 1.1 to 1.8 Density Units for a solid black region printed on
white paper is generally considered to be of acceptable quality in
the industry.
[0030] "Renewable resource" refers to a natural resource that can
be replenished within a 100 year time frame. The resource may be
replenished naturally, or via agricultural techniques. Renewable
resources include plants, animals, fish, bugs, insects, bacteria,
fungi, and forestry products. They may be naturally occurring,
hybrids, or genetically engineered organisms. Natural resources
such as crude oil, coal, and peat which take longer than 100 years
to form are not considered to be renewable resources.
[0031] "Synthetic polymer" refers to a polymer which is produced
from at least one monomer by a chemical process. A synthetic
polymer is not produced directly by a living organism.
[0032] "Thin film" is defined as a film having a caliper that is
suitable for use in packages such as bags, pouches, labels and
wraps for consumer goods, such as, for example, film calipers from
about 10 to about 250 microns. As used herein, the term "foamed
thin film" designates a film containing at least one layer having a
caliper from about 10 microns to about 250 microns and that
comprises gaseous bubbles, void volumes, or cells wherein that the
at least one layer exhibits a density reduction of at least about
5% by yield (as determined by ASTM D4321) versus a film of the same
thickness that does not comprise gaseous bubbles, void volumes, or
cells.
[0033] A package and a method of constructing a package that
includes at least one layer of printed foamed thin film which
comprise at least one polymer that is at least partially derived
from renewable or recycled resources is provided herein. The foamed
thin film has a caliper of from about 10 microns to about 250
microns thick. The foamed thin film comprises from about 5% to
about 50% density reduction as compared to a non-foamed thin film
of substantially the same composition and caliper.
[0034] The package may comprise a monolayer foamed film, or
multiple layers where at least one layer is foamed. A package may
include a foamed thin film co-extrusion that includes at least one
foamed thin film layer. A package may include a foamed thin film
laminate that includes at least one foamed thin film layer. The
foamed thin film layer may be, for example, blown, cast, biaxially
oriented cast, post film formation process oriented (i.e.,
stretched, drawn or tentered) in the cross or machine orientated
direction, foamed polyethylene or foamed polypropylene.
[0035] A package may include at least one layer of foamed thin film
made of a plastic resin and a whitening or coloring additive that
is added to the plastic resin. The resin could be a traditional
petro-based polyolefin, or it could be a renewable based
polyolefin, or a blend thereof. Alternatively it could be a blend
comprising a petro-based or renewable based polyolefin blend mixed
with a renewable "bio-new" material that is chemically different to
traditional petro-based polyolefins. The film could be comprised of
a material or mixture of materials having a total bio-based content
of about 10% to about 100% using ASTM D6866-10, method B.
[0036] In one embodiment, the package comprises from about 5% to
about 99% by weight of a polymer (A). Polymer (A) comprises at
least one or possibly more of a low density polyethylene (LDPE), a
polar copolymer of polyethylene such as ethylene vinyl acetate
(EVA), a linear low density polyethylene (LLDPE), a high density
polyethylene homopolymer/high density polyethylene copolymer, a
medium density polyethylene, a very low density polyethylene
(VLDPE), a plastomer, a polypropylene/copolypropylene/heterophasic
polypropylene, polyethylene terephthalate (PET), PLA (e.g., from
Natureworks), polyhydroxyalkanoate (PHA),
poly(ethylene-2,5-furandicarboxylate) (PEF), cellulose (available
from, for example, Innovia), NYLON 11 (i.e., Rilsan.RTM. from
Arkema), starch (either thermoplastic starch or starch fillers
bio-polyesters, (e.g., those made from bio-glycerol, organic acid,
and anhydride, as described in U.S. Patent Application No.
2008/0200591, incorporated herein by reference), polybutylene
succinate, polyglycolic acid (PGA), and polyvinyl chloride (PVC).
At least one of the constituents of polymer (A) is at least
partially derived from a renewable resource. Recycled materials may
also be in added. In specific cases, materials that are
biodegradable may be utilized. The whitening or coloring additive
is selected to produce a foamed thin film having an opacity value
of from about 35% to about 99%. The whitening agent is of
substantially the same composition and is present in substantially
the same amount as would be selected to produce substantially the
same light reflectivity in a non-foamed thin film of substantially
the same caliper and substantially the same composition. Some of
the "bio-new" materials may further contribute to increasing the
opacity of the film, as the presence of this additional material
within the film structure can lead to additional light
reflectivity, due to their typical incompatibility with the
polyolefin matrix. In addition to introducing renewable content and
opacity (depending on the exact blend), the addition of a "bio-new"
material in particular may modify the performance of the "easy
open" feature, depending on the exact type and % of "bio-new"
content.
Foamed Films
[0037] FIG. 1 is a top plan view of a foamed thin film 10 that has
indicia 15. Foamed thin films 10 can be used to make packages such
as bags, pouches, labels and wraps. Foamed thin films 10 typically
have a caliper (thickness) of between about 10 and 250 microns and
can be made of a foamed polyolefin resin. Many different blends of
components may be used in the polyolefin and components which are
selected for a variety of properties such as strength and opacity.
Polyethylene (e.g. Low Density Polyethylene (LDPE), Linear Low
Density Polyethylene (LLDPE), High Density Polyethylene (HDPE),
Medium Density Poly ethylene (MDPE), Metallocene Polethylene (mPE),
Ethyl Vinyl Acetate (EVA), cyclic polyolefins, ionomers (Na+ or
Zn+, elastomers, plastomers and mixtures thereof) and
polypropylene, and blends thereof are exemplary types of materials
that are often used in the manufacture of foamed thin films 10.
LLDPE resins could be manufactured with co-monomers that are either
butane, hexene or octane. The catalysts used to produce polymers
could be Ziegerl-Natta based, Chromium based, metallocene, single
site or other type of catalyst. Additionally, polyolefin blends may
include at least a portion of renewable materials--either
"bio-identical" or "bio-new" materials--which are further detailed
below. The thin film 10 shown in FIG. 1 is called a monofilm
because it consists of a single layer.
[0038] As can be seen best in FIG. 2, the foamed thin monofilm 10
is made up of a resin 12, such as, for example, polyolefin, in
having voids left by gas bubbles 14. One way to produce foamed
monofilm 10 is adding one or more chemical blowing agents such as,
for example, Sodium Hydro Carbonate Powder and an acidifier to the
master batch of resin 12 prior to heating. Upon heating, chemical
blowing agents release carbon dioxide. The carbon dioxide expands
and forms bubbles 14 in the monofilm 10 during subsequent
processing steps. One exemplary chemical equation describing the
transition of the blowing agent to carbon dioxide is:
NaHCO.sub.3(Sodium Hydro Carbonate
Powder)+H.sup.+(Acidifier).fwdarw.Na.sup.-+CO.sub.2+H.sub.2O
[0039] Some of the carbon dioxide bubbles 14 escape the molten
resin 12 while others are trapped in the resin 12 during cooling to
form voids that remain after solidification of the resin. An
alternative to the use of chemical blowing agents that react in the
resin to produce bubbles 14 is to inject a gas such as, for
example, carbon dioxide or nitrogen into the molten plastic within
the extruder prior to it leaving the die, during film manufacture
(such as practices in the Mucell process by the Trexel
Corporation). The bubbles 14 shown in FIG. 2 are generally cigar
shaped (in cross-sectional analysis), however, other shapes are
contemplated (such as spherical with a diameter from about 1 micron
to about 100 microns). The bubbles 14 are generally oriented in the
direction of film extrusion. In a foamed thin polyethylene monofilm
having a caliper of 40 microns, a typical cigar shaped bubble may
be 10 microns in diameter (typically <20 microns) and typically
from about 50 microns to about 300 microns in length. The foam
structure of a foamed thin monofilm 10 is generally closed towards
the surface such that substantially all of the bubbles 14 close to
the surface are closed. Because the bubbles 14 create voids that
occupy volume that would have been occupied by resin 12 in a
non-foamed thin film, the foamed thin monofilm 10 uses less resin
12 than its non-foamed counterpart (see e.g., non-foamed thin film
120 in FIG. 4) while maintaining substantially the same caliper.
While the bubbles are typically closed, open bubbles that can
provide surface irregularities, (e.g. troughs or dimples) may be
present.
[0040] The monofilm 10 may also be a top, or printed, layer of
foamed thin film co-extrusion (not shown) or a foamed thin film
laminate (not shown). Many film packages use thin film
co-extrusions or laminates because the composition of each layer
may be selected to contribute a desired quality to the resulting
package. To produce a foamed thin film co-extrusion, resins for
each layer are co-extruded while molten and cooled together to form
a layered thin film co-extrusion. Thus, the foamed thin film
co-extrusion includes layers of each type of resin directly
adjacent one another. Foamed thin film co-extrusions may include
layers that are selected to provide, for example, strength,
opacity, print quality, and moisture resistance.
[0041] Foamed thin film laminates are similar to thin film
co-extrusions because both include layers of different types that
are selected to contribute a desired quality to the resulting
package. However, rather than being combined in a molten form, the
layers of a thin film laminate are separately formed and cooled.
Laminates are often used when one or more of the layers is not well
suitable for co-extrusion, such as, for example, metallized layers
that require significantly different processing techniques as
compared to plastic layers. The separate layers are then fixed to
one another, such as, for example, using adhesive. According to the
present invention, foamed thin film co-extrusions and laminates
have a top layer that is foamed. Package indicia are printed on
this top layer. Further contemplated are coat-extruded laminates
where at least one layer is a foamed layer which can be either the
previously formed substrate that is later coat-extruded with a
different layer, or the foamed layer can be the coat-extruded
layer. In the case of the foamed layer being a previously foamed
substrate that is later coat-extruded with a different layer, the
foamed layer can be printed before, during, or after the
coat-extrusion process. In the case of the foamed layer being the
coat extruded layer, it is printed after the coat extrusion process
at any time when the layer is sufficiently cooled for printing.
[0042] Regardless of whether the printed foamed layer is a
monofilm, or a layer in a multi-layer structure, a foamed film
layer can be printed at any convenient time. It can be printed on
one or both sides, and the sides may be printed concurrently or in
sequence. The foamed thin film or foamed film layer can receive
printing by one or both of flexographic and rotogravure printing
processes.
Printing on Foamed Thin Films
[0043] Flexographic printing is a method of direct rotary printing
that uses a resilient relief image in a plate of rubber or
photopolymer to print indicia on plastic film used to make
packages. In many instances, the plate or plates are installed on a
rotatable print cylinder that prints on a continuous sheet of
plastic film as it passes beneath the print cylinder. FIG. 4 is a
cross section view of a prior art non-foamed thin film 120 being
imprinted with indicia (such as indicia 15 shown in FIG. 1). A
printer surface 112 of a printer plate 100, such as, for example, a
flexographic plate contacts a printed surface 122 of the non-foamed
thin film 120. As can be seen from FIG. 6, the printer surface 112
is substantially planar to provide a full coverage of ink on the
printed surface.
[0044] It has been discovered that using a flat flexographic
printer surface such as the printer surface 112 to print on foamed
thin films (e.g., foamed thin film 10) produces less than printed
indicia of acceptable quality. Voids in the ink are visible to the
naked eye, making the print quality unacceptable for many packaging
applications. Various adjustments to the flexographic print process
used with non-foamed thin films have been made in an attempt to
achieve an acceptable level of ink coverage on foamed thin films.
For example, the pressure with which the printer surface 112
contacts the printed surface on the foamed thin film has been
increased and the viscosity of the ink has been decreased in an
effort to better fill the sunken contours of the rough surface of
the foamed thin film 10. Neither of these two approaches was able
to produce printed indicia of acceptable quality on the foamed thin
film.
[0045] In light of the difficulties with achieving acceptable print
quality on foamed thin films, one way to produce printed packages
with foamed thin film would be to cover the foamed thin film with a
printable non-foamed layer, such as, for example, a co-extruded or
laminated layer. However, inclusion of a specialized print layer on
the foamed thin film would cancel out much of the cost savings
realized by the use of foamed thin film. Therefore, it is desirable
to develop a method for printing directly on a foamed thin film
whether the foamed thin film later comprises a monofilm or is used
as a layer in a multi-layer structure.
[0046] FIG. 2 illustrates a dotted, or half tone, flexographic
printer plate 30 being used to imprint indicia 15 (FIG. 1) on the
foamed thin film 10. The dotted printer plate 30 includes a printer
surface 31 having a plurality of raised dots 32. The raised dots 32
have top surfaces (35 in FIG. 3) that contact a printed surface 16
of the foamed thin film 10 to produce printed indicia of acceptable
quality (e.g., indicia 15) on the foamed thin film. Dotted or half
tone printer plates 30 are currently used on many substrates to
produce shading in an image. This shading is accomplished by
printing dots that have space between them such that the dots, in
aggregate, cover less than the full area of the area being printed.
The ratio between the print area covered by the top surfaces of the
dots and the total surface area being printed is known in the
industry as the dot percentage.
[0047] FIG. 3 is a top plan view of the dotted flexographic printer
plate 30. A relief image 39 of indicia 15 (FIG. 1) is defined by
the raised dots 32. When the top surfaces 35 of the raised dots 32
contact the printed surface 16 (FIG. 2) the indicia 15 is imprinted
on the printed surface 16 without visible voids in coverage. It has
been discovered that using a dotted printer plate 30 plate with a
dot percentage of no more than about 70% will produce printed
indicia of acceptable quality (e.g. indicia 15) on foamed thin film
10.
[0048] Surprisingly, print quality appears to drop off at dot
percentages greater than 70% as voids in the ink become visible.
One reason that dotted print plates may work better than solid
print plates on foamed thin film 10 may be that the flexible raised
dots 32 are able to move and conform to the rough surface, such as
into the recessed areas of the rough printed surface 16 of the
foamed thin film 10. Also surprisingly, increased viscosity ink,
such as, for example, a 20 second increase in viscosity over the
viscosity of ink used on non-foamed thin films also enhances the
quality of ink coverage when used in addition to the dotted print
plate 30. In some circumstances, it may be advantageous to also
increase the pressure with which the printer surface 31 contacts
the printed surface 16. Another measure that has been observed to
improve print quality on foamed thin films is use of a softer
durometer material on the print plate 30.
[0049] For example, in one test, a dotted printer plate 30 having a
dot percentage between about 50% to about 60% was used to produce
printed indicia of acceptable quality on a 40 .mu.m foamed thin
film with approximately 20% resin reduction. The pressure on the
print cylinder was increased by 20.mu. and the pressure on the
anilox roller was increased by 10.mu. as compared to the pressures
that would be used with non-foamed thin film of the same caliper.
An ink having a 20 second increase in ink viscosity as compared to
inks used with non-foamed thin films was used. This configuration
produced a satisfactory level of ink coverage on foamed thin films.
In order to compensate for the use of the dotted printer plate, it
may be advantageous to increase the intensity of the ink by
approximately 30-50%. Intensity of an ink is an indication of the
strength of color of the ink. The following chart summarizes
printing parameters for direct flexographic printing on foamed
films as compared to printing parameters for printing on non-foamed
films.
TABLE-US-00001 Standard flexo Typical adapted settings Parameter
Method Unit print settings for foamed films Dot saturation -- %
0-100 0-70 range on flexo print plate Pressure Distance adjustment
to .mu.m reference +5 to +10 (increased (central cylinder) print
plate cylinder pressure) versus reference Pressure (Anilox Distance
adjustment to .mu.m reference +10 to +20 (increased roll) print
plate cylinder pressure) versus reference Ink viscosity DIN 53211
or sec 18-25 +5 to +10 versus ISO EN 2431 standard (with 4 mm hole
diameter)
[0050] It is believed that using dotted or halftone rotogravure
print plates having a dot percentage of no more than 70% will also
be effective to print regions of full coverage of ink 15 on foamed
thin film 10. It is also expected that increasing the viscosity and
intensity of the ink will have a beneficial effect on the print
quality of the indicia on foamed thin films.
Polymers Derived from Renewable & Sustainable Resources
[0051] A number of renewable resources contain polymers that are
suitable for use in consumer packages (i.e., the polymer that is
obtained from the renewable resource without intermediates).
Suitable extraction and/or purification steps may be necessary, but
no intermediate compound is required. Such polymers that are
derived directly from renewable resources include cellulose (e.g.
pulp fibers), starch, chitin, polypeptides, poly(lactic acid),
polyhydroxyalkanoates, and the like. We typically describe such
polymers as "bio-new" polymers. These polymers may be subsequently
chemically modified to improve end use characteristics (e.g.,
conversion of cellulose to yield carboxycellulose or conversion of
chitin to yield chitosan). However, in such cases, the resulting
polymer is a structural analog of the starting polymer. Any
polymers derived directly from renewable resources with no
intermediate compounds (and their derivatives) that are known in
the art may be useful herein. All of these materials are within the
scope of the present disclosure.
[0052] Synthetic polymers of the present disclosure can be derived
from a renewable resource via an indirect route involving one or
more intermediate compounds. Suitable intermediate compounds
derived from renewable resources include sugars, such as, for
example, monosaccharides, disaccharides, trisaccharides, and
oligosaccharides. Sugars such as sucrose, glucose, fructose and
maltose may be readily produced from renewable resources such as
sugar cane and sugar beets. Sugars may also be derived (e.g., via
enzymatic cleavage) from other agricultural products such as starch
or cellulose. For example, glucose may be prepared on a commercial
scale by enzymatic hydrolysis of corn starch. While corn is a
renewable resource in North America, other common agricultural
crops may be used as the base starch for conversion into glucose.
Wheat, buckwheat, arracaha, potato, barley, kudzu, cassava,
sorghum, sweet potato, yam, arrowroot, sago, and other similar
starchy fruit, seeds, or tubers may also be used in the preparation
of glucose.
[0053] Other suitable intermediate compounds derived from renewable
resources include monofunctional alcohols such as methanol or
ethanol and polyfunctional alcohols such as glycerol. Ethanol may
be derived from many of the same renewable resources as glucose.
For example, cornstarch may be enzymatically hydrolyzed to yield
glucose and/or other sugars. The resultant sugars can be converted
into ethanol by fermentation. As with glucose production, corn is
an ideal renewable resource in North America; however, other crops
may be substituted. Methanol may be produced from fermentation of
biomass. Glycerol is commonly derived via hydrolysis of
triglycerides present in natural fats or oils, which may be
obtained from renewable resources such as animals or plants.
[0054] Other intermediate compounds derived from renewable
resources include organic acids (e.g., citric acid, lactic acid,
alginic acid, amino acids etc.), aldehydes (e.g., acetaldehyde),
and esters (e.g., cetyl palmitate, methyl stearate, methyl oleate,
etc.). Additional intermediate compounds such as methane and carbon
monoxide may also be derived from renewable resources by
fermentation and/or oxidation processes.
[0055] Intermediate compounds derived from renewable resources may
be converted into polymers (e.g., glycerol to polyglycerol) or they
may be converted into other intermediate compounds in a reaction
pathway which ultimately leads to a polymer useful in a consumer
package. An intermediate compound may be capable of producing more
than one secondary intermediate compound. Similarly, a specific
intermediate compound may be derived from a number of different
precursors, depending upon the reaction pathways utilized.
[0056] Particularly desirable intermediates include olefins.
Olefins such as ethylene and propylene may also be derived from
renewable resources. For example, methanol derived from
fermentation of biomass may be converted to ethylene and or
propylene, which are both suitable monomeric compounds, as
described in U.S. Pat. Nos. 4,296,266 and 4,083,889. Ethanol
derived from fermentation of a renewable resource may be converted
into the monomeric compound ethylene via dehydration as described
in U.S. Pat. No. 4,423,270. Similarly, propanol or isopropanol
derived from a renewable resource can be dehydrated to yield the
monomeric compound of propylene as exemplified in U.S. Pat. No.
5,475,183. Propanol is a major constituent of fusel oil, a
by-product formed from certain amino acids when potatoes or grains
are fermented to produce ethanol.
[0057] Charcoal derived from biomass can be used to create syngas
(i.e., CO+H.sub.2) from which hydrocarbons such as ethane and
propane can be prepared (Fischer-Tropsch Process). Ethane and
propane can be dehydrogenated to yield the monomeric compounds of
ethylene and propylene.
[0058] Other sources of materials to form polymers derived from
renewable or sustainable resources include post-consumer recycled
materials. Sources of synthetic post-consumer recycled materials
can include plastic bottles (e.g., soda bottles), plastic films,
plastic packaging materials, plastic bags and other similar
materials which contain synthetic materials which can be
recovered.
[0059] In one aspect, the present disclosure is directed to films
having at least one layer of a composition comprising an intimate
admixture of a thermoplastic polymer and a wax having a melting
point greater than 25.degree. C. The wax can have a melting point
that is lower than the melting temperature of the thermoplastic
polymer. The wax can be present in the composition in an amount of
about 5 wt % to about 40 wt %, about 8 wt % to about 30 wt %, or
about 10 wt % to about 20 wt %, based upon the total weight of the
composition. The wax can comprise a lipid, which can be selected
from the group consisting of a monoglyceride, diglyceride,
triglyceride, fatty acid, fatty alcohol, esterified fatty acid,
epoxidized lipid, maleated lipid, hydrogenated lipid, alkyd resin
derived from a lipid, sucrose polyester, or combinations thereof.
The wax can comprise a mineral wax, such as a linear alkane, a
branched alkane, or combinations thereof. Specific examples of
mineral wax are paraffin and petrolatum. The wax can be selected
from the group consisting of hydrogenated soy bean oil, partially
hydrogenated soy bean oil, epoxidized soy bean oil, maleated soy
bean oil, tristearin, tripalmitin, 1,2-dipalmitoolein,
1,3-dipalmitoolein, 1-palmito-3-stearo-2-olein,
1-palmito-2-stearo-3-olein, 2-palmito-1-stearo-3-olein,
1,2-dipalmitolinolein, 1,2-distearo-olein, 1,3-distearo-olein,
trimyristin, trilaurin, capric acid, caproic acid, caprylic acid,
lauric acid, myristic acid, palmitic acid, stearic acid, and
combinations thereof. The wax can be selected from the group
consisting of: a hydrogenated plant oil, a partially hydrogenated
plant oil, an epoxidized plant oil, a maleated plant oil. Specific
examples of such plant oils include soy bean oil, corn oil, canola
oil, and palm kernel oil. The wax can be dispersed within the
thermoplastic polymer such that the wax has a droplet size of less
than 10 .mu.m, less than 5 .mu.m, less than 1 .mu.m, or less than
500 nm within the thermoplastic polymer. The wax can be a renewable
material.
[0060] In one aspect, the present disclosure is directed to films
having at least one layer of a composition comprising an intimate
admixture of a thermoplastic polymer and about 5 wt % to about 40
wt % of an oil, based upon the total weight of the composition,
wherein the oil has a melting point of 25.degree. C. or less and a
boiling point greater than 160.degree. C. The oil can comprise a
lipid, which can be selected from the group consisting of a
monoglyceride, diglyceride, triglyceride, fatty acid, fatty
alcohol, esterified fatty acid, epoxidized lipid, maleated lipid,
hydrogenated lipid, alkyd resin derived from a lipid, sucrose
polyester, or combinations thereof. The oil can comprise a mineral
oil, such as a linear alkane, a branched alkane, or combinations
thereof. The oil can be selected from the group consisting of soy
bean oil, epoxidized soy bean oil, maleated soy bean oil, corn oil,
cottonseed oil, canola oil, castor oil, coconut oil, coconut seed
oil, corn germ oil, fish oil, linseed oil, olive oil, oiticica oil,
palm kernel oil, palm oil, palm seed oil, peanut oil, rapeseed oil,
safflower oil, sperm oil, sunflower seed oil, tall oil, tung oil,
whale oil, triolein, trilinolein, 1-stearo-dilinolein,
1-palmito-dilinolein, lauroleic acid, linoleic acid, linolenic
acid, myristoleic acid, oleic acid, palmitoleic acid,
1,2-diacetopalmitin, and combinations thereof. The oil can be
dispersed within the thermoplastic polymer such that the oil has a
droplet size of less than 10 .mu.m, less than 5 .mu.m, less than 1
.mu.m, or less than 500 nm within the thermoplastic polymer. The
oil can be a renewable material.
[0061] In one aspect, the present disclosure is directed to films
having at least one layer of a composition comprising an intimate
admixture of a thermoplastic starch (TPS), a thermoplastic polymer
and an oil, wax, or combination thereof present in an amount of
about 5 wt % to about 40 wt %, based upon the total weight of the
composition.
[0062] Some or all of the above detailed materials may also be
bio-degradable.
Exemplary Synthetic Polymers
[0063] Olefins derived from renewable resources may be polymerized
to yield polyolefins. Such polymers are typically referred to as
"bio-identical" polymers. Ethylene and propylene derived from
renewable resources may be polymerized under the appropriate
conditions to prepare polyethylene and/or polypropylene having
desired characteristics for use in consumer packages. The
polyethylene and/or polypropylene may be high density, medium
density, low density, or linear-low density. Further, polypropylene
can include homopolymer-polypropylene or co-polymer polypropylene.
Polyethylene and/or polypropylene may be produced via free-radical
polymerization techniques, or by using Ziegler-Natta (ZN) catalysis
or Metallocene catalysts. Examples of such bio-sourced
polyethylenes and polypropylenes are described in U.S. Publication
Nos. 2010/0069691, 2010/0069589, 2009/0326293, and 2008/0312485;
PCT Application Nos. WO2010063947 and WO2009098267; and European
Patent No. 1102569. Other olefins that can be derived from
renewable resources include butadiene and isoprene. Examples of
such olefins are described in U.S. Publication Nos. 2010/0216958
and 2010/0036173.
[0064] Such polyolefins being derived from renewable resources can
also be reacted to form various copolymers, including for example,
random block copolymers, such as ethylene-propylene random block
copolymers (e.g., Borpact.TM. BC918CF manufactured by Borealis).
Such copolymers and methods of forming the same are contemplated
and described for example in European Patent No. 2121318. In
addition, the polyolefin derived from a renewable resource may be
processed according to methods known in the art into a form
suitable for the end use of the polymer. The polyolefin may
comprise mixtures or blends with other polymers such as polyolefins
derived from petrochemicals.
[0065] Bio-polyethylene terephthalate is available from Teijin
Fibers Ltd. It also can be produced from the polymerization of
bio-ethylene glycol with bio-terephthalic acid. Bio-ethylene glycol
can be derived from renewable resources via a number of suitable
routes, such as, for example, those described in WO/2009/155086 and
U.S. Pat. No. 4,536,584, each incorporated herein by reference.
Bio-terephthalic acid can be derived from renewable alcohols
through renewable p-xylene, as described in WO/2009/079213, which
is incorporated herein by reference. In some embodiments, a
renewable alcohol (e.g., isobutanol) is dehydrated over an acidic
catalyst in a reactor to form isobutylene. The isobutylene is
recovered and reacted under the appropriate high heat and pressure
conditions in a second reactor containing a catalyst known to
aromatize aliphatic hydrocarbons to form renewable p-xylene. In
another embodiment, a renewable alcohol (e.g., isobutanol) is
dehydrated and dimerized over an acid catalyst. The resulting
diisobutylene is recovered and reacted in a second reactor to form
renewable p-xylene. In yet another embodiment, a renewable alcohol
(e.g., isobutanol) containing up to 15 wt. % water is dehydrated,
or dehydrated and oligomerized, and the resulting oligomers are
aromatized to form renewable p-xylene. Renewable phthalic acid or
phthalate esters can be produced by oxidizing p-xylene over a
transition metal catalyst (see, e.g., Ind. Eng. Chem. Res.,
39:3958-3997 (2000)), optionally in the presence of one or more
alcohols.
[0066] Bio-poly(ethylene-2,5-furandicarboxylate), a.k.a., bio-PEF,
can be produced according to the route disclosed in Werpy and
Petersen, "Top Value Added Chemicals from Biomass. Volume
I--Results of Screening for Potential Candidates from Sugars and
Synthesis Gas, produced by the Staff at Pacific Northwest National
Laboratory (PNNL): National Renewable Energy Laboratory (NREL),
Office of Biomass Program (EERE)," 2004 and PCT Application No. WO
2010/077133, which are both incorporated herein by reference.
[0067] It should be recognized that any of the aforementioned
synthetic polymers (e.g., copolymers) may be formed by using a
combination of monomers derived from renewable resources and
monomers derived from non-renewable (e.g., petroleum) resources.
For example, the copolymer can comprise propylene repeat units
derived from a renewable resource and isobutylene repeat units
derived from a petroleum source.
[0068] In addition to being formed from the synthetic polymers
described herein, the consumer packages can further include
additional additives. For example, opacifying agents can be added.
Such opacifying agents can include iron oxides, carbon black,
aluminum, aluminum oxide, titanium dioxide, talc and combinations
thereof. These opacifying agents can comprise about 0.1% to about
5% by weight of the packages; and in certain embodiments, the
opacifying agents can comprise about 0.3% to about 3% of the
packages. It will be appreciated that other suitable opacifying
agents may be employed and in various concentrations. Examples of
opacifying agents are described in U.S. Pat. No. 6,653,523.
[0069] Furthermore, the consumer packages may comprise other
additives, such as other polymers (e.g., a polypropylene, a
polyethylene, a ethylene vinyl acetate, a polyethyelene
terephthalate, a polymethylpentene, any combination thereof, or the
like--whether derived from a renewable resource or petro-based
source), a filler (e.g., glass, talc, calcium carbonate, or the
like), a mold release agent, a flame retardant, an electrically
conductive agent, an anti-static agent, a pigment (inorganic or
organic), an antioxidant, an impact modifier, a stabilizer (e.g., a
UV absorber), wetting agents, dyes, or any combination thereof.
[0070] Some materials used in the structures described herein may
be a blend comprising a petro-based or renewable based
"bio-identical" polyolefin blend mixed with a renewable "bio-new"
material. Typically the "bio-new" material would be added to the
petro-based or renewable based "bio-identical" polyolefin in the
range 5-50 wt %, as higher than that would typically be difficult
to process. The blend could also contain some recycled materials,
typically up to around 50%--higher than that level could typically
cause gels to form in the film which act as imperfections.
Validation of Polymers Derived from Renewable Resources
[0071] A suitable validation technique is through .sup.14C
analysis. A small amount of the carbon dioxide in the atmosphere is
radioactive. .sup.14C carbon dioxide is created when nitrogen is
struck by an ultra-violet light produced neutron, causing the
nitrogen to lose a proton and form carbon of molecular weight 14
which is immediately oxidized to carbon dioxide. This radioactive
isotope represents a small but measurable fraction of atmospheric
carbon. Atmospheric carbon dioxide is cycled by green plants to
make organic molecules during photosynthesis. The cycle is
completed when the green plants or other forms of life metabolize
the organic molecules, thereby producing carbon dioxide which is
released back to the atmosphere. Virtually all forms of life on
Earth depend on this green plant production of organic molecules to
grow and reproduce. Therefore, the .sup.14C that exists in the
atmosphere becomes part of all life forms, and their biological
products. In contrast, fossil fuel based carbon does not have the
signature radiocarbon ratio of atmospheric carbon dioxide.
[0072] Assessment of the renewably based carbon in a material can
be performed through standard test methods. Using radiocarbon and
isotope ratio mass spectrometry analysis, the bio-based content of
materials can be determined. ASTM International, formally known as
the American Society for Testing and Materials, has established a
standard method for assessing the bio-based content of materials.
The ASTM method is designated ASTM D6866-10.
[0073] The application of ASTM D6866-10 to derive a "bio-based
content" is built on the same concepts as radiocarbon dating, but
without use of the age equations. The analysis is performed by
deriving a ratio of the amount of organic radiocarbon (.sup.14C) in
an unknown sample to that of a modern reference standard. The ratio
is reported as a percentage with the units "pMC" (percent modern
carbon).
[0074] The modern reference standard used in radiocarbon dating is
a NIST (National Institute of Standards and Technology) standard
with a known radiocarbon content equivalent approximately to the
year AD 1950. AD 1950 was chosen since it represented a time prior
to thermo-nuclear weapons testing which introduced large amounts of
excess radiocarbon into the atmosphere with each explosion (termed
"bomb carbon"). The AD 1950 reference represents 100 pMC.
[0075] "Bomb carbon" in the atmosphere reached almost twice normal
levels in 1963 at the peak of testing and prior to the treaty
halting the testing. Its distribution within the atmosphere has
been approximated since its appearance, showing values that are
greater than 100 pMC for plants and animals living since AD 1950.
It's gradually decreased over time with today's value being near
107.5 pMC. This means that a fresh biomass material such as corn
could give a radiocarbon signature near 107.5 pMC.
[0076] Combining fossil carbon with present day carbon into a
material will result in a dilution of the present day pMC content.
By presuming 107.5 pMC represents present day biomass materials and
0 pMC represents petroleum derivatives, the measured pMC value for
that material will reflect the proportions of the two component
types. A material derived 100% from present day soybeans would give
a radiocarbon signature near 107.5 pMC. If that material was
diluted with 50% petroleum derivatives, for example, it would give
a radiocarbon signature near 54 pMC (assuming the petroleum
derivatives have the same percentage of carbon as the
soybeans).
[0077] A biomass content result is derived by assigning 100% equal
to 107.5 pMC and 0% equal to 0 pMC. In this regard, a sample
measuring 99 pMC will give an equivalent bio-based content value of
92%.
[0078] Assessment of the materials described herein was done in
accordance with ASTM D6866. The mean values encompass an absolute
range of 6% (plus and minus 3% on either side of the bio-based
content value) to account for variations in end-component
radiocarbon signatures. It is presumed that all materials are
present day or fossil in origin and that the desired result is the
amount of bio-based component "present" in the material, not the
amount of bio-based material "used" in the manufacturing
process.
[0079] In one embodiment, a mono-layer film comprises a bio-based
content value from about 10% to about 100% using ASTM D6866-10,
method B. In another embodiment, a mono-layer film comprises a
bio-based content value from about 20% to about 100% using ASTM
D6866-10, method B. In yet another embodiment, a mono-layer film
comprises a bio-based content value from about 50% to about 100%
using ASTM D6866-10, method B.
[0080] In one embodiment, a multi-layer film comprises a bio-based
content value from about 10% to about 100% using ASTM D6866-10,
method B. In another embodiment, a multi-layer film comprises a
bio-based content value from about 20% to about 100% using ASTM
D6866-10, method B. In yet another embodiment, a multi-layer film
comprises a bio-based content value from about 50% to about 100%
using ASTM D6866-10, method B.
[0081] In order to apply the methodology of ASTM D6866-10 to
determine the bio-based content of a package, a representative
sample of the component must be obtained for testing. In one
embodiment, a representative portion of the package can be ground
into particulates less than about 20 mesh using known grinding
methods (e.g., Wiley.RTM. mill), and a representative sample of
suitable mass taken from the randomly mixed particles.
Other Materials
[0082] The consumer packages disclosed herein can optionally
include a colorant masterbatch. As used herein, a "colorant
masterbatch" refers to a mixture in which pigments are dispersed at
high concentration in a carrier material. The colorant masterbatch
is used to impart color to the final product. In some embodiments,
the carrier is a bio-based plastic or a petroleum-based plastic,
while in alternative embodiments, the carrier is a bio-based oil or
a petroleum-based oil. The colorant masterbatch can be derived
wholly or partly from a petroleum resource, wholly or partly from a
renewable resource, or wholly or partly from a recycled resource.
Non-limiting examples of the carrier include bio-derived or oil
derived polyethylene (e.g., linear low-density polyethylene
(LLDPE), low-density polyethylene (LDPE), high-density polyethylene
(HDPE)), bio-derived oil (e.g., olive oil, rapeseed oil, peanut
oil, soybean oil, or hydrogenated plant-derived oils),
petroleum-derived oil, recycled oil, bio-derived or petroleum
derived polyethylene terephthalate, polypropylene, and a mixture
thereof. The pigment of the carrier, which can be derived from
either a renewable resource or a non-renewable resource, can
include, for example, an inorganic pigment, an organic pigment, a
polymeric resin, or a mixture thereof. Non-limiting examples of
pigments include titanium dioxide (e.g., rutile, anatase), copper
phthalocyanine, antimony oxide, zinc oxide, calcium carbonate,
fumed silica, phthalocyamine (e.g., phthalocyamine blue),
ultramarine blue, cobalt blue, monoazo pigments, diazo pigments,
acid dye, base dye, quinacridone, and a mixture thereof. In some
embodiments, the colorant masterbatch can further include one or
more additives, which can either be derived from a renewable
resource or a non-renewable resource. Nonlimiting examples of
additives include slip agents, UV absorbers, nucleating agents, UV
stabilizers, heat stabilizers, clarifying agents, fillers,
brighteners, process aids, perfumes, flavors, and a mixture
thereof.
[0083] In some embodiments, color can be imparted to the films of
the present invention in any of the aspects by using direct
compounding (i.e., in-line compounding). In these embodiments, a
twin screw compounder is placed at the beginning of the injection
molding, blow molding, or film line and additives, such as
pigments, are blended into the resin just before article
formation.
[0084] Additional materials may be incorporated into the packages
of the present invention in any of the aspects to improve the
strength or other physical characteristics of the plastic. Such
additional materials include an inorganic salt, such as calcium
carbonate, calcium sulfate, talcs, clays (e.g., nanoclays),
aluminum hydroxide, CaSiO3, glass fibers, glass spheres,
crystalline silicas (e.g., quartz, novacite, crystallobite),
magnesium hydroxide, mica, sodium sulfate, lithopone, magnesium
carbonate, iron oxide, or a mixture thereof.
[0085] In some alternative embodiments to any of the embodiments
described herein, elements of the package, including the sealant,
barrier material, tie layers, or mixtures thereof, include recycled
material in place of, or in addition to, the bio-based material in
an amount of up to 100% of the bio-based material. As used herein,
"recycled" materials encompass post-consumer recycled (PCR)
materials, post-industrial recycled (PIR) materials, and a mixture
thereof.
[0086] In some embodiments, the structure described above may
incorporate a barrier layer. The barrier material is selected from
the group consisting of aluminum, metallized polyolefin substrate,
metallized polyethylene terephthalate substrate, metallised
cellulose, PVDC, PCTFE, sol-gel coating. Instead of a metallized
coating on polyolefins or polyethylene terephthalate, the following
coatings could be used--metal oxide, a nanoclay, an aluminum oxide,
a silicon oxide, diamond-like carbon (DLC), and mixtures thereof.
Other barrier substrates (used with or without a coating) could
include EVOH, PVOH, Nylon, PVC, liquid crystal polymer. The
substrates could include within their structure, an additional
barrier additive (not in coating form but embedded within the
polymer matrix)--one example of such additives could include
nanoclays). The total barrier layer including the substrate
typically has a thickness of about 6 [mu]m to about 200 [mu]m.
Typically the substrate underneath the coating is cast biaxially
oriented, although it could be a blown or cast film too. In some
preferred embodiments, the metal is vacuum metallized aluminum. In
some embodiments when the barrier material is a nanoclay, the
nanoclay is selected from the group consisting of montmorillonites,
vermiculite platelets, and mixtures thereof.
[0087] In embodiments of the consumer packages described herein,
the ink that is deposited can be either solvent-based or
water-based. In some embodiments, the ink is high abrasive
resistant. For example, the high abrasive resistant ink can include
coatings cured by ultraviolet radiation (UV) or electron beams
(EB). In some embodiments, the ink is derived from a petroleum
source. In some embodiments, the ink is derived from a renewable
resource, such as soy, a plant, or a mixture thereof. Non-limiting
examples of inks include ECO-SURE!.TM. from Gans Ink & Supply
Co. and the solvent-based VUTEk(R) and BioVu.TM. inks from EFI,
which are derived completely from renewable resources (e.g., corn).
The ink is present in a thickness of about 0.5 [mu]m to about 20
[mu]m, preferably about 1 [mu]m to about 10 [mu]m, more preferably
about 2.5 [mu]m to about 3.5 [mu]m.
[0088] In general, bio-new materials are often found to be more
polar than current petroleum based materials. So the use of bio-new
material in the printed layer may also enhance the printing
process.
[0089] In embodiments of the consumer packages described herein, an
optional lacquer functions to protect the ink layer from its
physical and chemical environment, when reverse printing has not
been used. In some embodiments, the lacquer is selected from the
group consisting of resin, additive, and solvent/water. In some
preferred embodiments, the lacquer is nitrocellulose-based lacquer.
The lacquer is formulated to optimize durability and provide a
glossy or matte finish. The lacquer is present in a thickness of up
to about 25 [mu]m, preferably up to about 5 [mu]m. The lacquer
could be renewable.
[0090] Non-limiting examples of the adhesive can include acrylic,
polyvinyl acetate, and other commonly used adhesive tie layers
suitable for polar materials. In some embodiments, the adhesive is
a renewable adhesive, such as BioTAK(R) by Berkshire Labels.
[0091] In some embodiments, particular material combinations that
enable the film structure to be biodegradable or degradable may be
selected.
[0092] In some embodiments, the consumer packages described herein
are substantially free of oxo-biodegradable additives (i.e., less
than about 1 wt. %, based on the total weight of the package or
article) but in some embodiments oxo-biodegradable additives may be
used. Oxo-biodegradable additives consist of transition metals that
theoretically foster oxidation and chain scission in plastics when
exposed to heat, air, light, or a mixture thereof. Although the
shortened polymer chains theoretically can be consumed by
microorganisms found in the disposal environment and used as a food
source, there is no data to support how long these plastic
fragments will persist in the soils or marine environments, or if
biodegradation of these fragments occurs at all. However, in some
specific material blends, such materials may enable faster
biodegradation.
[0093] In addition embodiments where a biodegradable package is
desired, certain additives may be added to tune the degradability
of polymers to meet a specific degradability. For example, numerous
additives are known to tune the degradation of polymers with or
without being triggered by some external stimulus (e.g., exposure
to light) as disclosed in US 2010/0222454 A1, US 2004/0010051 A1,
US2009/0286060 A1 and references therein. Additionally, the article
"Photodegradation, Photooxidation, and Photostabilization of
Polymers," by Ranby and Rabek describe photodegradant materials.
While not wishing to be bound by theory, one example of these
additives (photo acid or photobase generators) tune the local pH in
response to exposure to certain wavelengths of light, which results
in hydrolysis of a polyester. Once these polymers are hydrolyzed to
a lower molecular weight, they are truly biodegraded by
microorganisms.
[0094] While the present invention has been illustrated by the
description of embodiments thereof, and while the embodiments have
been described in considerable detail, it is not the intention of
the applicants to restrict or in any way limit the scope of the
appended claims to such detail. Additional advantages and
modifications will readily appear to those skilled in the art.
Therefore the invention, in its broader aspects, is not limited to
the specific details, the representative system, and illustrative
examples shown and described. Accordingly, departures may be made
from such details without departing from the spirit or scope of the
applicant's general inventive concept.
[0095] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm".
[0096] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0097] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
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