U.S. patent application number 16/618618 was filed with the patent office on 2020-06-11 for packaging with three-dimensional loop material.
The applicant listed for this patent is Dow Global Technologies LLC. Invention is credited to Eduardo Alvarez, Maria Isabel Arroyo Villan, Shaun Parkinson, Viraj Shah.
Application Number | 20200180841 16/618618 |
Document ID | / |
Family ID | 59091448 |
Filed Date | 2020-06-11 |
United States Patent
Application |
20200180841 |
Kind Code |
A1 |
Alvarez; Eduardo ; et
al. |
June 11, 2020 |
Packaging with Three-Dimensional Loop Material
Abstract
The present disclosure provides a packaging article (10). In an
embodiment, the packaging article comprises (A) a rigid container
(12) having side walls (14) and a bottom wall (16), the walls
defining a compartment (20), and (B) a sheet (22) of 3-dimensional
random loop material (3DRLM) in the compartment. A food item (C)
may be located in the compartment, the food item contacts the sheet
of 3DRLM.
Inventors: |
Alvarez; Eduardo; (Tarragona
South, ES) ; Arroyo Villan; Maria Isabel; (Tarragona
South, ES) ; Parkinson; Shaun; (Tarragona South,
ES) ; Shah; Viraj; (Freeport, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dow Global Technologies LLC |
Midland |
MI |
US |
|
|
Family ID: |
59091448 |
Appl. No.: |
16/618618 |
Filed: |
June 19, 2018 |
PCT Filed: |
June 19, 2018 |
PCT NO: |
PCT/US2018/034631 |
371 Date: |
December 2, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 43/162 20130101;
B65D 81/262 20130101; F25D 3/06 20130101; B65D 2581/051 20130101;
B65D 81/051 20130101; B65D 81/18 20130101 |
International
Class: |
B65D 81/26 20060101
B65D081/26; B65D 81/18 20060101 B65D081/18; F25D 3/06 20060101
F25D003/06; B65D 81/05 20060101 B65D081/05 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2017 |
EP |
17382317.0 |
Claims
1. A packaging article comprising: A. a rigid container having side
walls and a bottom wall, the walls defining a compartment; and B. a
sheet of 3-dimensional random loop material (3DRLM) in the
compartment.
2. The packaging article of claim 1 comprising (C) a food item in
the compartment; and the food item contacts a surface of the sheet
of 3DRLM.
3. The packaging article of claim 2 wherein a liquid from the food
item passes through the 3DRLM and onto the bottom wall.
4. The packaging article of claim 3 wherein the 3DRLM separates the
food item from the liquid on the bottom wall.
5. The packaging article of claim 2 comprising (D) a cold source in
the compartment.
6. The packaging article of claim 5 wherein the cold source is ice
in contact with the food item; and melted ice passes through the
sheet of 3DRLM and onto the bottom wall.
7. The packaging article of claim 6 wherein the sheet of 3DRLM
separates the food item from the liquid on the bottom wall when all
of the ice is melted.
8. The packaging article of claim 1 wherein the sheet of 3DRLM
extends across two opposing walls.
9. The packaging article of claim 1 wherein the container comprises
a top wall.
Description
BACKGROUND
[0001] Many fresh foods such as such as meat, poultry, fish,
vegetables, fruits, and berries are packaged in plastic trays with
a shrink wrap or stretch wrap film for protection, unitization and
transportation. These trays are typically thermoformed trays made
from rigid- or semi-rigid materials such as polystyrene or
polypropylene sheets. The fresh food item typically contains liquid
that drains or flows from the food item during storage. The liquid
accumulates in the bottom of the package. Liquid accumulation
increases the risk of microbiological growth, which can deteriorate
the fresh food, rendering the food unsafe for consumption. Liquid
accumulation in the fresh food package also negatively impacts the
appearance of the food item, during consumers away from purchasing
the food item.
[0002] Conventional fresh food packaging utilizes an absorbent pad
between the food item and the tray. Absorbent pads are typically
made of cellulose pulp and/or super absorbent polyacrylates,
encased in a non-woven textile wrapping bag. Absorbent pads can
only retain the drained liquid to a limited extent. Absorbent pads
do not completely eliminate microbiological growth inside of the
food package because the liquid remains in contact with the food
item at the interface of the absorbent pad. Also, the liquid in the
absorbent pad remains in either liquid form or hydrogel form,
increasing the risk of microbiological growth. Biocides cannot
typically be used inside of absorbent packages or absorbent pads
due to food contact regulations. Further, absorbent pads are known
to easily tear and/or adhere to a food item when consumers remove
the food item from a package, forcing consumers to contact the
absorbent pad.
[0003] The art therefore recognizes the need for a food package
that is capable of preventing liquid accumulation and minimizing
microbiological growth without the need for an absorbent pad.
SUMMARY
[0004] The present disclosure provides a packaging article. In an
embodiment, the packaging article comprises (A) a rigid container
having side walls and a bottom wall, the walls defining a
compartment, and (B) a sheet of 3-dimensional random loop material
(3DRLM) in the compartment. A food item (C) may be located in the
compartment, the food item contacts the sheet of 3DRLM.
Definitions and Test Methods
[0005] All references to the Periodic Table of the Elements herein
shall refer to the Periodic Table of the Elements, published and
copyrighted by CRC Press, Inc., 2003. Also, any references to a
Group or Groups shall be to the Groups or Groups reflected in this
Periodic Table of the Elements using the IUPAC system for numbering
groups. Unless stated to the contrary, implicit from the context,
or customary in the art, all components and percents are based on
weight. For purposes of United States patent practice, the contents
of any patent, patent application, or publication referenced herein
are hereby incorporated by reference in their entirety (or the
equivalent US version thereof is so incorporated by reference).
[0006] The numerical ranges disclosed herein include all values
from, and including, the lower value and the upper value. For
ranges containing explicit values (e.g., 1, or 2, or 3 to 5, or 6,
or 7) any subrange between any two explicit values is included
(e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).
[0007] Unless stated to the contrary, implicit from the context, or
customary in the art, all components and percents are based on
weight, and all test methods are current as of the filing date of
this disclosure.
[0008] Apparent density. A sample material is cut into a square
piece of 38 cm.times.38 cm (15 in.times.15 in) in size. The volume
of this piece is calculated from the thickness measured at four
points. The division of the weight by the volume gives the apparent
density (an average of four measurements is taken) with values
reported in grams per cubic centimeter, g/cc.
[0009] Bending Stiffness. The bending stiffness is measured in
accordance with DIN 53121 standard, with compression molded plaques
of 550 .mu.m thickness, using a Frank-PTI Bending Tester. The
samples are prepared by compression molding of resin granules per
ISO 293 standard. Conditions for compression molding are chosen per
ISO 1872-2007 standard. The average cooling rate of the melt is
15.degree. C./min. Bending stiffness is measured in 2-point bending
configuration at room temperature with a span of 20 mm, a sample
width of 15 mm, and a bending angle of 40.degree.. Bending is
applied at 6.degree./second (s) and the force readings are obtained
from 6 to 600 s, after the bending is complete. Each material is
evaluated four times with results reported in Newton millimeters
("Nmm").
[0010] "Blend," "polymer blend" and like terms is a composition of
two or more polymers. Such a blend may or may not be miscible. Such
a blend may or may not be phase separated. Such a blend may or may
not contain one or more domain configurations, as determined from
transmission electron spectroscopy, light scattering, x-ray
scattering, and any other method known in the art. Blends are not
laminates, but one or more layers of a laminate can comprise a
blend. .sup.13C Nuclear Magnetic Resonance (NMR)
[0011] Sample Preparation
[0012] The samples are prepared by adding approximately 2.7 g of a
50/50 mixture of tetrachloroethane-d2/orthodichlorobenzene that is
0.025M in chromium acetylacetonate (relaxation agent) to 0.21 g
sample in a 10 mm NMR tube. The samples are dissolved and
homogenized by heating the tube and its contents to 150.degree.
C.
[0013] Data Acquisition Parameters
[0014] The data is collected using a Bruker 400 MHz spectrometer
equipped with a Bruker Dual DUL high-temperature CryoProbe. The
data is acquired using 320 transients per data file, a 7.3 sec
pulse repetition delay (6 sec delay+1.3 sec acq. time), 90 degree
flip angles, and inverse gated decoupling with a sample temperature
of 125.degree. C. All measurements are made on non-spinning samples
in locked mode. Samples are homogenized immediately prior to
insertion into the heated (130.degree. C.) NMR Sample changer, and
are allowed to thermally equilibrate in the probe for 15 minutes
prior to data acquisition.
[0015] "Composition" and like terms is a mixture of two or more
materials. Included in compositions are pre-reaction, reaction and
post-reaction mixtures, the latter of which will include reaction
products and by-products as well as unreacted components of the
reaction mixture and decomposition products, if any, formed from
the one or more components of the pre-reaction or reaction
mixture.
[0016] The terms "comprising," "including," "having," and their
derivatives, are not intended to exclude the presence of any
additional component, step or procedure, whether or not the same is
specifically disclosed. In order to avoid any doubt, all
compositions claimed through use of the term "comprising" may
include any additional additive, adjuvant, or compound, whether
polymeric or otherwise, unless stated to the contrary. In contrast,
the term, "consisting essentially of" excludes from the scope of
any succeeding recitation any other component, step or procedure,
excepting those that are not essential to operability. The term
"consisting of" excludes any component, step or procedure not
specifically delineated or listed.
[0017] Crystallization Elution Fractionation (CEF) Method
[0018] Comonomer distribution analysis is performed with
Crystallization Elution Fractionation (CEF) (PolymerChar in Spain)
(B Monrabal et al, Macromol. Symp. 257, 71-79 (2007)).
Ortho-dichlorobenzene (ODCB) with 600 ppm antioxidant butylated
hydroxytoluene (BHT) is used as solvent. Sample preparation is done
with autosampler at 160.degree. C. for 2 hours under shaking at 4
mg/ml (unless otherwise specified). The injection volume is 300 m.
The temperature profile of CEF is: crystallization at 3.degree.
C./min from 110.degree. C. to 30.degree. C., the thermal
equilibrium at 30.degree. C. for 5 minutes, elution at 3.degree.
C./min from 30.degree. C. to 140.degree. C. The flow rate during
crystallization is at 0.052 ml/min. The flow rate during elution is
at 0.50 ml/min. The data is collected at one data point/second. CEF
column is packed by the Dow Chemical Company with glass beads at
125 .mu.m+6% (MO-SCI Specialty Products) with 1/8 inch stainless
tubing. Glass beads are acid washed by MO-SCI Specialty with the
request from The Dow Chemical Company. Column volume is 2.06 ml.
Column temperature calibration is performed by using a mixture of
NIST Standard Reference Material Linear polyethylene 1475a (1.0
mg/ml) and Eicosane (2 mg/ml) in ODCB. Temperature is calibrated by
adjusting elution heating rate so that NIST linear polyethylene
1475a has a peak temperature at 101.0.degree. C., and Eicosane has
a peak temperature of 30.0.degree. C. The CEF column resolution is
calculated with a mixture of NIST linear polyethylene 1475a (1.0
mg/ml) and hexacontane (Fluka, purum, >97.0, 1 mg/ml). A
baseline separation of hexacontane and NIST polyethylene 1475a is
achieved. The area of hexacontane (from 35.0 to 67.0.degree. C.) to
the area of NIST 1475a from 67.0 to 110.0.degree. C. is 50 to 50,
the amount of soluble fraction below 35.0.degree. C. is <1.8 wt
%. The CEF column resolution is defined in the following
equation:
Resolution = Peak temperature of NIST 1475 a - Peak Temperature of
Hexacontane Half - height Width of NIST 1475 a + Half - height
Width of Hexacontane ##EQU00001##
[0019] where the column resolution is 6.0.
[0020] Density is measured in accordance with ASTM D 792 with
values reported in grams per cubic centimeter, g/cc.
[0021] Differential Scanning Calorimetry (DSC). Differential
Scanning Calorimetry (DSC) is used to measure the melting and
crystallization behavior of a polymer over a wide range of
temperatures. For example, the TA Instruments Q1000 DSC, equipped
with an RCS (refrigerated cooling system) and an autosampler is
used to perform this analysis. During testing, a nitrogen purge gas
flow of 50 ml/min is used. Each sample is melt pressed into a thin
film at about 175.degree. C.; the melted sample is then air-cooled
to room temperature (approx. 25.degree. C.). The film sample is
formed by pressing a "0.1 to 0.2 gram" sample at 175.degree. C. at
1,500 psi, and 30 seconds, to form a "0.1 to 0.2 mil thick" film. A
3-10 mg, 6 mm diameter specimen is extracted from the cooled
polymer, weighed, placed in a light aluminum pan (ca 50 mg), and
crimped shut. Analysis is then performed to determine its thermal
properties. The thermal behavior of the sample is determined by
ramping the sample temperature up and down to create a heat flow
versus temperature profile. First, the sample is rapidly heated to
180.degree. C., and held isothermal for five minutes, in order to
remove its thermal history. Next, the sample is cooled to
-40.degree. C., at a 10.degree. C./minute cooling rate, and held
isothermal at -40.degree. C. for five minutes. The sample is then
heated to 150.degree. C. (this is the "second heat" ramp) at a
10.degree. C./minute heating rate. The cooling and second heating
curves are recorded. The cool curve is analyzed by setting baseline
endpoints from the beginning of crystallization to -20.degree. C.
The heat curve is analyzed by setting baseline endpoints from
-20.degree. C. to the end of melt. The values determined are peak
melting temperature (Tm), peak crystallization temperature (Tc),
onset crystallization temperature (Tc onset), heat of fusion (Hf)
(in Joules per gram), the calculated % crystallinity for
polyethylene samples using: % Crystallinity for PE=((Hf)/(292
J/g)).times.100, and the calculated % crystallinity for
polypropylene samples using: % Crystallinity for PP=((Hf)/165
J/g)).times.100. The heat of fusion (Hf) and the peak melting
temperature are reported from the second heat curve. Peak
crystallization temperature and onset crystallization temperature
are determined from the cooling curve.
[0022] Elastic Recovery. Resin pellets are compression molded
following ASTM D4703, Annex A1, Method C to a thickness of
approximately 5-10 mil. Microtensile test specimens of geometry as
detailed in ASTM D1708 are punched out from the molded sheet. The
test specimens are conditioned for 40 hours prior to testing in
accordance with Procedure A of Practice D618.
[0023] The samples are tested in a screw-driven or
hydraulically-driven tensile tester using flat, rubber faced grips.
The grip separation is set at 22 mm, equal to the gauge length of
the microtensile specimens. The sample is extended to a strain of
100% at a rate of 100%/min and held for 30 s. The crosshead is then
returned to the original grip separation at the same rate and held
for 60 s. The sample is then strained to 100% at the same 100%/min
strain rate.
[0024] Elastic recovery may be calculated as follows:
Elastic Recovery = ( Initial Applied Strain - Permanent Set )
Initial Applied Strain .times. 100 % ##EQU00002##
[0025] An "ethylene-based polymer" is a polymer that contains more
than 50 weight percent polymerized ethylene monomer (based on the
total weight of polymerizable monomers) and, optionally, may
contain at least one comonomer. Ethylene-based polymer includes
ethylene homopolymer, and ethylene copolymer (meaning units derived
from ethylene and one or more comonomers). The terms
"ethylene-based polymer" and "polyethylene" may be used
interchangeably. Nonlimiting examples of ethylene-based polymer
(polyethylene) include low density polyethylene (LDPE) and linear
polyethylene. Nonlimiting examples of linear polyethylene include
linear low density polyethylene (LLDPE), ultra low density
polyethylene (ULDPE), very low density polyethylene (VLDPE),
multi-component ethylene-based copolymer (EPE),
ethylene/.alpha.-olefin multi-block copolymers (also known as
olefin block copolymer (OBC)), single-site catalyzed linear low
density polyethylene (m-LLDPE), substantially linear, or linear,
plastomers/elastomers, and high density polyethylene (HDPE).
Generally, polyethylene may be produced in gas-phase, fluidized bed
reactors, liquid phase slurry process reactors, or liquid phase
solution process reactors, using a heterogeneous catalyst system,
such as Ziegler-Natta catalyst, a homogeneous catalyst system,
comprising Group 4 transition metals and ligand structures such as
metallocene, non-metallocene metal-centered, heteroaryl,
heterovalent aryloxyether, phosphinimine, and others. Combinations
of heterogeneous and/or homogeneous catalysts also may be used in
either single reactor or dual reactor configurations.
[0026] "High density polyethylene" (or "HDPE") is an ethylene
homopolymer or an ethylene/.alpha.-olefin copolymer with at least
one C.sub.4-C.sub.10 .alpha.-olefin comonomer, or C.sub.4-C.sub.8
.alpha.-olefin comonomer and a density from greater than 0.94 g/cc,
or 0.945 g/cc, or 0.95 g/cc, or 0.955 g/cc to 0.96 g/cc, or 0.97
g/cc, or 0.98 g/cc. The HDPE can be a monomodal copolymer or a
multimodal copolymer. A "monomodal ethylene copolymer" is an
ethylene/C.sub.4-C.sub.10 .alpha.-olefin copolymer that has one
distinct peak in a gel permeation chromatography (GPC) showing the
molecular weight distribution. A "multimodal ethylene copolymer" is
an ethylene/C.sub.4-C.sub.10 .alpha.-olefin copolymer that has at
least two distinct peaks in a GPC showing the molecular weight
distribution. Multimodal includes copolymer having two peaks
(bimodal) as well as copolymer having more than two peaks.
Nonlimiting examples of HDPE include DOW.TM. High Density
Polyethylene (HDPE) Resins (available from The Dow Chemical
Company), ELITE.TM. Enhanced Polyethylene Resins (available from
The Dow Chemical Company), CONTINUUM.TM. Bimodal Polyethylene
Resins (available from The Dow Chemical Company), LUPOLEN.TM.
(available from LyondellBasell), as well as HDPE products from
Borealis, Ineos, and ExxonMobil.
[0027] An "interpolymer" is a polymer prepared by the
polymerization of at least two different monomers. This generic
term includes copolymers, usually employed to refer to polymers
prepared from two different monomers, and polymers prepared from
more than two different monomers, e.g., terpolymers, tetrapolymers,
etc.
[0028] "Low density polyethylene" (or "LDPE") consists of ethylene
homopolymer, or ethylene/.alpha.-olefin copolymer comprising at
least one C.sub.3-C.sub.10 .alpha.-olefin, preferably
C.sub.3-C.sub.4 that has a density from 0.915 g/cc to 0.940 g/cc
and contains long chain branching with broad MWD. LDPE is typically
produced by way of high pressure free radical polymerization
(tubular reactor or autoclave with free radical initiator).
Nonlimiting examples of LDPE include MarFlex.TM. (Chevron
Phillips), LUPOLEN.TM. (LyondellBasell), as well as LDPE products
from Borealis, Ineos, ExxonMobil, and others.
[0029] "Linear low density polyethylene" (or "LLDPE") is a linear
ethylene/.alpha.-olefin copolymer containing heterogeneous
short-chain branching distribution comprising units derived from
ethylene and units derived from at least one C.sub.3-C.sub.10
.alpha.-olefin comonomer or at least one C.sub.4-C.sub.8
.alpha.-olefin comonomer, or at least one C.sub.6-C.sub.8
.alpha.-olefin comonomer. LLDPE is characterized by little, if any,
long chain branching, in contrast to conventional LDPE. LLDPE has a
density from 0.910 g/cc, or 0.915 g/cc, or 0.920 g/cc, or 0.925
g/cc to 0.930 g/cc, or 0.935 g/cc, or 0.940 g/cc. Nonlimiting
examples of LLDPE include TUFLIN.TM. linear low density
polyethylene resins (available from The Dow Chemical Company),
DOWLEX.TM. polyethylene resins (available from the Dow Chemical
Company), and MARLEX.TM. polyethylene (available from Chevron
Phillips).
[0030] "Ultra low density polyethylene" (or "ULDPE") and "very low
density polyethylene" (or "VLDPE") each is a linear
ethylene/.alpha.-olefin copolymer containing heterogeneous
short-chain branching distribution comprising units derived from
ethylene and units derived from at least one C.sub.3-C.sub.10
.alpha.-olefin comonomer, or at least one C.sub.4-C.sub.8
.alpha.-olefin comonomer, or at least one C.sub.6-C.sub.8
.alpha.-olefin comonomer. ULDPE and VLDPE each has a density from
0.885 g/cc, or 0.90 g/cc to 0.915 g/cc. Nonlimiting examples of
ULDPE and VLDPE include ATTANE.TM. ultra low density polyethylene
resins (available form The Dow Chemical Company) and FLEXOMER.TM.
very low density polyethylene resins (available from The Dow
Chemical Company).
[0031] "Multi-component ethylene-based copolymer" (or "EPE")
comprises units derived from ethylene and units derived from at
least one C.sub.3-C.sub.10 .alpha.-olefin comonomer, or at least
one C.sub.4-C.sub.8 .alpha.-olefin comonomer, or at least one
C.sub.6-C.sub.8 .alpha.-olefin comonomer, such as described in
patent references U.S. Pat. Nos. 6,111,023; 5,677,383; and
6,984,695. EPE resins have a density from 0.905 g/cc, or 0.908
g/cc, or 0.912 g/cc, or 0.920 g/cc to 0.926 g/cc, or 0.929 g/cc, or
0.940 g/cc, or 0.962 g/cc. Nonlimiting examples of EPE resins
include ELITE.TM. enhanced polyethylene (available from The Dow
Chemical Company), ELITE AT.TM. advanced technology resins
(available from The Dow Chemical Company), SURPASS.TM. Polyethylene
(PE) Resins (available from Nova Chemicals), and SMART.TM.
(available from SK Chemicals Co.).
[0032] "Single-site catalyzed linear low density polyethylenes" (or
"m-LLDPE") are linear ethylene/.alpha.-olefin copolymers containing
homogeneous short-chain branching distribution comprising units
derived from ethylene and units derived from at least one
C.sub.3-C.sub.10 .alpha.-olefin comonomer, or at least one
C.sub.4-C.sub.8 .alpha.-olefin comonomer, or at least one
C.sub.6-C.sub.8 .alpha.-olefin comonomer. m-LLDPE has density from
0.913 g/cc, or 0.918 g/cc, or 0.920 g/cc to 0.925 g/cc, or 0.940
g/cc. Nonlimiting examples of m-LLDPE include EXCEED.TM.
metallocene PE (available from ExxonMobil Chemical), LUFLEXEN.TM.
m-LLDPE (available from LyondellBasell), and ELTEX.TM. PF m-LLDPE
(available from Ineos Olefins & Polymers).
[0033] "Ethylene plastomers/elastomers" are substantially linear,
or linear, ethylene/.alpha.-olefin copolymers containing
homogeneous short-chain branching distribution comprising units
derived from ethylene and units derived from at least one
C.sub.3-C.sub.10 .alpha.-olefin comonomer, or at least one
C.sub.4-C.sub.8 .alpha.-olefin comonomer, or at least one
C.sub.6-C.sub.8 .alpha.-olefin comonomer. Ethylene
plastomers/elastomers have a density from 0.870 g/cc, or 0.880
g/cc, or 0.890 g/cc to 0.900 g/cc, or 0.902 g/cc, or 0.904 g/cc, or
0.909 g/cc, or 0.910 g/cc, or 0.917 g/cc. Nonlimiting examples of
ethylene plastomers/elastomers include AFFINITY.TM. plastomers and
elastomers (available from The Dow Chemical Company), EXACT.TM.
Plastomers (available from ExxonMobil Chemical), Tafmer.TM.
(available from Mitsui), Nexlene.TM. (available from SK Chemicals
Co.), and Lucene.TM. (available LG Chem Ltd.).
[0034] Melt flow rate (MFR) is measured in accordance with ASTM D
1238, Condition 280.degree. C./2.16 kg (g/10 minutes).
[0035] Melt index (MI) is measured in accordance with ASTM D 1238,
Condition 190.degree. C./2.16 kg (g/10 minutes).
[0036] "Melting Point" or "Tm" as used herein (also referred to as
a melting peak in reference to the shape of the plotted DSC curve)
is typically measured by the DSC (Differential Scanning
Calorimetry) technique for measuring the melting points or peaks of
polyolefins as described in U.S. Pat. No. 5,783,638. It should be
noted that many blends comprising two or more polyolefins will have
more than one melting point or peak, many individual polyolefins
will comprise only one melting point or peak.
[0037] Molecular weight distribution (Mw/Mn) is measured using Gel
Permeation Chromatography (GPC). In particular, conventional GPC
measurements are used to determine the weight-average (Mw) and
number-average (Mn) molecular weight of the polymer and to
determine the Mw/Mn. The gel permeation chromatographic system
consists of either a Polymer Laboratories Model PL-210 or a Polymer
Laboratories Model PL-220 instrument. The column and carousel
compartments are operated at 140.degree. C. Three Polymer
Laboratories 10-micron Mixed-B columns are used. The solvent is
1,2,4 trichlorobenzene. The samples are prepared at a concentration
of 0.1 grams of polymer in 50 milliliters of solvent containing 200
ppm of butylated hydroxytoluene (BHT). Samples are prepared by
agitating lightly for 2 hours at 160.degree. C. The injection
volume used is 100 microliters and the flow rate is 1.0
ml/minute.
[0038] Calibration of the GPC column set is performed with 21
narrow molecular weight distribution polystyrene standards with
molecular weights ranging from 580 to 8,400,000, arranged in 6
"cocktail" mixtures with at least a decade of separation between
individual molecular weights. The standards are purchased from
Polymer Laboratories (Shropshire, UK). The polystyrene standards
are prepared at 0.025 grams in 50 milliliters of solvent for
molecular weights equal to or greater than 1,000,000, and 0.05
grams in 50 milliliters of solvent for molecular weights less than
1,000,000. The polystyrene standards are dissolved at 80.degree. C.
with gentle agitation for 30 minutes. The narrow standards mixtures
are run first and in order of decreasing highest molecular weight
component to minimize degradation. The polystyrene standard peak
molecular weights are converted to polyethylene molecular weights
using the following equation (as described in Williams and Ward, J.
Polym. Sci., Polym. Let., 6, 621 (1968)):
M.sub.polypropylene=0.645(M.sub.polystyrene).
[0039] Polypropylene equivalent molecular weight calculations are
performed using Viscotek TriSEC software Version 3.0.
[0040] An "olefin-based polymer," as used herein, is a polymer that
contains more than 50 weight percent polymerized olefin monomer
(based on total amount of polymerizable monomers), and optionally,
may contain at least one comonomer. Nonlimiting examples of
olefin-based polymer include ethylene-based polymer and
propylene-based polymer.
[0041] A "polymer" is a compound prepared by polymerizing monomers,
whether of the same or a different type, that in polymerized form
provide the multiple and/or repeating "units" or "mer units" that
make up a polymer. The generic term polymer thus embraces the term
homopolymer, usually employed to refer to polymers prepared from
only one type of monomer, and the term copolymer, usually employed
to refer to polymers prepared from at least two types of monomers.
It also embraces all forms of copolymer, e.g., random, block, etc.
The terms "ethylene/.alpha.-olefin polymer" and
"propylene/.alpha.-olefin polymer" are indicative of copolymer as
described above prepared from polymerizing ethylene or propylene
respectively and one or more additional, polymerizable
.alpha.-olefin monomer. It is noted that although a polymer is
often referred to as being "made of" one or more specified
monomers, "based on" a specified monomer or monomer type,
"containing" a specified monomer content, or the like, in this
context the term "monomer" is understood to be referring to the
polymerized remnant of the specified monomer and not to the
unpolymerized species. In general, polymers herein are referred to
has being based on "units" that are the polymerized form of a
corresponding monomer.
[0042] A "propylene-based polymer" is a polymer that contains more
than 50 weight percent polymerized propylene monomer (based on the
total amount of polymerizable monomers) and, optionally, may
contain at least one comonomer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 is an exploded perspective view of a packaging
article in accordance with an embodiment of the present
disclosure.
[0044] FIG. 1A is an enlarged perspective view of Area 1A of FIG.
1.
[0045] FIG. 2 is a perspective view of the packaging article of
FIG. 1.
[0046] FIG. 2A is a sectional view taken along line 2A-2A of FIG.
2.
[0047] FIG. 3 is an exploded perspective view of a packaging
article in accordance with another embodiment of the present
disclosure.
[0048] FIG. 4 is a perspective view of the packaging article of
FIG. 3.
[0049] FIG. 4A is a sectional view taken along line 4A-4A of FIG.
4.
[0050] FIG. 5 is a perspective view of a packaging article in
accordance with another embodiment of the present disclosure.
[0051] FIG. 5A is a sectional view taken along line 5A-5A of FIG.
5.
DETAILED DESCRIPTION
[0052] The present disclosure provides a packaging article. In an
embodiment, the packaging article includes (A) a rigid container
having side walls and a bottom wall. The walls define a
compartment. The packaging article also includes (B) a sheet of
3-dimensional random loop material (3DRLM) in the compartment.
A. Container
[0053] Referring to the drawings and initially to FIGS. 1-2, a
packaging article is indicated generally by the reference numeral
10. The packaging article 10 includes a container 12. The container
12 includes sidewalls 14, a bottom wall 16 and an optional top wall
18. The sidewalls 14 extend between the bottom wall 16 and an
optional top wall 18. Although FIG. 1 shows container 12 with four
sidewalls 14, it is understood that the container can have from,
three, or four, to five, or six, or seven, or eight, or more
sidewalls.
[0054] The top wall 18 is optional. The container 12 can have an
open top-void of a top wall. When the top wall is present, the top
wall 18 may or may not be attached to one or more sidewalls.
[0055] In an embodiment, the top wall is present and the top wall
is a discrete stand-alone component, that is placed on the
sidewalls, forming a closed compartment (along with the bottom
wall). Attachment between the stand-alone top wall may be by way of
snap-fit, friction-fit, and combinations thereof.
[0056] In an embodiment, the top wall 18 is present and is hingedly
attached to a sidewall 14, to provide a clamshell container as
shown in FIGS. 1-2. A "clamshell container" is a rigid container
with a top portion (top wall 18 wall) and a bottom portion (walls
14-16), the top portion heat formed to the bottom portion by way of
a hinge 19. Clamshell containers are popular because they are
inexpensive, versatile, provide excellent protection to food items
such as produce, and present a pleasing consumer package. Clamshell
containers are most often used with consumer packs of high value
produce items like small fruit, berries, mushrooms, etc., or items
that are easily damaged by crushing. Clamshells containers are used
extensively with precut produce and prepared salads.
[0057] The walls 14-16 (an optionally top wall 18) form a
compartment 20. The compartment 20 is accessible by removing the
top wall 18 (when present) from the sidewalls 14.
[0058] The walls 14-18 are made of a rigid material. Nonlimiting
examples of suitable material for the walls 14-18 include
cardboard, corrugated cardboard, polymeric material, metal, wood,
fiberglass, insulative material, and any combination thereof.
[0059] The container may comprise two or more embodiments disclosed
herein.
B. Sheet of 3-Dimensional Random Loop Material
[0060] The packaging article 10 includes at least one sheet 22 of a
3-dimensional random loop material 30. As shown in FIG. 1A, a
"3-dimensional random loop material" (or "3DRLM") is a mass or a
structure of a multitude of loops 32 formed by allowing continuous
fibers 34, to wind, permitting respective loops to come in contact
with one another in a molten state and to be heat-bonded, or
otherwise melt-bonded, at most of the contact points 36. Even when
a great stress to cause significant deformation is given, the 3DRLM
30 absorbs the stress with the entire net structure composed of
three-dimensional random loops melt-integrated, by deforming
itself; and once the stress is lifted, elastic resilience of the
polymer manifests itself to allow recovery to the original shape of
the structure. When a net structure composed of continuous fibers
made from a known non-elastic polymer is used as a cushioning
material, plastic deformation is developed and the recovery cannot
be achieved, thus resulting in poor heat-resisting durability. When
the fibers are not melt-bonded at contact points, the shape cannot
be retained and the structure does not integrally change its shape,
with the result that a fatigue phenomenon occurs due to the
concentration of stress, thus unbeneficially degrading durability
and deformation resistance. In certain embodiments, melt-bonding is
the state where all contact points are melt-bonded.
[0061] A nonlimiting method for producing 3DRLM 30 includes the
steps of (a) heating a molten olefin-based polymer, at a
temperature 10.degree. C.-140.degree. C. higher than the melting
point of the polymer in a typical melt-extruder; (b) discharging
the molten interpolymer to the downward direction from a nozzle
with plural orifices to form loops by allowing the fibers to fall
naturally (due to gravity). The polymer may be used in combination
with a thermoplastic elastomer, thermoplastic non-elastic polymer
or a combination thereof. The distance between the nozzle surface
and take-off conveyors installed on a cooling unit for solidifying
the fibers, melt viscosity of the polymer, diameter of orifice and
the amount to be discharged are the elements which decide loop
diameter and fineness of the fibers. Loops are formed by holding
and allowing the delivered molten fibers to reside between a pair
of take-off conveyors (belts, or rollers) set on a cooling unit
(the distance therebetween being adjustable), bringing the loops
thus formed into contact with one another by adjusting the distance
between the orifices to this end such that the loops in contact are
heat-bonded, or otherwise melt-bonded, as they form a
three-dimensional random loop structure. Then, the continuous
fibers, wherein contact points have been heat-bonded as the loops
form a three-dimensional random loop structure, are continuously
taken into a cooling unit for solidification to give a net
structure. Thereafter, the structure is cut into a desired length
and shape. The method is characterized in that the olefin-based
polymer is melted and heated at a temperature 10.degree.
C.-140.degree. C. higher than the melting point of the interpolymer
and delivered to the downward direction in a molten state from a
nozzle having plural orifices. When the polymer is discharged at a
temperature less than 10.degree. C. higher than the melting point,
the fiber delivered becomes cool and less fluidic to result in
insufficient heat-bonding of the contact points of fibers.
[0062] Properties, such as, the loop diameter and fineness of the
fibers constituting the cushioning net structure provided herein
depend on the distance between the nozzle surface and the take-off
conveyor installed on a cooling unit for solidifying the
interpolymer, melt viscosity of the interpolymer, diameter of
orifice and the amount of the interpolymer to be delivered
therefrom. For example, a decreased amount of the interpolymer to
be delivered and a lower melt viscosity upon delivery result in
smaller fineness of the fibers and smaller average loop diameter of
the random loop. On the contrary, a shortened distance between the
nozzle surface and the take-off conveyor installed on the cooling
unit for solidifying the interpolymer results in a slightly greater
fineness of the fiber and a greater average loop diameter of the
random loop. These conditions in combination afford the desirable
fineness of the continuous fibers of from 100 denier to 100000
denier and an average diameter of the random loop of not more than
100 mm, or from 1 millimeter (mm), or 2 mm, or 10 mm to 25 mm, or
50 mm. By adjusting the distance to the aforementioned conveyor,
the thickness of the structure can be controlled while the
heat-bonded net structure is in a molten state and a structure
having a desirable thickness and flat surface formed by the
conveyors can be obtained. Too great a conveyor speed results in
failure to heat-bond the contact points, since cooling proceeds
before the heat-bonding. On the other hand, too slow a speed can
cause higher density resulting from excessively long dwelling of
the molten material. In some embodiments the distance to the
conveyor and the conveyor speed should be selected such that the
desired apparent density of 0.005-0.1 g/cc or 0.01-0.05 g/cc can be
achieved.
[0063] In an embodiment, the 3DRLM 30 has, one, some, or all of the
properties (i)-(iii) below:
[0064] (i) an apparent density from 0.016 g/cc, or 0.024 g/cc, or
0.032 g/cc, or 0.040 g/cc, or 0.050 g/cc, or 0.060 to 0.070, or
0.080, or 0.090, or 0.100, or 0.150; and/or
[0065] (ii) a fiber diameter from 0.1 mm, or 0.5 mm, or 0.7 mm, or
1.0 mm or 1.5 mm to 2.0 mm to 2.5 mm, or 3.0 mm; and/or
[0066] (iii) a thickness (machine direction) from 1.0 cm, 2.0 cm,
or 3.0, cm, or 4.0 cm, or 5.0 cm, or 10 cm, or 20 cm, to 50 cm, or
75 cm, or 100 cm, or more. It is understood that the thickness of
the 3DRLM 30 will vary based on the type of product to be
packaged.
[0067] The 3DRLM 30 is formed into a three dimensional geometric
shape to form a sheet (i.e., a prism). The 3DRLM 30 is an elastic
material which can be compressed and stretched and return to its
original geometric shape. An "elastic material," as used herein, is
a rubber-like material that can be compressed and/or stretched and
which expands/retracts very rapidly to approximately its original
shape/length when the force exerting the compression and/or the
stretching is released. The three dimensional random loop material
30 has a "neutral state" when no compressive force and no stretch
force is imparted upon the 3DRLM 30. The three dimensional random
loop material 30 has "a compressed state" when a compressive force
is imparted upon the 3DRLM 30. The three dimensional random loop
material 30 has "a stretched state" when a stretching force is
imparted upon the 3DRLM 30.
[0068] The three dimensional random loop material 30 is composed of
one or more olefin-based polymers. The olefin-based polymer can be
one or more ethylene-based polymers, one or more propylene-based
polymers, and blends thereof.
[0069] In an embodiment, the ethylene-based polymer is an
ethylene/.alpha.-olefin polymer. Ethylene/.alpha.-olefin polymer
may be a random ethylene/.alpha.-olefin polymer or an
ethylene/.alpha.-olefin multi-block polymer. The .alpha.-olefin is
a C.sub.3-C.sub.20 .alpha.-olefin, or a C.sub.4-C.sub.12
.alpha.-olefin, or a C.sub.4-C.sub.8 .alpha.-olefin. Nonlimiting
examples of suitable .alpha.-olefin comonomer include propylene,
butene, methyl-1-pentene, hexene, octene, decene, dodecene,
tetradecene, hexadecene, octadecene, cyclohexyl-1-propene (allyl
cyclohexane), vinyl cyclohexane, and combinations thereof.
[0070] In an embodiment, the ethylene-based polymer is a
homogeneously branched random ethylene/.alpha.-olefin
copolymer.
[0071] "Random copolymer" is a copolymer wherein the at least two
different monomers are arranged in a non-uniform order. The term
"random copolymer" specifically excludes block copolymers. The term
"homogeneous ethylene polymer" as used to describe ethylene
polymers is used in the conventional sense in accordance with the
original disclosure by Elston in U.S. Pat. No. 3,645,992, the
disclosure of which is incorporated herein by reference, to refer
to an ethylene polymer in which the comonomer is randomly
distributed within a given polymer molecule and wherein
substantially all of the polymer molecules have substantially the
same ethylene to comonomer molar ratio. As defined herein, both
substantially linear ethylene polymers and homogeneously branched
linear ethylene are homogeneous ethylene polymers.
[0072] The homogeneously branched random ethylene/.alpha.-olefin
copolymer may be a random homogeneously branched linear
ethylene/.alpha.-olefin copolymer or a random homogeneously
branched substantially linear ethylene/.alpha.-olefin copolymer.
The term "substantially linear ethylene/.alpha.-olefin copolymer"
means that the polymer backbone is substituted with from 0.01 long
chain branches/1000 carbons to 3 long chain branches/1000 carbons,
or from 0.01 long chain branches/1000 carbons to 1 long chain
branches/1000 carbons, or from 0.05 long chain branches/1000
carbons to 1 long chain branches/1000 carbons. In contrast, the
term "linear ethylene/.alpha.-olefin copolymer" means that the
polymer backbone has no long chain branching.
[0073] The homogeneously branched random ethylene/.alpha.-olefin
copolymers may have the same ethylene/.alpha.-olefin comonomer
ratio within all copolymer molecules. The homogeneity of the
copolymers may be described by the SCBDI (Short Chain Branch
Distribution Index) or CDBI (Composition Distribution Branch Index)
and is defined as the weight percent of the polymer molecules
having a comonomer content within 50 percent of the median total
molar comonomer content. The CDBI of a polymer is readily
calculated from data obtained from techniques known in the art,
such as, for example, temperature rising elution fractionation
(abbreviated herein as "TREF") as described in U.S. Pat. No.
4,798,081 (Hazlitt et al.), or in U.S. Pat. No. 5,089,321 (Chum et
al.) the disclosures of all of which are incorporated herein by
reference. The SCBDI or CDBI for the homogeneously branched random
ethylene/.alpha.-olefin copolymers is preferably greater than about
30 percent, or greater than about 50 percent.
[0074] The homogeneously branched random ethylene/.alpha.-olefin
copolymer may include at least one ethylene comonomer and at least
one C.sub.3-C.sub.20 .alpha.-olefin, or at least one
C.sub.4-C.sub.12 .alpha.-olefin comonomer. For example and not by
way of limitation, the C.sub.3-C.sub.20 .alpha.-olefins may include
but are not limited to propylene, isobutylene, 1-butene, 1-hexene,
4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, and 1-decene,
or, in some embodiments, 1-butene, 1-hexene, 4-methyl-1-pentene and
1-octene.
[0075] The homogeneously branched random ethylene/.alpha.-olefin
copolymer may have one, some, or all of the following properties
(i)-(iii) below:
[0076] (i) a melt index (1.sub.2) from 1 g/10 min, or 5 g/10 min,
or 10 g/10 min, or 20 g/10 min to 30 g/10 min, or 40 g/10 min, or
50 g/10 min, and/or
[0077] (ii) a density from 0.075 g/cc, or 0.880 g/cc, or 0.890 g/cc
to 0.90 g/cc, or 0.91 g/cc, or 0.920 g/cc, or 0.925 g/cc;
and/or
[0078] (iii) a molecular weight distribution (Mw/Mn) from 2.0, or
2.5, or 3.0 to 3.5, or 4.0.
[0079] In an embodiment, the ethylene-based polymer is a
heterogeneously branched random ethylene/.alpha.-olefin
copolymer.
[0080] The heterogeneously branched random ethylene/.alpha.-olefin
copolymers differ from the homogeneously branched random
ethylene/.alpha.-olefin copolymers primarily in their branching
distribution. For example, heterogeneously branched random
ethylene/.alpha.-olefin copolymers have a distribution of
branching, including a highly branched portion (similar to a very
low density polyethylene), a medium branched portion (similar to a
medium branched polyethylene) and an essentially linear portion
(similar to linear homopolymer polyethylene).
[0081] Like the homogeneously branched random
ethylene/.alpha.-olefin copolymer, the heterogeneously branched
random ethylene/.alpha.-olefin copolymer may include at least one
ethylene comonomer and at least one C.sub.3-C.sub.20 .alpha.-olefin
comonomer, or at least one C.sub.4-C.sub.12 .alpha.-olefin
comonomer. For example and not by way of limitation, the
C.sub.3-C.sub.20 .alpha.-olefins may include but are not limited
to, propylene, isobutylene, 1-butene, 1-hexene, 4-methyl-1-pentene,
1-heptene, 1-octene, 1-nonene, and 1-decene, or, in some
embodiments, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.
In one embodiment, the heterogeneously branched
ethylene/.alpha.-olefin copolymer may comprise greater than about
50% by wt ethylene comonomer, or greater than about 60% by wt., or
greater than about 70% by wt. Similarly, the heterogeneously
branched ethylene/.alpha.-olefin copolymer may comprise less than
about 50% by wt .alpha.-olefin monomer, or less than about 40% by
wt., or less than about 30% by wt.
[0082] The heterogeneously branched random ethylene/.alpha.-olefin
copolymer may have one, some, or all of the following properties
(i)-(iii) below:
[0083] (i) a density from 0.900 g/cc, or 0.0910 g/cc, or 0.920 g/cc
to 0.930 g/cc, or 0.094 g/cc;
[0084] (ii) a melt index (I.sub.2) from 1 g/10 min, or 5 g/10 min,
or 10 g/10 min, or 20 g/10 min to 30 g/10 min, or 40 g/10 min, or
50 g/10 min; and/or
[0085] (iii) an Mw/Mn from 3.0, or 3.5 to 4.0, or 4.5.
[0086] In an embodiment, the 3DRLM 30 is composed of a blend of a
homogeneously branched random ethylene/.alpha.-olefin copolymer and
a heterogeneously branched ethylene/.alpha.-olefin copolymer, the
blend having one, some, or all of the properties (i)-(v) below:
[0087] (i) a Mw/Mn from 2.5, or 3.0 to 3.5, or 4.0, or 4.5;
[0088] (ii) a melt index (I.sub.2) from 3.0 g/10 min, or 4.0 g/10
min, or 5.0 g/10 min, or 10 g/10 min to 15 g/10 min, or 20 g/10
min, or 25 g/10 min;
[0089] (iii) a density from 0.895 g/cc, or 0.900 g/cc, or 0.910
g/cc, or 0.915 g/cc to 0.920 g/cc, or 0.925 g/cc; and or
[0090] (iv) an I.sub.10/I.sub.2 ratio from 5 g/10 min, or 7 g/10
min to 10 g/10 min, or 15 g/10 min; and/or
[0091] (v) a percent crystallinity from 25%, or 30%, or 35%, or 40%
to 45%, or 50%, or 55%.
[0092] According to Crystallization Elution Fractionation (CEF),
the ethylene/.alpha.-olefin copolymer blend may have a weight
fraction in a temperature zone from 90.degree. C. to 115.degree. C.
or about 5% to about 15% by wt., or about 6% to about 12%, or about
8% to about 12%, or greater than about 8%, or greater than about
9%. Additionally, as detailed below, the copolymer blend may have a
Comonomer Distribution Constant (CDC) of at least about 100, or at
least about 110.
[0093] The present ethylene/.alpha.-olefin copolymer blend may have
at least two, or three melting peaks when measured using
Differential Scanning Calorimetry (DSC) below a temperature of
130.degree. C. In one or more embodiments, the
ethylene/.alpha.-olefin copolymer blend may include a highest
temperature melting peak of at least 115.degree. C., or at least
120.degree. C., or from about 120.degree. C. to about 125.degree.
C., or from about from 122 to about 124.degree. C. Without being
bound by theory, the heterogeneously branched
ethylene/.alpha.-olefin copolymer is characterized by two melting
peaks, and the homogeneously branched ethylene/.alpha.-olefin
copolymer is characterized by one melting peak, thus making up the
three melting peaks.
[0094] Additionally, the ethylene/.alpha.-olefin copolymer blend
may comprise from about 10 to about 90% by weight, or about 30 to
about 70% by weight, or about 40 to about 60% by weight of the
homogeneously branched ethylene/.alpha.-olefin copolymer.
Similarly, the ethylene/.alpha.-olefin copolymer blend may comprise
from about 10 to about 90% by weight, about 30 to about 70% by
weight, or about 40 to about 60% by weight of the heterogeneously
branched ethylene/.alpha.-olefin copolymer. In a specific
embodiment, the ethylene/.alpha.-olefin copolymer blend may
comprise from about 50% to about 60% by weight of the homogeneously
branched ethylene/.alpha.-olefin copolymer, and 40% to about 50% of
the heterogeneously branched ethylene/.alpha.-olefin copolymer.
[0095] Moreover, the strength of the ethylene/.alpha.-olefin
copolymer blend may be characterized by one or more of the
following metrics. One such metric is elastic recovery. Here, the
ethylene/.alpha.-olefin copolymer blend has an elastic recovery,
Re, in percent at 100 percent strain at 1 cycle of between 50-80%.
Additional details regarding elastic recovery are provided in U.S.
Pat. No. 7,803,728, which is incorporated by reference herein in
its entirety.
[0096] The ethylene/.alpha.-olefin copolymer blend may also be
characterized by its storage modulus. In some embodiments, the
ethylene/.alpha.-olefin copolymer blend may have a ratio of storage
modulus at 25.degree. C., G' (25.degree. C.) to storage modulus at
100.degree. C., G' (100.degree. C.) of about 20 to about 60, or
from about 20 to about 50, or about 30 to about 50, or about 30 to
about 40.
[0097] Moreover, the ethylene/.alpha.-olefin copolymer blend may
also be characterized by a bending stiffness of at least about 1.15
Nmm at 6 s, or at least about 1.20 Nmm at 6 s, or at least about
1.25 Nmm at 6 s, or at least about 1.35 Nmm at 6 s. Without being
bound by theory, it is believed that these stiffness values
demonstrate how the ethylene/.alpha.-olefin copolymer blend will
provide cushioning support when incorporated into 3DRLM fibers
bonded to form a cushioning net structure.
[0098] In an embodiment, the ethylene-based polymer is an
ethylene/.alpha.-olefin interpolymer composition having one, some,
or all of the following properties (i)-(v) below:
[0099] (i) a highest DSC temperature melting peak from 90.0.degree.
C. to 115.0.degree. C.; and/or
[0100] (ii) a zero shear viscosity ratio (ZSVR) from 1.40 to 2.10;
and/or
[0101] (iii) a density in the range of from 0.860 to 0.925 g/cc;
and/or
[0102] (iv) a melt index (I.sub.2) from 1 g/10 min to 25 g/10 min;
and/or
[0103] (v) a molecular weight distribution (Mw/Mn) in the range of
from 2.0 to 4.5.
[0104] In an embodiment, the ethylene-based polymer contains a
functionalized commoner such as an ester. The functionalized
comonomer can be an acetate comonomer or an acrylate comonomer.
Nonlimiting examples of suitable ethylene-based polymer with
functionalized comonomer include ethylene vinyl acetate (EVA),
ethylene methyl acrylate EMA, ethylene ethyl acrylate (EEA), and
any combination thereof.
[0105] In an embodiment, the olefin-based polymer is a
propylene-based polymer. The propylene-based polymer can be a
propylene homopolymer or a propylene/.alpha.-olefin polymer. The
.alpha.-olefin is a C.sub.2 .alpha.-olefin (ethylene) or a
C.sub.4-C.sub.12 .alpha.-olefin, or a C.sub.4-C.sub.8
.alpha.-olefin. Nonlimiting examples of suitable .alpha.-olefin
comonomer include ethylene, butene, methyl-1-pentene, hexene,
octene, decene, dodecene, tetradecene, hexadecene, octadecene,
cyclohexyl-1-propene (allyl cyclohexane), vinyl cyclohexane, and
combinations thereof.
[0106] In an embodiment, the propylene interpolymer includes from
82 wt % to 99 wt % units derived from propylene and from 18 wt % to
1 wt % units derived from ethylene, having one, some, or all of the
properties (i)-(vi) below:
[0107] (i) a density of from 0.840 g/cc, or 0.850 g/cc to 0.900
g/cc; and/or
[0108] (ii) a highest DSC melting peak temperature from
50.0.degree. C. to 120.0.degree. C.; and/or
[0109] (iii) a melt flow rate (MFR) from 1 g/10 min, or 2 g/10 min
to 50 g/10 min, or 100 g/10 min; and/or
[0110] (iv) a Mw/Mn of less than 4; and/or
[0111] (v) a percent crystallinity in the range of from 0.5% to
45%; and/or
[0112] (vi) a DSC crystallization onset temperature, Tc-Onset, of
less than 85.degree. C.
[0113] In an embodiment, the olefin-based polymer used in the
manufacture of the 3DRLM 30 contains one or more optional
additives. Nonlimiting examples of suitable additives include
stabilizer, antimicrobial agent, antifungal agent, antioxidant,
processing aid, ultraviolet (UV) stabilizer, slip additive,
antiblocking agent, color pigment or dyes, antistatic agent,
filler, flame retardant, and any combination thereof.
[0114] Returning to FIGS. 1-2, the packaging article 10 includes a
sheet 22 made of 3DRLM 30 (hereafter "sheet 22"). The sheet 22 can
move to/from a compressed state, to/from a neutral state, and
to/from a stretched state. The composition, and/or the size, and/or
the shape of the sheet 22 can be tailored to accommodate the size
and shape of the compartment 20.
[0115] In an embodiment, the sheet 22 extends between and contacts
at least two opposing sidewalls 14 of the container 12. In a
further embodiment, the sheet 22 extends between and contacts four
sidewalls 14. Although FIGS. 1-2 show a single sheet 22, it is
understood two, three, four or more sheets can be placed within the
compartment 20. In addition to lining the bottom wall 16, one or
more additional sheets may line one, some, or all of the sidewalls,
14, for example. Alternatively, a single sheet may be configured to
line each wall--sidewalls 14 and bottom wall 16.
[0116] In an embodiment, sheet 22 is sized and shaped to friction
fit against the four sidewalls 14 and is also sized to line the
bottom wall 16. In a further embodiment, sheet 22 is removable from
the container 10. Sheet 22 is thereby reusable and/or
recyclable.
C. Food Item
[0117] The packaging article 10 includes a food item 24 as shown in
FIGS. 1-2. The food item 24 can be a meat item, a poultry item, a
fish item, a shellfish item, a vegetable item, a fruit item, a
berry item, derivative thereofs (such as slices and/or portions of
the food item), and combinations thereof. Nonlimiting examples of
suitable meat items include beef, pork, lamb, and goat. Nonlimiting
examples of suitable poultry items include chicken, turkey, and
duck. Nonlimiting examples of suitable fish items include tuna,
salmon, pollock, catfish, swordfish, tilapia, and cod. Nonlimiting
examples of suitable shellfish items include shrimp, crab, lobster,
clams, mussels, oysters, and scallops. Nonlimiting examples of
suitable fruit items include cherries, kiwi, peppers and tomatoes.
Nonlimiting examples of suitable vegetable items include celery,
lettuce, cauliflower, broccoli, carrots, and eggplant.
[0118] Nonlimiting examples of suitable berry items include acai
berry, amalika, baneberry, barbados cherry, barberry, bearberry,
bilberry, bittersweet berry, blackberry, blueberry, black mulberry,
boysenberry, buffalo berry, bunchberry, chokeberry, chokecherry,
cloudberry, cowberry, cranberry, currant, dewberry, elderberry,
farkleberry, goji berry, gooseberry, grape, holly berry,
huckleberry, Indian plum, ivy berry, juneberry, juniper berry,
lingonberry, logan berry, mulberry, nannyberry, persimmon,
pokeberry, raspberry, salmonberry, strawberry, sugarberry,
tayberry, thimbleberry, wineberry, wintergreen, an youngberry.
[0119] The food item 24 has a liquid 26 that accumulates on and/or
flows from the food item 24 over time during storage, as shown in
FIG. 2A. The liquid 26 emanates from the food item 24 and thereby
includes components of the food item. Nonlimiting examples of
components of the liquid 26 include water, microorganisms,
proteins, fats, blood, small particles of the food item (water
soluble particles and/or water insoluble particles), juice from the
food item, and combinations thereof.
[0120] The liquid 26 may manifest as a result of injury to one or
more individual pieces of the food item during handling and/or
storage, the injury triggering liquid drainage that emanates from
the food item. Alternatively, the food item may naturally generate
excess liquid over time during storage as is common with fresh cut
meat, raw meat, fresh fish, or chicken, for example. Regardless of
the origin of the liquid 26, it is known that prolonged contact
between the food item 24 and the liquid 26 is detrimental to the
freshness, consumption, and viability of the food item 24. Over
time, microorganism growth in liquid 26 can degrade the food item
24. In sum, contact between the food item 24 and the liquid 26
increases the risk of spoilage to the bulk food item in the
container 12.
[0121] FIGS. 1-2 show the food item as a raspberry 24a. During
processing, handling, and/or storage, one or more individual
raspberries may be injured, causing liquid, in this case raspberry
juice 26a, to drain from the raspberry 24a. The open loop structure
of the 3DRLM 30 enables the liquid 26a to drain through the sheet
22 and away from food item 24a. In this way, the sheet separates
the food item 24a from the liquid 26a thereby advantageously
increasing shelf life of the food item (the raspberries 24a),
reducing spoilage of the food item, and protecting the food item
from the liquid 26a.
[0122] FIG. 2A shows the liquid 26, as raspberry juice 26a, flowing
through the 3DRLM 30. After flowing from the raspberries 24a, and
through the 3DRLM 30, the raspberry juice 26a accumulates on the
bottom wall 16. The sheet 22 (vis-a-vis the open loop structure of
the 3DRLM 30) enables drainage of the raspberry juice 26a from the
raspberries 24a and concomitantly the sheet 22 separates the
raspberries 24a from the raspberry juice 26a accumulated on the
bottom wall 16. The present packaging article provides the
following synergistic advantages: (1) drainage of liquid 26 away
from the food item 24, (2) separation between the food item and the
liquid, and (3) prevention of contact between the food item and the
accumulated liquid on the bottom wall. In this way, the sheet 22
separates the food item 24 from the liquid 26 thereby
advantageously increasing shelf life, reducing spoilage, and
protecting the food item 24 from the liquid 26.
[0123] The sheet 22 may include an optional a coating or a film
layer containing an antimicrobial material that kills
microorganisms or inhibits microbial growth.
[0124] In an embodiment the thickness of the sheet 22 is configured
so that all, or substantially all, of the liquid 26 drained from
the food item 24 during storage remains away from, and out of
contact with, the food item 24. The sheet 22 separates the food
item 24 from the liquid 26 on the bottom wall 16.
[0125] The container 10 may or may not include ports for draining
the liquid from the compartment 20. In an embodiment, the container
10 includes ports 40 for draining, or otherwise removing, the
accumulated liquid from the bottom wall 16.
D. Cold source
[0126] The present disclosure provides another packaging article as
shown in FIGS. 3-5A. In an embodiment, a packaging article 110 is
provided, the packaging article 110 including a container 112
having sidewalls 114 and a bottom wall 116. The walls 114-116
define a compartment 120. The container 112 may include an optional
top wall (not shown). The packaging article includes a sheet 122 of
3DRLM 130 located in the compartment 120.
[0127] In an embodiment, the container 112 is an insulated
container. An "insulated container," as used herein is a container
that that prevents, or reduces, the passage of heat. Nonlimiting
examples of an insulated container include a vacuum flask
(Thermos.TM. bottle), a container with a thermal blanket or a
thermal liner, a molded expanded polystyrene (EPS) container, a
molded polyurethane foam container, a molded polyethylene foam
container, a container with a liner of reflective material
(metallized film), a container with a liner of bubble wrap, and any
combination thereof.
[0128] In an embodiment, the sheet 122 extends between and contacts
at least two opposing sidewalls 114 of the container 112 as
disclosed above. In a further embodiment, the sheet 122 extends
between and contacts four sidewalls 114 as disclosed above. Sheet
122 may be sized and shaped to friction fit against the four
sidewalls 114 and also sized to line the bottom wall 116 as
disclosed above. Sheet 122 is removable from container 112 and is
thereby reusable and/or recyclable.
[0129] A food item 124 is present in the compartment 120.
[0130] The packaging article 110 includes a cold source 128. A
"cold source," as used herein, is an object that produces, or
radiates, cold. Nonlimiting examples of a suitable cold source
include a wet ice pack, ice, a bottle of ice, a dry ice (frozen
CO.sub.2) pack, a refrigerant pack (typically water and ammonium
nitrate, and including a frozen gel pack), and any combination
thereof.
[0131] The food item 124 contacts a surface of the sheet 122 and/or
contacts the cold source 128. The cold source 128 is placed
adjacent to, and/or on top of the food item 124. Alternatively, the
cold source 128 is placed between the sheet 122 and the food item
124.
[0132] In an embodiment, the food item is fresh fish 124a and the
cold source is ice 128a, as shown in FIGS. 3-5A. The fresh fish
124a contacts a surface of the sheet 122. Alternatively, the ice
128a is placed on the sheet 122, with the fresh fish 124a placed on
the ice 128a. The ice 128a lies below, adjacent to, and on top of
the fresh fish 124a. As the ice 128a melts, the fresh fish 124a
eventually contacts the sheet 122.
[0133] As the ice 128a melts, liquid 126a is formed. The liquid
126a includes water, particles of the fish, microbes, and other
organisms from the fish, and any combination thereof. The liquid
126a drains through the sheet 122 by way of the open loop structure
of the 3DRLM 130, as shown in FIG. 4A. The sheet 122 separates the
fresh fish 124a from the liquid 126a (melted ice or water) that
accumulates on the bottom wall 116. In an embodiment, the sheet 122
is sized and shaped to have sufficient height to separate the fresh
fish 124a from the accumulated liquid 126a when all the ice 128a is
melted. In other words, when all the ice 128a is melted, the sheet
122 is thick enough to prevent contact between the fresh fish 124a
(resting on the top surface of the sheet 122) and the liquid 126a
that is accumulated on the bottom wall 116.
[0134] In an embodiment, the container 112 includes ports 140 for
draining the accumulated liquid 126a from the container 112 as
shown in FIG. 4A.
[0135] In an embodiment, the packaging article 110 includes two
containers-container 112 and container 212. Container 212 is the
same as, or substantially the same as, container 112. Container 212
has sidewalls 214 and bottom wall 216 the same as, or similar to,
the respective walls 114, 116 of container 112. Containers 112, 212
are stackable with container 212 placed upon the container 112.
Container 212 matingly fits on container 112, as shown in FIGS. 5,
5A.
[0136] The container 212 contains a sheet 222 of 3DRLM 230, and a
second batch of the food item, in this case, a second batch of
fresh fish 224a. It is understood that the second batch of the food
item may be the same or different food item as the original food
item. The container also contains a cold source, ice 228a.
[0137] In an embodiment, a third sheet of 3DRLM (not shown) is
placed between the top of container 112 and the bottom of container
212. The third sheet provides support and stability to the
container 212 as the ice 128 in the container 112 melts.
[0138] In an embodiment, the container 212 includes ports 240 which
enable the liquid 226a to drain from the container 212. The liquid
226a drains into the container 112 and continues to drain through
the sheet 122 and eventually to the bottom wall 116 of the
container 112. The ports 140 enable the liquid 226a (from container
212) and the liquid 126a to drain from the container 112.
[0139] The packaging article 110 is scalable with the provision of
one, two, three or more containers, each container having a
respective sheet of 3DRLM, respective food item, and optional cold
source. The present packaging article 110 provides the synergistic
advantages: (1) drainage of liquid away from the food item 24
(located in multiple containers), (2) separation between the food
item and the liquid, and (3) prevention of contact between the food
item and the accumulated liquid on the bottom wall.
[0140] It is specifically intended that the present disclosure not
be limited to the embodiments and illustrations contained herein,
but include modified forms of those embodiments including portions
of the embodiments and combinations of elements of different
embodiments as come with the scope of the following claims.
* * * * *