U.S. patent application number 16/604257 was filed with the patent office on 2020-05-21 for multilayer films containing a slip agent.
The applicant listed for this patent is Dow Global Technologies LLC PBB Polisur S.R.L.. Invention is credited to Marcelo Delmar Cantu, Silvina Vanesa D'Agosto, Jorge Caminero Gomes, Nicolas Cardoso Mazzola.
Application Number | 20200156358 16/604257 |
Document ID | / |
Family ID | 62104387 |
Filed Date | 2020-05-21 |
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United States Patent
Application |
20200156358 |
Kind Code |
A1 |
D'Agosto; Silvina Vanesa ;
et al. |
May 21, 2020 |
Multilayer Films Containing a Slip Agent
Abstract
The present disclosure provides a multilayer film containing at
least three layers, including (A) a core layer containing a high
density polyethylene (HDPE) having a density from 0.940 g/cc to
0.980 g/cc; and (B) skin layers on opposite sides of the core
layer. Each skin layer includes (i) a propylene homopolymer; (ii)
from 2,000 to 3,500 ppm of a slip agent; and (iii) from 4,000 to
10,000 ppm of an antiblock agent.
Inventors: |
D'Agosto; Silvina Vanesa;
(Buenos Aires, AR) ; Mazzola; Nicolas Cardoso;
(Jundiai, BR) ; Cantu; Marcelo Delmar; (Jundiai,
BR) ; Gomes; Jorge Caminero; (Jundiai, BR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dow Global Technologies LLC
PBB Polisur S.R.L. |
Midland
Buenos Aires |
MI |
US
AR |
|
|
Family ID: |
62104387 |
Appl. No.: |
16/604257 |
Filed: |
April 9, 2018 |
PCT Filed: |
April 9, 2018 |
PCT NO: |
PCT/US2018/026704 |
371 Date: |
October 10, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62484527 |
Apr 12, 2017 |
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62517305 |
Jun 9, 2017 |
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62564633 |
Sep 28, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 27/18 20130101;
B32B 27/26 20130101; B32B 27/22 20130101; B32B 2274/00 20130101;
B32B 2307/544 20130101; B32B 27/32 20130101; B32B 2307/50 20130101;
B32B 2250/03 20130101; B32B 2250/242 20130101; B32B 2307/746
20130101; B32B 2264/102 20130101; B32B 2264/104 20130101; B32B
2307/732 20130101; B32B 2250/04 20130101; B32B 2383/00 20130101;
B32B 2439/70 20130101; B32B 27/08 20130101; B32B 2250/40 20130101;
B32B 27/20 20130101; B32B 2270/00 20130101; B32B 2323/10 20130101;
B32B 2307/54 20130101; B32B 2323/043 20130101 |
International
Class: |
B32B 27/32 20060101
B32B027/32; B32B 27/08 20060101 B32B027/08; B32B 27/20 20060101
B32B027/20 |
Claims
1. A multilayer film comprising at least three layers comprising:
(A) a core layer comprising a high density polyethylene (HDPE)
having a density from 0.940 g/cc to 0.980 g/cc; (B) skin layers on
opposite sides of the core layer, each skin layer comprising (i) a
propylene homopolymer; (ii) from 2,000 to 3,500 ppm of a slip
agent; and (iii) from 4,000 to 10,000 ppm of an antiblock
agent.
2. The multilayer film of claim 1, wherein the multilayer film has
a thickness from 15 .mu.m to 100 .mu.m.
3. The multilayer film of claim 1, wherein the multilayer film has
a coefficient of friction (COF) from 0.05 to 0.38.
4. The multilayer film of claim 1, wherein from 40 vol % to 90 vol
% of the multilayer film is the core layer and a combined volume of
the skin layers is from 10 vol % to 60 vol % of the multilayer
film, the multilayer film having a twist retention after 7 days
from 66% to 100% and a yield tension from 5 MPa to 15.5 MPa.
5. The multilayer film of claim 1, wherein the multilayer film
consists of three layers.
6. The multilayer film of claim 1, wherein the multilayer film is a
cast film.
7. The multilayer film of claim 1, wherein the HDPE has a melt
index from 0.1 g/10 min to 1 g/10 min.
8. The multilayer film of claim 1, wherein the propylene
homopolymer has a melt flow rate from 2 g/10 min to 15.0 g/10
min.
9. The multilayer film of claim 1, wherein the slip agent is
selected from the group consisting of a fatty acid amide, a
silicone, and combinations thereof.
10. The multilayer film of claim 1, wherein the antiblock agent is
selected from the group consisting of silica, talc, calcium
carbonate, and combinations thereof.
11. The multilayer film of claim 1, wherein from 40 vol % to 90 vol
% of the multilayer film is the core layer and a combined volume of
the skin layers is from 10 vol % to 60 vol % of the multilayer
film, the multilayer film having a coefficient of friction (COF)
from 0.05 to 0.38, a twist retention after 7 days from 66% to 100%,
and a yield tension from 5 MPa to 15.5 MPa, and each skin layer
comprises: (i) the propylene homopolymer having a melt flow rate
from 2 g/10 min to 15.0 g/10 min; (ii) the slip agent selected from
the group consisting of erucamide, oleamide, palmitamide,
stearamide, behenamide, polydimethylsiloxane, and combinations
thereof; and (iii) silica.
12. An article comprising: a confectionary; a multilayer film in
contact with the confectionary, the multilayer film comprising at
least three layers comprising (A) a core layer comprising a high
density polyethylene (HDPE) having a density from 0.940 g/cc to
0.980 g/cc; (B) skin layers on opposite sides of the core layer,
each skin layer comprising (i) a propylene homopolymer; (ii) from
2,000 to 3,500 ppm of a slip agent; and (iii) from 4,000 to 10,000
ppm of an antiblock agent.
13. The article of claim 12, wherein the multilayer film is in
direct contact with the confectionary.
14. The article of claim 12, wherein the multilayer film is twisted
around the confectionary.
15. The article of claim 12, wherein from 40 vol % to 90 vol % of
the multilayer film is the core layer and a combined volume of the
skin layers is from 10 vol % to 60 vol % of the multilayer film,
the multilayer film having a coefficient of friction (COF) from
0.05 to 0.38, a twist retention after 7 days from 66% to 100%, and
a yield tension from 5 MPa to 15.5 MPa.
Description
BACKGROUND
[0001] The present disclosure relates to multilayer films
containing a slip agent.
[0002] Film layers formed from polyolefins are used in multilayer
films for confectionary packaging, and specifically for twist
packaging for wrapping confectionaries. Multilayer film twist
packaging requires a balance of (i) high twist retention to retain
the wrapped form, (ii) low coefficient of friction (COF) (e.g.,
equal to or less than 0.38) to improve machine processing of the
multilayer film, and (iii) low yield tension (e.g., less than 16
MPa) to enable permanent deformation of the multilayer film and
fold/twist retention with a lower tension applied to the multilayer
film. However, polyolefin film layers typically exhibit one or more
of poor twist retention, high COF, and high yield tension.
[0003] The art recognizes the need for a multilayer film with skin
layers containing a polyolefin that exhibits a low COF, high twist
retention, and low yield tension.
SUMMARY
[0004] The present disclosure provides a multilayer film containing
at least three layers, including: [0005] (A) a core layer
comprising a high density polyethylene (HDPE) having a density from
0.940 g/cc to 0.980 g/cc; [0006] (B) skin layers on opposite sides
of the core layer, each skin layer comprising [0007] (i) a
propylene homopolymer; [0008] (ii) from 2,000 to 3,500 ppm of a
slip agent; and [0009] (iii) from 4,000 to 10,000 ppm of an
antiblock agent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a twist-wrapped
confectionary in accordance with an embodiment of the present
disclosure.
[0011] FIG. 2 is a perspective view of an unwrapped
confectionary.
DEFINITIONS
[0012] Any reference to the Periodic Table of Elements is that as
published by CRC Press, Inc., 1990-1991. Reference to a group of
elements in this table is by the new notation for numbering
groups.
[0013] For purposes of United States patent practice, the contents
of any referenced patent, patent application or publication are
incorporated by reference in their entirety (or its equivalent US
version is so incorporated by reference) especially with respect to
the disclosure of definitions (to the extent not inconsistent with
any definitions specifically provided in this disclosure) and
general knowledge in the art.
[0014] The numerical ranges disclosed herein include all values
from, and including, the lower and 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.).
[0015] Unless stated to the contrary, implicit from the context, or
customary in the art, all parts and percents are based on weight
and all test methods are current as of the filing date of this
disclosure.
[0016] The term "composition" refers to a mixture of materials
which comprise the composition, as well as reaction products and
decomposition products formed from the materials of the
composition.
[0017] The terms "blend" or "polymer blend," as used herein, is a
blend of two or more polymers. Such a blend may or may not be
miscible (not phase separated at molecular level). 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
other methods known in the art.
[0018] 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. The term "or," unless stated
otherwise, refers to the listed members individually as well as in
any combination. Use of the singular includes use of the plural and
vice versa.
[0019] An "ethylene-based polymer" is a polymer that contains more
than 50 weight percent polymerized ethylene monomer (based on the
total amount of polymerizable monomers) and, optionally, may
contain at least one comonomer. Ethylene-based polymer includes
ethylene homopolymer, and ethylene copolymer (having units derived
from ethylene and one or more comonomers). The terms
"ethylene-based polymer" and "polyethylene" may be used
interchangeably. A nonlimiting example of an ethylene-based polymer
(polyethylene) is high density polyethylene (HDPE).
[0020] An "olefin-based polymer" or "polyolefin" 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.
[0021] 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, 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.
[0022] 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. Propylene-based polymer includes
propylene homopolymer (having units derived from propylene and no
comonomer), and propylene copolymer (having units derived from
propylene and one or more comonomers). The terms "propylene-based
polymer" and "polypropylene" may be used interchangeably. A
nonlimiting example of a propylene-based polymer (polypropylene) is
a propylene/.alpha.-olefin copolymer with at least one C.sub.2 or
C.sub.4-C.sub.10 .alpha.-olefin comonomer, or a C.sub.2
.alpha.-olefin comonomer.
TEST METHODS
[0023] Coefficient of Friction (COF) is measured according to ASTM
D1894. The substrate employed for COF determinations is DOW HDPE
DGDB-2480 NT, which is a high-density polyethylene commercially
available from The Dow Chemical Company, Midland, Mich., USA.
[0024] Density is measured in accordance with ASTM D792, Method B.
The result is recorded in g/cc.
[0025] Melt index (MI) (12) in g/10 min for ethylene-based polymers
is measured using ASTM D-1238-04 (190.degree. C./2.16 kg).
[0026] Melt flow rate (MFR) in g/10 min for propylene-based
polymers is measured using ASTM D-1238-04 (230.degree. C./2.16
kg).
[0027] Twist retention after 7 days aging is determined by the
following procedure. The film is cut into a 80 mm.times.80 mm
sample. A person then folds the film sample around a piece of
Arcor.TM. Butter Toffee (a hard candy). The person then twists
opposing ends of the film tightly around the hard candy piece to
resemble the twist-wrapped hard candy single as shown in FIG. 1.
Each film sample is cut in the same direction along extrusion and
the twist procedure is made by the same individual to minimize
variations between samples. Five or six wrapped candies are
produced. Each wrapped candy is stored at ambient conditions
(23.degree. C., 760 mmHg, 50% relative humidity) and visually
observed each day over a period of 7 days to determine whether the
multilayer film retains its fold/twist or whether the film unwraps.
An unwrapped hard candy is one whereby the fold/twist is not
retained, such that the film becomes displaced from its original
twist-wrapped hard candy form, as shown in FIG. 2. The number of
samples that retain their fold/twist is recorded each day. Twist
retention after 7 days aging is reported as the percentage of
samples that retain their fold/twist after 7 days.
[0028] Yield tension is measured in accordance with ASTM D882.
Yield tension is measured in the machine direction of the film.
Differential Scanning Calorimetry (DSC)
[0029] Differential Scanning calorimetry (DSC) can be used to
measure the melting, crystallization, and glass transition behavior
of a polymer over a wide range of temperature. 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 190.degree. C.; the
melted sample is then air-cooled to room temperature (25.degree.
C.). A 3-10 mg, 6 mm diameter specimen is extracted from the cooled
polymer, weighed, placed in a light aluminum pan (50 mg), and
crimped shut. Analysis is then performed to determine its thermal
properties.
[0030] 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 3 minutes in order to remove
its thermal history. Next, the sample is cooled to -80.degree. C.
at a 10.degree. C./minute cooling rate and held isothermal at
-80.degree. C. for 3 minutes. The sample is then heated to
180.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 values determined are extrapolated onset of melting,
Tm, and extrapolated onset of crystallization, Tc. Heat of fusion
(Hf) (in Joules per gram), the calculated % crystallinity for
polyethylene samples using the following equation: %
Crystallinity=((Hf)/292 J/g).times.100; and the calculated %
crystallinity for polypropylene samples using the following
equation: % Crystallinity=((Hf)/165 J/g).times.100.
[0031] The heat of fusion (Hf) and the peak melting temperature are
reported from the second heat curve. Peak crystallization
temperature is determined from the cooling curve.
[0032] Melting point, Tm, is determined from the DSC heating curve
by first drawing the baseline between the start and end of the
melting transition. A tangent line is then drawn to the data on the
low temperature side of the melting peak. Where this line
intersects the baseline is the extrapolated onset of melting (Tm).
This is as described in Bernhard Wunderlich, The Basis of Thermal
Analysis, in Thermal Characterization of Polymeric Materials 92,
277-278 (Edith A. Turi ed., 2d ed. 1997).
.sup.13C NMR Experimental Procedure for Propylene-Based
Polymers
[0033] .sup.13C NMR is used for ethylene content and is performed
as follows:
[0034] Sample Preparation (propylene-based polymers)--The samples
are prepared by adding approximately 2.7 g of a 50/50 mixture of
tetrachloroethane-d.sub.2/orthodichlorobenzene containing 0.025 M
Cr(AcAc).sub.3 to 0.20-0.30 g sample in a Norell 1001-7 10 mm NMR
tube. The samples are dissolved and homogenized by heating the tube
and its contents to 150.degree. C. using a heating block and heat
gun. Each sample is visually inspected to ensure homogeneity.
[0035] Data Acquisition Parameters (propylene-based polymers)--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 6 sec pulse repetition delay,
90 degree flip angles, and inverse gated decoupling with a sample
temperature of 120.degree. C. All measurements are made on
non-spinning samples in locked mode. Samples are allowed to
thermally equilibrate for 7 minutes prior to data acquisition.
Percent mm tacticity and wt % ethylene is then determined according
to methods commonly used in the art.* *References: For composition
(wt % E): S. Di Martino and M. Kelchtermans; J. Appl. Polym. Sci.,
V 56, 1781-1787 (1995); Tacticity, detailed assignments: V. Busico,
R. Cipullo; Prog. Polym. Sci. V 26, 443-533 (2001).
DETAILED DESCRIPTION
[0036] The present disclosure provides a multilayer film. In an
embodiment, the multilayer film contains at least three layers,
including (A) a core layer containing a high density polyethylene
(HDPE) having a density from 0.940 g/cc to 0.980 g/cc; and (B) skin
layers on opposite sides of the core layer. Each skin layer
includes (i) a propylene homopolymer; (ii) from 2,000 to 3,500 ppm
of a slip agent; and (iii) from 4,000 to 10,000 ppm of an antiblock
agent.
A. Core Layer
[0037] The multilayer film contains a core layer. The core layer
contains a high density polyethylene (HDPE) having a density from
0.940 g/cc to 0.980 g/cc.
[0038] "High density polyethylene" (or "HDPE") is an ethylene
homopolymer or an ethylene/.alpha.-olefin copolymer with at least
one C4-C10 .alpha.-olefin comonomer, or C8 .alpha.-olefin comonomer
and a density from 0.940 g/cc, or 0.945 g/cc, or 0.950 g/cc, or
0.955 g/cc, or 0.958 g/cc to 0.960 g/cc, or 0.962 g/cc, or 0.965
g/cc, or 0.970 g/cc, or 0.975 g/cc, or 0.980 g/cc. In an
embodiment, the HDPE has a density from greater than 0.940 g/cc, or
0.945 g/cc, or 0.950 g/cc, or 0.955 g/cc, or 0.958 g/cc to 0.960
g/cc, or 0.962 g/cc, or 0.965 g/cc, or 0.970 g/cc, or 0.975 g/cc,
or 0.980 g/cc. The HDPE can be a monomodal copolymer or a
multimodal copolymer. A "monomodal ethylene copolymer" is an
ethylene/C4-C10 .alpha.-olefin copolymer that has one distinct peak
in a gel permeation chromatography (GPC) showing the molecular
weight distribution. A nonlimiting example of a suitable monomodal
HDPE is AXELERON.TM. FO 6318 BK CPD, available from The Dow
Chemical Company. A "multimodal ethylene copolymer" is an
ethylene/C4-C10 .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
suitable multimodal 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.
[0039] In an embodiment, the HDPE includes from greater than 50 wt
%, or 55 wt %, or 60 wt %, or 65 wt % to 70 wt %, or 75 wt %, or 80
wt %, or 85 wt %, or 90 wt %, or 95 wt %, or 97 wt %, or 99 wt %,
or 100 wt % units derived from ethylene and a reciprocal amount, or
from 0 wt %, or 1 wt %, or 3 wt %, or 5 wt %, or 10 wt %, or 15 wt
%, or 20 wt %, or 25 wt %, or 30 wt % to 35 wt %, or 40 wt %, or 45
wt %, or less than 50 wt % units derived from a comonomer, based on
the total weight of the HDPE.
[0040] In an embodiment, the HDPE has a melt index (MI) of from 0.1
g/10 min, or 0.5 g/10 min to 1.0 g/10 min, or 1.5 g/10 min, or 2.0
g/10 min. In another embodiment, the HDPE has a melt index (MI)
from 0.1 g/10 min to less than 2.0 g/10 min.
[0041] In an embodiment, the HDPE has one, some, or all of the
following properties: [0042] (i) a density of from 0.940 g/cc, or
0.945 g/cc, or 0.950 g/cc, or 0.955 g/cc, or 0.958 g/cc to 0.960
g/cc, or 0.962 g/cc, or 0.965 g/cc, or 0.970 g/cc, or 0.975 g/cc,
or 0.980 g/cc; and/or [0043] (ii) a melt index (MI) of from 0.1
g/10 min, or 0.5 g/10 min to 1.0 g/10 min, or 1.5 g/10 min, or 2.0
g/10 min; and/or [0044] (iii) from greater than 50 wt %, or 55 wt
%, or 60 wt %, or 65 wt % to 70 wt %, or 75 wt %, or 80 wt %, or 85
wt %, or 90 wt %, or 95 wt %, or 97 wt %, or 99 wt %, or 100 wt %
units derived from ethylene and a reciprocal amount, or from 0 wt
%, or 1 wt %, or 3 wt %, or 5 wt %, or 10 wt %, or 15 wt %, or 20
wt %, or 25 wt %, or 30 wt % to 35 wt %, or 40 wt %, or 45 wt %, or
less than 50 wt % units derived from a comonomer, based on the
total weight of the HDPE.
[0045] In an embodiment, the HDPE has at least 2, or all 3 of
properties (i)-(iii).
[0046] In an embodiment, the HDPE is an ethylene homopolymer. In
another embodiment, the HDPE is an ethylene homopolymer with a
density of 0.962 g/cc and a melt index of 0.85 g/10 min. In a
further embodiment, the HDPE is ELITE.TM. 5960G, available from The
Dow Chemical Company.
[0047] In an embodiment, the core layer contains from 80 wt %, or
85 wt %, or 90 wt %, or 95 wt % to 97 wt %, or 98 wt %, or 99 wt %,
or 100 wt % of the HDPE, based on the total weight of the core
layer.
[0048] In an embodiment, the core layer includes an optional
additive. Nonlimiting examples of suitable additives include
antioxidants, antistatic agents, stabilizing agents, nucleating
agents, colorants, ultra violet (UV) absorbers or stabilizers,
flame retardants, compatibilizers, plasticizers, fillers,
processing aids, crosslinking agents (e.g., peroxides), and
combinations thereof.
[0049] In an embodiment, the core layer excludes an antiblocking
agent and/or a slip agent.
[0050] In an embodiment, the core layer contains from 80 wt %, or
85 wt %, or 90 wt %, or 95 wt % to 97 wt %, or 98 wt %, or 99 wt %,
or 100 wt % of the HDPE, and from 0 wt %, or 0.01 wt %, or 0.05 wt
%, or 0.1 wt %, or 0.2 wt % to 0.3 wt %, or 0.4 wt %, or 0.5 wt %,
or 1.0 wt %, or 2.0 wt %, or 3.0 wt % additive, based on the total
weight of the core layer.
[0051] In an embodiment, the core layer consists essentially of, or
consists of, from 80 wt %, or 85 wt %, or 90 wt %, or 95 wt % to 97
wt %, or 98 wt %, or 99 wt %, or 100 wt % of the HDPE, and from 0
wt %, or 0.01 wt %, or 0.05 wt %, or 0.1 wt %, or 0.2 wt % to 0.3
wt %, or 0.4 wt %, or 0.5 wt %, or 1.0 wt %, or 2.0 wt %, or 3.0 wt
% additive, based on the total weight of the core layer.
[0052] The HDPE may be the sole polymeric component in the core
layer, or the HDPE may be present in a blend with one or more
polymeric components in combination with the HDPE. A nonlimiting
example of a suitable polymeric component is a polyolefin, such as
an ethylene-based polymer or a propylene-based polymer. The
optional polyolefin is different than the HDPE. However, it is
understood that the core layer may include a blend of two or more
different HDPE. In an embodiment, the core layer excludes an
optional polyolefin. In another embodiment, the core layer excludes
propylene-based polymers.
[0053] The core layer has two opposing surfaces. In an embodiment,
the core layer is a continuous layer with two opposing
surfaces.
[0054] In an embodiment, the core layer has a thickness of from 6.0
.mu.m, or 7.0 .mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m, or
11.0 .mu.m, or 12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0
.mu.m, or 16.0 .mu.m, or 17.0 .mu.m, or 18.0 .mu.m, or 19.0 .mu.m,
or 19.8 .mu.m to 22.2 .mu.m, or 23.0 .mu.m, or 25 .mu.m, or 30
.mu.m, or 35 .mu.m, or 40 .mu.m, or 45 .mu.m, or 50 .mu.m, or 65
.mu.m, or 70 .mu.m, or 75 .mu.m, or 80 .mu.m, or 85 .mu.m, or 90
.mu.m.
[0055] The core layer may comprise two or more embodiments
disclosed herein.
B. Skin Layers
[0056] The multilayer film contains skin layers on opposite sides
of the core layer. Each skin layer includes (i) a propylene
homopolymer; (ii) from 2,000 to 3,500 ppm of a slip agent; (iii)
from 4,000 to 10,000 ppm of an antiblock agent; and, optionally,
(iv) an additive.
[0057] In an embodiment, each skin layer consists essentially of,
or consists of, (i) a propylene homopolymer; (ii) from 2,000 to
3,500 ppm of a slip agent; (iii) from 4,000 to 10,000 ppm of an
antiblock agent; and, optionally, (iv) an additive.
[0058] In an embodiment, each skin layer has a thickness of from
0.75 .mu.m, or 1.0 .mu.m, or 1.5 .mu.m, or 2.0 .mu.m, or 3.0 .mu.m,
or 4.0 .mu.m, or 5.0 .mu.m, or 6.0 .mu.m, or 6.5 .mu.m to 7.0
.mu.m, or 7.5 .mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m, or
11.0 .mu.m, or 12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0
.mu.m, or 20.0 .mu.m, or 25.0 .mu.m, or 30 .mu.m. Each skin layer
may have the same thickness or a different thickness.
[0059] The skin layers may comprise two or more embodiments
disclosed herein.
[0060] i. Propylene Homopolymer
[0061] Each skin layer contains a propylene homopolymer. The
propylene homopolymer contains 100 wt % units derived from
propylene.
[0062] The propylene homopolymer is void of comonomer (e.g.,
ethylene). In an embodiment, the propylene homopolymer consists of
propylene and an optional additive.
[0063] A nonlimiting example of a suitable propylene homopolymer is
CUYOLEN.TM. 1102L, available from Petroquimica Cuyo S.A.I.C.
[0064] In an embodiment, the propylene homopolymer has a melt flow
rate (MFR) from 2.0 g/10 min, or 3.0 g/10 min, or 4.0 g/10 min to
5.0 g/10 min, or 6.0 g/10 min, or 7.0 g/10 min, or 8.0 g/10 min, or
9.0 g/10 min, or 10.0 g/10 min, or 15.0 g/10 min, or 20.0 g/10 min,
or 25.0 g/10 min. In an embodiment, the propylene homopolymer has a
melt flow rate (MFR) from greater than 2.0 g/10 min to 25 g/10 min,
or from greater than 2.0 g/10 min to 15.0 g/10 min, or from 2.5
g/10 min to 6.0 g/10 min.
[0065] In an embodiment, the propylene homopolymer has a density
from 0.900 g/cc, or 0.902 g/cc, 0.903 g/cc, or 0.904 g/cc to 0.906
g/cc, or 0.908 g/cc.
[0066] In an embodiment, the propylene homopolymer has a melting
temperature, Tm, from 155.degree. C., or 157.degree. C., or
159.degree. C. to 161.degree. C., or 163.degree. C., or 165.degree.
C.
[0067] In an embodiment, the propylene homopolymer has one, some,
or all of the following properties: [0068] (i) a MFR from 2.0 g/10
min, or 3.0 g/10 min, or 4.0 g/10 min to 5.0 g/10 min, or 6.0 g/10
min, or 7.0 g/10 min, or 8.0 g/10 min, or 9.0 g/10 min, or 10.0
g/10 min, or 15.0 g/10 min, or 20.0 g/10 min, or 25.0 g/10 min;
and/or [0069] (ii) a density from 0.900 g/cc, or 0.902 g/cc, 0.903
g/cc, or 0.904 g/cc to 0.906 g/cc, or 0.908 g/cc; and/or [0070]
(iii) a melting temperature, Tm, from 155.degree. C., or
157.degree. C., or 159.degree. C. to 161.degree. C., or 163.degree.
C., or 165.degree. C.
[0071] In an embodiment, the propylene homopolymer has at least 2,
or all of properties (i)-(iii).
[0072] In an embodiment, the propylene homopolymer has a melt flow
rate (MFR) of 5.0 g/10 min, a density of 0.903 g/cc, and/or a
melting point of 161.degree. C. In a further embodiment, the
propylene homopolymer is CUYOLEN.TM. 1102L, available from
Petroquimica Cuyo S.A.I.C.
[0073] In an embodiment, each skin layer contains from 70 wt %, or
75 wt %, or 77 wt % to 80 wt %, or 83 wt %, or 85 wt %, or 90 wt %,
or 95 wt %, or 96 wt %, or 97 wt %, or 98 wt %, or 99 wt %, or 99.3
wt %, or 99.4 wt %, or less than 100 wt % propylene homopolymer,
based on the total weight of each skin layer.
[0074] The propylene homopolymer may comprise two or more
embodiments disclosed herein.
[0075] ii. Slip Agent
[0076] Each skin layer contains a slip agent. A "slip agent" is a
compound that has a coefficient of friction (COF) from 0.02 to
0.15. In an embodiment, the slip agent has a COF of from 0.02, or
0.04, or 0.06, or 0.07, or 0.08, or 0.09, or 0.10 to 0.15.
[0077] Nonlimiting examples of suitable slip agents include fatty
acid amides, silicone, plasticizers, organic amines, dibasic
esters, stearates, sulfates, fatty acids, mineral oil, vegetable
oils, fluorinated organic resins, graphite, tungsten disulfide,
molybdenum disulfide, and combinations thereof.
[0078] In an embodiment, the slip agent is a fatty acid amide. A
"fatty acid amide" is a molecule having the Structure (I):
##STR00001##
wherein R is a C.sub.3 to C.sub.27 alkyl moiety. In an embodiment,
R is a C.sub.11 to C.sub.25, or a C.sub.15 to C.sub.23 alkyl
moiety. In another embodiment, R is a C.sub.21 alkyl moiety. R can
be saturated, mono-unsaturated, or poly-unsaturated. In an
embodiment, R is mono-unsaturated. Nonlimiting examples of suitable
fatty acid amides include erucamide, oleamide, palmitamide,
stearamide, and behenamide. Additionally, the fatty acid amide can
be a mixture of two or more fatty acid amides. In an embodiment,
the fatty acid amide is erucamide.
[0079] In an embodiment, the slip agent is a silicone. A "silicone"
is a polymer generally comprising siloxane-based monomer residue
repeating units. A "siloxane" is a monomer residue repeat unit
having the Structure (II):
##STR00002##
wherein R.sup.1 and R.sup.2 each independently is hydrogen or a
hydrocarbyl group. A "hydrocarbyl group" is a univalent group
formed by removing a hydrogen atom from a hydrocarbon (e.g., alkyl
groups, such as ethyl, or aryl groups, such as phenyl). The
siloxane monomer residue can be any dialkyl, diaryl, dialkaryl, or
diaralkyl siloxane, having the same or differing alkyl, aryl,
alkaryl, or aralkyl moieties. In an embodiment, each of R.sup.1 and
R.sup.2 is independently a C.sub.1 to C.sub.20, or C.sub.1 to
C.sub.12, or C.sub.1 to C.sub.6 alkyl, aryl, alkaryl, or aralkyl
moiety. R.sup.1 and R.sup.2 can have the same or a different number
of carbon atoms. In an embodiment, the hydrocarbyl group for each
of R.sup.1 and R.sup.2 is an alkyl group that is saturated and
optionally straight-chain. The alkyl group can be the same or can
be different for each of R.sup.1 and R.sup.2. Non-limiting examples
of alkyl groups suitable for use in R.sup.1 and R.sup.2 include
methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, isobutyl, t-butyl, or
combinations of two or more thereof. Nonlimiting examples of
suitable silicone include polydimethylsiloxane (PDMS),
poly(ethyl-methylsiloxane), and combinations thereof.
[0080] In an embodiment, the slip agent is selected from a fatty
acid amide, a silicone, and combinations thereof. In another
embodiment, the slip agent is selected from erucamide, oleamide,
palmitamide, stearamide, behenamide, PDMS, and combinations
thereof.
[0081] In an embodiment, the slip agent excludes silicones. In a
further embodiment, the slip agent excludes polydimethylsiloxane
(PDMS).
[0082] In an embodiment, the slip agent is a stearate. Nonlimiting
examples of suitable stearates include zinc stearate, lead
stearate, calcium stearate, and combinations thereof.
[0083] In an embodiment, the slip agent is a sulfate. A nonlimiting
example of a suitable sulfate is zinc sulfate.
[0084] In an embodiment, the slip agent is a fatty acid.
Nonlimiting examples of suitable fatty acids include palmitic acid,
stearic acid, and combinations thereof.
[0085] In an embodiment, the slip agent is a fluorinated organic
resin. A "fluorinated organic resin" is a polymer of one or more
fluorinated monomers selected from tetrafloroethylene, vinylidene
fluoride, and chlorotrifluoroethylene.
[0086] In an embodiment, each skin layer contains from 2,000 ppm,
or 2,500 ppm, or 3,000 ppm, or 3,100 ppm, or 3,200 ppm to 3,300
ppm, or 3,400 ppm, or 3,500 ppm slip agent.
[0087] In an embodiment, each skin layer contains from 0.20 wt %,
or 0.25 wt %, or 0.30 wt %, or 0.31 wt %, or 0.32 wt % to 0.33 wt
%, or 0.34 wt %, or 0.35 wt % slip agent, based on the total weight
of each skin layer.
[0088] The slip agent may comprise two or more embodiments
disclosed herein.
[0089] iii. Antiblock Agent
[0090] Each skin layer contains an antiblock agent. An "antiblock
agent" is a compound that minimizes, or prevents, blocking (i.e.,
adhesion) between two adjacent layers of film by creating a
microscopic roughening of the film layer surface, which reduces the
available contact area between adjacent layers.
[0091] Nonlimiting examples of suitable antiblock agents include
silica, talc, calcium carbonate, and combinations thereof. In an
embodiment, the antiblock agent is silica (SiO.sub.2). The silica
may be organic silica or synthetic silica.
[0092] In an embodiment, each skin layer contains from 4,000 ppm,
or 4,500 ppm, or 5,000 ppm, or 5,500 ppm, or 6,000 ppm to 6,500
ppm, or 7,000 ppm, or 7,500 ppm, or 8,000 ppm, or 8,500 ppm, or
9,000 ppm, or 9,500 ppm, or 10,000 ppm antiblock agent.
[0093] In an embodiment, each skin layer contains from 0.40 wt %,
or 0.45 wt %, or 0.50 wt %, or 0.55 wt %, or 0.60 wt % to 0.65 wt
%, or 0.70 wt %, or 0.75 wt %, or 0.80 wt %, or 0.85 wt %, or 0.90
wt %, or 0.95 wt %, or 1.00 wt % antiblock agent, based on the
total weight of each respective skin layer.
[0094] The antiblock agent may comprise two or more embodiments
disclosed herein.
[0095] iv. Optional Additives
[0096] In an embodiment, each skin layer includes an optional
additive. The optional additive may be any additive disclosed
herein. In an embodiment, each skin layer contains an additive
selected from antioxidants, antistatic agents, stabilizing agents,
nucleating agents, colorants, ultra violet (UV) absorbers or
stabilizers, flame retardants, compatibilizers, plasticizers,
fillers, processing aids, crosslinking agents (e.g., peroxides),
and combinations thereof.
[0097] In an embodiment, each skin layer contains from 0 wt %, or
0.01 wt %, or 0.05 wt %, or 0.1 wt %, or 0.2 wt % to 0.3 wt %, or
0.4 wt %, or 0.5 wt %, or 1.0 wt %, or 2.0 wt %, or 3.0 wt %
additive, based on the total weight of each skin layer.
[0098] The propylene homopolymer may be the sole polymeric
component in each skin layer, or the propylene homopolymer may be
present in a blend with one or more polymeric components in
combination with the propylene homopolymer. A nonlimiting example
of a suitable polymeric component is a polyolefin, such as an
ethylene-based polymer or a propylene-based polymer. The optional
polyolefin is different than the propylene homopolymer. However, it
is understood that each skin layer may include a blend of two or
more different propylene homopolymers. In an embodiment, each skin
layer excludes an optional polyolefin. In another embodiment, each
skin layer excludes ethylene-based polymers. In an embodiment, each
skin layer includes from 15 wt %, or 16 wt % to 18 wt %, or 20 wt
%, or 22 wt %, or 25 wt %, or 30 wt % ethylene-based polymer, based
on the total weight of each skin layer.
[0099] In an embodiment, each skin layer contains: [0100] (i) from
70 wt %, or 75 wt %, or 77 wt % to 80 wt %, or 83 wt %, or 85 wt %,
or 90 wt %, or 95 wt %, or 96 wt %, or 97 wt %, or 98 wt %, or 99
wt %, or 99.3 wt %, or 99.4 wt % propylene homopolymer, the
propylene homopolymer having one, some, or all of the following
properties: [0101] (a) a MFR from 2.0 g/10 min, or 3.0 g/10 min, or
4.0 g/10 min to 5.0 g/10 min, or 6.0 g/10 min, or 7.0 g/10 min, or
8.0 g/10 min, or 9.0 g/10 min, or 10.0 g/10 min, or 15.0 g/10 min,
or 20.0 g/10 min, or 25.0 g/10 min; and/or [0102] (b) a density
from 0.900 g/cc, or 0.902 g/cc, 0.903 g/cc, or 0.904 g/cc to 0.906
g/cc, or 0.908 g/cc; and/or [0103] (c) a melting temperature, Tm,
from 155.degree. C., or 157.degree. C., or 159.degree. C. to
161.degree. C., or 163.degree. C., or 165.degree. C.; [0104] (ii)
from 2,000 ppm, or 2,500 ppm, or 3,000 ppm, or 3,100 ppm, or 3,200
ppm to 3,300 ppm, or 3,400 ppm, or 3,500 ppm slip agent, such as a
fatty acid amide (e.g., erucamide); [0105] (iii) from 4,000 ppm, or
4,500 ppm, or 5,000 ppm, or 5,500 ppm, or 6,000 ppm to 6,500 ppm,
or 7,000 ppm, or 7,500 ppm, or 8,000 ppm, or 8,500 ppm, or 9,000
ppm, or 9,500 ppm, or 10,000 ppm antiblock agent such as silica;
[0106] (iv) from 0 wt %, or 0.01 wt %, or 0.05 wt %, or 0.1 wt %,
or 0.2 wt % to 0.3 wt %, or 0.4 wt %, or 0.5 wt %, or 1.0 wt %, or
2.0 wt %, or 3.0 wt % additive; and [0107] (v) from 0 wt %, or 15
wt %, or 16 wt % to 18 wt %, or 20 wt %, or 22 wt %, or 25 wt %, or
30 wt % ethylene-based polymer, based on the total weight of each
skin layer; and each skin layer has a thickness of from 0.75 .mu.m,
or 1.0 .mu.m, or 1.5 .mu.m, or 2.0 .mu.m, or 3.0 .mu.m, or 4.0
.mu.m, or 5.0 .mu.m, or 6.0 .mu.m, or 6.5 .mu.m to 7.0 .mu.m, or
7.5 .mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m, or 11.0
.mu.m, or 12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0 .mu.m,
or 20.0 .mu.m, or 25.0 .mu.m, or 30 .mu.m.
[0108] In an embodiment, each skin layer contains: [0109] (i) from
70 wt %, or 75 wt %, or 77 wt % to 80 wt %, or 83 wt %, or 85 wt %,
or 90 wt %, or 95 wt %, or 96 wt %, or 97 wt %, or 98 wt %, or 99
wt %, or 99.3 wt %, or 99.4 wt % propylene homopolymer, the
propylene homopolymer having one, some, or all of the following
properties: [0110] (a) a MFR from 2.0 g/10 min, or 3.0 g/10 min, or
4.0 g/10 min to 5.0 g/10 min, or 6.0 g/10 min, or 7.0 g/10 min, or
8.0 g/10 min, or 9.0 g/10 min, or 10.0 g/10 min, or 15.0 g/10 min,
or 20.0 g/10 min, or 25.0 g/10 min; and/or [0111] (b) a density
from 0.900 g/cc, or 0.902 g/cc, 0.903 g/cc, or 0.904 g/cc to 0.906
g/cc, or 0.908 g/cc; and/or [0112] (c) a melting temperature, Tm,
from 155.degree. C., or 157.degree. C., or 159.degree. C. to
161.degree. C., or 163.degree. C., or 165.degree. C.; [0113] (ii)
from 0.20 wt %, or 0.25 wt %, or 0.30 wt %, or 0.31 wt %, or 0.32
wt % to 0.33 wt %, or 0.34 wt %, or 0.35 wt % slip agent, such as a
fatty acid amide (e.g., erucamide); [0114] (iii) from 0.40 wt %, or
0.45 wt %, or 0.50 wt %, or 0.55 wt %, or 0.60 wt % to 0.65 wt %,
or 0.70 wt %, or 0.75 wt %, or 0.80 wt %, or 0.85 wt %, or 0.90 wt
%, or 0.95 wt %, or 1.00 wt % antiblock agent, such as silica;
[0115] (iv) from 0 wt %, or 0.01 wt %, or 0.05 wt %, or 0.1 wt %,
or 0.2 wt % to 0.3 wt %, or 0.4 wt %, or 0.5 wt %, or 1.0 wt %, or
2.0 wt %, or 3.0 wt % additive; and [0116] (v) from 0 wt %, or 15
wt %, or 16 wt % to 18 wt %, or 20 wt %, or 22 wt %, or 25 wt %, or
30 wt % ethylene-based polymer, based on the total weight of each
skin layer; and each skin layer has a thickness of from 0.75 .mu.m,
or 1.0 .mu.m, or 1.5 .mu.m, or 2.0 .mu.m, or 3.0 .mu.m, or 4.0
.mu.m, or 5.0 .mu.m, or 6.0 .mu.m, or 6.5 .mu.m to 7.0 .mu.m, or
7.5 .mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m, or 11.0
.mu.m, or 12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0 .mu.m,
or 20.0 .mu.m, or 25.0 .mu.m, or 30 .mu.m.
[0117] It is understood that the sum of the components in each of
the skin layers disclosed herein, including the foregoing layers,
yields 100 weight percent (wt %), based on the total weight of the
respective skin layer.
[0118] Each skin layer may have the same or a different
composition. In an embodiment, each skin layer has the same
composition.
[0119] Each skin layer has two opposing surfaces. In an embodiment,
each skin layer is a continuous layer with two opposing
surfaces.
[0120] The skin layers may comprise two or more embodiments
disclosed herein.
C. Multilayer Film
[0121] The multilayer film contains at least three layers including
(A) a core layer containing a high density polyethylene (HDPE)
having a density from 0.940 g/cc to 0.980 g/cc and, optionally, an
additive; and (B) skin layers on opposite sides of the core layer.
Each skin layer includes (i) a propylene homopolymer; (ii) from
2,000 to 3,500 ppm of a slip agent; (iii) from 4,000 to 10,000 ppm
of an antiblock agent; and, optionally, (iv) an additive. The core
layer and the skin layers may be any core layer and skin layer
disclosed herein.
[0122] The multilayer film contains three layers, or more than
three layers. For example, the multilayer film can have three,
four, five, six, seven, eight, nine, ten, eleven, or more layers.
In an embodiment, the multilayer film contains only three
layers.
[0123] In an embodiment, the multilayer film consists essentially
of, or consists of, at least three layers including (A) the core
layer containing HDPE having a density from 0.940 g/cc to 0.980
g/cc and, optionally, an additive; and (B) skin layers on opposite
sides of the core layer. Each skin layer includes (i) the propylene
homopolymer; (ii) from 2,000 to 3,500 ppm of the slip agent; (iii)
from 4,000 to 10,000 ppm of the antiblock agent; and, optionally,
(iv) an additive.
[0124] The skin layers may be in direct contact or in indirect
contact with the core layer. In an embodiment, the skin layers
directly contact the core layer. The term "directly contacts," as
used herein, is a layer configuration whereby the core layer is
located immediately adjacent to each skin layer and no intervening
layers, or no intervening structures, are present between the core
layer and each skin layer. In another embodiment, the skin layers
indirectly contact the core layer. The term "indirectly contacts,"
as used herein, is a layer configuration whereby an intervening
layer, or an intervening structure, is present between the core
layer and each skin layer.
[0125] In an embodiment, the multilayer film has a thickness of
from 15 .mu.m, or 20 .mu.m, or 25 .mu.m, or 30 .mu.m, or 33 .mu.m
to 37 .mu.m, or 40 .mu.m, or 45 .mu.m, or 50 .mu.m, or 55 .mu.m, or
60 .mu.m, or 65 .mu.m, or 70 .mu.m, or 75 .mu.m, or 80 .mu.m, or 85
.mu.m, or 90 .mu.m, or 95 .mu.m, or 100 .mu.m.
[0126] In an embodiment, the core layer is from 40 vol %, or 45 vol
%, or 50 vol %, or 55 vol % to 60 vol %, or 65 vol %, or 70 vol %,
or 75 vol % or 80 vol %, or 85 vol %, or 90 vol % of the total
volume of the multilayer film.
[0127] In an embodiment, the combined volume of the skin layers is
from 10 vol %, or 15 vol %, or 20 vol %, or 25 vol %, or 30 vol %,
or 35 vol %, or 40 vol % to 45 vol %, or 50 vol %, or 55 vol %, or
60 vol % of the total volume of the multilayer film. In an
embodiment, the volume of each individual skin layer is from 5 vol
%, or 7.5 vol %, or 10 vol %, or 12.5 vol %, or 15 vol %, or 20 vol
% to 22.5 vol %, or 25 vol %, or 27.5 vol %, or 30 vol % of the
total volume of the multilayer film.
[0128] In an embodiment, the core layer has a thickness of from 6.0
.mu.m, or 7.0 .mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m, or
11.0 .mu.m, or 12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0
.mu.m, or 16.0 .mu.m, or 17.0 .mu.m, or 18.0 .mu.m, or 19.0 .mu.m,
or 19.8 .mu.m to 22.2 .mu.m, or 23.0 .mu.m, or 25 .mu.m, or 30
.mu.m, or 35 .mu.m, or 40 .mu.m, or 45 .mu.m, or 50 .mu.m, or 65
.mu.m, or 70 .mu.m, or 75 .mu.m, or 80 .mu.m, or 85 .mu.m, or 90
.mu.m; and each skin layer has a thickness of from 0.75 .mu.m, or
1.0 .mu.m, or 1.5 .mu.m, or 2.0 .mu.m, or 3.0 .mu.m, or 4.0 .mu.m,
or 5.0 .mu.m, or 6.0 .mu.m, or 6.5 .mu.m to 7.0 .mu.m, or 7.5
.mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m, or 11.0 .mu.m, or
12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0 .mu.m, or 20.0
.mu.m, or 25.0 .mu.m, or 30 .mu.m.
[0129] In an embodiment, the multilayer film has a slip factor of
from 25,000, or 26,000, or 30,000, or 35,000, or 39,000 to 40,000,
or 45,000, or 49,000, or 50,000, or 52,000, or 55,000, or 60,000.
The "slip factor" of the multilayer film is calculated in
accordance with the following Equation (I):
slip factor = thickness of film .times. ( ( ( wt % skin layer 1 100
) .times. total ppm of slip agent in skin layer 1 ) + ( ( wt % core
layer 100 ) .times. total ppm of slip agent in core layer ) + ( (
wt % skin layer 2 100 ) .times. total ppm of slip agent in skin
layer 2 ) ) Equation ( I ) ##EQU00001##
In Equation (I), the weight percent ("wt %") of each respective
layer is based on the total weight of the film.
[0130] In an embodiment, the multilayer film has a coefficient of
friction (COF) from 0.05, or 0.10, or 0.15, or 0.19, or 0.20, or
0.24 to 0.25, or 0.26, or 0.27, or 0.28, or 0.29, or 0.30, or 0.31,
or 0.32, or 0.33, or 0.34, or 0.35, or 0.36, or 0.37, or 0.38.
[0131] In an embodiment, the multilayer film has a twist retention
after aging 7 days of from 66%, or 70% to 75%, or 80%, or 85%, or
90%, or 95%, or 100%. A higher twist retention after aging 7 days
(.gtoreq.66%) indicates the multilayer film maintains a
folded/twisted formation after aging. Consequently, the present
multilayer film is suitable for twist packaging.
[0132] In an embodiment, the multilayer film has a yield tension
from 5 MPa, or 8 MPa, or 10 MPa, or 13 MPa to 14 MPa, or 15 MPa, or
15.5 MPa, or less than 16 MPa. During folding and/or twisting of
the multilayer film, tension is applied to the multilayer film and
the film elongates and recovers to its original dimensions when the
tension is removed, until the tension that is applied is the "yield
tension," at which point the multilayer film elongates but
deformation is permanent (indicating the multilayer film maintains
its folded/twisted formation). A low yield tension of from 5 MPa to
15.5 MPa, or less than 16 MPa is advantageous because it enables
permanent deformation of the multilayer film and fold/twist
retention with a lower tension applied to the multilayer film.
[0133] In an embodiment, the multilayer film has at least three
layers including:
(A) a core layer containing from 80 wt %, or 85 wt %, or 90 wt %,
or 95 wt % to 97 wt %, or 98 wt %, or 99 wt %, or 100 wt % HDPE,
and from 0 wt %, or 0.01 wt %, or 0.05 wt %, or 0.1 wt %, or 0.2 wt
% to 0.3 wt %, or 0.4 wt %, or 0.5 wt %, or 1.0 wt %, or 2.0 wt %,
or 3.0 wt % additive, based on the total weight of the core layer,
the HDPE having one, some, or all of the following properties:
[0134] (i) a density 0.940 g/cc, or 0.945 g/cc, or 0.950 g/cc, or
0.955 g/cc, or 0.958 g/cc to 0.960 g/cc, or 0.962 g/cc, or 0.965
g/cc, or 0.970 g/cc, or 0.975 g/cc, or 0.980 g/cc; and/or [0135]
(i) a melt index (MI) of 0.1 g/10 min, or 0.5 g/10 min to 1.0 g/10
min, or 1.5 g/10 min, or 2.0 g/10 min; and/or [0136] (iii) from
greater than 50 wt %, or 55 wt %, or 60 wt %, or 65 wt % to 70 wt
%, or 75 wt %, or 80 wt %, or 85 wt %, or 90 wt %, or 95 wt %, or
97 wt %, or 99 wt %, or 100 wt % units derived from ethylene and a
reciprocal amount, or from 0 wt %, or 1 wt %, or 3 wt %, or 5 wt %,
or 10 wt %, or 15 wt %, or 20 wt %, or 25 wt %, or 30 wt % to 35 wt
%, or 40 wt %, or 45 wt %, or less than 50 wt % units derived from
a comonomer, based on the total weight of the HDPE; (B) skin layers
on opposite sides of the core layer, each skin layer containing:
[0137] (i) from 70 wt %, or 75 wt %, or 77 wt % to 80 wt %, or 83
wt %, or 85 wt %, or 90 wt %, or 95 wt %, or 96 wt %, or 97 wt %,
or 98 wt %, or 99 wt %, or 99.3 wt %, or 99.4 wt % propylene
homopolymer, the propylene homopolymer having one, some, or all of
the following properties: [0138] (a) a MFR from 2.0 g/10 min, or
3.0 g/10 min, or 4.0 g/10 min to 5.0 g/10 min, or 6.0 g/10 min, or
7.0 g/10 min, or 8.0 g/10 min, or 9.0 g/10 min, or 10.0 g/10 min,
or 15.0 g/10 min, or 20.0 g/10 min, or 25.0 g/10 min; and/or [0139]
(b) a density from 0.900 g/cc, or 0.902 g/cc, 0.903 g/cc, or 0.904
g/cc to 0.906 g/cc, or 0.908 g/cc; and/or [0140] (c) a melting
temperature, Tm, from 155.degree. C., or 157.degree. C., or
159.degree. C. to 161.degree. C., or 163.degree. C., or 165.degree.
C.; [0141] (ii) from 0.20 wt %, or 0.25 wt %, or 0.30 wt %, or 0.31
wt %, or 0.32 wt % to 0.33 wt %, or 0.34 wt %, or 0.35 wt % slip
agent, such as a fatty acid amide (e.g., erucamide); [0142] (iii)
from 0.40 wt %, or 0.45 wt %, or 0.50 wt %, or 0.55 wt %, or 0.60
wt % to 0.65 wt %, or 0.70 wt %, or 0.75 wt %, or 0.80 wt %, or
0.85 wt %, or 0.90 wt %, or 0.95 wt %, or 1.00 wt % antiblock
agent, such as silica; [0143] (iv) from 0 wt %, or 0.01 wt %, or
0.05 wt %, or 0.1 wt %, or 0.2 wt % to 0.3 wt %, or 0.4 wt %, or
0.5 wt %, or 1.0 wt %, or 2.0 wt %, or 3.0 wt % additive; and
[0144] (v) from 0 wt %, or 15 wt %, or 16 wt % to 18 wt %, or 20 wt
%, or 22 wt %, or 25 wt %, or 30 wt % ethylene-based polymer, based
on the total weight of each skin layer; and the multilayer film has
one, some, or all of the following properties: (1) a total
thickness of from 15 .mu.m, or 20 .mu.m, or 25 .mu.m, or 30 .mu.m,
or 33 .mu.m to 37 .mu.m, or 40 .mu.m, or 45 .mu.m, or 50 .mu.m, or
55 .mu.m, or 60 .mu.m, or 65 .mu.m, or 70 .mu.m, or 75 .mu.m, or 80
.mu.m, or 85 .mu.m, or 90 .mu.m, or 95 .mu.m, or 100 .mu.m; and/or
(2) the core layer is from 40 vol %, or 45 vol %, or 50 vol %, or
55 vol % to 60 vol %, or 65 vol %, or 70 vol %, or 75 vol % or 80
vol %, or 85 vol %, or 90 vol % of the total volume of the
multilayer film; and/or (3) the core layer has a thickness of from
6.0 .mu.m, or 7.0 .mu.m, or 8.0 .mu.m, or 9.0 .mu.m, or 10.0 .mu.m,
or 11.0 .mu.m, or 12.0 .mu.m, or 13.0 .mu.m, or 14.0 .mu.m, or 15.0
.mu.m, or 16.0 .mu.m, or 17.0 .mu.m, or 18.0 .mu.m, or 19.0 .mu.m,
or 19.8 .mu.m to 22.2 .mu.m, or 23.0 .mu.m, or 25 .mu.m, or 30
.mu.m, or 35 .mu.m, or 40 .mu.m, or 45 .mu.m, or 50 .mu.m, or 65
.mu.m, or 70 .mu.m, or 75 .mu.m, or 80 .mu.m, or 85 .mu.m, or 90
.mu.m; and/or (4) the combined volume of the skin layers is from 10
vol %, or 15 vol %, or 20 vol %, or 25 vol %, or 30 vol %, or 35
vol %, or 40 vol % to 45 vol %, or 50 vol %, or 55 vol %, or 60 vol
% of the total volume of the multilayer film; and/or (5) each skin
layer has a thickness of from 0.75 .mu.m, or 1.0 .mu.m, or 1.5
.mu.m, or 2.0 .mu.m, or 3.0 .mu.m, or 4.0 .mu.m, or 5.0 .mu.m, or
6.0 .mu.m, or 6.5 .mu.m to 7.0 .mu.m, or 7.5 .mu.m, or 8.0 .mu.m,
or 9.0 .mu.m, or 10.0 .mu.m, or 11.0 .mu.m, or 12.0 .mu.m, or 13.0
.mu.m, or 14.0 .mu.m, or 15.0 .mu.m, or 20.0 .mu.m, or 25.0 .mu.m,
or 30 .mu.m; and/or (6) a slip factor of from 25,000, or 26,000, or
30,000, or 35,000, or 39,000 to 40,000, or 45,000, or 49,000, or
50,000, or 52,000, or 55,000, or 60,000; and/or (7) a coefficient
of friction (COF) from 0.05, or 0.10, or 0.15, or 0.19, or 0.20, or
0.24 to 0.25, or 0.26, or 0.27, or 0.28, or 0.29, or 0.30, or 0.31,
or 0.32, or 0.33, or 0.34, or 0.35,or 0.36, or 0.37, or 0.38;
and/or (8) a twist retention after aging 7 days of from 66%, or 70%
to 75%, or 80%, or 85%, or 90%, or 95%, or 100%; and/or (9) a yield
tension from 5 MPa, or 8 MPa, or 10 MPa, or 13 MPa to 14 MPa, or 15
MPa, or 15.5 MPa.
[0145] In an embodiment, the multilayer film has at least 2, or at
least 3, or at least 4, or at least 5, or at least 6, or at least
7, or at least 8, or all 9 of properties (1)-(9).
[0146] It is understood that the sum of the components in each of
the layers disclosed herein, including the foregoing layers, yields
100 weight percent (wt %), based on the total weight of the
respective layer.
[0147] In an embodiment, the multilayer film is a coextruded film
produced via a cast process. The multilayer film produced via a
cast process excludes multilayer films produced via a blown
process. Not wishing to be bound by any particular theory,
Applicants believe the cast process results in a multilayer film
with higher stiffness, which results in improved (i.e., higher)
twist retention.
[0148] In an embodiment, the multilayer film is not an oriented
film. In a further embodiment, the multilayer film is not biaxially
oriented. In other words, the multilayer film is not stretched
after extrusion.
[0149] In an embodiment, the multilayer film is coextruded and is
not laminated.
[0150] The multilayer film may comprise two or more embodiments
disclosed herein.
D. Article
[0151] The present disclosure also provides an article containing a
multilayer film. The multilayer film may be any multilayer film
disclosed herein.
[0152] In an embodiment, the article includes a confectionary and a
multilayer film in contact with the confectionary. In an
embodiment, the multilayer film contains at least three layers
including (A) a core layer containing a high density polyethylene
(HDPE) having a density from 0.940 g/cc to 0.980 g/cc and,
optionally, an additive; and (B) skin layers on opposite sides of
the core layer. Each skin layer includes (i) a propylene
homopolymer; (ii) from 2,000 to 3,500 ppm of a slip agent; (iii)
from 4,000 to 10,000 ppm of an antiblock agent; and, optionally,
(iv) an additive.
[0153] The article includes a confectionary. Nonlimiting examples
of suitable confectionaries include sugar confections, chocolate
confections, and combinations thereof. Nonlimiting examples of
sugar confections include lollipops, hard candies, soft candies,
licorice, caramels, gum, candied nuts, candied fruits, fudge,
taffy, marzipan, taffy, brittle, marshmallows, mints, and
combinations thereof. Nonlimiting examples of chocolate confections
include fudge, chocolate pieces, chocolate bars, chocolate-covered
nuts, chocolate-covered fruits, chocolate mints, and truffles.
[0154] The multilayer film may be in direct or in indirect contact
with the confectionary. In an embodiment, the multilayer film is in
direct contact with the confectionary.
[0155] The multilayer film may be twisted and/or folded around the
confectionary. In an embodiment, the multilayer film is folded and
subsequently twisted at opposing ends of the confectionary.
[0156] The article may comprise two or more embodiments disclosed
herein.
[0157] By way of example, and not limitation, some embodiments of
the present disclosure will now be described in detail in the
following Examples.
EXAMPLES
[0158] Materials used in the examples are provided in Table 1A
below.
TABLE-US-00001 TABLE 1A Material/Description Properties Source
ELITE .TM. 5960G MI (I2)(190.degree. C. /2.16 kg) = The Dow (HDPE)
(ethylene 0.85 g/10 min, Density = Chemical homopolymer) 0.962
g/cc, Melting point = Company 134.degree. C. HDPE 05962B MI
(I2)(190.degree. C./2.16 kg) = The Dow (HDPE) (ethylene/ Melting
point = 132.degree. C. Chemical 1-octene copolymer) Company
CUYOLENT .TM. MFR (230.degree. C./2.16 kg) = Petroquimica 1102L
(propylene 5 g/10 min, Density = 0.903 Cuyo S.A.I.C. homopolymer)
g/cc Melt point = 161.degree. C.; propylene = 100 wt %; ethylene =
0 wt % VERSIFY .TM. 3000 MFR (230.degree. C./2.16 kg) = The Dow
(propylene/ethylene 8.0 g/10 min, Density = Chemical copolymer)
0.891 g/cc, Melting Company point = 108.degree. C., ethylene = 4.5
wt % VERSIFY .TM. 2000 MFR (230.degree. C./2.16 kg) = The Dow
(propylene/ethylene 2.0 g/10 min, Density = Chemical copolymer)
0.888 g/cc, Melting point = Company 107.degree. C., ethylene = 4.5
wt % VERSIFY .TM. 3401 MFR (230.degree. C./2.16 kg) = The Dow
(propylene/ethylene 8.0 g/10 min, Density = Chemical copolymer)
0.863 g/cc, Melting point = Company 55.degree. C., ethylene = 12-15
wt % Slip Agent MFR (190.degree. C./2.16 kg) = 30 Ampacet
Masterbatch Ampacet g/10 min, Density = 0.82 g/cc, Code 901021 BX
Erucamide Content = 2 wt % (in polyethylene matrix) Antiblock Agent
MFR (190.degree. C/2.16 kg) = 20 Ampacet Masterbatch Ampacet g/10
min, Density = 1.05 g/cc, Code 901300 BX Silica Content = 20 wt %
(in polyethylene matrix)
[0159] Multilayer film samples are fabricated on a Collins cast
line with the conditions provided in
[0160] Table 1B.
TABLE-US-00002 TABLE 1B Cast Film Fabrication Conditions Layer
Distribution: Skin Layer (B1)/Core Layer (A)/Skin Layer (B2) Layer
Ratio 20/60/20 Die Gap (mm) 0.7 Blower (%) 23 Takeoff (m/min) 23
Total Output (kg/h) 8.6 Die Temperature (.degree. C.) 280 Core
Layer (A) Temperature Zone 2: 210.degree. C. Skin Layer (B2)
Extruder Temperature Zone 2: 220.degree. C. Extruder Temperature
Zone 3: 230.degree. C. Temperature Zone 3: 250.degree. C.
Temperature Zone 4: 240.degree. C. Temperature Zone 4: 270.degree.
C. Temperature Zone 5: 260.degree. C. Temperature Zone 5:
280.degree. C. Temperature Zone 6: 260.degree. C. Temperature Zone
6: 280.degree. C. Temperature Zone 7: 260.degree. C. Rotations Per
Minute (rpm): 58 Rotations Per Minute (rpm): 45 Amps (A): 4.1 Amps
(A): 1 Melt Temperature: 260.degree. C. Melt Temperature:
250.degree. C. Melt Pressure: 141 bar Melt Pressure: 56 bar Output:
4.96 kg/h Output: 1.79 kg/h Skin Layer (B1) Temperature Zone 2:
210.degree. C. Extruder Temperature Zone 3: 230.degree. C.
Temperature Zone 4: 240.degree. C. Temperature Zone 5: 260.degree.
C. Temperature Zone 6: 280.degree. C. Rotations Per Minute (rpm):
45 Amps (A): 1 Melt Temperature: 249.degree. C. Melt Pressure: 55
bar Output: 1.83 kg/h
[0161] The layer configurations and the multilayer film structures
are provided below in Table 2. Each multilayer film structure is
formed with a core layer (A) having a volume that is 60 volume % of
the multilayer film, and two skin layers (B1 and B2). Each skin
layer (B1 and B2) has a volume that is 20 volume % of the
multilayer film. In other words, the combined skin layers (B1 and
B2) make up 40 volume % of the multilayer film. In Table 2, the
amount of slip agent and antiblock agent refers to the amount of
respective slip agent and antiblock agent contained in the layer
(rather than the amount of slip agent masterbatch and/or antiblock
agent masterbatch contained in the layer). In Table 2, the contents
of each layer are recited in weight percent (wt %) and/or ppm
(parts per million), based on the total weight of the respective
layer. For example, the skin layer (B1) of Ex 3 contains 78.5 wt %
CUYOLEN.TM. 1102L; 3,500 ppm slip agent (i.e., 0.35 wt % slip
agent); 8,000 ppm antiblock agent (i.e., 0.8 wt % antiblock agent);
and 20.35 wt % masterbatch polyethylene carrier ("MB PE") (i.e.,
the combined amount of (i) 17.15 wt % polyethylene carrier from the
slip agent masterbatch and (ii) 3.2 wt % polyethylene carrier from
the antiblock agent masterbatch), based on the total weight of the
skin layer (B1).
[0162] The multilayer film samples are tested for COF, twist
retention, and yield tension. The results are provided below in
Table 2.
TABLE-US-00003 TABLE 2 Skin Layer Core Skin Layer Yield (B1) Layer
(A) (B2) Thickness Slip Tension Twist Retention (20 vol %) (60 vol
%) (20 vol %) (.mu.m) Factor (MPa) COF.sup.+ Day 1 Day 2 Day 3 Day
4 Day 7 TR (%) Ex 1 86% CUYOLEN 100% 86% CUYOLEN 34 26,880 15.3
0.38 4 4 4 4 4 100 1102L ELITE 1102L 13% MB PE 5960G 13% MB PE
2,000 ppm 2,000 ppm slip agent slip agent 8,000 ppm 8,000 ppm
antiblock agent antiblock agent Ex 2 81% CUYOLEN 100% 81% CUYOLEN
35 42,240 15.1 0.33 4 4 4 4 4 100 1102L ELITE 1102L 17.9% MB PE
5960G 17.9% MB PE 3,000 ppm 3,000 ppm slip agent slip agent 8,000
ppm 8,000 ppm antiblock agent antiblock agent Ex 3 78.5% 100% 78.5%
35 48,720 14.1 0.33 4 4 4 4 4 100 CUYOLEN ELITE CUYOLEN 1102L 5960G
1102L 20.35% MB PE 20.35% MB PE 3,500 ppm 3,500 ppm slip agent slip
agent 8,000 ppm 8,000 ppm antiblock agent antiblock agent CS 1 100%
95% 100% 28 0 NM 0.52 4 4 4 4 4 100 CUYOLEN ELITE CUYOLEN 1102L
5960G 1102L 5% VERSIFY 3401 CS 2 100% 98.0% 100% 32 7,740 NM NM 4 2
1 1 1 25 HDPE ELITE HDPE 05962B 5960G 05962B 1.96% MB PE 400 ppm
slip CS 3 100% 100% 100% 21 0 NM 0.91 5 5 5 5 5 100 VERSIFY ELITE
VERSIFY 2000 5960G 2000 CS 4 100% 100% 100% 22 0 NM 0.96 5 5 5 5 5
100 VERSIFY ELITE VERSIFY 3000 5960G 3000 CS 5 100% 100% 100% 29 0
NM 0.54 5 5 5 5 5 100 VERSIFY ELITE VERSIFY 3000 5960G 3000
.sup.+Coefficient of Friction (COF) was not measured for CS 2
because it exhibited poor twist retention (i.e., .ltoreq.50% twist
retention), indicating the multilayer film is not suitable for
twist packaging. CS = Comparative Sample NM = not measured MB PE =
the total amount of masterbatch polyethylene carrier
[0163] Comparative sample films containing three layers including
(A) a core layer containing HDPE having a density of 0.940-0.980
g/cc; and (B) skin layers on opposite sides of the core layer, the
skin layers containing (i) a propylene/ethylene copolymer and no
propylene homopolymer; (ii) no slip agent; and (iii) no antiblock
agent (CS 3-5) exhibit high COF (>0.38), indicating the
multilayer films are not suitable for twist packaging because
machine processing of the multilayer film is inhibited when the
multilayer film has a COF greater than 0.38.
[0164] Applicant surprisingly discovered multilayer films
containing three layers including (A) a core layer containing HDPE
having a density of 0.940-0.980 g/cc; and (B) skin layers on
opposite sides of the core layer, each skin layer containing (i) a
propylene homopolymer; (ii) 2,000-3,500 ppm of a slip agent; and
(iii) 4,000-10,000 ppm of an antiblock agent (Ex 1, Ex 2, Ex 3)
advantageously exhibit a unique balance of high twist retention
(66%-100%) to retain the wrapped form, low COF (0.05-0.38) to
improve machine processing of the multilayer film, and low yield
tension (.ltoreq.15.5 MPa) to enable permanent deformation of the
multilayer film and fold/twist retention with a lower tension
applied to the multilayer film, indicating the multilayer films are
suitable for twist packaging.
[0165] 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 within the scope of the following claims.
* * * * *