U.S. patent application number 16/370359 was filed with the patent office on 2019-07-25 for polypropylene compositions and methods to produce the same.
The applicant listed for this patent is ExxonMobil Chemical Patents Inc.. Invention is credited to Gary M. Brown, Aspy K. Mehta, Andy H. Tsou, Donald A. Winesett, Dalia G. Yablon.
Application Number | 20190225793 16/370359 |
Document ID | / |
Family ID | 54354773 |
Filed Date | 2019-07-25 |
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United States Patent
Application |
20190225793 |
Kind Code |
A1 |
Mehta; Aspy K. ; et
al. |
July 25, 2019 |
POLYPROPYLENE COMPOSITIONS AND METHODS TO PRODUCE THE SAME
Abstract
Compositions comprising a continuous phase of at least one
polypropylene; within the range of from 5 wt % to 50 wt % of a
mineral hydroxide filler by weight of the composition, having an
aspect ratio within the range of from 5 or 6 or 8 to 20 or 40 or
100 or 200 or 800 or 1000; and within the range of from 5 wt % to
40 wt % of a olefin block-containing copolymer by weight of the
composition. Also described is a method of forming the compositions
comprising combining the components as "masterbatches" or as neat
ingredients, or some combination thereof.
Inventors: |
Mehta; Aspy K.; (Humble,
TX) ; Tsou; Andy H.; (Houston, TX) ; Winesett;
Donald A.; (Houston, TX) ; Brown; Gary M.;
(Baytown, TX) ; Yablon; Dalia G.; (Sharon,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Chemical Patents Inc. |
Baytown |
TX |
US |
|
|
Family ID: |
54354773 |
Appl. No.: |
16/370359 |
Filed: |
March 29, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14672669 |
Mar 30, 2015 |
10287431 |
|
|
16370359 |
|
|
|
|
61986548 |
Apr 30, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L 2205/03 20130101;
C08L 23/12 20130101; C08L 53/025 20130101; C08J 2323/10 20130101;
C08K 2201/016 20130101; C08L 23/12 20130101; C08K 3/013 20180101;
C08L 2205/025 20130101; C08L 53/02 20130101; C08K 7/04 20130101;
C08K 3/013 20180101; C08J 3/201 20130101; C08L 53/02 20130101 |
International
Class: |
C08L 53/02 20060101
C08L053/02; C08K 7/04 20060101 C08K007/04; C08K 3/013 20060101
C08K003/013; C08J 3/20 20060101 C08J003/20; C08L 23/12 20060101
C08L023/12 |
Claims
1. The method of claim 15, wherein the composition comprises a
continuous phase of polypropylene; within the range of from 5 wt %
to 50 wt % of a mineral hydroxide filler by weight of the
composition, the mineral hydroxide filler having an aspect ratio
within the range of from 5 to 1000; and within the range of from 5
wt % to 40 wt % of a olefin block-containing copolymer by weight of
the composition wherein the polypropylene is present within a range
from 10 wt % to 29.5 wt % by weight of the composition, wherein the
composition has a 1% Secant Flexural Modulus (ISO) of greater than
2000 MPa and a Notched Izod Impact Resistance (-29 .degree. C.,
ISO) of greater than 5 kJ/m.sup.2, wherein polar-graft polymers are
absent and the filler excludes silicate fillers.
2. The method of claim 1, wherein the mineral hydroxide filler is a
metal salt of an oxysulfate, aluminoxysulfate, aluminosilicate,
silicate, borate, or combination thereof.
3. The method of claim 16, wherein the olefin block-containing
copolymer is selected from the group consisting of
styrene-butadiene-styrene block copolymers,
styrene-isoprene-styrene block copolymers,
styrene-ethylene/propylene-styrene block polymers,
styrene-ethylene/butene/styrene block polymers, and hydrogenated
versions thereof and blends thereof.
4. The composition method of claim 16, wherein the olefin
block-containing copolymer is a styrene-olefin block copolymer
having within the range of from 5 wt % to 25 wt % styrene-derived
units by weight of the copolymer, which may or may not be
hydrogenated.
5. The method claim 16, wherein the polypropylene has a MFR within
the range of from 4 g/10 min to 100 g/10 min.
6. The method of claim 16, wherein the polypropylene has a melting
point temperature ("T.sub.m", DSC) within the range of from 130
.degree. C. to 170 .degree. C.
7. The method claim 1, having a 1% Secant Flexural Modulus (ISO) of
greater than 3000 to 5000 MPa.
8. The method claim 1, having a Notched Izod Impact Resistance (-29
.degree. C., ISO) of 6 to 20 greater than 2 kJ/m.sup.2.
9. The composition method of claim 16, wherein the slope (m) of the
Chord Modulus (y) as a function of 1% Secant Flexural Modulus (x)
line is greater than 1.8.
10. The method of claim 1, having a heat distortion temperature
("HDT") within the range of from 90 .degree. C. to 130 .degree.
C.
11. The method of claim 1, having a flow direction Coefficient of
Linear Thermal Expansion ("CLTE") within the range of from
0.50.times.10.sup.-5/.degree. C. to 3.0.times.10.sup.-5/.degree.
C.; and a cross-flow direction CLTE within the range of from
8.0.times.10.sup.-5/.degree. C. to 15.0.times.10.sup.-5/.degree.
C.
12. The method of claim 1, wherein the MFR of the composition is
within the range of from 5 g/10 min to 100 g/10 min.
13. The method of claim 1, wherein polar-graft polymers are
absent.
14. An automotive component comprising the composition obtained
from the method of claim 1.
15. A method of forming a composition comprising combining and melt
processing: a first mixture of a propylene-based polymer and a
mineral hydroxide filler having an aspect ratio within the range of
from 5 to 1000; with a second mixture of a propylene-based polymer
and olefin block-containing copolymer; and isolating the
composition; wherein the composition comprises a continuous phase
of polypropylene and within the range of from 5 wt % to 50 wt % of
the filler and within the range of from 5 wt % to 40 wt % of a
olefin block-containing copolymer.
16. A method of forming a composition comprising combining and melt
processing: a neat mineral hydroxide filler having an aspect ratio
within the range of from 5 to 1000; with a polypropylene and olefin
block-containing copolymer, together or separately; and isolating
the composition; wherein the composition comprises a continuous
phase of polypropylene and within the range of from 5 wt % to 50 wt
% of the filler and within the range of from 5 wt % to 26 wt % of a
olefin block-containing copolymer.
17. The method of claim 16, wherein the components are added in the
order of: polypropylene, neat mineral hydroxide filler, and olefin
block-containing copolymer, wherein the neat mineral hydroxide
filler is dispersed within the melted polypropylene, and the olefin
block-containing copolymer is added and dispersed within the
polypropylene-filler mix.
18. The method of claim 15, wherein the olefin block-containing
copolymer is selected from the group consisting of
styrene-butadiene-styrene block copolymers,
styrene-isoprene-styrene block copolymers,
styrene-ethylene/propylene/styrene block polymers,
styrene-ethylene/butene/styrene block polymers, and hydrogenated
versions thereof and blends thereof.
19. The method of claim 15, wherein the olefin block-containing
copolymer is a styrene-olefin block copolymer having within the
range of from 5 wt % to 25 wt % styrene-derived units by weight of
the copolymer, which may or may not be hydrogenated.
20. The method of claim 15, wherein the polypropylene has a MFR
within the range of from 4 g/10 min to 100 g/10 min.
21. The method of claim 15, wherein the polypropylene has a melting
point temperature ("T.sub.m", DSC) within the range of from 130
.degree. C. to 170 .degree. C.
22. The method of claim 15, wherein the composition has a 1% Secant
Flexural Modulus (ISO) of greater than 2000 MPa.
23. The method of claim 16, wherein the composition has a Notched
Izod Impact Resistance (-29 .degree. C., ISO) of greater than 2
kJ/m.sup.2.
24. The method of claim 15, wherein the slope (m) of the Chord
Modulus (y) as a function of 1% Secant Flexural Modulus (x) line is
greater than 1.8.
25. The method of claim 15, wherein the MFR of the composition is
within the range of from 5 g/10 min to 50 g/10 min.
26. A method of forming a composition comprising combining and melt
processing: a first mixture of a propylene-based polymer and a
mineral hydroxide filler having an aspect ratio within the range of
from 5 to 1000; with a second mixture of a propylene-based polymer
and olefin block-containing copolymer; and isolating the
composition; wherein the composition comprises a continuous phase
of polypropylene, within a range from 10 wt % to 29.5 wt % of
polypropylene by weight of the composition, wherein the
polypropylene has a melting point temperature ("Tm", DSC) within
the range of from 130 .degree. C. to 170.degree. C.; and within the
range of from 30 wt % to 50 wt % of a mineral hydroxide filler by
weight of the composition, the mineral hydroxide filler having an
aspect ratio within the range of from 5 to 1000; and within the
range of from 5 wt % to 40 wt % of a olefin block-containing
copolymer by weight of the composition, wherein the olefin
block-containing copolymer is selected from the group consisting of
styrene-butadiene-styrene block copolymers,
styrene-isoprene-styrene block copolymers,
styrene-ethylene/propylene-styrene block polymers,
styrene-ethylene/butene/styrene block polymers, and hydrogenated
versions thereof and blends thereof, wherein the composition has a
1% Secant Flexural Modulus (ISO) of greater than 2000 MPa and a
Notched Izod Impact Resistance (-29 .degree. C., ISO) of greater
than 5 kJ/m.sup.2, wherein polar-graft polymers are absent and the
filler excludes silicate fillers.
27. The method of method of 26, wherein the mineral hydroxide
filler is a metal salt of an oxysulfate, aluminoxysulfate, borate,
or combination thereof.
28. The method of claim 26, wherein the olefin block-containing
copolymer is a styrene-olefin block copolymer having within the
range of from 5 wt % to 25 wt % styrene-derived units by weight of
the copolymer, which may or may not be hydrogenated.
29. The method of claim 1, wherein the polypropylene has a MFR
within the range of from 4 g/10 min to 100 g/10 min.
30. The method of claim 26, wherein the polypropylene has: 1) a MFR
within the range of from 4 g/10 min to 100 g/10 min; 2) a 1% Secant
Flexural Modulus (ISO) of 3000 to 5000 MPa; 3) a Notched Izod
Impact Resistance (-29 .degree. C., ISO) of 6 to 20 kJ/m.sup.2; 4)
a slope (m) of the Chord Modulus (y) as a function of 1% Secant
Flexural Modulus (x) line that is greater than 1.8; 5) a heat
distortion temperature ("HDT") within the range of from 90 .degree.
C. to 130 .degree. C.; and 6) a flow direction Coefficient of
Linear Thermal Expansion ("CLTE") within the range of from
0.50.times.10.sup.-5/.degree. C. to 3.0.times.10.sup.-5/.degree. C.
and a cross-flow direction CLTE within the range of from
8.0.times.10.sup.-5/.degree. C. to 15.0.times.10.sup.-5/.degree.
C.
31. The method of claim 26, wherein the MFR of the composition is 5
g/10 min to 100 g/10 min.
32. An automotive component comprising the composition obtained
from the method of claim 26.
33. The method of claim 1, wherein the mineral hydroxide filler is
magnesium oxysulfate.
34. The method of claim 26, wherein the mineral hydroxide filler is
magnesium oxysulfate.
35. The method of claim 1, wherein: a) the olefin block-containing
copolymer is selected from the group consisting of
styrene-butadiene-styrene block copolymers,
styrene-isoprene-styrene block copolymers,
styrene-ethylene/propylene-styrene block polymers,
styrene-ethylene/butene/styrene block polymers, and hydrogenated
versions thereof and blends thereof; b) the olefin block-containing
copolymer is a styrene-olefin block copolymer having within the
range of from 5 wt % to 25 wt % styrene-derived units by weight of
the copolymer, which may or may not be hydrogenated; c) the
polypropylene has a MFR within the range of from 4 g/10 min to 100
g/10 min and a melting point temperature ("T.sub.m", DSC) within
the range of from 130.degree. C. to 170.degree. C.; d) the
composition has a 1% Secant Flexural Modulus (ISO) of 3000 to 5000
MPa; e) the composition has a Notched Izod Impact Resistance (-29
.degree. C., ISO) of 6 to 20 kJ/m.sup.2; f) the slope (m) of the
Chord Modulus (y) as a function of 1% Secant Flexural Modulus (x)
line is greater than 1.8; g) the composition has a heat distortion
temperature ("HDT") within the range of from 90.degree. C. to 130
.degree. C.; h) the composition has a flow direction Coefficient of
Linear Thermal Expansion ("CLTE") within the range of from
0.50.times.10.sup.-5/.degree. C. to 3.0.times.10.sup.-5/.degree. C.
and a cross-flow direction CLTE within the range of from
8.0.times.10.sup.-5/.degree. C. to 15.0.times.10.sup.-5/.degree.
C.; i) the composition has a an MFR of from 5 g/10 min to 100 g/10
min; and j) the mineral hydroxide filler is a magnesium salt of an
oxysulfate, aluminoxysulfate, borate, or combination thereof.
36. The method of claim 26, wherein the mineral hydroxide filler is
a magnesium salt of an oxysulfate, aluminoxysulfate, borate, or
combination thereof.
37. The method of claim 1, wherein the mineral hydroxide filler is
a neat mineral hydroxide filler having an aspect ratio within the
range of from 5 to 1000; wherein the composition comprises a
continuous phase of polypropylene, 30 wt % to 50 wt % of the
filler, 5 wt % to 26 wt % the a olefin block-containing copolymer,
wherein the polypropylene, neat mineral hydroxide filler, and
olefin block-containing copolymer are added in the order of:
polypropylene, neat mineral hydroxide filler, then olefin
block-containing copolymer, wherein the neat mineral hydroxide
filler is dispersed within the melted polypropylene, and the olefin
block-containing copolymer is added and dispersed within the
polypropylene-filler mix.
38. The method of claim 35, wherein the mineral hydroxide filler is
a neat mineral hydroxide filler having an aspect ratio within the
range of from 5 to 1000; wherein the composition comprises a
continuous phase of polypropylene, 30 wt % to 50 wt % of the
filler, 5 wt % to 26 wt % the a olefin block-containing copolymer,
wherein the polypropylene, neat mineral hydroxide filler, and
olefin block-containing copolymer are added in the order of:
polypropylene, neat mineral hydroxide filler, then olefin
block-containing copolymer, wherein the neat mineral hydroxide
filler is dispersed within the melted polypropylene, and the olefin
block-containing copolymer is added and dispersed within the
polypropylene-filler mix.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. Ser. No.
14/672,669, filed Mar. 30, 2015, which claims priority to U.S. Ser.
No. 61/986,548 filed on Apr. 30, 2014, which is herein incorporated
by reference.
FIELD OF THE INVENTION
[0002] The inventions disclosed herein relate to a
polypropylene-based composition suitable for high impact, high
stiffness applications such as interior automotive components, as
well as the method for making such compositions.
BACKGROUND OF THE INVENTION
[0003] Polypropylene ("PP") is widely used in the automotive
industry as base polymer for a variety of internal (e.g.,
instrument panel) and external (e.g., body panels) components.
Typically, polypropylene-based compositions must provide a
properties profile that includes high stiffness, high toughness at
low temperatures, high resistance to distortion at elevated
temperatures (i.e. high Heat Distortion Temperature or HDT), a
Class `A` surface to provide an aesthetic appeal, low shrinkage and
easy moldability, all at a competitive price to the manufacturer. A
key requirement is a strong combination of high stiffness
(rigidity) and high toughness at low temperatures (resistance to
deformation). A representation of the stiffness/low-temperature
toughness balance that is available today is illustrated in FIG.
1A, and summarized in Table 1, which is a plot of Notched Izod
Impact strength (ISO 180) at sub-zero temperatures (typically
-29.degree. C.; range -20 to -40.degree. C.), plotted against
ambient temperature Flexural Modulus (ISO 178), for compositions
with melt flow rate ("MFR", 230.degree. C., 2.16 kg) values in the
range 10 to 30 g/10 min. The data encompass a broad range of
current commercial products from a variety of suppliers. These
products contain fillers, which contribute towards increased
rigidity. Typically, mineral fillers such as talc are used.
[0004] Today's best automotive compounds displaying high stiffness
(Modulus) and high low-temperature toughness (Impact Strength) fall
in a region of the landscape, by way of a plot of -29.degree. C.
Notched Izod as a function of ambient temperature Flexural Modulus,
bounded by a line connecting the data points for industry standards
ADX5023 (Advanced Composites Inc.) and EF341-AE (Borealis), within
or left (below) of this boundary line as depicted in FIG. 1A.
[0005] The automotive industry is looking for even
higher-performing compositions, which would allow OEMs to continue
light-weighting to improve fuel economy and reduce emissions. Cost
reduction is also a primary driver, providing the impetus to
advance the development of polyolefin-based compositions. To extend
the stiffness/toughness boundary, will require the use of a
high-crystallinity polypropylene matrix, combined with even
higher-performing impact modifier and filler components. What is
needed is a polypropylene-based composition that has a higher
Modulus and Impact Strength.
[0006] Relevant publications include WO 2013/169325; an MOS-HIGE
pamphlet published by Mitsui Plastics Inc. (2009); and a
presentation "Hyperform HPR-803" by Milliken & Company (2010);
U.S. Pat. No. 8,927,638; EP 1 548 054 A1; EP 2 386 602; U.S. Pat.
No. 5,571,581; and U.S. Pat. No. 5,252,659.
SUMMARY OF THE INVENTION
[0007] Disclosed and described is a composition comprising (or
consisting essentially of, or consisting of) a continuous phase of
polypropylene; within the range of from 5 wt % to 50 wt % of a
filler by weight of the composition, having an aspect ratio within
the range of from 5 to 1000; and within the range of from 5 wt % to
40 wt % of a olefin block-containing copolymer by weight of the
composition making up a discreet phase, or "rubber" domains.
[0008] Also disclosed are methods of forming the compositions
comprising combining the components as "masterbatches" or as neat
ingredients, or some combination thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1A is a plot of the ISO-based -29.degree. C. Notched
Izod versus Flexural Modulus of various commercial grade TPOs; FIG.
1B is the same, but with added inventive Examples.
[0010] FIG. 2 is the Molded-part Flexural Modulus of
polypropylene/elastomer bi-blends (4.6 MFR polypropylene, different
elastomers) plotted as a function of elastomer loading.
[0011] FIG. 3 is a bar graph of the Flexural Modulus enhancement
efficiency of different fillers in blends with polypropylene (MPa/1
wt % filler loading).
[0012] FIG. 4 is a plot of the Chord (between 0.05 and 0.25%
strain) Modulus and 1% secant modulus for i) Unfilled ICP
polypropylene (PP-8224 E2, ExxonMobil) and ii) filled composition
(30 wt % MOS in 4.6 MFR polypropylene).
[0013] FIGS. 5A-C are plots of the ASTM Chord Modulus versus the
ASTM 1% Sec Flex Modulus (A-neat ICP; B-talc filled compositions;
C-MOS-filled PP bi-blends).
[0014] FIG. 6 is a plot of the ISO-based Stiffness/Impact Balance
of One-Step Compounded Example 12 (arrow) plotted alongside
Masterbatch-based Examples 1, 2, 3, 5, 6. 7 (with increasing
modulus: BMU-147 control, and Examples 2, 1, 3, 7, 5, 6, 12).
[0015] FIG. 7 contains Atomic Force Microscopy (AFM) phase images
of Morphologies of Examples 8, 9, 10 and 11; where AFM is from
Asylum Research, CA; Light: Soft phase, Dark: Hard phase; and where
FIG. 7 refers to Examples 8, 9, 10, and 11 as ("A"), ("B"), ("C"),
and ("D"), respectively.
DETAILED DESCRIPTION
[0016] The automotive industry seeks polypropylene-based
Thermoplastic Polyolefin compositions ("TPO", or simply
"compositions") having a combination of high stiffness and high
low-temperature impact strength. Few if any current commercial TPOs
displays a stiffness/low-temperature toughness balance of 3000 MPa
Flexural Modulus and 10 kJ/m.sup.2 Notched Izod impact at
-29.degree. C. (ISO measurement protocol). The inventors have
developed compositions that meet this target using a polypropylene
polymer, a block copolymer as described herein, and a high aspect
ratio filler. The stiffness/toughness balance achieved, when
observed on a plot of -29.degree. C. Notched Izod Impact versus
ambient temperature Flexural Modulus, appears well differentiated
from today's industry standards. The block copolymer elastomer is
demonstrated to provide substantially higher impact strength than
ethylene plastomers (e.g., ethylene/octene), widely used in
compound formulations as an impact modifier. A distinguishing
feature of the prototype TPO compositions described herein is,
versus both neat ICPs/TPOs and talc-filled compounds, the
substantial difference between Chord Modulus and Secant Flexural
Modulus values, which increases with an increase in overall
stiffness. This differentiation is one characterizing feature of
the inventive compositions versus known mineral filler-based
automotive compounds. Typical automotive compositions containing 30
wt % mineral filler are characterized by enhanced stiffness and
resistance to elevated temperatures, but with relatively low
toughness. Surprisingly, a composition of, for example, 30 wt %
high aspect ratio filler and 30 wt % elastomer, provides a unique
combination of high stiffness and high low-temperature impact
strength.
[0017] Thus, the invention described herein is directed to a
polypropylene composition and methods of forming the composition.
In particular, described herein is a composition comprising (or
consisting essentially of) a continuous phase of polypropylene,
within the range of from 5 or 10 or 15 wt % to 35 or 40 or 50 wt %
of a filler by weight of the composition, having an aspect ratio
within the range of from 5 or 6 or 8 to 20 or 40 or 100 or 200 or
800 or 1000; and within the range of from 5 or 10 wt % to 25 or 30
or 40 wt % of a olefin block-containing copolymer by weight of the
composition. The olefin block-containing copolymer typically forms
discontinuous domains within the polypropylene matrix.
[0018] As used herein, the "filler" is a material in particulate,
plate, and/or strand form that is not soluble or meltable in the
other polymers of the composition at the temperatures at which it
is processed, preferably up to 250.degree. C., having the above
mentioned aspect ratio (length/width of the material), determined
by any suitable means of measuring the physical dimensions of small
particles, but preferably using AFM micrograph technique.
Preferably, the filler is a mineral hydroxide filler, which
comprises Group 1 to 14 compounds (especially Groups 2, and 12-14)
alone or with silicon or sulfur in oxidized and/or hydrated form,
including natural minerals such as micas, silicates, carbonates,
etc. Most preferably, the filler comprises hydrated compounds
including hydroxides of Ca, Mg, Al, and/or B (with or without
sulfur or silicon). Finally, even more preferably, the filler is a
metal salt of an oxysulfate, aluminoxysulfate, aluminosilicate,
silicate, borate, or combination thereof, examples of which include
magnesium or calcium oxysulfate. Most preferably, the filler is a
magnesium oxysulfate (MOS) in the form of whiskers. Also, in
certain preferred embodiments, the filler excludes glass
(predominately silicate) fillers.
[0019] As used herein, the "olefin block-containing copolymer" is a
copolymer or terpolymer (hereinafter "copolymer") that contains
olefin blocks and at least one other polymerizable monomer-derived
unit such as styrene, acrylate, etc., where the "olefin block" is
one or two or more .alpha.-olefin derived units such as ethylene
and propylene derived groups, wherein each group occurs in long
sequences. Desirable olefin block-containing copolymers include
styrene-butadiene-styrene (SBS), styrene-butadiene/butylene-styrene
(SBBS), styrene-isoprene-styrene (SIS),
styrene-ethylene/propylene-styrene (SEPS),
styrene-ethylene/propylene (SEP), styrene-ethylene/butylene-styrene
(SEBS), styrene-ethylene/ethylene/propylene-styrene (SEEPS), and
styrene-isobutylene-styrene (SIBS), and hydrogenated versions
thereof (of the unsaturated non-styrenic block portions).
Preferably, the olefin block-containing copolymer is selected from
the group consisting of styrene-butadiene-styrene block copolymers,
styrene-isoprene-styrene block copolymers, more preferably
hydrogenated versions of these polymers such as
styrene-ethylene/propylene-styrene block polymers and
styrene-ethylene/butene-styrene block polymers, and mixtures
thereof. Even more preferably, the olefin block-containing
copolymer is a hydrogenated styrene-olefin block-styrene copolymer
having within the range of from 5 wt % to 25 wt % styrene-derived
units by weight of the copolymer. The olefin block containing
copolymers could be tri-blocks or di-blocks or a combination of
both.
[0020] As used herein, the phrase "consisting essentially of" means
that that the composition being referred to does not include any
unnamed components to a level of greater than 5 or 3 or 1 wt %. The
inventive compositions may alternatively "consist of" the named
components.
[0021] As used herein, the "polypropylene" is a homopolymer or
copolymer of propylene-derived units and within the range from 0.05
or 0.1 or 0.5 wt % to 2.0 or 4.0 wt % ethylene or C.sub.4 to
C.sub.10 .alpha.-olefin comonomer derived units. Preferably, the
polypropylene useful herein is a homopolymer of propylene-derived
units. The polypropylene is preferably a high crystallinity
polypropylene, having a crystallinity of at least 40%, more
preferably at least 70% or 80% or 90% as determined by DSC. The
term "crystalline" as used herein, characterizes those polymers
that possess high degrees of inter- and intra-molecular order in
the solid state. The "polypropylene" can be a polymer of one
measured MFR or a mixture of two or more polypropylenes having
distinct MFR values, the overall MFR for the mixture being the
"MFR" of the "polypropylene". For example, a 2 to 8 MFR
polypropylene homopolymer may be blended with a 55 to 75 MFR
polypropylene homopolymer to form the "polypropylene" suitable for
the composition.
[0022] Melting point (T.sub.m) and percent crystallinity of
polypropylenes described herein are determined using the following
procedure according to ASTM E 794-85. Differential scanning
calorimetric (DSC) data is obtained using a TA Instruments model
2910 machine or a Perkin-Elmer DSC 7 machine. In the event that the
TA Instruments 2910 machine and the Perkin-Elmer DSC-7 machine
produce different DSC data, the data from the TA Instruments model
2910 shall be used. Samples weighing approximately 5-10 mg are
sealed in aluminum sample pans. The DSC data is recorded by first
cooling the sample to -50.degree. C. and then gradually heating it
to 200.degree. C. at a rate of 10.degree. C./minute. The sample is
kept at 200.degree. C. for 5 minutes before a second
cooling-heating cycle is applied. Both the first and second cycle
thermal events are recorded. Areas under the melting curves are
measured and used to determine the heat of fusion and the degree of
crystallinity. The percent crystallinity (X%) is calculated using
the formula, X%=[area under the curve (Joules/gram)/B
(Joules/gram)].about.100, where B is the heat of fusion for the
homopolymer of the major monomer component. These values for B are
to be obtained from the POLYMER HANDBOOK, Fourth Edition (John
Wiley & Sons, New York, 1999). A value of 189 J/g (B) is
understood to be the heat of fusion for 100% crystalline
polypropylene.
[0023] Preferably, the polypropylene has a melting point
temperature ("T.sub.m", DSC) within the range of from 130.degree.
C. or 140.degree. C. or 150.degree. C. to 160.degree. C. or
165.degree. C. or 170.degree. C. Also, the polypropylene preferably
has a Melt Flow Rate ("MFR", 230.degree. C./2.16 kg) within the
range of from 4 or 12 g/10 min to 70 or 80 or 100 g/10 min. As used
herein, "MFR" is measured per ASTM-D-1238, and throughout the
specification, polymers and/or polymer compositions may be referred
to as being, for example, "4.5 MFR" which means it has an MFR of
4.5 g/10 min as is known in the art. The Melt Index ("MI"),
typically used for ethylene-based polymers, is also measured by the
same ASTM at 190.degree. C./2.16 kg.
[0024] The composition is made up of the combination of at least
the filler, the olefin block-containing copolymer, both within the
range of the named weight percent proportions by weight of the
entire composition, and the remainder being the polypropylene. The
composition may also include minor amounts of other ingredients
such as antioxidants, nucleating agents, colorants, antiblock, and
other common additives as is known in the art. Preferably, the
composition has a MFR within the range of from 5 g/10 min to 30 or
40 or 50 g/10 min.
[0025] The inventive compositions have several desirable properties
measurable by ASTM or ISO methods. The composition preferably has a
Flexural Modulus (ISO) (Note: ISO Flexural Modulus is exclusively a
chord modulus) of greater than 2000 or 2500 or 3000 MPa; or within
the range of from 2000 or 3000 MPa to 5000 MPa. Also, the
compositions preferably have a Notched Izod Impact Resistance
(-29.degree. C., ISO) of greater than 2 or 6 or 8 or 10 kJ/m.sup.2;
or within a range of from 2 or 6 or 8 kJ/m.sup.2 to 15 or 20
kJ/m.sup.2. Most desirably, these features of Modulus and Impact
Resistance are found together in the inventive compositions.
[0026] FIG. 1B shows graphically this relationship. Preferably, the
compositions fall above and to the right of a line defined by the
ISO-based -29.degree. C. Notched Izod as a function of the
ISO-based Flexural Modulus, y=-0.0038x+15.27. Even more preferably
the compositions fall above the line (have a greater y-intercept)
of a line having a y-intercept of 16 or 16.5 or 17, and most
preferably, the compositions fall between and on lines having a
y-intercept of 15.5 or 16 or 16.5 to 22 or 23 or 25.
[0027] The compositions preferably have a heat distortion
temperature ("HDT") within the range of from 90 or 95.degree. C. to
100 or 110 or 130.degree. C. Finally, the compositions preferably
have a flow direction Coefficient of Linear Thermal Expansion
("CLTE") within the range of from 0.50.times.10.sup.-5/.degree. C.
to 3.0.times.10.sup.-5/.degree. C.; and a cross-flow direction CLTE
within the range of from 8.0.times.10'/.degree. C. to
15.0.times.10'/.degree. C. Preferably, polar-graft polymers, such
as maleic anhydride-grafted polypropylene, are absent from the
inventive compositions, meaning they are not added to the
composition.
[0028] Preferably, for the inventive compositions, the Chord
Modulus changes by at least 2 or 2.5 or 3 or 3.5 times (or changes
by a coefficient within the range of from 2 or 2.5 to 3.5 or 4 or
4.5) the change in 1% Secant Flexural Modulus over a range of 10 to
40 wt % loading of the filler. Stated another way, the composition
can be characterized in part such that the slope (m) of the Chord
Modulus (y) as a function of 1% Secant Flexural Modulus (x) line is
greater than 1.8, more preferably greater than 2.0 or 2.5, most
preferably greater than 3.0 or 3.4, as demonstrated, for example,
in FIGS. 6A-6C.
[0029] The inventive compositions may be formed by any suitable
means of melt mixing such as by melt extrusion, etc., and the
individual components may be combined in any order. A preferred
method of forming a composition comprises (or consists essentially
of) combining and melt processing (e.g., such as by extrusion) a
first mixture of a propylene-based polymer and a filler with a
second mixture of a propylene-based polymer and olefin
block-containing copolymer, followed by isolating the composition;
wherein the composition comprises a continuous phase of
polypropylene and discontinuous domains of filler and olefin
block-containing copolymer in the proportions set forth above. The
melt temperature can be any desirable temperature above the lowest
melting polymeric component, but below the temperature at which
decomposition occurs in the polypropylene or block copolymer, most
preferably within the range of from 180 or 190 or 200.degree. C. to
210 or 220 or 240.degree. C.
[0030] In a preferred method of forming the compositions described
herein, the filler is combined with the other ingredients as a
masterbatch. By "masterbatch" what is meant is a mixture of the
named ingredient with some other diluent such as a polymer,
especially a polymer very similar to or identical to the other
components of the compositions. The most preferable polymer diluent
is polypropylene, especially one that is identical to that used in
the composition. Desirably, the filler may be present in the
masterbatch within a range of from 10 or 20 or 30 wt % to 60 or 70
or 80 or 90 wt % by weight of the entire masterbatch. Likewise, the
olefin block-containing copolymer may also be in the form of a
masterbatch, preferably mixed in similar proportions with a
polypropylene either similar to or identical to the polypropylene
in the composition.
[0031] Another desirable method of forming a composition comprises
(or consists essentially of) combining and melt processing a neat
filler, as opposed to a masterbatch, the filler having an aspect
ratio within the range of from 5 to 1000; with a polypropylene and
olefin block-containing copolymer, together or separately, followed
by isolating the composition; wherein the composition comprises a
continuous phase of polypropylene and within the range of from 5 wt
% to 50 wt % of the filler and within the range of from 5 wt % to
26 wt % of a olefin block-containing copolymer. By "neat" what is
meant is that the component is not diluted or blended ("blend" and
"mix" are used interchangeably, simply meaning to intimately
combine two or more components) with any other substance until it
is used in the composition. Most preferably, in this method the
components are added in the order of: polypropylene, neat filler,
and olefin block-containing copolymer, wherein the neat filler is
added to the melted polypropylene and this mixture is then added as
a melt to the olefin block-containing copolymer. When using the
filler in neat form a pre-treatment is typically performed: i)
Pre-drying, since the preferred magnesium oxysulfate (MOS) filler
is hygroscopic, ii) Contacted with magnesium oxide to neutralize
the filler which is slightly alkaline, and iii) Contacted with
magnesium stearate, to improve the dispersion of the fibers in the
polypropylene matrix. With masterbatches, this pretreatment is
typically performed during preparation, though predrying the
masterbatch, prior to use is desirable and was performed.
[0032] In any case, once isolated the inventive compositions can be
formed by any suitable means into articles of manufacture,
especially automotive components that comprise (or consist
essentially of) the composition. The compositions may be suitable
for both internal (e.g., instrument panel) and external (e.g., body
panels) automotive components. Some suitable methods of forming the
composition into articles include injection molding and
thermoforming.
[0033] The various descriptive elements and numerical ranges
disclosed herein for the inventive compositions and methods of
making the compositions can be combined with other descriptive
elements and numerical ranges to describe the invention; further,
for a given element, any upper numerical limit can be combined with
any lower numerical limit described herein, including the examples.
The features of the invention are demonstrated in the following
non-limiting examples.
EXAMPLES
[0034] In Table 1 are published data related to comparative
polypropylene compositions suitable for such applications as
interior and exterior automotive components. These data are plotted
in FIG. 1A.
TABLE-US-00001 TABLE 1 Comparative Polypropylene Compositions
Flexural Modulus Notched Izod (ISO 180; (ISO 178; MFR
Grade/Supplier MPa) kJ/m.sup.2) (dg/min) EF341-AE/Borealis 3300 2.8
(-20.degree. C.) 15 ED230HP/Borealis.sup.1 1900 4 (-20.degree. C.)
10 ED230HP/Borealis 2800 2 (-40.degree. C.) 18 ADX-2001/Adv Comp
Inc.sup.2 1820 6.5 (-40.degree. C.) 23 ADX-5017/Adv Comp Inc 2016 6
(-40.degree. C.) 28 ADX-5028/Adv Comp Inc 1700 8.9 (-40.degree. C.)
11 ADX-5023/Adv Comp Inc 1900 8 (-29.degree. C.) 20 ADX-5016/Adv
Comp Inc 2000 5 (-40.degree. C.) 20 ATX-904-20/Adv Comp Inc 2593
2.6 (-29.degree. C.) 13 ATX-639MX2N/Adv Comp Inc 1690 7.7
(-40.degree. C.) 7 ATX-832N/Adv Comp Inc 2180 5 (-40.degree. C.) 30
ATX-646M/Adv Comp Inc 1618 4 (-40.degree. C.) 24 ATX-781/Adv Comp
Inc 1254 6.7 (-40.degree. C.) 15 ELAN ST-716/Putsch.sup.3 1600 7
(-20.degree. C.) 14 BMU-147/ExxonMobil.sup.4 1900 5.4 (-29.degree.
C.) 14 .sup.1Borealis Polyolefine GmbH, Schwechat, Austria
.sup.2Advanced Composites Inc, Subsidiary of Mitsui, Sidney, Ohio
.sup.3Putsch GmbH, Nurnberg, Germany .sup.4ExxonMobil Chemical Co.
(EMCC), Houston, Texas
[0035] The thermoplastic polyolefin composition ADX-5023 (Advanced
Composites Inc.) is a well-regarded industry standard for use in
interior automotive applications (need high level of
low-temperature impact strength). The TPO Daplen.TM. EF-341 AE
(Borealis) is similarly regarded for use in exterior applications
(need high level of stiffness). These two products form "book-ends"
for the desired properties profile of high stiffness coupled with
high low-temperature impact strength. As is seen in FIG. 1A and
FIG. 1B, they set the boundary of high performance available from
current commercial products. All the other products fall inside, or
to the left of this boundary line. A "target" for new TPO
compositions would be those that fall to the right and above the
line in FIG. 1A and B (e.g, 2500 to 3000 MPa at 10 kJ/m.sup.2 or
higher at -29.degree. C.).
Choice of Impact Modifier
[0036] An example of a polyolefin modifier is an ethylene
plastomer, particularly ethylene--octene plastomers (example:
Exact.TM. from ExxonMobil, Engage.TM. from Dow Chemical). To scope
the performance of ethylene plastomers, a bi-blend (64 wt % PP, 36
wt % plastomer) of an EMCC 52 MFR Ziegler-Natta produced
polypropylene homopolymer and Dow's Engage 8180 plastomer (having a
melt index (ASTM-D-1238, 190 C/ 2.16 kg) of 0.5 g/10 min, a density
of 0.863 g/cm.sup.3, and comprising 43 wt % C8) was prepared via
melt mixing on a 30 mm ZSK twin-screw extruder. The product was
tested for ASTM Notched Izod (ASTM D-256), and it was found that
the 23.degree. C. Notched Izod was 78 kJ/m.sup.2 or more (no
breaks), the 0.degree. C. was 73 kJ/m.sup.2 or more (also, no
breaks), and the -18.degree. C. was 16.7 kJ/m.sup.2, where there
was a complete break. The unfilled bi-blend at 36 wt % plastomer (a
higher-than-normal loading of rubber impact modifier) shows
insufficient low-temperature impact resistance, with complete
breaks at -18.degree. C. A higher level of impact modification is
desired beyond what plastomers can offer.
[0037] Several other elastomers were evaluated that are not
typically used with polypropylene, including cis-1,4-polyisoprene
(natural rubber TSR-L with -70.degree. C. T.sub.g; synthetic rubber
NIPOL.TM. IR 2200 L, -70.degree. C. T.sub.g from Zeon Chemicals,
Louisville, Ky.), cis-1,4-polybutadiene (BUDENE.TM. 1207,
-100.degree. C. T.sub.g from Goodyear Chemical, Akron, Ohio),
hydrogenated SIS block copolymer (SEPTON.TM. 2004, 18 wt % styrene,
from Kuraray America Inc., Houston, Tex.), vinyl-bond hydrogenated
SIBS (HYBRAR.TM. 7311, 12 wt % styrene, vinyl-polydiene soft block,
also from Kuraray), and EXACT.TM. 5361 Elastomer, 3 dg/min MI at
190C/2.16 kg, 0.860 g/cm.sup.3 density, ethylene-octene copolymer,
from ExxonMobil Chemical Ge Company, Houston, Tex., as the
plastomer control. 70/30 blends (PP/elastomer impact modifier) were
prepared on a 30 mm ZSK, twin screw extruder. The PP component for
all the bi-blends was a 4.6 MFR Ziegler-Natta based homopolymer
(ExxonMobil Chemical Company). The blends were injection molded
into ASTM specimens on a Nissei injection press (model NS20-2A) and
low-temperature Notched Izod impact data were measured. The impact
data are shown in Table 2, where "NB" means "no break" and "C"
means complete break.
TABLE-US-00002 TABLE 2 ASTM Notched Izod of 4.6 MFR Polypropylene
with different elastomers (30 wt %) Temperature Exact Natural
Budene Septon Hybrar (.degree. C.) ICP control 5361 Rubber 1207
2004 7311 23 >72 (NB) >50 (NB) >68 (NB) 9.1 (C) >81
(NB) >73 (NB) 0 >62 (NB) 31.6 (C) 12.9 (C) 4.5 (C) >86
(NB) 14.2 (C) -18 9.3 (C) 8.9 (C) 5.8 (C) 4 (C) >68 (NB) 1.9 (C)
-29 7.1 (C) 6.9 (C) 5.1 (C) 3.4 (C) 18.9 (C) 1.8 (C) ASTM Flexural
Modulus (MPa) 864 883 787 883 925 462
[0038] Among the 70/30 bi-blends tested, all with the same
polypropylene, and compounded and injection molded the same way,
the hydrogenated SIS (SEPTON.TM. 2004) provided markedly improved
-29.degree. C. Notched Izod impact. In addition, this blend also
had the highest flex modulus. The modulus numbers were similar,
aside from the low value of the final composition (PP/HYBRAR.TM.
7311 bi-blend), which comprises miscible components.
[0039] The hydrogenated SIS elastomer maintained its impact
modification capability in blends with moderately high MFR
polypropylenes. To provide good flowability during injection
molding of the final filled composition, polypropylenes of
moderately high MFR of greater than 50 g/10 min are preferred.
Table 3 illustrates the Notched Izod impact and the -29.degree. C.
Gardner impact (where "P" means "partial break", "D" means "ductile
failures", "DB" means "ductile/brittle", and "S" means "shatter")
for bi-blends of ExxonMobil Ziegler-Natta polypropylenes (70 wt %)
of three different MFRs (4.6, 35 and 65 g/10 min) with the
hydrogenated SIS elastomer (30 wt %). The blends were prepared on a
30 mm ZSK twin-screw extruder and ASTM specimens were injection
molded on the Nissei injection press. Example compositions include:
[0040] 4.5 MFR PP (70 wt %)+Septon 2004 (30 wt %) [0041] 35 MFR PP
(70 wt %)+Septon 2004 (30 wt %) [0042] 65 MFR PP (70 wt %)+Septon
2004 (30 wt %) [0043] 65 MFR PP (70 wt %)+Exact 5361 plastomer (30
wt %), control blend
TABLE-US-00003 [0043] TABLE 3 ASTM Notched Izod (kJ/m.sup.2) and
Gardner Impact for blends of Septon 2004 (30 wt %) with different
polypropylenes (70 wt %) of different MFR values 65 MFR 4.5 MFR 35
MFR PP + 65 MFR Temperature PP + PP + Septon PP + (.degree. C.)
Septon 2004 Septon 2004 2004 Exact 5361 23 >75 (NB) >71 (NB)
>69 (NB) 8 (C) 0 >65 (NB) >76 (NB) >70 (NB) 4 (C) -18
38 (P) >67 (NB) 24 (C) 3 (C) -29 10 (C) 19 (C) 12 (C) 3 (C) ASTM
Gardner Impact (in lb) 313 (12 D) >320 (NB) >320 (NB) 230
(6D, 6 DB, 1 S)
[0044] The results in Table 3 indicate that the hydrogenated SIS
elastomer provides good, stable impact modification of
polypropylene through 65 MFR. Its impact modification capability
far outweighs that of the plastomer Exact 5361 (3 g/10 min melt
index (190/2.16 ASTM-D-1238), density of 0.860 g/cm.sup.3, and
comprising 42 wt % C8), for a 65 MFR polypropylene. This stability
of the impact resistance with polypropylenes of increasing MFR is
not typical and indicates potential for a favorable
impact/processability balance. Also shown in Table 3 are values for
Gardner impact at -29.degree. C. The data confirm the Notched Izod
numbers, showing the 35 and 65 MFR PP blends to have very high
resistance to impact at low temperatures.
[0045] The morphologies (Field-Emission SEM micrographs with one
AFM phase micrograph) of the blends of hydrogenated SIS elastomer
with 4.6, 35 and 65 MFR PPs show hydrogenated SIS dispersions.
These are observed to be space-filling arrangements of large
(approx. 2 .mu.m.times.2 .mu.m) and small (approx. 0.5
.mu.m.times.0.5 .mu.m) domains. The AFM micrograph shows microphase
separation of the polystyrene domains within the hydrogenated SIS
dispersions. In the field-emission scanning electron micrographs,
dispersions of different aspect ratio are observed, dependent on
the viscosity ratio between the hydrogenated SIS and the different
polypropylenes. The dispersions cover the range from lamellar
(ribbons) to discrete domains (droplets).
[0046] The drop-off in Flexural Modulus of the bi-blend with
increasing levels of Septon 2004 elastomer was compared versus
similar bi-blends of the same PP (4.6 MFR) with other elastomeric
impact modifiers. The data are shown in FIG. 2, which plots ASTM
Flexural Modulus (D-790) versus elastomer loading for different
bi-blend compositions, all melt compounded under similar mixing
conditions (bench scale twin-screw extruder; 125 rpm, 190.degree.
C., 3 min). The drop-off in blend Flexural Modulus with increased
loading of the SIS matched that seen with a variety of other
elastomeric modifiers, indicating a similar response for all the
elastomers tested.
Choice of Polypropylene
[0047] The desirable polypropylene for use in the inventive
compositions preferably has a high crystallinity to provide high
inherent matrix stiffness and an appropriate molecular weight that
offered balance between easy moldability (lower MW preferred) and
inherent matrix toughness (higher MW preferred). The results in
Table 4, for 80/20 blends of PP/Exact 5361, demonstrate the issue
of balanced MW. The 4.6 MFR polypropylene (ExxonMobil Chemical Co.)
contributes to higher impact resistance, compared to the 110 MFR
polypropylene (Sunoco
[0048] F-1000HC from Braskem-Sunoco, Philadelphia, Pennsylvania).
As shown previously in Table 3, an MFR increase to about 65 g/10
min provides an appropriate impact versus moldability balance.
ExxonMobil grade PP-9999SS (65 MFR; 4.sup.th generation
Ziegler-Natta catalyst) produced the most preferred blends.
TABLE-US-00004 TABLE 4 ASTM Notched Izod for 80/20 wt/wt blends of
polypropylene with Exact 5361 Temperature, .degree. C. 4.6 MFR iPP
110 MFR iPP 23 18 3.5 0 6.5 2.5 -18 3.5 3.0
Choice of Filler
[0049] Different fillers were studied to compare their efficiencies
to enhance modulus (i.e. MPa enhancement per 1 wt % filler
loading), a higher efficiency value being more desirable. Details
on the fillers evaluated are shown in Table 5. The study involved
the preparation of melt blends of the different fillers in
polypropylene (4.6 MFR from ExxonMobil Chemical Co.) on a
bench-scale twin screw extruder. Compounding conditions were:
100-125 screw rpm, 190.degree. C.-200.degree. C. melt temperature,
3 min mixing time. The fillers were incorporated via a masterbatch
(MB) and/or as neat preparations.
TABLE-US-00005 TABLE 5 Properties of the fillers Specific Gravity
Aspect Filler (g/cm.sup.3) Form Ratio Grade/Supplier Talc, Mg
silicate hydroxide 2.75 Lamellar ~5 JETFIL .TM. 700C,
[Mg.sub.3Si.sub.4O.sub.10(OH).sub.2] platelets Luzenac (neat)
America, Greenwood Village, Colorado Clay (Kaolin), 2.2 Lamellar
~20 POLESTAR .TM. 400, [Al.sub.2Si.sub.2O.sub.5(OH).sub.4],
Hydrated layers (neat) Imerys, France Al silicate Wollastonite,
CaSiO.sub.3, Ca 2.95 Acicular 10-20 ASPECT .TM. 3992, metasilicate
(neat) Nyco Minerals Inc., Willsboro, New York Carbon nanofibers
(CNF) 1.95 Long fibers 40-800 PR-24, PR-19, [carbon] (neat)
Pyrograf Products Inc., Cedarville, Ohio MOS,
[MgSO.sub.4.cndot..sub.5Mg(OH).sub.2.cndot.3H.sub.2O], 2.3 Whiskers
10-40 MOS-HIGE .TM. MB, Mg oxysulfate (MB and Mitsui; H803 neat)
whiskers, Milliken Chem, Spartanburg, S. Carolina Halloysite, 2.0
Nanotubes 10-40 Pleximer,
[Al.sub.2Si.sub.2O.sub.5(OH).sub.4.cndot.2H.sub.2O], (MB)
NATRUALNANO .TM., Aluminosilicate Rochester, New York Multiwall
nanotubes 1.7 Nanotubes 40-200 PLASTICYL .TM. MB, [carbon] (MB)
Nanocyl, Sambreville, Belgium Graphene [carbon] 2.2 Nano- 100+
xGNP25 .TM., XG platelets Sciences, Lansing, (neat) Michigan
[0050] The filler efficiency numbers obtained (essentially, the
slope of Flexural modulus versus filler loading for each PP/filler
bi-blend set) are compared in FIG. 3. The carbon nanofibers and the
magnesium oxy-sulfate (MOS) whiskers (or fibers) gave the highest
level of PP modulus reinforcement. Graphene and carbon multi-wall
nanotubes (MWNT) showed low filler efficiency, even though they
offer high aspect ratio. These fillers are difficult to handle and
to disperse via melt mixing.
[0051] Based on these results, additional polymer melt blends of
the carbon nanofibers and MOS whiskers (or fibers) were prepared
and tested. Micrographs of the neat carbon nanofibers and the
magnesium oxy-sulfate whiskers reveal the carbon nanofibers to be
long generally straight fibers, with diameters of 0.1 to 0.3 .mu.m;
very rarely are the two ends of the same fiber observed. The fibers
are clearly of high aspect ratio, but with significant
intermingling. The MOS fibers are of lower aspect ratio and
bundled, but with much less intermingling. Fibrous fillers with
high levels of intermingling are generally more difficult to
uniformly disperse, to take full advantage of the high aspect
ratio. The carbon nanofiber compound comprised 20 wt % original
PR-24 and 20 wt % Exact.TM. 9361 ExxonMobil plastomer (3.5 MI,
density of 0.864 g/cm.sup.3, and comprising C2/C4) in polypropylene
(5 MFR from ExxonMobil Chemical), compounded on a Leistritz twin
screw extruder (27 mm, L/D 48-52) at American Leistritz Extruders
lab in Somerville, NJ. The magnesium oxy-sulfate masterbatch
compound comprised 50 wt % original HPR-803 whiskers, also
compounded in polypropylene (4.6 MFR) on the same Leistritz
compounding extruder. The carbon nanofibers are observed to reside
in the polypropylene matrix phase, which is desirable. They are
observed to exist in several orientations within the MD-ND plane,
diminishing the opportunity for maximum stiffness reinforcement.
Their fiber lengths are difficult to discern, given the various
orientations, they appear to be significantly shorter than the neat
fibers shown previously. By contrast, the magnesium oxy-sulfate
whiskers appear to generally lie along the MD-ND plane. Long
fibers/whiskers are observed, suggesting a measure of aspect ratio
retention. The whiskers are however still assembled in bundles,
suggesting the need for improved dispersability.
[0052] The product ingredients for developing high-performing
filled compounds to achieve the challenging product targets are
thus: a composition comprising (or consisting essentially of) a
continuous phase of polypropylene; within the range of from 5 or 10
or 15 wt % to 35 or 40 or 50 wt % of a filler by weight of the
composition, having an aspect ratio within the range of from 5 or 6
or 8 to 20 or 40 or 100 or 200 or 800 or 1000; and within the range
of from 5 or 10 wt % to 25 or 30 or 40 wt % of a olefin
block-containing copolymer by weight of the composition. A
preferred example includes a continuous phase of high crystallinity
polypropylene having an MFR of about 65 g/10 min (PP-9999SS,
ExxonMobil Chemical); hydrogenated styrene-isoprene-styrene block
copolymer for high impact resistance at low temperatures (Septon
2004); and a magnesium oxy-sulfate filler such as i--MOS MB from
Mitsui Chemicals, and ii--Neat HPR-803 whiskers from Milliken
Chemicals for high filler efficiency (MPa enhancement per 1 wt %
loading).
Compound Preparation
[0053] Different melt-compounding approaches were adopted to
prepare composite formulations comprising polypropylene, filler and
elastomer.
[0054] A. Masterbatch Approach
[0055] Two MOS masterbatches were used for compound preparation:
[0056] A commercially available magnesium oxy-sulfate masterbatch
from Mitsui [0057] Chemicals (Mos Hige MB, 70 wt % Mos Hige A), and
[0058] An internally produced MOS masterbatch (50 wt % Hyperform
803 MOS fibers from Milliken Chemical in 50 wt % 4.6 MFR PP resin,
prepared at American Leistritz Extruders Lab in Somerville,
N.J.)
[0059] The masterbatch of the hydrogenated SIS elastomer, Septon
2004, involved the 65 MFR PP (44 wt % Septon 2004, 56 wt %
polypropylene) and was prepared on a 30 mm ZSK twin-screw extruder
(150 rpm, 210.degree. C.). 1000 to 1500 ppm each of Irganox.TM.
1010 phenolic stabilizer (Ciba Specialty Chemicals (BASF America),
Florham Park, N.J.) and Ultranox.TM. 626 organophosphite stabilizer
(Chemtura Corp., Middlebury, Conn.), along with nucleating agent
(fine-sized sodium benzoate or Millad 3988 from Milliken; 2000-3000
ppm) were incorporated during preparation of the elastomer
masterbatch.
[0060] The above masterbatches, along with additional amounts, if
needed, of the neat 65 MFR polypropylene (stabilized and nucleated)
and Septon 2004 were melt-compounded on a 3 lb (1350 g) Banbury
mixer, to obtain different compositions varying in elastomer and
filler content. A stabilizer package of 1000-1500 ppm each of
Irganox.TM. 1010 phenolic stabilizer (Ciba Specialty Chemicals
(BASF America), Florham Park, N.J.) and Ultranox.TM. 626
organophosphite stabilizer (Chemtura Corp., Middlebury, Conn.) was
used during compounding. The Banbury drops were ground and fed to
the 30 mm ZSK twin-screw extruder to obtain pelletized products for
testing.
[0061] B. One-Step Mixing of Neat Ingredients
[0062] In this compounding mode, neat ingredients were added to a
twin-screw mixing extruder to produce a directly-finished
end-product. In this approach, neat polypropylene was introduced at
the main feed of a 27 mm Leistritz twin-screw extruder (American
Leistritz Extruders Lab, Somerville, N.J.). The screw design
typically involved an L/D of about 48 - 52.
[0063] Neat MOS fibers were introduced about 12 D further down the
screw from the main feed, via a side-stuffer. The hydrogenated
elastomer was fed through a second side-stuffer, about 15 D down
from the first side-stuffer. Mixing elements at the feed end were
chosen to quickly melt the polypropylene, so that the fibers were
fed into molten polymer. Following fiber incorporation, relatively
mild mixing conditions were set, to avoid fiber breakage but still
disperse the fibers and elastomer within the polypropylene matrix.
It was desired that the fibers remain in the polypropylene phase,
rather than the elastomer, to afford maximum reinforcement.
[0064] The MOS was treated, prior to being fed to the extruder: i)
pre-dried, since MOS fibers are hygroscopic, ii) contacted with
magnesium oxide (neutralize alkaline MOS), and iii) contacted with
magnesium stearate (dispersant for fibers). The molten compound
strands were extruded onto a conveyor belt, rather than into a
water bath, for moisture control. The strands were chopped into
pellets for property testing.
[0065] C. Small-Scale Mixing on Micro-Compounder
[0066] For preliminary scoping studies (<100 g), a Thermo-Haake
MiniLab micro-compounder with robotic feeding, pelletization and
collection capability was used (Thermo Scientific, Waltham, Mass.).
Mixing was accomplished via counter-rotating, conical twin screws.
Typical run conditions were 200.degree. C. melt temperature, 125
rpm screw speed and 3 min mixing time.
[0067] The preparation of prototype compounds for broad-based
property testing was usually performed using the first two mixing
approaches, where sufficient product quantities were accessible.
Micro-compounder experiments were generally restricted to scoping
studies, for example, comparing the influence of alternate neat
ingredients on a particular property (e.g., the influence of MOS
versus talc on modulus reinforcement).
Testing
[0068] The two testing standards available for the measurement of
stiffness and impact performance are ASTM and ISO. Both standards
are used, though ISO appears predominant, world-wide, for
certifying automotive materials. Corresponding test designations
for the target physical properties are shown in Table 6.
TABLE-US-00006 TABLE 6 Measurement Standard of Key Composition
Properties Property ASTM ISO Flexural Modulus (1% Secant) D-790 178
Notched Izod Impact (I/temperature) D-256 180 Heat Distortion
Temperature (HDT) D-648 75-2 Coefficient of Linear Thermal
Expansion (CLTE) E-831 11359-1.2 Ductile-Brittle Transition
Temperature D-3763 6603-2 (Instrumented Impact) Melt Flow Rate
(MFR) (230.degree. C., 2.16 kg) D-1238 1133
[0069] There are differences between ASTM and ISO testing,
particularly for the two main properties of Flexural modulus and
impact strength. On modulus, there are differences in specimen
dimensions and the speed of testing. More important, the ISO
Flexural modulus is exclusively a Chord Modulus (slope `m` of Chord
drawn between 0.05% and 0.25% strain as specified by ISO), while
ASTM permits determination of tangent, secant, or Chord moduli. The
ASTM 1% secant Flexural modulus value (slope `m` of line drawn from
origin to point on curve at 1% strain) is a widely reported number
(e.g., on product data sheets from suppliers) used to characterize
the stiffness of polypropylene-based compositions. The differences
between these two for a neat ICP and a filled polypropylene are
shown in FIG. 4. For neat polypropylenes (unfilled homopolymers and
copolymers, including impact copolymers), there is very little
difference between the two. By contrast, the MOS-filled
polypropylene composition shows a much higher Chord Modulus
value.
[0070] The relationships between Chord and 1% secant Flexural
moduli for a variety of neat polypropylenes, talc-filled
polypropylenes (loading levels 10 to 40 wt %); and MOS-filled
polypropylenes (loading levels 10 to 40 wt %) are shown in FIG. 5.
FIGS. 5A, 5B and 5C, illustrate the differences among unfilled,
talc-filled and MOS-filled compositions. In particular, FIG. 5C
plots MOS-filled polypropylene compositions (1 to 40 wt % MOS).
Data points of MOS incorporation via the MOS masterbatch (Mitsui)
and via compounding of neat MOS fibers (Milliken) are both
included. The responses of the two appear very similar, leading to
a single trend line. Of note is the substantial slope of the
relationship for this high aspect ratio filler, with Chord Modulus
values significantly higher than those of 1% secant and far removed
from the x=y line. The difference (".DELTA.") between the two
moduli numbers increases with increasing stiffness. This
relationship was unexpected and quite different from that displayed
by neat and talc-filled polypropylenes. Thus, there are significant
differences in the values of Flexural Modulus reported via ASTM and
ISO standards.
[0071] Regarding impact strength, specifically Notched Izod at low
temperatures, there are again differences between the ASTM and ISO
standards. The testing protocols differ in the specification of
specimen dimensions, pendulum size and data reporting. Data
measurements indicate that the ISO standard is far more rigorous
than ASTM, resulting in lower values. The results show that ASTM
testing provides more favorable Notched Izod, but lower Flexural
modulus values.
[0072] Measurements on experimental compounds are reported here via
both ASTM and ISO standards, however ISO-based data formed the
basis for assessing the performance of the compositions. The
instrumented impact measurement of ductile--brittle temperature was
conducted via ASTM (D 3763).
Compound Preparation
[0073] A. Via Masterbatch (i.e. No Neat MOS Fiber Addition)
[0074] The following products were used to prepare Examples 1
through 7: [0075] Two pre-prepared masterbatches (30 mm ZSK
twin-screw extruder) of Septon 2004, hydrogenated SIS block
copolymer in polypropylene [0076] MB 1: 44 wt % Septon 2004, 56 wt
% 65 MFR PP-9999SS from ExxonMobil Chemical [0077] MB 2: 44 wt %
Septon 2004, 56 wt % 4.6 MFR PP from ExxonMobil Chemical [0078]
Mitsui's MOS masterbatch (70 wt % Mos Hige A, 30 wt % Mitsui ICP
J-747) [0079] Internal MOS masterbatch prepared on Leistritz (50%
Milliken's HPR-803, 50% 4.6 MFR PP) [0080] Neat PP-9999SS [0081]
Neat Septon 2004
[0082] These seven composition Examples are described in Table 7.
The hydrogenated styrene-isoprene-styrene block copolymer was the
elastomer (Septon 2004). Two polypropylene homopolymers were used,
the 65 MFR ExxonMobil polypropylene PP-9999SS, and the 4.6 MFR
polypropylene (from ExxonMobil). MOS fibers were the filler (Mitsui
MOS masterbatch). Property data on the compositions are described
in Table 8, where "CLTE/flow" is the CLTE in the flow direction,
while "x-flow" is the CLTE in the cross-flow direction. The MFR of
the composition is in parenthesis in column 1. The "BMU-147" is
ExxonMobil's Exxtral.TM. grade which is shown as a comparative,
which is 18 wt % talc filled and 23 wt % total rubber content.
TABLE-US-00007 TABLE 7 Example Compositions Prepared from MOS and
Septon 2004 Materbatches Ingredient 1 2 3 4 5 6 7 Hydrogenated SIS
31 31 30 31.2 25.5 25.1 30.2 MOS Fiber filler 30 30 29.5 20.4 40.7
45.3 25 65 MFR PP 26 -- 11 39.7 16.3 10.2 19.8 4.6 MFR PP -- 26
29.5 -- -- -- 25 ICP base (from MOS 13 13 -- 8.7 17.5 19.4 --
MB)
TABLE-US-00008 TABLE 8 ISO Properties of the Example Compositions
made from Masterbatches CLTE/x- Example Modulus I/23 I/0 I/-18
I/-29 HDT CLTE/flow flow (MFR) (MPa) (kJ/m.sup.2) (kJ/m.sup.2)
(kJ/m.sup.2) (kJ/m.sup.2) (.degree. C.) (.degree. C..sup.-1)
(.degree. C..sup.-1) 1 (22.6) 2799 67 58 40 10 106 2E.sup.-5
14.9E.sup.-5 10P 10P 10P 4P 6C 2 (7.9) 2734 67 49 11 8 101
1.7E.sup.-5 10.3E.sup.-5 10P 10P 2P 1P 8C 9C 3 (8.1) 2998 66 34 11
6 109 1.8E.sup.-5 14.7E.sup.-5 10P 10P 5P 1P 5C 9C 5 (20.2) 3935 68
27 5 5 111 1.3E.sup.-5 14.1E.sup.-5 10P 10P 3P 1P 3C 1H 8C 6 (17.6)
4041 69 30 6 4 112 1.2E.sup.-5 14.1E.sup.-5 10P 10P 7P 1P 3C 9C 7
(9.5) 3026 62 26 10 6 109 2E.sup.-5 15E.sup.-5 10P 10P 4P 10C 6C
BMU- 1856 53 21 8 5 99 4.4E.sup.-5 12.6E.sup.-5 147 (14) 10P 10P
10C 10C
[0083] In Table 8,I/23 through I/-29 are Notched Izod at 23.degree.
C., 0.degree. C., -18.degree. C., -29.degree. C. by ISO 180; 10
specimens at each temperature; P=partial breaks, H=hinged breaks,
C=complete breaks. HDT means HDT-B by ISO 75-2. Finally, CLTE is
the Coefficient of Linear Thermal Expansion by ISO 11359.
[0084] A plot of the stiffness/low temperature toughness balance is
shown in FIG. 1B, where the -29.degree. C. Notched Izod impact
numbers are plotted against Flexural modulus, following the ISO
testing standard. FIG. 1B also shows data on current commercial
automotive compounds, including well-regarded industry standards
previously described in Table 1.
[0085] The plot in FIG. 1B shows the prototype Examples to exhibit
a profile of higher stiffness and higher impact resistance than
commercially available products, including current industry
standards. All of the inventive Examples are located along a band
to the right of the boundary line that sets the limit for high
stiffness/high low-temperature impact for current commercial
compounds. The data indicate that the target profile of 2500 to
3000 MPa Flexural modulus and 10 kJ/m.sup.2 Notched Izod at
-29.degree. C. falls within the envelope of the inventive Examples.
The inventive Examples define a family of higher-performing product
compounds than current industry standards. Improved
application-specific properties (e.g., highest stiffness or highest
impact) can be designed from the base ingredients by changing the
compositional makeup.
[0086] From the data in Table 7 and FIG. 1B, Example 1 is observed
to display a favorable profile of high stiffness and high
low-temperature Izod Impact, so multi-axial impact testing was
conducted. Measurements were made on an Instron.TM. Dynatup 9250HV
unit, per ASTM D-3763 (6 specimens per test condition). This test
determines the energy needed for sample failure at low
temperatures, and the failure mode. Compounds that display ductile
failures at low temperatures with high energy requirements are
favored products. The test results are shown in Table 9. Example 1
displays low temperature ductility similar to the performance of
the EMCC commercial product Exxtral.TM. H-1025 (control), which is
well-regarded for its cold temperature impact resistance.
TABLE-US-00009 TABLE 9 Low-temperature Ductility on Example 1 and
Exxtral H-1025 Property Example 1 Exxtral H-1025 Appearance
Adequate Adequate Ductility (-29.degree. C., 15 mph, 10 lb) 5/6
ductile, 6/6 ductile 1/6 ductile-brittle Ductility (-29.degree. C.,
5 mph, 10 lb) 6/6 ductile 6/6 ductile Ductility (0.degree. C., 5
mph, 10 lb) 6/6 ductile 6/6 ductile
[0087] Finally, as a check on the data measurement step, key
measured properties of the control compound, Exxtral.TM. BMU-147,
were compared against typical values reported in the ExxonMobil
datasheet. Those results are in Table 10.
TABLE-US-00010 TABLE 10 Measured ISO values and Data sheet ISO
values Measured Published Datasheet Property ISO Value ISO Flexural
Modulus at 23.degree. C. (MPa) 1856 1760 Notched Izod Impact at
23.degree. C. (kJ/m.sup.2) 52 39 Heat Distortion Temp. at 1.8 MPa
55 53 (.degree. C.)
[0088] B. Via One-step Mixing of Neat Ingredients (i.e. Mixing Neat
PP, Elastomer, MOS Fibers)
[0089] The mixing was conducted on a 27 mm, Leistritz twin-screw
extruder, as previously described. The screw and feed designs were
set-up to obtain adequate mixing of the ingredients, while
preserving the aspect ratio of the MOS fibers. This involved using
a side-stuffer downstream to feed the MOS fibers, after they were
thoroughly dried and treated with magnesium oxide and magnesium
stearate. Optionally, the MOS fibers were lightly treated with
Luperox 101 (Arkema), an organic peroxide
(2,5-Bis(tert-butylperoxy)-2,5-dimethylhexane), to promote some
grafting to polypropylene and also to lower the hydrophilicity of
the MOS fibers. The screw elements were chosen to achieve fast
melting of the polypropylene fed at the main hopper to ensure fiber
feed into molten polymer, and to minimize working the melt
downstream of fiber addition, to reduce fiber breakage. The screw
had an L/D of 52.
[0090] Four compound Examples were prepared as shown in Table 11.
Property data (ASTM) on Examples 8 through 11 are shown in Table
11, wherein "I" is Izod Impact (kJ/m.sup.2). Also, in Table 11 "P"
means "partial break", "H" means "hinged break" and "C" means
"complete break"; and the HDT is at 0.45 MPa by ASTM D-648(C).
Examples 8, 9, 10 and 11 were run sequentially on the Leistritz
twin-screw extruder. The data indicate a drop-off of peroxide
influence, after the compounding of Example 8. The MFR of Example 8
shows the expected increase in compound MFR due to the presence of
peroxide (30 MFR for the filled final compound versus about 5 MFR
for both the PP and elastomer starting ingredients). Examples 9 and
10 display MFRs lower than Example 8, but comparable to each other,
despite the doubling of peroxide (0.5 wt % to 1 wt % respectively).
Example 11 has an even lower MFR (2.2). A markedly higher modulus
value is observed for Example 8. The modulus and heat distortion
temperatures (HDT) of the Examples are internally consistent (i.e
high modulus is accompanied by high HDT).
TABLE-US-00011 TABLE 11 Example Compounds Prepared on Leistritz
twin-screw extruder via one-step Mixing from Neat Ingredients
Ingredient (wt %) 8 9 10 11 Septon 2004 20 30 30 30 Neat MOS fibers
(HPR-803) 40 40 40 50 .6 MFR PP (w/ nucleating agent) 40 30 30 20
Peroxide 0.5 0.5 1.0 0.5
TABLE-US-00012 TABLE 12 Property Data on Compound Examples Prepared
via One-Step Mixing HDT Modulus I/23 I/0 I/-18 1/-29 (.degree. C.)
MFR (ASTM 1% (ASTM, (ASTM, (ASTM, (ASTM, (ASTM Example (g/10 min)
sec, MPa) kJ/m.sup.2) kJ/m.sup.2) kJ/m.sup.2) kJ/m.sup.2) HDT-B) 8
30.3 3790 3.2, C 2.3, C 1.9, C 1.5, C 143 9 14.3 2136 12.7, P 5.9,
C 4.3, C 3.7, C 130 10 14.4 2198 12.2, P 5.6, C 4.4, C 3.8, C 131
11 2.2 1651 15.6, P 9.4, P 6.3, H 4.9, H 121
[0091] A surprising observation was the poor impact performance of
Examples 8 through 11, even at ambient temperature. The Notched
Izod impact values are substantially lower than Examples 1 through
7, prepared via masterbatch (see Table 8 and FIG. 1B). The
influence of peroxide in lowering the molecular weight of the
matrix PP in Example 8, leading to a reduction of impact strength
is well known and was anticipated. However all the other Examples
show similarly low impact numbers, despite (1) having more
elastomer (30 versus 20 wt % in Example 8), and (2) being of higher
molecular weight and not influenced by the presence of
peroxide.
[0092] AFM phase images (AFM from Asylum Research, CA) of the
morphologies of Examples 8 through 11, shown in FIG. 7, reveal
lighter images that reflect soft phases (elastomer) while darker
images indicate hard phases (PP). The image of Example 8 indicates
a PP continuous phase, with a dispersed phase of the hydrogenated
SIS elastomer. MOS filler moieties are observed to reside primarily
within the PP matrix, examples of which are identified by arrows.
Compared to Example 8, Examples 9 and 10 contain a higher level of
the elastomer (from 20 to 30 wt %), while Example 11 has the
highest loading of MOS filler (50 wt %), also at 30 wt % elastomer.
Surprisingly, at the higher elastomer level (approx. 30 wt %), the
phase morphology inverts, with the elastomer now assuming the
continuous phase position. The MOS filler appears to remain
primarily in the PP phase (dispersed phase), frequently adjacent to
the elastomer. This inversion occurs at about 30 wt % elastomer,
but not at 20% (Example 8 versus 9). This morphology is undesirable
for favorable physical properties, as reflected by the data above.
Additional results have shown the inversion to occur when the
elastomer content exceeds 26 wt % using this method of making the
composition. These data suggest that to obtain good properties via
a one-step mixing approach, that (1) the elastomer loading be no
more than 26 wt % to maintain an elastomer-dispersed phase
morphology for impact toughening; and (2) do not add or otherwise
expose the ingredients to peroxide to maintain the polypropylene
matrix at a sufficiently high molecular weight to provide adequate
matrix toughness.
[0093] Based on the constraints discussed above, Example 12 was
compounded on the same Leistritz twin-screw extruder. Neat MOS
fibers (30 wt %) were again used, but with no peroxide treatment.
The elastomer (Septon 2004) level was 26 wt %, to maintain PP as
the continuous phase, using 10 wt % of 4.6 MFR polypropylene and 34
wt % of 65 MFR polypropylene. The extrusion process conditions were
similar to those used for Examples 8 through 11. It was of interest
to see if under these restrictions, the stiffness/impact balance of
the one-step compounded Example 12 matched the performance of
compounds obtained via the masterbatch approach. ISO-based property
data on the compound, Example 12, are presented in Table 13.
TABLE-US-00013 TABLE 13 ISO-based Property Data on Inventive
Example 12 Prepared via one-step Mixing. Modulus CLTE/ Example
(Chord) I/23 I/0 I/-18 I/-29 HDT Flow CLTE/x- (MFR) (MPa)
(kJ/m.sup.2) (kJ/m.sup.2) (kJ/m.sup.2) (kJ/m.sup.2) (.degree. C.)
(.degree. C..sup.-1) flow (.degree. C..sup.-1) 12 (12.6) 4280 26,
10P 7.4 4.6 4.1 126 2.0E.sup.-5 14.6E.sup.-5 10P 5P 10C 5C
[0094] The stiffness/toughness profile of Example 12, prepared via
one-step mixing, is observed to fit the properties trend (also
ISO-based) of compounds prepared via the masterbatch route, which
have similar levels of elastomer and MOS. This is shown in FIG. 6,
where Example 12 is positioned alongside Examples 5 and 6. All
three of these compounds contain about 25 wt % of the elastomer.
Their impact strengths are comparable, while small differences are
observed in Flexural Modulus (slightly lower values for Examples 5
and 6 versus Example 12). This lowering in Examples 5 and 6, via
the MB approach, is likely due to competing composition-based
influences: a higher MOS level providing increased reinforcement
versus an ICP matrix providing lower inherent stiffness.
[0095] The above results suggest that the one-step compound
preparation mode: (1) will provide compounds with comparable
stiffness/impact balance to those made via the masterbatch
approach, under conditions where the elastomer is present as
dispersed phase within the PP matrix; and (2) is restricted in the
amount of elastomer that can be incorporated to systems where
polypropylene phase continuity exists. High-impact compositions,
involving significant levels of elastomer, may be outside the
capability of this compound preparation mode.
[0096] Now, having described the various features of the
invention(s), described here in numbered paragraphs is:
[0097] P1. A composition comprising (or consisting essentially of,
or consisting of) a continuous phase of polypropylene; within the
range of from 5 wt % to 50 wt % of a filler by weight of the
composition, having an aspect ratio within the range of from 5 or 6
or 8 to 20 or 40 or 100 or 200 or 800 or 1000; and within the range
of from 5 wt % to 40 wt % of a olefin block-containing copolymer by
weight of the composition, preferably forming a discreet phase
within the continuous phase.
[0098] P2. The composition of paragraph 1, wherein the filler is a
mineral hydroxide filler; preferably, wherein the filler is a metal
salt of an oxysulfate, aluminoxysulfate, aluminosilicate, silicate,
borate, or combination thereof; most preferably, wherein the filler
is a magnesium or calcium oxysulfate (e.g., MgSO.sub.4.
5Mg(OH).sub.2. 3H.sub.2O).
[0099] P3. The composition of paragraph 1 or 2, wherein the olefin
block-containing copolymer is selected from the group consisting of
styrene-butadiene-styrene block copolymers,
styrene-isoprene-styrene block copolymers,
styrene-ethylene/propylene-styrene block polymers,
styrene-ethylene/butene-styrene block polymers, and hydrogenated
versions thereof and blends thereof.
[0100] P4. The composition of any one of the previous numbered
paragraphs, wherein the olefin block-containing copolymer is a
styrene-olefin block copolymer having within the range of from 5 wt
% to 25 wt % styrene-derived units by weight of the copolymer,
which may or may not be hydrogenated.
[0101] P5. The composition of any one of the previous numbered
paragraphs, wherein the polypropylene has a melt flow rate ("MFR",
230.degree. C./2.16 kg) within the range of from 4 or 12 g/10 min
to 70 or 80 g/10 min.
[0102] P6. The composition of any one of the previous numbered
paragraphs, wherein the polypropylene has a melting point
temperature ("T.sub.m", DSC) within the range of from 130 or 140 or
150.degree. C. to 160 or 165 or 170.degree. C.
[0103] P7. The composition of any one of the previous numbered
paragraphs, having a 1% Secant Flexural Modulus (ISO) of greater
than 2000 or 2500 or 3000 MPa; or within the range of from 2000 or
3000 MPa to 5000 MPa.
[0104] P8. The composition of any one of the previous numbered
paragraphs, having a Notched Izod Impact Resistance (-29.degree.
C., ISO) of greater than 2 or 5 or 8 or 10 kJ/m.sup.2; or within a
range of from 2 or 5 or 10 kJ/m.sup.2 to 15 or 20 kJ/m.sup.2.
[0105] P9. The composition of any one of the previous numbered
paragraphs, wherein the Chord Modulus changes by at least 2 or 2.5
or 3 or 3.5 times (or changes by a coefficient within the range of
from 2 or 2.5 to 3.5 or 4 or 4.5) the change in 1% Secant Flexural
Modulus over a range of 10 to 40 wt % loading of the filler;
alternatively, wherein the slope (m) of the Chord Modulus (y)
versus 1% secant Flexural Modulus (x) line is greater than 1.8,
more preferably greater than 2.0 or 2.5, most preferably greater
than 3.0 or 3.4.
[0106] P10. The composition of any one of the previous numbered
paragraphs, having a heat distortion temperature ("HDT") within the
range of from 90 or 95.degree. C. to 100 or 110 or 130.degree.
C.
[0107] P11. The composition of any one of the previous numbered
paragraphs, having a flow direction Coefficient of Linear Thermal
Expansion ("CLTE") within the range of from
0.50.times.10.sup.-5/.degree. C. to 3.0.times.10.sup.-5/.degree.
C.; and a cross-flow direction CLTE within the range of from
8.0.times.10.sup.-5/.degree. C. to 15.0.times.10.sup.-5/.degree.
C.
[0108] P12. The composition of any one of the previous numbered
paragraphs, wherein the MFR of the composition is within the range
of from 5 g/10 min to 30 or 50 g/10 min.
[0109] P13. The composition of any one of the previous numbered
paragraphs, wherein polar-graft polymers are absent; and preferably
where peroxides are absent.
[0110] P14. The composition of any one of the previous numbered
paragraphs, wherein on a line defined by the ISO-based -29.degree.
C. Notched Izod as a function of the ISO-based Flexural Modulus,
y=-0.0038x+15.27, the compositions fall above and to the right of
the line; wherein the compositions fall above lines of similar
slope and having y-intercepts of 16 or 16.5 or 17.
[0111] P15. An automotive component comprising (or consisting
essentially of) the composition of any one of the previous numbered
paragraphs.
[0112] P16. A method of forming the composition of any one of the
previous numbered paragraphs, the method comprising (or consisting
essentially of) combining and melt processing: a first mixture of a
propylene-based polymer and a filler having an aspect ratio within
the range of from 5 to 1000; with a second mixture of a
propylene-based polymer and olefin block-containing copolymer; and
isolating the composition; wherein the composition comprises a
continuous phase of polypropylene and within the range of from 5 wt
% to 50 wt % of the filler and within the range of from 5 wt % to
40 wt % of a olefin block-containing copolymer.
[0113] P17. A method of forming the composition of any one of the
previous numbered paragraphs 1-14, the method comprising (or
consisting essentially of) combining and melt processing: a neat
filler having an aspect ratio within the range of from 5 to 1000;
with a polypropylene and olefin block-containing copolymer,
together or separately; and isolating the composition; wherein the
composition comprises a continuous phase of polypropylene and
within the range of from 5 wt % to 50 wt % of the filler and within
the range of from 5 wt % to 26 wt % of a olefin block-containing
copolymer.
[0114] P18. The method of paragraph 15 or 17, wherein the
components are added in the order of: polypropylene, neat filler,
and olefin block-containing copolymer, wherein the neat filler is
dispersed within the melted polypropylene, and the olefin
block-containing copolymer is added and dispersed within the
polypropylene-filler mix.
[0115] Also disclosed herein is the use of the filler in a
composition comprising (or consisting essentially of) polypropylene
and within the range of from 5 wt % to 40 wt % of a olefin
block-containing copolymer by weight of the composition.
[0116] Also disclosed herein is the use of a composition in any one
of the previous numbered paragraphs 1 to 13 in an article of
manufacture as described herein.
[0117] For all jurisdictions in which the doctrine of
"incorporation by reference" applies, all of the test methods,
patent publications, patents and reference articles are hereby
incorporated by reference either in their entirety or for the
relevant portion for which they are referenced.
* * * * *