U.S. patent application number 13/159660 was filed with the patent office on 2011-12-15 for olefin block copolymer composition with low tack.
This patent application is currently assigned to Dow Global Technologies LLC. Invention is credited to Ashish Batra, Dana Breed, Pradeep Jain, Robert T. Johnston, Jeffrey C. Munro, Jose M. Rego, Alec Y. Wang.
Application Number | 20110306715 13/159660 |
Document ID | / |
Family ID | 44454032 |
Filed Date | 2011-12-15 |
United States Patent
Application |
20110306715 |
Kind Code |
A1 |
Batra; Ashish ; et
al. |
December 15, 2011 |
OLEFIN BLOCK COPOLYMER COMPOSITION WITH LOW TACK
Abstract
Disclosed are oil-extended olefin block copolymer compositions
with low, or no, tack. A unique comonomer content in the soft
segment of the OBC in conjunction with the presence of a polyolefin
provides the present oil-extended OBC composition with softness,
low (or no) tack, and low (or no) oil-bleed.
Inventors: |
Batra; Ashish; (Carmel,
IN) ; Munro; Jeffrey C.; (Houston, TX) ; Rego;
Jose M.; (Houston, TX) ; Breed; Dana; (Lake
Jackson, TX) ; Jain; Pradeep; (Lake Jackson, TX)
; Johnston; Robert T.; (Lake Jackson, TX) ; Wang;
Alec Y.; (Lake Jackson, TX) |
Assignee: |
Dow Global Technologies LLC
Midland
MI
|
Family ID: |
44454032 |
Appl. No.: |
13/159660 |
Filed: |
June 14, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61354309 |
Jun 14, 2010 |
|
|
|
Current U.S.
Class: |
524/505 |
Current CPC
Class: |
C08K 3/013 20180101;
C08L 53/00 20130101; C08L 23/06 20130101; C08L 2205/03 20130101;
C08L 9/00 20130101; C08L 23/16 20130101; C08L 2312/00 20130101;
C08L 23/04 20130101; C08K 3/26 20130101; C08L 91/00 20130101; C08L
2207/062 20130101; C08L 23/04 20130101; C08L 2666/24 20130101; C08L
23/16 20130101; C08K 3/26 20130101; C08L 23/06 20130101; C08L 53/00
20130101; C08L 91/00 20130101; C08L 2205/03 20130101; C08L 2312/00
20130101; C08L 53/00 20130101; C08L 2666/04 20130101; C08L 91/00
20130101; C08K 3/013 20180101; C08L 23/04 20130101; C08L 53/00
20130101; C08L 23/16 20130101; C08L 23/06 20130101; C08L 53/00
20130101; C08L 91/00 20130101; C08K 3/013 20180101; C08L 23/04
20130101; C08L 53/00 20130101 |
Class at
Publication: |
524/505 |
International
Class: |
C08L 53/00 20060101
C08L053/00 |
Claims
1. An oil-extended olefin block copolymer composition comprising:
an olefin block copolymer comprising hard segments and soft
segments, the soft segments comprising from about 9 mol % to less
than 15 mol % comonomer content; an oil; one or more polyolefin; a
filler; and the composition has the following properties after
exposure to 70.degree. C. for one week a tack force less than 0.1N;
and a Shore A hardness from about 50 to about 90.
2. The composition of claim 1 wherein the olefin block copolymer
comprises an ethylene/octene multi-block copolymer comprising from
about 5 wt % to about 30 wt % hard segments and from about 95 wt %
to about 70 wt % soft segments.
3. The composition of claim 1 wherein the olefin block copolymer
has a density from about 0.86 g/cc to about 0.88 g/cc.
4. The composition of claim 1 comprising from about 2 wt % to about
40 wt % olefin block copolymer; from about 20 wt % to about 50 wt %
oil, from about 5 wt % to about 50 wt % polyolefin, and from about
20 wt % to about 40 wt % filler.
5. The composition of claim 1 wherein the polyolefin is selected
from the group consisting of a polyethylene, a polypropylene, an
ethylene-propylene-diene monomer rubber and combinations
thereof.
6. The composition of Claim lhaving a normalized oil bleed index of
less than 20 after 3 weeks at 23 C.
7. The composition of claim 1 having a normalized oil bleed index
of less than 50 after 3 weeks at 70 C.
8. An oil-extended olefin block copolymer composition comprising:
an olefin block copolymer comprising hard segments and soft
segments, the soft segments comprising from about 9 mol % to less
than 15 mol % comonomer content; an oil; one or more polyolefin; a
filler; and the composition has the following properties after
exposure to 70.degree. C. for one week a normalized oil bleed index
of less than 50; and a Shore A hardness from about 50 to about
90.
9. The composition of claim 8 having a tack force from 0.0 N to
less than 0.1N after exposure to 70 C for one week.
10. The composition of claim 8 wherein the polyolefin is a
polyethylene with a density greater than 0.95 g/cc.
11. The composition of claim 8 comprising from about 2 wt % to
about 30 wt % olefin block copolymer, from about 30 wt % to about
40 wt % oil, from about 5 wt % to about 25 wt % polyethylene, and
from about 25 wt % to about 30 wt % filler.
12. An oil-extended olefin block copolymer composition comprising:
an olefin block copolymer comprising hard segments and soft
segments, the soft segments comprising from about 9 mol % to less
than 15 mol % comonomer content; an oil; a polyethylene; a filler;
and the composition has the following properties after exposure to
70.degree. C. for one week a tack force less than 0.020N; and a
Shore A hardness from about 40 to about 90.
13. The composition of claim 12 having a tack force from 0.0 N to
less than 0.1N after exposure to 70 C for one week.
14. The composition of claim 12 wherein the polyolefin is a
polyethylene with a density greater than 0.95 g/cc.
15. The composition of claim 12 having a compression set value from
about 40% to about 70% as measured in accordance with ASTM D
395.
16. The composition of claim 12 further comprising an
ethylene-propylene-diene monomer rubber.
17. A molded oil-extended olefin block copolymer composition
comprising: an olefin block copolymer comprising hard segments and
soft segments, the soft segments comprising from about 9 mol % to
less than 15 mol % comonomer content; an oil; one or more
polyolefin; a filler; and the composition has the following
properties after exposure to 70.degree. C. for one week a tack
force less than 0.1N; and a Shore A hardness from about 50 to about
90 wherein the molded composition was prepared using a 0.41 .mu.m
surface roughness mold.
18. The molded oil-extended composition of claim 17 further
comprising an ethylene-propylene-diene monomer rubber.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Patent Application
Ser. No. 61/354,309, filed on Jun. 14, 2010.
BACKGROUND
[0002] Olefin block copolymers (OBCs) are useful for producing soft
compounds such as soft-touch articles. OBCs find application in
soft compounds such as overmolded grips because the block
architecture of the OBC results in good tensile strength,
compression set and temperature resistance. To make soft
compositions (i.e., compositions with a low durometer value and/or
a low Shore A hardness value), OBCs are mixed with an oil. When
exposed to elevated temperature, however, these oil-extended
compositions can exhibit tackiness. Tack is problematic because it
produces undesirable haptics (stickiness) and/or undesirable
surface appearance in articles fabricated from these compounds.
[0003] A need exists for oil-extended OBC compositions with low, or
no, tack. A need further exists for an oil-extended OBC composition
with low, or no, tack when exposed to elevated temperature for an
extended period of time.
SUMMARY
[0004] The present disclosure is directed to oil-extended OBC
compositions with low, or no, tack. The unique comonomer content in
the soft segment of the OBC in conjunction with the presence of a
polyolefin and a filler provides the present oil-extended OBC
compositions with low, or no, tack.
[0005] In an embodiment, an oil-extended olefin block copolymer
composition is provided and includes an olefin block copolymer. The
olefin block copolymer contains hard segments and soft segments.
The soft segments include from about 9 mol % to less than 15 mol %
comonomer content. The composition also includes an oil, one or
more polyolefin, and a filler. The composition has the following
properties after exposure to 70.degree. C. for one week (i) a tack
force less than 0.1N, and (ii) a Shore A hardness from about 40 to
about 90.
[0006] The present disclosure provides another composition. In an
embodiment, an oil-extended olefin block copolymer composition is
provided and includes an olefin block copolymer. The olefin block
copolymer contains hard segments and soft segments. The soft
segments include from about 9 mol % to less than 15 mol % comonomer
content. The composition also includes an oil, one or more
polyolefin, and a filler. The composition has the following
properties after exposure to 70.degree. C. for one week: (i) a
normalized oil bleed index of less than 50, and (ii) a Shore A
hardness from about 40 to about 90.
[0007] The present disclosure provides another composition. In an
embodiment, an oil-extended olefin block copolymer is provided and
includes an olefin block copolymer. The olefin block copolymer
contains hard segments and soft segments. The soft segments include
from about 9 mol % to less than 15 mol % comonomer content. The
composition also includes an oil, a polyethylene, and a filler. The
composition has the following properties after exposure to
70.degree. C. for one week: (i) a tack force less than 0.013N and
(ii) a Shore A hardness from about 40 to about 90.
[0008] The present disclosure provides another composition. In an
embodiment, an oil-extended olefin block copolymer is provided and
includes an olefin block copolymer. The olefin block copolymer
contains hard segments and soft segments. The soft segments include
from about 9 mol % to less than 15 mol % comonomer content. The
composition also includes an oil, a polyethylene, an
ethylene-propylene-diene monomer rubber (EPDM) and a filler. The
composition has the following properties after exposure to
70.degree. C. for one week: (i) a tack force less than 0.10N and
(ii) a Shore A hardness from about 40 to about 90.
[0009] An advantage of the present disclosure is the provision of
an oil-extended OBC composition with low tack, or no tack.
[0010] An advantage of the present disclosure is the provision of
an oil-extended OBC composition with reduced, or no, oil-bleed.
[0011] An advantage of the present disclosure is the provision of
an oil-extended OBC composition with softness, and/or low (or no)
tack and/or low (or no) oil-bleed.
[0012] An advantage of the present disclosure is the provision of
an oil-extended polyolefin that is halogen-free.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows examples of various grayscales used for the
normalized oil bleed index (NOBI).
[0014] FIG. 2 is a graph showing the tack force and Shore A
hardness values for various comparative and inventive oil extended
compositions.
[0015] FIG. 3 is a graph showing NOBI and Shore A hardness values
for various comparative and inventive oil extended
compositions.
[0016] FIG. 4 is a graph showing NOBI and Shore A hardness values
for various comparative and inventive oil extended
compositions.
[0017] FIG. 5 is a graph showing compression set and Shore A
hardness values for various comparative and inventive oil extended
compositions.
[0018] FIG. 6 shows Tack Force data for Examples 4-11 and
Comparative Examples A-E.
[0019] FIG. 7 shows Rheology Ratio (ratio of viscosity determined
by DMS at 190.degree. C. at 100 s.sup.-1 to that at 0.1 s.sup.-1)
for Examples 4-11 and Comparative Examples A-E.
[0020] FIG. 8 shows Ultimate Tensile Strength for Examples 4-11 and
Comparative Examples A-E.
[0021] FIG. 9 shows Compression Set at 70.degree. C. for Examples
4-11 and Comparative Examples A-E.
[0022] FIG. 10 shows Tack Force Data for Examples 12-15 and
Comparative Examples F-K.
[0023] FIG. 11 shows Compression Set at 70.degree. C. for Examples
12-15 and Comparative Examples F-K.
[0024] FIG. 12 shows Ultimate Tensile Strength for Examples 12-15
and Comparative Examples F-K.
DETAILED DESCRIPTION
[0025] The present disclosure provides an oil-extended olefin block
copolymer (OBC) composition. An "oil-extended OBC composition," as
used herein, is an OBC composition that contains an (i) OBC and
(ii) at least 20 wt % oil, based on the total weight of the
composition. In an embodiment, an oil-extended olefin block
copolymer composition is provided and includes an olefin block
copolymer, an oil, one or more polyolefin, and a filler.
[0026] 1. Olefin Block Copolymer
[0027] The term "olefin block copolymer" or "OBC" is an
ethylene/a-olefin multi-block copolymer and includes ethylene and
one or more copolymerizable a-olefin comonomer in polymerized form,
characterized by multiple blocks or segments of two or more
polymerized monomer units differing in chemical or physical
properties. The terms "interpolymer" and "copolymer" are used
interchangeably herein. In some embodiments, the multi-block
copolymer can be represented by the following formula:
(AB).sub.n
where n is at least 1, preferably an integer greater than 1, such
as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or
higher, "A" represents a hard block or segment and "B" represents a
soft block or segment. Preferably, As and Bs are linked in a
substantially linear fashion, as opposed to a substantially
branched or substantially star-shaped fashion. In other
embodiments, A blocks and B blocks are randomly distributed along
the polymer chain. In other words, the block copolymers usually do
not have a structure as follows. [0028] AAA-AA-BBB-BB
[0029] In still other embodiments, the block copolymers do not
usually have a third type of block, which comprises different
comonomer(s). In yet other embodiments, each of block A and block B
has monomers or comonomers substantially randomly distributed
within the block. In other words, neither block A nor block B
comprises two or more sub-segments (or sub-blocks) of distinct
composition, such as a tip segment, which has a substantially
different composition than the rest of the block.
[0030] The olefin block copolymer includes various amounts of
"hard" and "soft" segments. "Hard" segments are blocks of
polymerized units in which ethylene is present in an amount greater
than about 95 weight percent, or greater than about 98 weight
percent based on the weight of the polymer. In other words, the
comonomer content (content of monomers other than ethylene) in the
hard segments is less than about 5 weight percent, or less than
about 2 weight percent based on the weight of the polymer. In some
embodiments, the hard segments include all, or substantially all,
units derived from ethylene. "Soft" segments are blocks of
polymerized units in which the comonomer content (content of
monomers other than ethylene) is greater than about 5 weight
percent, or greater than about 8 weight percent, greater than about
10 weight percent, or greater than about 15 weight percent based on
the weight of the polymer. In some embodiments, the comonomer
content in the soft segments can be greater than about 20 weight
percent, greater than about 25 weight percent, greater than about
30 weight percent, greater than about 35 weight percent, greater
than about 40 weight percent, greater than about 45 weight percent,
greater than about 50 weight percent, or greater than about 60
weight percent.
[0031] The soft segments can be present in an OBC from about 1
weight percent to about 99 weight percent of the total weight of
the OBC, or from about 5 weight percent to about 95 weight percent,
from about 10 weight percent to about 90 weight percent, from about
15 weight percent to about 85 weight percent, from about 20 weight
percent to about 80 weight percent, from about 25 weight percent to
about 75 weight percent, from about 30 weight percent to about 70
weight percent, from about 35 weight percent to about 65 weight
percent, from about 40 weight percent to about 60 weight percent,
or from about 45 weight percent to about 55 weight percent of the
total weight of the OBC. Conversely, the hard segments can be
present in similar ranges. The soft segment weight percentage and
the hard segment weight percentage can be calculated based on data
obtained from DSC or NMR. Such methods and calculations are
disclosed in, for example, U.S. Pat. No. 7,608,668, entitled
"Ethylene/a-Olefin Block Inter-polymers," filed on Mar. 15, 2006,
in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al. and
assigned to Dow Global Technologies Inc., the disclosure of which
is incorporated by reference herein in its entirety. In particular,
hard and soft segment weight percentages and comonomer content may
be determined as described in Column 57 to Column 63 of U.S. Pat.
No. 7,608,668.
[0032] The term "crystalline" if employed, refers to a polymer that
possesses a first order transition or crystalline melting point
(Tm) as determined by differential scanning calorimetry (DSC) or
equivalent technique. The term may be used interchangeably with the
term "semicrystalline". The term "amorphous" refers to a polymer
lacking a crystalline melting point as determined by differential
scanning calorimetric (DSC) or equivalent technique.
[0033] The term "multi-block copolymer" or "segmented copolymer" is
a polymer comprising two or more chemically distinct regions or
segments (referred to as "blocks") preferably joined in a linear
manner, that is, a polymer comprising chemically differentiated
units which are joined end-to-end with respect to polymerized
ethylenic functionality, rather than in pendent or grafted fashion.
In an embodiment, the blocks differ in the amount or type of
incorporated comonomer, density, amount of crystallinity,
crystallite size attributable to a polymer of such composition,
type or degree of tacticity (isotactic or syndiotactic),
region-regularity or regio-irregularity, amount of branching
(including long chain branching or hyper-branching), homogeneity or
any other chemical or physical property. Compared to block
interpolymers of the prior art, including interpolymers produced by
sequential monomer addition, fluxional catalysts, or anionic
polymerization techniques, the present OBC is characterized by
unique distributions of both polymer polydispersity (PDI or Mw/Mn
or MWD), block length distribution, and/or block number
distribution, due, in an embodiment, to the effect of the shuttling
agent(s) in combination with multiple catalysts used in their
preparation.
[0034] In an embodiment, the OBC is produced in a continuous
process and possesses a polydispersity index, PDI, from about 1.7
to about 3.5, or from about 1.8 to about 3, or from about 1.8 to
about 2.5, or from about 1.8 to about 2.2. When produced in a batch
or semi-batch process, the OBC possesses PDI from about 1.0 to
about 3.5, or from about 1.3 to about 3, or from about 1.4 to about
2.5, or from about 1.4 to about 2.
[0035] In addition, the olefin block copolymer possesses a PDI
fitting a Schultz-Flory distribution rather than a Poisson
distribution. The present OBC has both a polydisperse block
distribution as well as a polydisperse distribution of block sizes.
This results in the formation of polymer products having improved
and distinguishable physical properties. The theoretical benefits
of a polydisperse block distribution have been previously modeled
and discussed in Potemkin, Physical Review E (1998) 57 (6), pp.
6902-6912, and Dobrynin, J. Chem. Phvs. (1997) 107 (21), pp
9234-9238.
[0036] In an embodiment, the present olefin block copolymer
possesses a most probable distribution of block lengths. In an
embodiment, the olefin block copolymer is defined as having:
[0037] (A) Mw/Mn from about 1.7 to about 3.5, at least one melting
point, Tm, in degrees Celsius, and a density, d, in grams/cubic
centimeter, where in the numerical values of Tm and d correspond to
the relationship:
Tm>-2002.9+4538.5(d)-2422.2(d).sup.2, and/or
[0038] (B) Mw/Mn from about 1.7 to about 3.5, and is characterized
by a heat of fusion, .DELTA.H in J/g, and a delta quantity,
.DELTA.T, in degrees Celsius defined as the temperature difference
between the tallest DSC peak and the tallest Crystallization
Analysis Fractionation ("CRYSTAF") peak, wherein the numerical
values of .DELTA.T and .DELTA.H have the following
relationships:
.DELTA.T>-0.1299 .DELTA.H+62.81 for .DELTA.H greater than zero
and up to 130 J/g
.DELTA.T.gtoreq.48.degree. C. for .DELTA.H greater than 130 J/g
wherein the CRYSTAF peak is determined using at least 5 percent of
the cumulative polymer, and if less than 5 percent of the polymer
has an identifiable CRYSTAF peak, then the CRYSTAF temperature is
30.degree. C.; and/or
[0039] (C) elastic recovery, Re, in percent at 300 percent strain
and 1 cycle measured with a compression-molded film of the
ethylene/.alpha.-olefin interpolymer, and has a density, d, in
grams/cubic centimeter, wherein the numerical values of Re and d
satisfy the following relationship when ethylene/a-olefin
interpolymer is substantially free of crosslinked phase:
Re>1481-1629(d); and/or
[0040] (D) has a molecular weight fraction which elutes between
40.degree. C. and 130.degree. C. when fractionated using TREF,
characterized in that the fraction has a molar comonomer content of
at least 5 percent higher than that of a comparable random ethylene
interpolymer fraction eluting between the same temperatures,
wherein said comparable random ethylene interpolymer has the same
comonomer(s) and has a melt index, density and molar comonomer
content (based on the whole polymer) within 10 percent of that of
the ethylene/.alpha.-olefin interpolymer; and/or
[0041] (E) has a storage modulus at 25.degree. C., G'(25.degree.
C.), and a storage modulus at 100.degree. C., G'(100.degree. C.),
wherein the ratio of G'(25.degree. C.) to G'(100.degree. C.) is in
the range of about 1:1 to about 9:1.
[0042] The olefin block copolymer may also have:
[0043] (F) a molecular fraction which elutes between 40.degree. C.
and 130.degree. C. when fractionated using TREF, characterized in
that the fraction has a block index of at least 0.5 and up to about
1 and a molecular weight distribution, Mw/Mn, greater than about
1.3; and/or
[0044] (G) average block index greater than zero and up to about
1.0 and a molecular weight distribution, Mw/Mn greater than about
1.3. It is understood that the olefin block copolymer may have one,
some, all, or any combination of properties (A)-(G).
[0045] Suitable monomers for use in preparing the present OBC
include ethylene and one or more addition polymerizable monomers
other than ethylene. Examples of suitable comonomers include
straight-chain or branched .alpha.-olefins of 3 to 30, preferably 3
to 20, carbon atoms, such as propylene, 1-butene, 1-pentene,
3-methyl-l-butene, 1-hexene, 4-methyl-1-pentene,
3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,
1-hexadecene, 1-octadecene and 1-eicosene; cyclo-olefins of 3 to
30, preferably 3 to 20, carbon atoms, such as cyclopentene,
cycloheptene, norbornene, 5-methyl-2-norbornene,
tetracyclododecene, and
2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene;
di-and polyolefins, such as butadiene, isoprene,
4-methyl-1,3-pentadiene, 1,3-pentadiene, 1,4-pentadiene,
1,5-hexadiene, 1,4-hexadiene, 1,3-hexadiene, 1,3-octadiene,
1,4-octadiene, 1,5-octadiene, 1,6-octadiene, 1,7-octadiene,
ethylidenenorbornene, vinyl norbornene, dicyclopentadiene,
7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, and
5,9-dimethyl-1,4,8-decatriene; and 3-phenylpropene,
4-phenylpropene, 1,2-difluoroethylene, tetrafluoroethylene, and
3,3,3-trifluoro-1-propene.
[0046] In an embodiment, the olefin block copolymer has a density
from about 0.85 g/cc to about 0.89 g/cc, or from about 0.86 g/cc to
about 0.88 g/cc or from about 0.870 g/cc to about 0.879 g/cc.
[0047] In an embodiment, the olefin block copolymer has a melt
index (MI) from about 0.1 g/10 min to about 30 g/10, or from about
0.1 g/10 min to about 10 g/10 min, or from about 0.1 g/10 min to
about 1.0 g/10 min, or from about 0.1 g/10 min to about 0.5 g/10
min or from about 0.3 g/10 min to about 0.6 g/10 min as measured by
ASTM D 1238 (190.degree. C./2.16 kg).
[0048] The olefin block copolymer has a 2% secant modulus greater
than zero and less than about 150, or less than about 140, or less
than about 120, or less than about 100, MPa as measured by the
procedure of ASTM D 882-02.
[0049] The present OBC has a melting point of less than about
125.degree. C. The melting point is measured by the differential
scanning calorimetry (DSC) method described in WO 2005/090427
(US2006/0199930), the entire content of which is incorporated by
reference herein.
[0050] In an embodiment, the olefin block copolymer contains from
about 5 wt % to about 30 wt %, or from about 10 wt % to about 25 wt
%, or from about 11 wt % to about 20 wt % of a hard segment. The
hard segment contains from about 0.0 mol % to less than 0.9 mol %
units derived from comonomer. The olefin block copolymer also
contains from about 70 wt % to about 95 wt %, or from about 75 wt %
to about 90 wt %, or from about 80 wt % to about 89 wt % of a soft
segment. The soft segment contains less than 15 mol %, or from
about 9 mol % to about 14.9 mol % units derived from comonomer. In
an embodiment, the comonomer is butene or octene.
[0051] Applicants surprisingly discovered that provision of a soft
segment comonomer content in the range of less than 15 mol %, or
from about 9 mol % to about 14.9 mol %, unexpectedly produces a
polymeric composition with no, or substantially no, tackiness or
stickiness. For example, it has been found that olefin block
copolymer with 18 mol % or greater comonomer content in the soft
segment develops tackiness after aging at 50.degree. C. or higher.
Applicants have surprisingly discovered that lowering the soft
segment comonomer content to less than 15 mol %, or from about 9
mol % to about 14.9 mol %, increases soft segment crystallinity and
unexpectedly reduces stickiness or tackiness of fabricated
articles.
[0052] In an embodiment, the oil-extended OBC composition includes
from about 20 wt % to about 40 wt % OBC, or from about 25 wt % to
about 30 wt % OBC, based on total weight of the oil extended
composition. In a further embodiment, the OBC is an ethylene/octene
multi-block copolymer with from about 5 wt % to about 30 wt % hard
segment and from about 95 wt % to about 70 wt % soft segment, based
on total weight of the copolymer. The soft segment contains from 9
mol % to 14.9 mol % units derived from octene. The OBC has an
overall octene content of 6.0 mol % to 14.2 mol %.
[0053] In some embodiments, the OBC is present in an amount of 10
phr to 90 phr (2 wt % to about 36 wt % based on total weight of the
oil extended composition), or in an amount of 30 phr to 70 phr (6
wt % to about 28 wt % based on total weight of the oil extended
composition) or in an amount of 40 phr to 60 phr (8 wt % to about
24 wt % based on total weight of the oil extended composition),
based on total elastomer being 100 phr (20 wt % to about 40 wt %
based on total weight of the oil extended composition).
[0054] 2. Oil
[0055] The oil-extended OBC composition includes an oil. The oil
can be an aromatic oil, a mineral oil, a napththenic oil, a
paraffinic oil, a triglyceride-based vegetable oil such as castor
oil, a synthetic hydrocarbon oil such as polypropylene oil, a
silicone oil, or any combination thereof. A nonlimiting example of
a suitable oil is a white mineral oil sold under the tradename
HYDROBRITE.RTM. 550.
[0056] In an embodiment, the oil-extended OBC composition contains
from about 20 wt % to about 60 wt % oil, or from about 30 wt % to
about 50 wt % oil. Weight percent is based on the total weight of
the oil-extended OBC composition.
[0057] 3. Polyolefin
[0058] The oil-extended OBC composition includes one or more
polyolefin. The polyolefin may be a different OBC, a polyethylene
(or ethylene-based polymer), a polypropylene (or propylene-based
polymer), an EPDM and any combination thereof.
[0059] In an embodiment, the polyolefin is a polyethylene. The
polyethylene is selected from ultralow density polyethylene
(ULDPE), low density polyethylene (LDPE), linear low density
polyethylene (LLDPE), medium density polyethylene (MDPE), high
density polyethylene (HDPE), high melt strength high density
polyethylene (HMS-HDPE), ultrahigh density polyethylene (UHDPE),
and combinations thereof. In a further embodiment, the polyethylene
has a density greater than 0.950 g/cc (i.e., a HDPE).
[0060] In an embodiment, the polyolefin is a polypropylene. The
polypropylene is selected from random copolymer polypropylene
(rcPP), impact copolymer polypropylene (hPP+at least one
elastomeric impact modifier) (ICPP) or high impact polypropylene
(HIPP), high melt strength polypropylene (HMS-PP), isotactic
polypropylene (iPP), syndiotactic polypropylene (sPP), and
combinations thereof.
[0061] In an embodiment, the polyolefin is an
ethylene-propylene-diene monomer rubber (EPDM). EPDM materials are
linear interpolymers of ethylene, propylene, and a nonconjugated
diene such as 1,4-hexadiene, dicyclopentadiene, or ethylidene
norbornene. A preferred class of interpolymers having the
properties disclosed herein is obtained from polymerization of
ethylene, propylene, and a non-conjugated diene to make an EPDM
elastomer. Suitable non-conjugated diene monomers can be a straight
chain, branched chain or cyclic hydrocarbon diene having from 6 to
15 carbon atoms. Examples of suitable non-conjugated dienes
include, but are not limited to, straight chain acyclic dienes,
such as 1,4-hexadiene, 1,6-octadiene, 1,7-octadiene, 1,9-decadiene,
branched chain acyclic dienes, such as 5-methyl-1,4-hexadiene;
3,7-dimethyl-1,6-octadiene; 3,7-dimethyl-1,7-octadiene and mixed
isomers of dihydromyricene and dihydroocinene, single ring
alicyclic dienes, such as 1,3-cyclopentadiene; 1,4-cyclohexadiene;
1,5-cyclooctadiene and 1,5-cyclododecadiene, and multi-ring
alicyclic fused and bridged ring dienes, such as tetrahydroindene,
methyl tetrahydroindene, dicyclopentadiene,
bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene, cycloalkenyl
and cycloalkylidene norbornenes, such as 5-methylene-2-norbornene
(MNB); 5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene,
5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2-norbornene,
5-vinyl-2-norbornene, and norbornadiene. Of the dienes typically
used to prepare EPDMs, the particularly preferred dienes are
1,4-hexadiene (HD), 5-ethylidene-2-norbornene (ENB),
5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB),
and dicyclopentadiene (DCPD). The especially preferred dienes are
5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).
[0062] In some embodiments, the EPDM polymers have an ethylene
content of from about 50% to about 75% by weight, a propylene
content of from about 20% to about 49% by weight, and a
nonconjugated diene content from about 1% to about 10% by weight,
all weights based upon the total weight of the polymer. Examples of
representative EPDM polymers for use include Nordel IP 4770R,
Nordel 3722 IP available from The Dow Chemical Company, Midland,
Mich., Vistalon 3666 available from ExxonMobil, Baton Rouge, La.,
and Keltan 5636A available from DSM Elastomers Americas, Addis,
La.
[0063] The EPDM polymers, also known as elastomeric copolymers of
ethylene, a higher-alpha-olefin and a polyene, have molecular
weights from about 20,000 to about 2,000,000 daltons or more. Their
physical form varies from waxy materials to rubbers to hard
plastic-like polymers. They have dilute solution viscosities (DSV)
from about 0.5 to about 10 dl/g, measured at 30.degree. C. on a
solution of 0.1 gram of polymer in 100 cc of toluene. The EPDM
polymers also have a Mooney viscosity of greater than 50 ML(1+4) at
125.degree. C.; and, a density of 0.870 g/cc to 0.885 g/cc or from
0.875 g/cc to 0.885 g/cc.
[0064] In some embodiments, the EPDM is present in an amount of 10
phr to 90 phr (2 wt % to about 36 wt % of the total oil-extended
composition), or in an amount of 30 phr to 70 phr (6 wt % to about
28 wt % of the total oil-extended composition) or in an amount of
40 phr to 60 phr (8 wt % to about 24 wt % of the total oil-extended
composition), based on total elastomer being 100 phr (20 wt % to
about 40 wt % based on total weight of the oil extended
composition).
[0065] In an embodiment, the oil-extended OBC composition includes
from about 5 wt % to about 25 wt % polyolefin, or from about 5 wt %
to about 15 wt % polyolefin. In a further embodiment, the
polyolefin is HDPE.
[0066] In another embodiment, the oil-extended OBC composition
includes an OBC, a polyethylene and EPDM.
[0067] 4. Filler
[0068] The oil-extended OBC composition includes a filler.
Nonlimiting examples of suitable fillers include talc, calcium
carbonate, chalk, calcium sulfate, clay, kaolin, silica, glass,
fumed silica, mica, wollastonite, feldspar, aluminum silicate,
calcium silicate, alumina, hydrated alumina such as alumina
trihydrate, glass microsphere, ceramic microsphere, thermoplastic
microsphere, barite, wood flour, glass fibers, carbon fibers,
marble dust, cement dust, magnesium oxide, magnesium hydroxide,
antimony oxide, zinc oxide, barium sulfate, titanium dioxide, and
titanates.
[0069] In an embodiment, the oil-extended OBC composition contains
from about 10 wt % to about 50 wt % filler, or from about 20 wt %
to about 30 wt % filler. In a further embodiment, the filler is
calcium carbonate.
[0070] The OBC, oil, polyolefin, and the filler are compounded to
form the oil-extended OBC composition such as by way of melt
blending and/or extrusion blending, for example. The composition
may then be molded into desired structures such as plaques, films,
and/or pellets.
[0071] In an embodiment, the oil-extended OBC composition is
halogen-free.
[0072] In an embodiment, the oil-extended OBC composition is
phthalate-free.
[0073] Applicants surprisingly discovered that provision of (i) an
OBC with a soft segment comonomer content in the range of less than
15 mol %, or from about 9 mol % to about 14.9 mol %, and (ii) a
polyolefin in the present oil-extended composition and (iii) a
filler unexpectedly produces an oil-extended OBC composition with
no, or substantially no, tack or stickiness. The term "tack," as
used herein, is the ability of one material to adhere to another
material. Tack is quantified in terms of tack force. The "tack
force" is a measure of the force (in Newtons) required to separate
two materials in contact with each other. The measurement for tack
force is described in detail in the following "test methods"
section. The term "tack-free," as used herein, is a polymeric
composition with a tack force of less than 0.013 N after exposure
to 70.degree. C. for one week.
[0074] After exposure to 70.degree. C. for one week, the present
oil-extended OBC composition has a tack force of 0.0 N to less than
0.1 N, or from about 0.0 N (or greater than 0.0 N) to less than
about 0.05N, or from about 0.0 N (or greater than 0.0N) to less
than about 0.04N, or from about 0.0 N (or greater than 0.0N) to
less than 0.03N, or from about 0.0 N (or greater than 0.0N) to less
than 0.02N, or from about 0.0 N (or greater than 0.0 N) to less
than 0.013N.
[0075] Applicants also have surprisingly discovered that an
oil-extended composition with (i) 2%-60 wt % OBC, the OBC having a
soft segment comonomer content from about 9 mol % to less than 15
mol % blended with (ii) a polyolefin unexpectedly reduces oil-bleed
while maintaining softness in oil-extended OBC compositions. The
term "oil-bleed-out" or "oil-bleed" is the phenomenon whereby oil
migrates from the interior of a polymeric component to the surface
of the polymeric component. Oil-bleed makes the surface sticky
and/or slippery. Oil-bleed typically results in adverse "feel"
(haptics) and/or adverse "optics" (visual appearance). The term
"oil exudation" is the process of oil moving from an interior
location to a surface of a polymeric component. Oil exudation
yields oil-bleed. In other words, oil-bleed is the end result of
oil exudation. Oil-bleed is accelerated by elevated
temperatures.
[0076] Oil-bleed is evaluated by way of a normalized oil-bleed
index (NOBI). NOBI is an optical measurement of the amount of oil
absorbed on cigarette paper from on oil-containing polymeric
composition. NOBI is calculated according to the following
equation:
Normalized Oil-bleed Index=100(% grayscale sample-% grayscale
control)/(100-% grayscale control)
[0077] The term "% grayscale sample" is the percent grayscale
measured on the aged sample and "% grayscale control" is a
measurement on an unaged untreated sheet of cigarette paper. NOBI
has a range from 0-100. When NOBI=100, the paper is saturated and
the test does not register oil-bleed beyond that level.
[0078] In an embodiment, the oil-extended OBC composition has a
normalized oil-bleed index of less than 20, or less than 10, or
from 0 to less than 20, or from 0 to less than 10, or from 0 to
less than 5, after 1 week at 23.degree. C.
[0079] In an embodiment, the oil-extended OBC composition has a
NOBI of less than 20, or from about 5 to less than 20, after 3
weeks at 23.degree. C.
[0080] In an embodiment, the present composition has a NOBI of less
than 50, or from 0 to less than 50, or from 0 to less than 10 after
3 weeks at 70.degree. C.
[0081] In an embodiment, the present oil-extended OBC composition
has Shore A hardness from about 40 to about 90, or from about 50 to
about 90.
[0082] The disclosure provides another composition. In an
embodiment, an oil-extended olefin block copolymer composition is
provided and includes an OBC, an oil, a polyolefin, and a filler.
The OBC is an ethylene/a-olefin multi-block copolymer with hard
segments and soft segments. The soft segments contain from about 9
mol % to less than 15 mol % comonomer content. The composition has
a NOBI value less than 50, or from 10 to less than 50, after
exposure to 70.degree. C. for one week, and/or after exposure to
70.degree. C. for three weeks. The composition also has a Shore A
hardness from about 50 to about 90.
[0083] In an embodiment, the composition, when exposed to
70.degree. C. for one week exhibits a tack force less than 0.1N, or
from about 0.0 N (or greater than 0.0 N) to less than about 0.05N,
or from about 0.0 N (or greater than 0.0N) to less than about
0.04N, or from about 0.0 N (or greater than 0.0N) to less than
0.03N, or from about 0.0 N (or greater than 0.0N) to less than
0.02N, or from about 0.0 N (or greater than 0.0 N) to less than
0.013N.
[0084] In an embodiment, the polyolefin is a polyethylene with a
density greater than 0.950 g/cc (a high density polyethylene).
[0085] In an embodiment, the composition includes from about 20 wt
% to about 30 wt % OBC, from about 30 wt % to about 40 wt % oil,
from about 5 wt % to about 15 wt % polyethylene, and from about 25
wt % to about 30 wt % filler. In a further embodiment, the OBC is
an ethylene/octene multi-block copolymer.
[0086] The disclosure provides another composition. In an
embodiment, an oil-extended olefin block copolymer is provided and
includes an OBC, a polyethylene, and a filler. The OBC is an
ethylene/a-olefin multi-block interpolymer with hard segments and
soft segments, the soft segments containing from about 9 mol % to
less than 15 mol % comonomer content. The composition has the
following properties after exposure to 70.degree. C. for one week:
(i) a tack force less than 0.013N, or from 0.0 N to less than 0.013
N; and (ii) a Shore A hardness from about 40 to about 90, or from
about 50 to about 70.
[0087] In an embodiment, the composition has a NOBI of less than
50, or from 0 to less than 50 after 1 week at 70.degree. C. In a
further embodiment, the composition has a NOBI of less than 50, or
from 0 to less than 50, or from 0 to less than 10 after 3 weeks at
70.degree. C.
[0088] In an embodiment, the polyethylene has a density greater
than 0.95 g/cc.
[0089] In an embodiment, the composition has a compression set
value from about 40% to about 70%, or from about 45% to about 65%,
or from about 50% to about 60%. Compression set is measured in
accordance with ASTM D 395.
[0090] Any of the foregoing oil-extended olefin block copolymer
compositions may comprise two or more embodiments disclosed
herein.
[0091] The OBC can be modified by such processes as e-beam or
peroxide treatment in order to alter the rheology of the polymer.
E-beaming and peroxide are provided as examples only and are not
meant to be limiting. These treatments result in both chain
scission and cross-linking events. When these events are properly
balanced, for example by controlling the e-beam dose, the rheology
ratio of the OBC can be increased without a significant decrease in
the molecular weight of the polymer.
[0092] Any of the foregoing oil-extended olefin block copolymer
compositions can be made into an article or be made into a
component of an article. Nonlimiting examples of suitable articles
include durable articles for the automotive, construction, medical,
food and beverage, electrical, appliance, business machine, and
consumer applications. In some embodiments, the compositions are
used to manufacture flexible durable parts or articles selected
from toys, grips, soft touch handles, bumper rub strips, floorings,
auto floor mats, wheels, casters, furniture and appliance feet,
tags, seals, gaskets such as static and dynamic gaskets, automotive
doors, bumper fascia, grill components, rocker panels, hoses,
linings, office supplies, seals, liners, diaphragms, tubes, lids,
stoppers, plunger tips, delivery systems, kitchen wares, shoes,
shoe bladders and shoe soles. In some embodiments, the compositions
are used to manufacture durable parts or articles that require a
high tensile strength and low compression set. In further
embodiments, the compositions are used to manufacture durable parts
or articles that require a high upper service temperature and a low
modulus.
[0093] Definitions
[0094] All references to the Periodic Table of the Elements herein
shall refer to the Periodic Table of the Elements, published and
copyrighted by CRC Press, Inc., 2003. Also, any references to a
Group or Groups shall be to the Groups or Groups reflected in this
Periodic Table of the Elements using the IUPAC system for numbering
groups. Unless stated to the contrary, implicit from the context,
or customary in the art, all parts and percents are based on
weight. For purposes of United States patent practice, the contents
of any patent, patent application, or publication referenced herein
are hereby incorporated by reference in their entirety (or the
equivalent US version thereof is so incorporated by reference),
especially with respect to the disclosure of synthetic techniques,
definitions (to the extent not inconsistent with any definitions
provided herein) and general knowledge in the art.
[0095] Any numerical range recited herein, includes all values from
the lower value to the upper value, in increments of one unit,
provided that there is a separation of at least 2 units between any
lower value and any higher value. As an example, if it is stated
that the amount of a component, or a value of a compositional or a
physical property, such as, for example, amount of a blend
component, softening temperature, melt index, etc., is between 1
and 100, it is intended that all individual values, such as, 1, 2,
3, etc., and all subranges, such as, 1 to 20, 55 to 70, 97 to 100,
etc., are expressly enumerated in this specification. For values
which are less than one, one unit is considered to be 0.0001,
0.001, 0.01 or 0.1, as appropriate. These are only examples of what
is specifically intended, and all possible combinations of
numerical values between the lowest value and the highest value
enumerated, are to be considered to be expressly stated in this
application. In other words, any numerical range recited herein
includes any value or subrange within the stated range. Numerical
ranges have been recited, as discussed herein, reference melt
index, melt flow rate, and other properties.
[0096] 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.
[0097] The term "composition," as used herein, includes a mixture
of materials which comprise the composition, as well as reaction
products and decomposition products formed from the materials of
the composition.
[0098] The term "comprising," and derivatives thereof, is not
intended to exclude the presence of any additional component, step
or procedure, whether or not the same is disclosed herein. In order
to avoid any doubt, all compositions claimed herein 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.
[0099] Normalized oil-bleed index (NOBI) is an optical measurement
of the amount of oil absorbed on cigarette paper from an
oil-containing polymer composition.
[0100] The term "polymer" is a macromolecular compound prepared by
polymerizing monomers of the same or different type. "Polymer"
includes homopolymers, copolymers, terpolymers, interpolymers, and
so on. The term "interpolymer" means a polymer prepared by the
polymerization of at least two types of monomers or comonomers. It
includes, but is not limited to, copolymers (which usually refers
to polymers prepared from two different types of monomers or
comonomers, terpolymers (which usually refers to polymers prepared
from three different types of monomers or comonomers),
tetrapolymers (which usually refers to polymers prepared from four
different types of monomers or comonomers), and the like.
[0101] Test Methods
[0102] Compression set is measured according to ASTM D 395. The
sample is prepared by stacking 25.4 mm diameter round discs of 3.2
mm, 2.0 mm, and 0.25 mm thickness until a total thickness of 12.7
mm is reached. The discs are cut from injection molded plaques that
are 4'' by 6'' by 0.125''. Compression set is measured after 24
hours at 25% strain at 70.degree. C. or 23.degree. C.
[0103] Density is measured in accordance with ASTM D 792.
[0104] Differential scanning calorimetry (DSC) is performed on
compression molded specimens using a TA Instruments Q100 or Q1000
DSC and a crimp-sealed Perkin Elmer pan. Samples are equilibrated
at -90.degree. C. for 5 min, then heated at 10.degree. C./min to
180.degree. C. (capturing the "1.sup.st Heat DSC Curve"), held for
5 min, then cooled at 10.degree. C./min. to -90.degree. C.
(capturing the "crystallization curve"), held for 5 minutes, then
heated at 10.degree. C./min to 180.degree. C. (capturing the
"2.sup.nd Heat DSC Curve"). The data is analyzed using TA Universal
Analysis software after run completion.
[0105] Melt Index (MI) is measured in accordance with ASTM D 1238,
Condition 190.degree. C./2.16 kg.
[0106] Normalized oil-bleed index (NOBI) is an optical measurement
to compare oil-bleed characteristics. Molded plaques are aged for
24 hrs, 1 week, and 3 weeks (at 23.degree. C. and 70.degree. C.)
while resting on sheets of ZigZag.TM. cigarette paper (available
from ZigZag Corp.). After aging, the cigarette paper is removed and
optically scanned against a black background to measure the extent
of oil-bleed.
[0107] The scanning is performed using the Xerox WorkCentre M118i
copier/fax/scanner. The image is scanned in "Text" mode at 200dpi,
and saved as a TIFF file. The TIFF file is opened in MS Paintbrush,
cropped on two sides, then saved. The image is then opened in
Photoshop CS2 (v.9) and cropped on the other two sides. The TIFF
file is opened in MS Paintbrush, cropped on two sides, then saved.
The "text mode" image is a bi-tonal image. The percentage of black
pixels in the image is the desired result. The text mode image is
obtained in this software by first converting it to an 8-bit
grayscale image so that a grayscale histogram could be created,
with just 2 levels of grayscale, 0 (black) to 255 (white). The
percentile of the 0 grayscale level in the histogram is the same as
the percentage of black pixels. (This value is called "% gray
scale" but may more accurately be described as "% black pixels" in
the bi-tonal image).
[0108] A normalized oil-bleed index (NOBI) is calculated according
to the following equation:
Normalized Oil-bleed Index=100(% grayscale sample-% grayscale
control)/(100-% grayscale control)
[0109] The term "% grayscale sample" is the percent grayscale
measured on the aged sample and "% grayscale control" is a
measurement on an un-aged, untreated sheet of cigarette paper. NOBI
has a range from 0 to 100. When NOBI=100, the paper is saturated
and the test does not register oil-bleed beyond that level. FIG. 1
shows four examples of grayscale: 20.1%, 34.6%, 51.6%, and 100%
grayscale.
[0110] Shore A hardness is measured on molded plaques in accordance
with ASTM D 2240. This test method permits hardness measurements
based on either initial indentation or indentation after a
specified period of time, or both. In this case, a specified time
of 10 seconds is used.
[0111] Small angle x-ray scattering (SAXS) data are collected using
a Rigaku Micro Source X-ray Generator with Cu radiation and a 2D
area detector. The samples are positioned in the beam using a
precision step motor controlled via PC using Labview software. Data
are analyzed using SCATTER and are corrected for air
background.
[0112] Tack Force is measured as follows. Samples are compression
molded or injection molded into plaques with a thickness of 0.125
inches. Samples are cut into 1''.times.6'' strips and marked in 1''
intervals. Samples are aged at elevated temperature if warranted.
Mylar.RTM. sheets are cut into 1''.times.6'' strips, formed into
loops with dimensions of 1''.times.5''. After aging, the samples
are cooled to room temperature. Double-sided tape is used to affix
the specimen to platform to prevent it from rising up off the
surface. The loop is placed into the pneumatic grips of Instron.TM.
5564 and aligned parallel to the plaque. The loop is lowered at a
rate of 300%/minute covering the 1''.times.1'' surface of the
plaque. A new loop is used with each measurement taken. The Average
Tack Force (N) and standard deviation are reported after five
readings per specimen. One measurement is taken per each
1''.times.1'' portion of a sample.
Surface Roughness
[0113] Surface roughness is created on a mold by sanding a
mirror-finished plate. The surface roughness of the mold is
measured using a profilometer (Dektak 150 stylus profilometer)
using the following parameters. Surface roughness is measured both
in a direction parallel to and perpendicular to the sanding
direction. Surface roughness values reported are Ra, average
roughness, for the perpendicular direction. Ra (Average Roughness),
formerly known as Arithmetic Average (AA) and Center Line Average
(CL), is the arithmetic average deviation from the mean line within
the assessment length.
[0114] Ten line scans per sample
[0115] Scan Type Standard Scan
[0116] Stylus Radius: 2.5 .mu.m
[0117] Scan Length 15000.0 .mu.m
[0118] Duration 90 sec
[0119] Resolution 0.556 .mu.m/sample
[0120] Force 1.00 mg
[0121] Measurement Range 524 .mu.m
[0122] Profile Hills&Valleys
[0123] Display Range Auto
[0124] Short Pass Filter Cutoff 100.0 .mu.m
[0125] Long Pass Filter Cutoff 1500.0 .mu.m
[0126] R. Cursor Pos: 100.0 .mu.m Width: 40.0 .mu.m
[0127] M. Cursor Pos: 14750.0 .mu.m Width: 40.0 .mu.m
[0128] By way of example and not by limitation, examples of the
present disclosure will now be provided.
EXAMPLES
[0129] 1. Materials
[0130] A. Olefin Block Copolymer
[0131] Olefin block copolymer is available from The Dow Chemical
Company (Midland, Mich.).
[0132] (i) INFUSE.TM. 9007-0.5 g/10 min MI, 0.866 g/cc density
olefin block copolymer (OBC), with 11/89 hard/soft segment split by
weight percent and 18 mol % octene in the soft segment, and 15.6
mol % total octene.
[0133] (ii) INFUSE.TM. 9000-0.5 g/10 min MI, 0.877 g/cc density
OBC, with 25/75 hard/soft segment split by weight percent, 18 mol %
octene in the soft segment, and 12.7 mol % total octene.
[0134] (iii) OBC 3-0.5 g/10 min MI, 0.877 g/cc density OBC, 130 ppm
Zn, with 11/89 hard/soft segment split by weight percent, 13 mol %
octene in the soft segment, 11.2 mol % total octene. The properties
for three OBCs are shown in Table 1 below.
TABLE-US-00001 TABLE 1 INFUSE INFUSE Property Method 9007 9000 OBC
3 Melt Index dg/min ASTM D 0.5 0.5 0.5 1238 Density g/cm.sup.3 ASTM
D 792 0.866 0.877 0.877 Melting .degree. C. DSC 120 120 120 Point
Tg .degree. C. DSC -60 -60 -54 Hardness Shore A ASTM D 60 75 76
2240 100% MPa ASTM D 1.4 2.6 2.8 Modulus 1708 Ultimate MPa ASTM D
11.1 14.1 19.7 Tensile 1708 Strength Tensile % ASTM D 1560 1270 975
Elongation 1708 Compression % ASTM D 395 17 15 23 Set, 23.degree.
C. Compression % ASTM D 395 53 40 60 Set, 70.degree. C.
[0135] B. Oil
[0136] Hydrobrite 550 (Sonneborn)--mineral oil with nominal 70%
paraffinic and 30% naphthenic content, and average 541 MW.
[0137] C. Polyolefin
[0138] Dow DMDA-8920 NT 7 (Dow HDPE 8920) is a high density
polyethylene available from The Dow Chemical Company, Dow HDPE 8920
has a density of 0.954 g/cc, MI of 20 g/10/min, and a melting point
of 130.degree. C.
[0139] Dow hPP 700-12 is a polypropylene available from The Dow
Chemical Company. Dow hPP 700-12 has a density of (1900 g/cc (ASTM
D792), and a melt flow rate of 12 (230 .degree. C./2,16 kg, ASTM
D1238).
[0140] NORDEL IP 4770 is an ethylene-propylene-diene monomer rubber
(EPDM) available from The Dow Chemical Company (Midland, Mich.) and
has the following properties: density of 0.872 g/cc, Mooney
viscosity (ML 1+4, 257 F) of 70, ethylene content of 70 wt % and
ENB content of 5 wt %.
[0141] Vistalon 3666 is an EPDM available from ExxonMobil Chemical
Company (Houston, Tex.) and has the following properties: Mooney
viscosity of 52, ethylene content of 64 wt %, and ENB content of
4.5 wt %.
[0142] D. Filler
[0143] Calcium carbonate--Atomite (available from IMERYS
Performance Minerals)
[0144] 2. Preparation
[0145] The compositions of Samples A', B', 1, 2 and 3 are provided
in Table 2 below. Samples A and B are comparative. Amounts are
given in weight percent based on total weight of the
composition.
TABLE-US-00002 TABLE 2 Sample # A' B' 1 2 3 61 53 53 62 Shore A 70
Shore A Shore A Shore A Shore A KRATON G1651 E 22.0 0 0 0 0 INFUSE
9007 0 27.1 0 0 0 OBC 3 0 0 28.2 27.0 26.0 Oil (Hydrobrite 550)
41.8 35.1 36.6 35.2 33.7 Filler 21.7 27.0 28.2 27.0 26.0 (Atomite
CaCO.sub.3) Polyolefin 0 0 7.0 10.8 14.3 (DOW HDPE 8920) Polyolefin
14.3 10.8 0 0 0 (DOW hPP 700-12)
[0146] Samples 1-3 of Table 2 are compounded by way of a Werner
& Pleiderer ZSK-30 twin screw extruder, and a Zenith pump
powered by a Dayton DC motor. Samples 1-3 are pelletized with a
Gala LPU lab underwater pelleting system. The processing conditions
are provided in Tables 3-4 below.
TABLE-US-00003 TABLE 3 Compounding Conditions Sample # 1 2 3 Shore
A 53 62 70 Zone 1 Temp/Feed .degree. C. n/a n/a n/a Zone 2 Temp
.degree. C. 120 122 119 Zone 3 Temp .degree. C. 175 172 168 Zone 4
Temp .degree. C. 170 175 172 Zone 5 Temp .degree. C. 165 166 168
Die Temp .degree. C. 140 119 111 Adaptor .degree. C. 150 150 150
Pelletizer RPM rpm1 400 1400 1400 Die Pressure psig 147 157 161
Melt temp .degree. C. 147 157 161 Extruder RPM rpm 202 202 200
Extruder Torque % 44 42 44 Feeder #1 lb/hr 7.0 7.9 8.7 Feeder #2
lb/hr 5.6 5.6 5.6 Oil pump #1 lb/hr 5.1 5.1 5.1 Oil pump #2 lb/hr
2.2 2.2 2.2 Total Run Rate lb/hr 19.9 20.8 21.6
[0147] Samples 1-3 are molded into 4''.times.6''.times.0.125''
minor polished plaques under the following conditions shown in
Table 4 below.
TABLE-US-00004 TABLE 4 Injection Molding Conditions Temperatures
All Samples Zone 1 Temp .degree. .degree. C. 204 Zone 2 Temp
.degree. .degree. C. 204 Zone 3 Temp .degree. .degree. C. 204 Zone
4 Temp .degree. .degree. C. 204 Nozzle Temp .degree. C. 204 Molded
Temperature .degree. C. 16 Extruder RPM m/min 30 Back Pressure Bar
15 Dosage cm.sup.3 70 Optimal Injection Injection Speed
cm.sup.3/sec 25 Transfer Position cm.sup.3 15 Pressure at Transfer
Bar 264 Fill Time sec 2.37 Cushion cm.sup.3 6.2 Hold Pressure Bar
275 Time Hold Time sec 50 Cool Time sec 20 Dosage sec 6.2 Cycle
Time sec 79.5
[0148] FIG. 2 shows the tack force and Shore A hardness values for
Samples 1-3 after exposure to 70.degree. C. for 1 week. Also shown
in FIG. 2 is a tack-free zone as indicated by the upper horizontal
line of the box which indicates a tack force of 0.013 N. Samples
below this line are tack-free.
[0149] FIG. 3 shows NOBI and Shore A hardness values for Samples
1-3 after exposure to 23.degree. C. for 3 weeks.
[0150] FIG. 4 shows NOBI and Shore A hardness values for Samples
1-3 after exposure to 70.degree. C. for 3 weeks.
[0151] FIG. 5 shows the compression set (%) and Shore A hardness
values for Samples 1-3 after exposure to 70.degree. C. for 24
hours.
[0152] The data in FIGS. 2-5 show Samples 1-3 with low tack (or
tack-free), with low oil bleed (NOBI less than 50), and softness
(Shore A 50-90).
[0153] Table 5 shows the properties of Samples A, B and 1-3.
TABLE-US-00005 TABLE 5 Properties of Samples A', B' and 1-3 A' B' 1
2 3 Tack Force 0.0057 0.4429 0.0141 0.0118 0.0118 (70.degree. C., 1
week) [N] NOBI 12 7 4 2 6 (23.degree. C., 3 weeks) NOBI 28 44 11 6
4 (70.degree. C., 3 weeks) Compression 24 27 23 29 31 Set,
23.degree. C. Compression 49 71 51 49 52 Set, 70.degree. C. Tensile
1076 421 554 650 774 Strength, psi Tensile 272 229 203 291 403
stress at 100%, psi
Examples Set 2
[0154] The following set of Samples are prepared similarly to
Samples 1-3. Tables 6 and 7 show formulations and properties of
Samples with 160 phr oil and 190 phr oil respectively.
TABLE-US-00006 TABLE 6 Formulations (in phr) and Properties with
160 phr Oil 4 5 6 7 8 9 10 OBC 3 50 50 50 50 100 100 100 EPDM 1
(NORDEL 50 50 50 50 0 0 0 IP 4770) HDPE 8920 25 40 55 70 25 40 55
hPP 700-12 -- -- -- -- -- -- -- Oil - Hydrobrite 550 160 160 160
160 160 160 160 Filler Atomite 100 100 100 100 100 100 100
CaCO.sub.3 Hardness, Shore A 50 56 63 68 45 55 64 Tack (70.degree.
C., 1 0.0221 0.0064 0.0063 0.0058 0.0208 0.0185 0.0524 week) NOBI
(23 C., 3 0 4 3 7 16 1 17 weeks) NOBI (70.degree. C., 3 8 11 1 10 3
14 15 weeks Compression Set, 24 27 29 28 24 25 27 23.degree. C.
Compression Set, 57 56 61 55 56 58 58 70.degree. C. Tensile
Strength, 409 507 558 635 476 554 644 psi Tensile stress at 167 232
280 341 161 213 288 100%, psi Rheology Ratio 4.7 5.4 5.5 4.5 2.6
2.6 2.6 11 A B C D E OBC 3 100 0 0 0 0 50 EPDM 1 (NORDEL 0 100 100
100 100 50 IP 4770) HDPE 8920 70 25 40 55 70 -- hPP 700-12 -- -- --
-- -- 40 Oil - Hydrobrite 550 160 160 160 160 160 160 Filler
Atomite 100 100 100 100 100 100 CaCO.sub.3 Hardness, Shore A 70 47
54 63 68 61 Tack (70.degree. C., 1 0.0367 0.0073 0.0069 0.0055
0.0072 0.1200 week) NOBI (23 C., 3 4 8 9 2 8 -4 weeks) NOBI
(70.degree. C., 3 53 17 8 2 7 16 weeks Compression Set, 28 23 24 24
28 24 23.degree. C. Compression Set, 54 67 64 58 53 80 70.degree.
C. Tensile Strength, 714 388 464 510 573 295 psi Tensile stress at
343 155 200 265 322 824 100%, psi Rheology Ratio 2.6 8.0 7.9 7.5
8.2 9.7
TABLE-US-00007 TABLE 7 Formulations (in phr) and Properties with
190 phr Oil F G H I J 12 13 14 K 15 OBC 3 0 0 0 0 50 50 50 50 50 50
EPDM 1 (NORDEL IP 4770) 100 100 100 100 50 50 50 50 0 0 EPDM 2
(Vistalon 3666) 0 0 0 0 0 0 0 0 88 88 HDPE 8920 25 40 55 70 25 40
55 70 25 70 Oil--Hydrobrite 550 190 190 190 190 190 190 190 190 153
153 Filler--Atomite CaCO3 100 100 100 100 100 100 100 100 100 100
Hardness, Shore A 44 53 55 65 48 53 57 64 36 60 Tack Force
(70.degree. C., 0.0843 0.0448 0.0556 0.0077 0.0312 0.0196 0.0129
0.0191 0.1590 0.0081 1 week) [N] NOBI 23.degree. C. (3 weeks) 11 11
2 8 13 5 10 11 9 6 NOBI 70.degree. C. (3 weeks) 12 13 4 3 4 0 11 40
11 26 Compression Set (23.degree. C.) [%] 23 28 28 37 26 27 31 33
26 30 Compression Set (70.degree. C.) [%] 72 64 65 58 62 59 58 57
51 53 Tensile Stress at 100% [psi] 143 194 202 292 160 188 255 345
138 264 Tensile Strength [psi] 544 558 583 635 492 538 612 696 349
503 Rheology Ratio 14.0 10.9 33.3 13.3 6.4 5.8 4.7 9.2 30.2 9.6
[0155] As shown in FIG. 6 and FIG. 9, the inventive examples 4-11
from Table 5 with 160 phr oil have low tack and low compression
set. The inventive examples combine the advantage of the
formulations made with NORDEL 4770 (EPDM), i.e. low tack and high
rheology ratio, with the advantage of the formulations made with
OBC, i.e. low compression set in low Shore A range. In general, the
formulations made with OBC or OBC+EPDM have the lowest compression
set values in the range of Shore A materials prepared. Meanwhile,
low tack performance is achieved for the EPDM formulations and the
OBC/EPDM formulations down to about 50 Shore A. Examples 12-15 with
190 phr oil are shown in Table 6. Again, a combination of low tack
and low compression set is achieved with the inventive examples
formulated with OBC/EPDM blends. The tack and compression set data
for the examples in Table 6 are shown in FIG. 10 and FIG. 11.
[0156] This inventive combination of low tack, and low compression
set is unexpected especially when other properties are considered.
For a property such as ultimate tensile strength, property values
that are close to the mean values between the two single-component
elastomer cases are obtained (see FIG. 8), rather than values that
are close to those of one single-component elastomer case or the
other.
Examples of Effect of Surface Texture
[0157] Examples of the effect of surface texture on tack for two
different compounds are shown in Table 8 below. As shown, when
textured molds are used, the tack force is significantly lower. The
level of surface roughness required to achieve low tack varies with
the formulation, but as illustrated a mold with 0.41 .mu.m
roughness results in low tack for both formulations. The molding
conditions used for these examples are included below. Note that
these molding conditions differ from those used in the other
examples.
TABLE-US-00008 TABLE 8 L 16 17 M N 18 Composition OBC 3 100 100 100
100 100 100 (phr) Hydrobrite 550 130 130 130 130 130 130 Atomite
CaCO3 100 100 100 100 100 100 HDPE 8920 25 25 25 40 40 40 Mold Ra
(.mu.m) mirror 0.29 0.41 mirror 0.29 0.41 Properties Plaque Ra
(.mu.m) 0.12 0.28 0.49 0.12 0.25 0.41 Hardness, Shore A 53 53 53 62
62 62 Tack Force 0.720 0.008 0.008 0.814 0.482 0.012 (70.degree.
C., 1 week) [N] Tack Stdev 0.306 0.001 0.004 0.082 0.189 0.011
TABLE-US-00009 TABLE 9 Typical molding conditions Barrel and Mold
Temperatures Hopper zone (.degree. C.) 38 Zone 1 Temperature
(.degree. C.) 121 Zone 2 Temperature (.degree. C.) 232 Zone 3
Temperature (.degree. C.) 232 Zone 4 Temperature (.degree. C.) 232
Zone 5 Temperature (.degree. C.) 232 Nozzle Temperature (.degree.
C.) 170 Mold Temperature (.degree. F.) 120 Extruder RPM (1/min) 150
Backpressure (Bar) 15 Plast. Time (s) 7.97 Dosage (ccm) 80 Suckback
(ccm) 5 Optimal Injection Injection Speed #1 (ccm/s) 25 Injection
pressure #1 (bar) 2000 Injection Time #1 (s) 2.62 Switch Over
Position (ccm) 20 Switch over melt pressure (bar) 339 Max Melt
pressure (bar) 344 Cushion (ccm) 15.7 Hold Hold Pressure (Bar) 200
Hold Time (s.) 30 Time Cool Time (s.) 20 Cycle Time (s.) 61
[0158] 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.
* * * * *