U.S. patent application number 09/944423 was filed with the patent office on 2002-05-23 for compositions comprising hydrogenated block copolymers and end-use applications thereof.
Invention is credited to Bhattacharjee, Debkumar, Donald, Robert J., Esneault, Calvin P., Hahn, Stephen F., Hahnfeld, Jerry L., Parsons, Gary D., Pate, James E. III, Patel, Rajen M., Phipps, Laura M..
Application Number | 20020061982 09/944423 |
Document ID | / |
Family ID | 27495353 |
Filed Date | 2002-05-23 |
United States Patent
Application |
20020061982 |
Kind Code |
A1 |
Donald, Robert J. ; et
al. |
May 23, 2002 |
Compositions comprising hydrogenated block copolymers and end-use
applications thereof
Abstract
Flexible hydrogenated block copolymers can be successfully used
in a variety of applications including films, profiles, sheets,
coatings, injection molded articles, blow or rotational molded
articles and pultruded articles.
Inventors: |
Donald, Robert J.; (Midland,
MI) ; Hahnfeld, Jerry L.; (Midland, MI) ;
Parsons, Gary D.; (Midland, MI) ; Hahn, Stephen
F.; (Midland, MI) ; Patel, Rajen M.; (Lake
Jackson, TX) ; Esneault, Calvin P.; (Baton Rouge,
LA) ; Phipps, Laura M.; (Rochelle, VA) ; Pate,
James E. III; (Sanford, MI) ; Bhattacharjee,
Debkumar; (Lake Jackson, TX) |
Correspondence
Address: |
THE DOW CHEMICAL COMPANY
INTELLECTUAL PROPERTY SECTION
P. O. BOX 1967
MIDLAND
MI
48641-1967
US
|
Family ID: |
27495353 |
Appl. No.: |
09/944423 |
Filed: |
August 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09944423 |
Aug 31, 2001 |
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09575063 |
May 19, 2000 |
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60139075 |
Jun 11, 1999 |
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60146008 |
Jul 28, 1999 |
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60193313 |
Mar 30, 2000 |
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Current U.S.
Class: |
525/332.9 ;
525/338 |
Current CPC
Class: |
C09D 153/025 20130101;
C08F 8/04 20130101; C08F 8/04 20130101; C08L 53/025 20130101; C08L
53/025 20130101; C09D 153/025 20130101; C08L 53/025 20130101; C09D
153/02 20130101; C08L 2666/04 20130101; C08L 2666/14 20130101; C08F
297/04 20130101; C08L 2666/24 20130101; C08L 2666/24 20130101; C08L
2666/14 20130101; C08L 2666/24 20130101; C08L 2666/02 20130101;
C08L 2666/02 20130101; C08F 297/04 20130101; C08L 53/025 20130101;
C08L 53/025 20130101; C08L 2666/04 20130101; C09D 153/025 20130101;
C09D 153/025 20130101; C09D 153/025 20130101; C09D 153/02
20130101 |
Class at
Publication: |
525/332.9 ;
525/338 |
International
Class: |
C08F 036/00; C08F
236/10; C08F 008/02; C08F 008/42; C08C 019/02 |
Claims
What is claimed is:
1. A monolayer or multilayer article produced from a composition
comprising a hydrogenated block copolymer, wherein the hydrogenated
block copolymer comprises at least two distinct blocks of
hydrogenated vinyl aromatic polymer, and at least one block of
hydrogenated conjugated diene polymer, wherein the copolymer is
further characterized by: a) a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic
polymer block of greater than 40:60; b) a total number average
molecular weight (Mn.sub.t) of from 30,000 to 150,000, wherein each
hydrogenated vinyl aromatic polymer block (A) has a Mn.sub.a of
from 5,000 to 45,000 and each hydrogenated conjugated diene polymer
block (B) has a Mn.sub.b of from 12,000 to 110,000; and c) a
hydrogenation level such that each hydrogenated vinyl aromatic
polymer block has a hydrogenation level of greater than 90 percent
and each hydrogenated conjugated diene polymer block has a
hydrogenation level of greater than 95 percent.
2. The article of claim 1 wherein the hydrogenated vinyl aromatic
polymer block is selected from the group consisting of hydrogenated
polystyrene, hydrogenated alpha-methylstyrene polymer, hydrogenated
vinyltoluene polymer, a hydrogenated copolymer of styrene and
alpha-methylstyrene, and hydrogenated styrene-vinyltoluene
copolymer and the hydrogenated conjugated diene polymer block is
selected from the group consisting of hydrogenated polybutadiene,
hydrogenated polyisoprene, and a hydrogenated copolymer of
butadiene and isoprene.
3. The article of claim 1 wherein the composition additionally
comprises at least one additional polymer.
4. The article of claim 3 wherein the additional polymer is
selected from the group consisting of hydrogenated vinyl aromatic
homopolymers, other hydrogenated vinyl aromatic/conjugated diene
block copolymers, thermoplastic polyurethanes, polycarbonates (PC),
polyamides, polyethers, poly/vinyl chloride polymers,
poly/vinylidene chloride polymers, polyesters, polymers that
contain lactic acid residuals, partially or non-hydrogenated vinyl
aromatic/conjugated diene block polymers, a styrenic polymer,
acrylonitrile-butadiene-styrene (ABS) copolymers,
styrene-acrylonitrile copolymers (SAN), ABS/PC polymers,
polyethylene terephthalate, epoxy resins, ethylene vinyl alcohol
copolymers, ethylene acrylic acid copolymers, polyolefin carbon
monoxide interpolymers, chlorinated polyethylene, cyclic olefin
copolymers (COC's), and olefin homopolymers and copolymers.
5. The article of claim 4 wherein the additional polymer is
selected from the group consisting of a polyolefin,
ethylene-styrene interpolymer, a partially or non-hydrogenated
vinyl aromatic/conjugated diene block copolymer, a styrenic
polymer, hydrogenated polystyrene, an other hydrogenated vinyl
aromatic/conjugated diene block copolymer, and a cyclic olefin (co)
polymer derived from monomers selected from the following group:
substituted and unsubstituted norbomenes, dicyclopentadienes,
dihydrodicyclopentadienes, trimers of cyclopentadiene,
tetracyclododecenes, hexacycloheptadecenes, ethylidenyl norbornenes
and vinylnorbomenes.
6. The article of claim 4, wherein the hydrogenated block copolymer
is present in an amount of from 0.5 to 99.5 weight percent, based
on the total weight of the composition.
7. The article of claim 4 wherein the composition additionally
comprises a compatibilizer.
8. The article of claim 1, wherein the article is selected from the
group consisting of a film or sheet, an extruded profile, a coated
article, an injection molded article, a blow molded article, a
pultruded article, and a rotational molded article.
9. The article of claim 8 which is selected from a lumbar bag, a
blood bag, an IV solution bag, a dialysis bag, pharmaceutical
blister packaging, food packaging, a consumer wrapping film, a
fabric laminate, medical device film, transdermal patch, backing
layer film, a label, a glove, a gasket, hose, tube, pipe, wire,
cable, window profile, weather-stripping, automotive profile,
siding, sealing strips, medical tubing, hot water pipe, industrial
pipe, rod, membrane, automotive instrument panel, door panel or
seat skin; roofing material, geo-membrane, pond or pool liner,
molded sheet, signage, a coated polymeric material, a coated
fabric, a coated inorganic material, a coated paper, a coated
cardboard, a coated wood product, a coated metal product, a spin
coated product, an automotive bumper, an automotive exterior or
interior trim article, an automotive gasket or seal, a packaging
container, a co-injection molded article, an over-molded article, a
bellow, a boot, a water tank, a shoe bladder, an injection blow
molded article, a composite pipe, a safety barricade, a structural
beam, a reinforcing member, a toy, a handle, a bladder, or an
automotive interior cover.
10. A composition comprising: I) at least one hydrogenated block
copolymer which comprises at least two distinct blocks of
hydrogenated vinyl aromatic polymer, and at least one block of
hydrogenated conjugated diene polymer, wherein the hydrogenated
copolymer is further characterized by: a) a weight ratio of
hydrogenated conjugated diene polymer block to hydrogenated vinyl
aromatic polymer block of greater than 40:60; b) a total number
average molecular weight (Mn.sub.t) of from 30,000 to 150,000,
wherein each hydrogenated vinyl aromatic polymer block (A) has a
Mn.sub.a of from 5,000 to 45,000 and each hydrogenated conjugated
diene polymer block (B) has a Mn.sub.b of from 12,000 to 110,000;
and c) a hydrogenation level such that each hydrogenated vinyl
aromatic polymer block has a hydrogenation level of greater than 90
percent and each hydrogenated conjugated diene polymer block has a
hydrogenation level of greater than 95 percent, and II) at least
one additional polymer.
11. The composition of claim 10 wherein the other polymer is
selected from the group consisting of hydrogenated vinyl aromatic
homopolymers, other hydrogenated vinyl aromatic/conjugated diene
block copolymers, thermoplastic polyurethanes, polycarbonates (PC),
polyamides, polyethers, poly/vinyl chloride polymers,
poly/vinylidene chloride polymers, polyesters, polymers that
contain lactic acid residuals, partially or non-hydrogenated vinyl
aromatic/conjugated diene block polymers, a styrenic polymer,
acrylonitrile-butadiene-styrene (ABS) copolymers,
styrene-acrylonitrile copolymers (SAN), AB S/PC polymers,
polyethylene terephthalate, epoxy resins, ethylene vinyl alcohol
copolymers, ethylene acrylic acid copolymers, polyolefin carbon
monoxide interpolymers, chlorinated polyethylene, cyclic olefin
copolymers (COC's), and olefin homopolymers and copolymers.
12. The composition of claim 11 wherein the additional polymer is
selected from the group consisting of a polyolefin, a partially or
non-hydrogenated vinyl aromatic/conjugated diene block copolymer, a
styrenic polymer, hydrogenated polystyrene, an other hydrogenated
vinyl aromatic/conjugated diene block copolymer, and a cyclic
olefin (co) polymer derived from monomers selected from the
following group: substituted and unsubstituted norbomenes,
dicyclopentadienes, dihydrodicyclopentadienes, trimers of
cyclopentadiene, tetracyclododecenes, hexacycloheptadecenes,
ethylidenyl norbomenes and vinylnorbornenes.
13. The composition of claim 10, wherein the hydrogenated block
copolymer is present in an amount of from 0.5 to 99.5 weight
percent, based on the total weight of the composition.
14. The composition of claim 11 wherein the composition
additionally comprises a compatibilizer.
15. An emulsion or dispersion comprising: I') a dispersed polymer
phase comprising at least one hydrogenated block copolymer which
comprises at least two distinct blocks of hydrogenated vinyl
aromatic polymer, and at least one block of hydrogenated conjugated
diene polymer, wherein the hydrogenated copolymer is further
characterized by: a) a weight ratio of hydrogenated conjugated
diene polymer block to hydrogenated vinyl aromatic polymer block of
greater than 40:60; b) a total number average molecular weight
(Mn.sub.t) of from 30,000 to 150,000, wherein each hydrogenated
vinyl aromatic polymer block (A) has a Mn.sub.a of from 5,000 to
45,000 and each hydrogenated conjugated diene polymer block (B) has
a Mn.sub.b of from 12,000 to 1 10,000; and c) a hydrogenation level
such that each hydrogenated vinyl aromatic polymer block has a
hydrogenation level of greater than 90 percent and each
hydrogenated conjugated diene polymer block has a hydrogenation
level of greater than 95 percent, II') a surfactant, and III') a
continuous phase which is immiscible with the polymer phase.
16. The composition of claim 15 wherein the hydrogenated vinyl
aromatic polymer block is selected from the group consisting of
hydrogenated polystyrene, hydrogenated alpha-methylstyrene polymer,
hydrogenated vinyltoluene polymer, a hydrogenated copolymer of
styrene and alpha-methylstyrene, and hydrogenated
styrene-vinyltoluene copolymer and the hydrogenated conjugated
diene polymer block is selected from the group consisting of
hydrogenated polybutadiene, hydrogenated polyisoprene, and a
hydrogenated copolymer of butadiene and isoprene.
17. The composition of claim 15 additionally comprising a polymer
selected from the group consisting of hydrogenated vinyl aromatic
homopolymers, other hydrogenated vinyl aromatic/conjugated diene
block copolymers, thermoplastic polyurethanes, polycarbonates (PC),
polyamides, polyethers, poly/vinyl chloride polymers,
poly/vinylidene chloride polymers, polyesters, polymers that
contain lactic acid residuals, partially or non-hydrogenated vinyl
aromatic/conjugated diene block polymers, a styrenic polymer,
acrylonitrile-butadiene-styrene (ABS) copolymers,
styrene-acrylonitrile copolymers (SAN), ABS/PC polymers,
polyethylene terephthalate, epoxy resins, ethylene vinyl alcohol
copolymers, ethylene acrylic acid copolymers, polyolefin carbon
monoxide interpolymers, chlorinated polyethylene, cyclic olefin
copolymers (COC's), and olefin homopolymers and copolymers.
18. The composition of claim 17 wherein the additional polymer is
selected from the group consisting of a polyolefin, a partially or
non-hydrogenated vinyl aromatic/conjugated diene block copolymer, a
styrenic polymer, hydrogenated polystyrene, an other hydrogenated
vinyl aromatic/conjugated diene block copolymer, and a cyclic
olefin (co) polymer derived from monomers selected from the
following group: substituted and unsubstituted norbomenes,
dicyclopentadienes, dihydrodicyclopentadienes, trimers of
cyclopentadiene, tetracyclododecenes, hexacycloheptadecenes,
ethylidenyl norbornenes and vinylnorbornenes.
19. The composition of claim 17 wherein the composition
additionally comprises a compatibilizer.
20. The composition of claim 15 wherein the stabilizer is an alkali
or amine fatty acid salt or stearate; polyoxyethylene nonionic;
alkali metal lauryl sulfate, quaternary ammonium surfactant; alkali
metal alkylbenzene sulfonate, or an alkali metal soap.
21. The composition of claim 15 wherein the continuous phase
comprises water.
22. An article produced from the composition of claim 15.
Description
[0001] This application is a Continuation in Part application from
U.S. application Ser. No. 09/575,063, filed on May 19, 2000, which
claims benefit of U.S. Provisional Application No. 60/139,075 filed
on Jun. 11, 1999, U.S. Provisional Application No. 60/146,008 filed
on Jul. 28, 1999, and U.S. Provisional Application No. 60/193,313
filed on Mar. 30, 2000.
[0002] This invention relates to compositions of hydrogenated block
copolymers.
BACKGROUND OF THE INVENTION
[0003] Partially hydrogenated block copolymers of vinyl aromatic
and conjugated dienes such as hydrogenated
styrene-butadiene-styrene copolymers are well known in the art.
U.S. Pat. Nos. 3,333,024; 3,431,323; 3,598,886; 5,352,744;
3,644,588 and EP-505,110 disclose various hydrogenated block
copolymers. Partially hydrogenated refers to hydrogenation of the
diene portion of the block copolymer without aromatic hydrogenation
or aromatic hydrogenation of 90 percent or less. Although these
partially hydrogenated copolymers have been tested in various
applications, they suffer from one or more shortcomings, including
low heat resistance, poor physical properties, poor processability,
and poor light stability. Attempts have been made to remedy these
shortcomings by increasing the hydrogenation of the aromatic ring
of the block copolymer. However, polymer scientists contend that
fully hydrogenated styrene-butadiene-styrene copolymers have no
useful properties at elevated temperatures, even if only slightly
elevated. Thermoplastic Elastomers, 2nd edition, 1996, page 304,
lines 8-12 states "Thus, polystyrene remains the choice for any
amorphous hydrocarbon block copolymer. This last fact is clearly
demonstrated in the case of the fully hydrogenated VCH-EB-VCH
polymer. The interaction parameter is so severely reduced by
hydrogenation that at only slightly elevated temperatures, the
polymer loses all strength and appears to be homogeneously mixed at
ordinary melt temperatures."
[0004] Specifically, hydrogenated diblock copolymers tend to have
low viscosities and melt strengths making them difficult to
process. Diblocks also have other disadvantages, due to their poor
tensile properties. For the same reason they are not useful for
making flexible materials, while rigid materials made from
hydrogenated diblocks tend to be brittle.
[0005] Blends of partially hydrogenated block copolymers with other
polymers are also known. For example, blends of cyclic olefin
(co)polymers have been attempted as disclosed in EP-0726291,
wherein cyclic olefin (co)polymers are blended with vinyl
aromatic/conjugated diene block copolymers or hydrogenated versions
thereof. Cyclic olefin (co)polymers (COC's) are known to have
excellent heat distortion temperature, UV stability and
processability. However, such copolymers suffer from poor impact
resistance. Blends of COC's with partially hydrogenated block
copolymers still suffer from an imbalance of physical properties
due to the absence of aromatic hydrogenation within the block
copolymer.
[0006] Therefore, there remains a need for compositions of fully or
substantially hydrogenated block copolymers which have adequate
viscosity and melt strength to ease processability, can be used in
elastomeric applications and have a desirable balance of physical
properties.
[0007] Additionally, uses for clear, substantially or fully
hydrogenated block copolymers of vinyl aromatic and conjugated
diene monomers, and polymer blends thereof, are still desired,
wherein the copolymers are processable by conventional
manufacturing technologies and possess useful physical properties
at standard and elevated temperatures.
SUMMARY OF THE INVENTION
[0008] One aspect of the present invention is directed to
compositions comprising fully or substantially hydrogenated block
copolymers and various end-use applications thereof. The
hydrogenated block copolymer is a flexible hydrogenated block
copolymer, which comprises at least two distinct blocks of
hydrogenated polymerized vinyl aromatic monomer, herein referred to
as hydrogenated vinyl aromatic polymer blocks, and at least one
block of hydrogenated polymerized conjugated diene monomer, herein
referred to as hydrogenated conjugated diene polymer block, wherein
the flexible fully or substantially hydrogenated copolymer is
characterized by:
[0009] a) a weight ratio of hydrogenated conjugated diene polymer
block to hydrogenated vinyl aromatic polymer block of greater than
40:60;
[0010] b) a total number average molecular weight (Mn.sub.t) of
from 30,000 to 150,000, wherein each hydrogenated vinyl aromatic
polymer block (A) has a Mn.sub.a of from 5,000 to 45,000 and each
hydrogenated conjugated diene polymer block (B) has a Mn.sub.b of
from 12,000 to 1 10,000; and
[0011] c) a hydrogenation level such that each hydrogenated vinyl
aromatic polymer block has a hydrogenation level of greater than 90
percent and each hydrogenated conjugated diene polymer block has a
hydrogenation level of greater than 95 percent.
[0012] Compositions comprising hydrogenated block copolymers having
these Mn and hydrogenation characteristics can be transparent to
light at visible wavelengths and are ideally suited for
conventional manufacturing and fabrication technologies, while
possessing an excellent balance of properties at both standard and
elevated temperatures. It has been discovered that compositions
comprising hydrogenated copolymers having both the high
hydrogenation levels and Mn limitations, have superior properties
and processability characteristics, compared to the hydrogenated
copolymer compositions of the prior art. The combination of high
glass transition temperature, low water absorption, and excellent
melt processability makes these polymers and blends thereof, ideal
candidates for many applications including fabricated articles,
thermoformed articles, extruded articles, injection molded
articles, fibers, films and the like.
DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a plot of percent set strain versus percent
elongation for Inventive Examples 2, 3 and 4, and Comparative
Examples 1, 5 and 6.
[0014] FIG. 2 is a plot of percent set strain versus percent
elongation for Inventive Example 4, and Comparative Examples 1, and
5-8.
[0015] FIG. 3 is a plot of percent set strain versus percent
elongation for Inventive Example 3 and Comparative Examples 1, 5-6,
and 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] One aspect of the present invention is directed to
applications for flexible hydrogenated block copolymers.
Hydrogenated block copolymers are prepared by hydrogenating a block
copolymer produced from at least one vinyl aromatic monomer and at
least one conjugated diene monomer.
[0017] The vinyl aromatic monomer is typically a monomer of the
formula: 1
[0018] wherein R' is hydrogen or alkyl, Ar is phenyl, halophenyl,
alkylphenyl, alkylhalophenyl, naphthyl, pyridinyl, or anthracenyl,
wherein any alkyl group contains 1 to 6 carbon atoms which may be
mono or multisubstituted with functional groups such as halo,
nitro, amino, hydroxy, cyano, carbonyl and carboxyl. More
preferably Ar is phenyl or alkyl phenyl with phenyl being most
preferred. Typical vinyl aromatic monomers include styrene,
alpha-methylstyrene, all isomers of vinyl toluene, especially
paravinyltoluene, all isomers of ethyl styrene, propyl styrene,
butyl styrene, vinyl biphenyl, vinyl naphthalene, vinyl anthracene
and the like, and mixtures thereof. The block copolymer can contain
more than one specific polymerized vinyl aromatic monomer. In other
words, the block copolymer can contain a polystyrene block and a
poly-alpha-methylstyrene block. The hydrogenated vinyl aromatic
block may also be a copolymer, wherein the hydrogenated vinyl
aromatic portion is at least 50 weight percent of the
copolymer.
[0019] The conjugated diene monomer can be any monomer having 2
conjugated double bonds. Such monomers include for example
1,3-butadiene, 2-methyl-1,3-butadiene, 2-methyl-1,3 pentadiene,
isoprene and similar compounds, and mixtures thereof. The block
copolymer can contain more than one specific polymerized conjugated
diene monomer. In other words, the block copolymer can contain a
polybutadiene block and a polyisoprene block.
[0020] The conjugated diene polymer block can be prepared from
materials which remain amorphous after the hydrogenation process,
or materials which are capable of crystallization after
hydrogenation. Hydrogenated polyisoprene blocks remain amorphous,
while hydrogenated polybutadiene blocks can be either amorphous or
crystallizable depending upon their structure. Polybutadiene can
contain either a 1,2 configuration, which hydrogenates to give the
equivalent of a 1-butene repeat unit, or a 1,4-configuration, which
hydrogenates to give the equivalent of an ethylene repeat unit.
Polybutadiene blocks having at least approximately 40 weight
percent 1,2-butadiene content, based on the weight of the
polybutadiene block, provides substantially amorphous blocks with
low glass transition temperatures upon hydrogenation. Polybutadiene
blocks having less than approximately 40 weight percent
1,2-butadiene content, based on the weight of the polybutadiene
block, provide crystalline blocks upon hydrogenation. Depending on
the final application of the polymer it may be desirable to
incorporate a crystalline block (to improve solvent resistance) or
an amorphous, more compliant block. In some applications, the block
copolymer can contain more than one conjugated diene polymer block,
such as a polybutadiene block and a polyisoprene block. The
conjugated diene polymer block may also be a copolymer of a
conjugated diene, wherein the conjugated diene portion of the
copolymer is at least 50 weight percent of the copolymer. The
conjugated diene polymer block may also be a copolymer of more than
one conjugated diene, such as a copolymer of butadiene and
isoprene.
[0021] Other polymeric blocks may also be included in the
hydrogenated block copolymers of the present invention.
[0022] A block is herein defined as a polymeric segment of a
copolymer which exhibits microphase separation from a structurally
or compositionally different polymeric segment of the copolymer.
Microphase separation occurs due to the incompatibility of the
polymeric segments within the block copolymer. The separation of
block segments can be detected by the presence of distinct glass
transition temperatures. Microphase separation and block copolymers
are widely discussed in "Block Copolymers-Designer Soft Materials",
PHYSICS TODAY, February, 1999, pages 32-38.
[0023] The flexible hydrogenated block copolymers are defined as
having a weight ratio of hydrogenated conjugated diene polymer
block to hydrogenated vinyl aromatic polymer block of greater than
40:60; typically of greater than 40:60 to 95:5, preferably from
45:55 to 90:10, more preferably from 50:50 to 85:15 and most
preferably from 60:40 to 80:20, based on the total weight of the
hydrogenated conjugated diene and hydrogenated vinyl aromatic
polymer blocks. The total weights of the hydrogenated vinyl
aromatic polymer blocks and the hydrogenated conjugated diene
polymer block(s) is typically at least 80 weight percent,
preferably at least 90, and more preferably at least 95 weight
percent of the total weight of the hydrogenated copolymer.
[0024] The flexible hydrogenated block copolymers used in the
present invention are produced by the hydrogenation of block
copolymers including triblock, multi-block, tapered block, and star
block copolymers such as SBS, SBSBS, SIS, SISIS, SISBS and the like
(wherein S is polystyrene, B is polybutadiene and I is
polyisoprene). The block copolymers contain at least one triblock
segment comprised of a vinyl aromatic polymer block on each end.
The block copolymers may, however, contain any number of additional
blocks, wherein these blocks may be attached at any point to the
triblock polymer backbone. Thus, linear blocks would include for
example SBS, SBSB, SBSBS, SBSBSB, and the like. The copolymer can
also be branched, wherein polymer chains are attached at any point
along the copolymer backbone. In addition, blends of any of the
aforementioned block copolymers can also be used as well as blends
of the block copolymers with their hydrogenated homopolymer
counterparts. In other words, a hydrogenated SBS block copolymer
can be blended with a hydrogenated SBSBS block copolymer and/or a
hydrogenated polystyrene homopolymer. It should be noted here that
in the production of block copolymers, small amounts of residual
diblock copolymers can be produced.
[0025] The total number average molecular weight (Mn.sub.t) of the
flexible hydrogenated block copolymers used in the present
invention is typically from 30,000, preferably from 45,000, more
preferably from 55,000 and most preferably from 60,000 to 150,000,
typically to 140,000, generally to 135,000, preferably to 130,000,
more preferably to 125,000, and most preferably to 120,000. The Mn,
as referred to throughout the specification, is determined using
gel permeation chromatography (GPC). The molecular weight of the
hydrogenated block copolymer and properties obtained are dependent
upon the molecular weight of each of the hydrogenated polymeric
blocks.
[0026] Number average molecular weight (Mn) and weight average
molecular weight (Mw) can both be used to describe the polymers
described herein. Because these polymers tend to have very narrow
molecular weight polydispersities, the difference between Mn and Mw
will be minimal. The ratio of Mw to Mn is typically 1.1 or less. In
fact, in some cases the number average molecular weight and the
number average molecular weight will be virtually the same.
Therefore, Mn can also be read as Mw throughout this
application.
[0027] It should be noted that good properties are obtained at
hydrogenated vinyl aromatic polymer molecular weights which are
lower than the entanglement molecular weight of the hydrogenated
vinyl aromatic polymer. The entanglement molecular weight of a
polymer is associated with the chain length required for a given
polymer to show a dramatic increase in melt viscosity due to chain
entanglements. The entanglement molecular weights for many common
polymers have been measured and reported in Macromolecules, 1994,
Volume 27, page 4639. It is commonly observed for glassy polymers
that maximum values of strength and toughness are achieved at about
10 times the entanglement molecular weight (see, for instance,
Styrene Polymers in the Encyclopedia of Polymer Science and
Engineering, 2nd edition, Volume 16, pages 62-71, 1989). The
entanglement molecular weight is approximately 38,000 for
hydrogenated polystyrene (polyvinylcyclohexane). We have determined
that an optimum balance of properties and processability can be
obtained at hydrogenated vinyl aromatic polymer block molecular
weights (Mn) of 0.2 to 1.2 times the entanglement molecular weight
of a hydrogenated vinyl aromatic polymer.
[0028] The flexible hydrogenated block copolymers will typically
have hydrogenated vinyl aromatic polymer block Mn.sub.a's of from
6,000, preferably from 9,000, more preferably from 11,000, and most
preferably from 12,000 to 45,000, preferably to 35,000, more
preferably to 25,000 and most preferably to 20,000. The
hydrogenated diene polymer block will typically have a Mn.sub.b
from 12,000, preferably from 27,000, more preferably from 33,000
and most preferably from 36,000 to 110,000, preferably to 100,000,
more preferably to 90,000 and most preferably to 80,000.
[0029] It is important to note that each individual block of the
flexible hydrogenated block copolymer used in the present
invention, can have its own distinct Mn. In other words, for
example, two hydrogenated vinyl aromatic polymer blocks within the
hydrogenated block copolymer may each have a different Mn.
[0030] Methods of making block copolymers are well known in the
art. Typically, block copolymers are made by anionic
polymerization, examples of which are cited in Anionic
Polymerization: Principles and Practical Applications, H. L. Hsieh
and R. P. Quirk, Marcel Dekker, New York, 1996. In one embodiment,
block copolymers are made by sequential monomer addition to a
carbanionic initiator such as sec-butyl lithium or n-butyl lithium.
In another embodiment, the copolymer is made by coupling a triblock
material with a divalent coupling agent such as 1,2-dibromoethane,
dichlorodimethylsilane, or phenylbenzoate. In this embodiment, a
small chain (less than 10 monomer repeat units) of a conjugated
diene polymer can be reacted with the vinyl aromatic polymer
coupling end to facilitate the coupling reaction. Vinyl aromatic
polymer blocks are typically difficult to couple, therefore, this
technique is commonly used to achieve coupling of the vinyl
aromatic polymer ends. The small chain of diene polymer does not
constitute a distinct block since no microphase separation is
achieved. Coupling reagents and strategies which have been
demonstrated for a variety of anionic polymerizations are discussed
in Hsieh and Quirk, Chapter 12, pgs. 307-331. In another
embodiment, a difunctional anionic initiator is used to initiate
the polymerization from the center of the block system, wherein
subsequent monomer additions add equally to both ends of the
growing polymer chain. An example of a such a difunctional
initiator is 1,3-bis(1-phenylethenyl) benzene treated with
organolithium compounds, as described in U.S. Pat. Nos. 4,200,718
and 4,196,154 which are herein incorporated by reference.
[0031] After preparation of the block copolymer, the copolymer is
hydrogenated to remove sites of unsaturation in both the conjugated
diene polymer block and the vinyl aromatic polymer block segments
of the copolymer. Any method of hydrogenation can be used and such
methods typically include the use of metal catalysts supported on
an inorganic substrate, such as Pd on BaSO.sub.4 (U.S. Pat. No.
5,352,744) and Ni on kieselguhr (U.S. Pat. No. 3,333,024) both of
which are incorporated herein by reference. Additionally, soluble,
homogeneous catalysts such those prepared from combinations of
transition metal salts of 2-ethylhexanoic acid and alkyl lithiums
can be used to fully saturate block copolymers, as described in Die
Makromolekulare Chemie, Volume 160, pp. 291, 1972. The copolymer
hydrogenation can also be achieved using hydrogen and a
heterogeneous catalyst such as those described in U.S. Pat. No.
5,352,744, U.S. 5,612,422 and U.S. 5,645,253 which are herein
incorporated by reference. The catalysts described therein are
heterogeneous catalysts consisting of a metal crystallite supported
on a porous silica substrate. An example of a silica supported
catalyst which is especially useful in the polymer hydrogenation is
a silica which has a surface area of at least 10 m.sup.2/g which is
synthesized such that is contains pores with diameters ranging
between 3000 and 6000 angstroms. This silica is then impregnated
with a metal capable of catalyzing hydrogenation of the polymer,
such as nickel, cobalt, rhodium, ruthenium, palladium, platinum,
other Group VIII metals, combinations or alloys thereof. Other
heterogeneous catalysts can also be used, having average pore
diameters in the range of 500 to 3,000 angstroms.
[0032] Alternatively, the hydrogenation can be conducted in the
presence of a mixed hydrogenation catalyst characterized in that it
comprises a mixture of at least two components. The first component
comprises any metal which will increase the rate of hydrogenation
and includes nickel, cobalt, rhodium, ruthenium, palladium,
platinum, other Group VIII metals, or combinations thereof.
Preferably rhodium and/or platinum is used. The second component
used in the mixed hydrogenation catalyst comprises a promoter which
inhibits deactivation of the Group VIII metal(s) upon exposure to
polar materials, and is herein referred to as the deactivation
resistant component. Such components preferably comprise rhenium,
molybdenum, tungsten, tantalum or niobium or mixtures thereof.
[0033] The amount of the deactivation resistant component in the
mixed catalyst is at least an amount which significantly inhibits
the deactivation of the Group VIII metal component when exposed to
polar impurities within a polymer composition, herein referred to
as a deactivation inhibiting amount. Deactivation of the Group VIII
metal is evidenced by a significant decrease in hydrogenation
reaction rate. This is exemplified in comparisons of a mixed
hydrogenation catalyst and a catalyst containing only a Group VIII
metal component under identical conditions in the presence of a
polar impurity, wherein the catalyst containing only a Group VIII
metal component exhibits a hydrogenation reaction rate which is
less than 75 percent of the rate achieved with the mixed
hydrogenation catalyst.
[0034] Preferably, the amount of deactivation resistant component
is such that the ratio of the Group VIII metal component to the
deactivation resistant component is from 0.5:1 to 10:1, more
preferably from 1:1 to 7:1, and most preferably from 1:1 to
5:1.
[0035] The mixed catalyst can consist of the components alone, but
preferably the catalyst additionally comprises a support on which
the components are deposited. In one embodiment, the metals are
deposited on a support such as a silica, alumina or carbon. In a
more specific embodiment, a silica support having a narrow pore
size distribution and surface area greater than 10 meters squared
per gram (m.sup.2/g) is used.
[0036] The pore size distribution, pore volume, and average pore
diameter of the support can be obtained via mercury porosimetry
following the proceedings of
[0037] The pore size distribution is typically measured using
mercury porosimetry. However, this method is only sufficient for
measuring pores of greater than 60 angstroms. Therefore, an
additional method must be used to measure pores less than 60
angstroms. One such method is nitrogen desorption according to ASTM
D-4641-87 for pore diameters of less than about 600 angstroms.
Therefore, narrow pore size distribution is defined as the
requirement that at least 98 percent of the pore volume is defined
by pores having pore diameters greater than 300 angstroms and that
the pore volume measured by nitrogen desorption for pores less than
300 angstroms, be less than 2 percent of the total pore volume
measured by mercury porosimetry.
[0038] The surface area can be measured according to ASTM
D-3663-84. The surface area is typically between 10 and 100
m.sup.2/g, preferably between 15 and 90 with most preferably
between 50 and 85 m.sup.2/g.
[0039] The desired average pore diameter of the support for the
mixed catalyst is dependent upon the polymer which is to be
hydrogenated and its molecular weight (Mn). It is preferable to use
supports having higher average pore diameters for the hydrogenation
of polymers having higher molecular weights to obtain the desired
amount of hydrogenation. For high molecular weight polymers
(Mn>200,000 for example), the typical desired surface area can
vary from 15 to 25 m.sup.2/g and the desired average pore diameter
from 3,000 to 4000 angstroms. For lower molecular weight polymers
(Mn<100,000 for example), the typical desired surface area can
vary from 45 to 85 m.sup.2/g and the desired average pore diameter
from 300 to 700 angstroms.
[0040] Silica supports are preferred and can be made by combining
potassium silicate in water with a gelation agent, such as
formamide, polymerizing and leaching as exemplified in U.S. Pat.
No. 4,112,032. The silica is then hydrothermally calcined as in
Iler, R. K., The Chemistry of Silica, John Wiley and Sons, 1979,
pp. 539-544, which generally consists of heating the silica while
passing a gas saturated with water over the silica for about 2
hours or more at temperatures from about 600.degree. C. to about
850.degree. C. Hydrothermal calcining results in a narrowing of the
pore diameter distribution as well as increasing the average pore
diameter. Alternatively, the support can be prepared by processes
disclosed in Iler, R. K., The Chemistry of Silica, John Wiley and
Sons, 1979, pp. 510-581.
[0041] A silica supported catalyst can be made using the process
described in U.S. Pat. No. 5,110,779, which is incorporated herein
by reference. An appropriate metal, metal component, metal
containing compound or mixtures thereof, can be deposited on the
support by vapor phase deposition, aqueous or nonaqueous
impregnation followed by calcination, sublimation or any other
conventional method, such as those exemplified in Studies in
Surface Science and Catalysis, "Successful Design of Catalysts" V.
44, pg. 146-158, 1989 and Applied Heterogeneous Catalysis pgs.
75-123, Institute Fran.cedilla.ais du Petrole Publications, 1987.
In methods of impregnation, the appropriate metal containing
compound can be any compound containing a metal, as previously
described, which will produce a usable hydrogenation catalyst which
is resistant to deactivation. These compounds can be salts,
coordination complexes, organometallic compounds or covalent
complexes.
[0042] Typically, the total metal content of the mixed supported
catalyst is from 0.1 to 10 wt. percent based on the total weight of
the silica supported catalyst. Preferable amounts are from 2 to 8
wt. percent, more preferably 0.5 to 5 wt. percent based on total
catalyst weight.
[0043] Promoters, such as alkali, alkali earth or lanthanide
containing compounds, can also be used to aid in the dispersion of
the metal component onto the silica support or stabilization during
the reaction, though their use is not preferred.
[0044] The amount of mixed supported catalyst used in the
hydrogenation process is much smaller than the amount required in
conventional unsaturated polymer hydrogenation reactions due to the
high reactivity of the hydrogenation catalysts. Generally, amounts
of less than 1 gram of supported catalyst per gram of unsaturated
polymer are used, with less than 0.1 gram being preferred and less
than 0.05 being more preferred. The amount of supported catalyst
used is dependent upon the type of process, whether it is
continuous, semi-continuous or batch, and the process conditions,
such as temperature, pressure and reaction time wherein typical
reaction times may vary from about 5 minutes to about 5 hours.
Continuous operations can typically contain 1 part by weight
supported catalyst to 200,000 or more parts unsaturated polymer,
since the supported catalyst is reused many times during the course
of continuous operation. Typical batch processes can use 1 part by
weight supported catalyst to 5,000 parts unsaturated polymer.
Higher temperatures and pressures will also enable using smaller
amounts of supported catalyst.
[0045] The hydrogenation reaction can be conducted in the absence
of a solvent but is preferably conducted in a hydrocarbon solvent
in which the polymer is soluble and which will not hinder the
hydrogenation reaction. Preferably the solvent is a saturated
solvent such as cyclohexane, methylcyclohexane, ethylcyclohexane,
cyclooctane, cycloheptane, dodecane, dioxane, diethylene glycol
dimethyl ether, tetrahydrofuran, isopentane, decahydronaphthalene
or mixtures thereof, with cyclohexane being the most preferred.
[0046] Typical hydrogenation temperatures are from about 40.degree.
C. preferably from about 100.degree. C., more preferably from about
110.degree. C., and most preferably from about 120.degree. C. to
about 250.degree. C., preferably to about 200.degree. C., more
preferably to about 180.degree. C., and most preferably to about
170.degree. C.
[0047] The pressure of the hydrogenation reaction is not critical,
though hydrogenation rates increase with increasing pressure.
Typical pressures range from atmospheric pressure to 70 MPa, with
0.7 to 10.3 MPa being preferred.
[0048] The reaction vessel is purged with an inert gas to remove
oxygen from the reaction area. Inert gases include but are not
limited to nitrogen, helium, and argon, with nitrogen being
preferred.
[0049] The hydrogenating agent can be any hydrogen producing
compound which will efficiently hydrogenate the unsaturated
polymer. Hydrogenating agents include but are not limited to
hydrogen gas, hydrazine and sodium borohydride. In a preferred
embodiment, the hydrogenating agent is hydrogen gas.
[0050] Hydrogenated flexible block copolymers used in the present
invention are also defined as being substantially or fully
hydrogenated in that at least 90 percent of the aromatic rings of
the block copolymer are hydrogenated, and may be referred to as
substantially hydrogenated flexible block copolymers. The level of
hydrogenation is preferably greater than 95 percent of the
conjugated diene polymer block and greater than 90 percent of the
vinyl aromatic polymer block segments, more preferably greater than
99 percent of the conjugated diene polymer block and greater than
95 percent of the vinyl aromatic polymer block segments, even more
preferably greater than 99.5 percent of the conjugated diene
polymer block and greater than 98 percent of the vinyl aromatic
polymer block segments, and most preferably greater than 99.9
percent of the conjugated diene polymer block and 99.5 percent of
the vinyl aromatic polymer block segments. The term `level of
hydrogenation` refers to the percentage of the original unsaturated
bonds which become saturated upon hydrogenation. The level of
hydrogenation in hydrogenated vinyl aromatic polymers is determined
using UV-VIS spectrophotometry, while the level of hydrogenation in
hydrogenated diene polymers is determined using proton NMR.
[0051] Anionically polymerized block copolymers typically
microphase separate into well-defined morphologies, with morphology
dimensions typically ranging from 5 to 50 nanometers in size.
Typical morphologies include a continuous matrix phase of one
hydrogenated polymer with well-defined spheres, cylinders or
gyroids of the minor phase hydrogenated polymer blocks dispersed
within the matrix, and a lamellar cocontinuous phase, wherein both
hydrogenated polymer blocks are in a continuous phase interspersed
within each other. These different morphologies give rise to
different physical properties. Hydrogenated block copolymers in
which the hydrogenated conjugated diene polymer blocks are
continuous are typically elastomeric, highly resilient materials.
Conversely, materials in which the hydrogenated vinyl aromatic
polymer block segments are the continuous phase are typically
stiff, tough plastics. Hydrogenated block copolymers wherein both
hydrogenated polymer blocks are cocontinuous tend to have
intermediate properties.
[0052] In one embodiment, the composition comprises a hydrogenated
block copolymer comprising less than 80 weight percent hydrogenated
vinyl aromatic polymer blocks, based on the total weight of the
hydrogenated block copolymer, and has an aromatic hydrogenation
level of greater than 90 percent.
[0053] In another embodiment, the composition comprises a
hydrogenated block copolymer of a vinyl aromatic and a conjugated
diene, wherein the block copolymer is a pentablock copolymer
comprising 3 blocks of hydrogenated vinyl aromatic polymer and two
blocks of conjugated diene polymer. The hydrogenated pentablock
copolymer comprises less than 80 weight percent hydrogenated vinyl
aromatic polymer blocks, based on the total weight of the
hydrogenated block copolymer, and has an aromatic hydrogenation
level of greater than 90 percent.
[0054] Another aspect of the present invention relates to polymer
blends of the flexible hydrogenated block copolymers.
[0055] Compositions comprising flexible hydrogenated block
copolymers may additionally comprise at least one other natural or
synthetic polymer. Suitable polymeric materials include, but are
not limited to, hydrogenated vinyl aromatic homopolymers, other
hydrogenated block copolymers, including hydrogenated
styrene/butadiene or styrene/isoprene block copolymers,
thermoplastic polyurethanes, polycarbonates (PC), polyamides,
polyethers, poly/vinyl chloride polymers, poly/vinylidene chloride
polymers, polyesters, polymers that contain lactic acid residuals,
partially or non-hydrogenated block copolymers, thermoplastics such
as styrene-butadiene block copolymers, polystyrene (including high
impact polystyrene), acrylonitrile-butadiene-styrene (ABS)
copolymers, styrene-acrylonitrile copolymers (SAN), ABS/PC
compositions, polyethylene terephthalate, epoxy resins, ethylene
vinyl alcohol copolymers, ethylene acrylic acid copolymers,
polyolefin carbon monoxide interpolymers, chlorinated polyethylene,
cyclic olefin copolymers (COC's), olefin copolymers (especially
polyethylene copolymers such as ethylene-styrene interpolymers) and
homopolymers (e.g., those made using conventional heterogeneous
catalysts). Examples include polymers made by the process of U.S.
Pat. No. 4,076,698, incorporated herein by reference.
[0056] In one embodiment, the composition additionally comprises a
polyolefin elastomer or plastomer, especially a polyolefin
elastomer or plastomer made using a single-site catalyst system
(for example, a homogeneously branched ethylene polymer such as a
substantially linear ethylene interpolymer or a homogeneously
branched linear ethylene interpolymer).
[0057] Generally suitable polyolefins include, for example,
polyethylene (ethylene homopolymer), ethylene/alph.alpha.-olefin
interpolymers, alph.alpha.-olefin homopolymers, such as
polypropylene (propylene homopolymer), alph.alpha.-olefin
interpolymers, such as interpolymers of polypropylene and an
alph.alpha.-olefin having at least 4 carbon atoms.
[0058] Representative polyolefins include, for example, but are not
limited to, substantially linear ethylene polymers, homogeneously
branched linear ethylene polymers, heterogeneously branched linear
ethylene (including linear low density polyethylene (LLDPE), ultra
or very low density polyethylene (ULDPE or VLDPE) medium density
polyethylene (MDPE) and high density polyethylene (HDPE)), high
pressure low density polyethylene (LDPE), ethylene/acrylic acid
(EAA) copolymers, ethylene/methacrylic acid (EMAA) copolymers,
ethylene/acrylic acid (EAA) ionomers, ethylene/methacrylic acid
(EMAA) ionomers, ethylene/vinyl acetate (EVA) copolymers,
ethylene/vinyl alcohol (EVOH) copolymers, polypropylene
homopolymers and copolymers, ethylene/propylene polymers,
ethylene/styrene interpolymers, graft-modified polymers (e.g.,
maleic anhydride grafted polyethylene such as LLDPE g-MAH),
ethylene acrylate copolymers (e.g. ethylene/ethyl acrylate (EEA)
copolymers, ethylene/methyl acrylate (EMA), and ethylene/methmethyl
acrylate (EMMA) copolymers), polybutylene (PB), ethylene carbon
monoxide interpolymer (e.g., ethylene/carbon monoxide (ECO),
copolymer, ethylene/acrylic acid/carbon monoxide (EAACO)
terpolymer, ethylene/methacrylic acid/carbon monoxide (EMAACO)
terpolymer, ethylene/vinyl acetate/carbon monoxide (EVACO)
terpolymer and styrene/carbon monoxide (SCO), chlorinated
polyethylene and mixtures thereof.
[0059] Ethylene/styrene interpolymers are prepared by polymerizing
i) ethylene or one or more alpha-olefin monomers and ii) one or
more vinyl or vinylidene aromatic monomers and/or one or more
sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene
monomers, and optionally iii) other polymerizable ethylenically
unsaturated monomer(s).
[0060] Ethylene/styrene interpolymers can be substantially random,
psuedo-random, random, alternately, diadic, triadic, tetradic or
any combination thereof. That is, the interpolymer product can be
variably incorporated and optionally variably sequenced. Preferred
ethylene/styrene interpolymers are substantially random
ethylene/styrene interpolymers.
[0061] The term "variably incorporated" as used herein refers to a
ethylene/styrene interpolymer manufactured using at least two
catalyst systems wherein during interpolymerization the catalyst
systems are operated at different incorporation or reactivity
rates. For example, the interpolymer product having a total styrene
content of 36 weight percent is variably incorporated where one
catalyst system incorporates 22 weight percent styrene and the
other catalyst system incorporates 48 weight percent styrene and
the production split between the two catalyst systems is 47/53
weight percentages.
[0062] "Pseudo-random" ethylene/styrene interpolymers are described
in U.S. Pat. No. 5,703,187, the disclosure of which is incorporated
herein in its entirety by reference.
[0063] "Random" interpolymers are those in which the monomer units
are incorporated into the chain wherein there can exist various
combinations of ordering including blockiness where either the
aliphatic alpha-olefm monomer (A) or hindered vinylidene monomer
(B) or both can be repeated adjacent to one another.
[0064] "Alternating" ethylene/styrene interpolymers are those in
which the aliphatic alph.alpha.-olefin monomer (A) and hindered
vinylidene monomer (B) occur in repeat alternate sequences on the
polymer chain in atactic or stereospecific structures (such as
isotactic or syndiotactic) or in combinations of the general
formula (AB)n wherein n is an integer from 1 to 4000. The term
"substantially random" as used herein in reference to
ethylene/styrene interpolymers generally means that the
distribution of the monomers of the interpolymer can be described
by the Bernoulli statistical model or by a first or second order
Markovian statistical model, as described by J. C. Randall in
POLYMER SEQUENCE DETERMINATION, Carbon-13 NMR Method, Academic
Press New York, 1977, pp. 71-78. Substantially random interpolymers
do not contain more than 15 mole percent of the total amount of
vinyl or vinylidene aromatic monomer in blocks of vinyl or
vinylidene aromatic monomer of more than 3 units.
[0065] Preferably, the substantially random interpolymer is not
characterized by a high degree (greater than 50 mol%) of either
isotacticity or syndiotacticity. This means that in the
carbon.sup.-13 NMR spectrum of the substantially random
interpolymer, the peak areas corresponding to the main chain
methylene and methine carbons representing either meso diad
sequences or racemic diad sequences should not exceed 75 percent of
the total peak area of the main chain methylene and methine
carbons. By the subsequently used term "substantially random
interpolymer" it is meant a substantially random interpolymer
produced from the above-mentioned monomers.
[0066] Suitable .alpha.-olefin monomers which are useful for
preparing the substantially random ethylene/styrene interpolymer
include, for example, .alpha.-olefin monomers containing from about
2 to about 20, preferably from about 2 to about 12, more preferably
from about 2 to about 8 carbon atoms. Preferred such monomers
include ethylene, propylene, butene-1,4-methyl-1-pentene, hexene-1
and octene-1. Most preferred are ethylene or a combination of
ethylene with C.sub.3-C.sub.8 .alpha.-olefins. These
.alpha.-olefins do not contain an aromatic moiety.
[0067] Suitable vinyl or vinylidene aromatic monomers which can be
employed to prepare the substantially random ethylene/styrene
interpolymer include, for example, those represented by the
following formula: 2
[0068] wherein R.sup.1 is selected from the group of radicals
consisting of hydrogen and alkyl radicals containing from about 1
to about 4 carbon atoms, preferably hydrogen or methyl; each
R.sup.2 is independently selected from the group of radicals
consisting of hydrogen and alkyl radicals containing from about 1
to about 4 carbon atoms, preferably hydrogen or methyl; Ar is a
phenyl group or a phenyl group substituted with from about 1 to
about 5 substituents selected from the group consisting of halo,
C.sub.1-4-alkyl, and C.sub.1-4-haloalkyl; and n has a value from
zero to about 4, preferably from zero to about 2, most preferably
zero. Particularly suitable such monomers include styrene and lower
alkyl- or halogen-substituted derivatives thereof. Exemplary
monovinyl or monovinylidene aromatic monomers include styrene,
vinyl toluene, .alpha.-methylstyrene, t-butyl styrene or
chlorostyrene, including all isomers of these compounds. Preferred
monomers include styrene, .alpha.-methyl styrene, the lower
alkyl-(C.sub.1-C.sub.4) or phenyl-ring substituted derivatives of
styrene, such as for example, ortho-, meta-, and
para-methylstyrene, the ring halogenated styrenes, para-vinyl
toluene or mixtures thereof. A more preferred aromatic monovinyl
monomer is styrene.
[0069] By the term "sterically hindered aliphatic or cycloaliphatic
vinyl or vinylidene monomers" in reference to substantially random
ethylene/styrene interpolymers, it is meant addition polymerizable
vinyl or vinylidene monomers corresponding to the formula: 3
[0070] wherein A.sup.1 is a sterically bulky, aliphatic or
cycloaliphatic substituent of up to 20 carbons, R.sup.1 is selected
from the group of radicals consisting of hydrogen and alkyl
radicals containing from about 1 to about 4 carbon atoms,
preferably hydrogen or methyl; each R.sup.2 is independently
selected from the group of radicals consisting of hydrogen and
alkyl radicals containing from about 1 to about 4 carbon atoms,
preferably hydrogen or methyl; or alternatively R.sup.1 and A.sup.1
together form a ring system.
[0071] By the term "sterically bulky" as used in reference to
substantially random ethylene/styrene interpolymers it is meant
that the monomer bearing this substituent is normally incapable of
addition polymerization by standard Ziegler-Natta polymerization
catalysts at a rate comparable with ethylene polymerizations.
[0072] .alpha.-Olefin monomers containing from about 2 to about 20
carbon atoms and having a linear aliphatic structure such as
ethylene, propylene, butene-1, hexene-1 and octene-1 are not
considered to be sterically hindered aliphatic monomers. With
regard to substantially random ethylene/styrene interpolymer,
preferred sterically hindered aliphatic or cycloaliphatic vinyl or
vinylidene compounds are monomers in which one of the carbon atoms
bearing ethylenic unsaturation is tertiary or quaternary
substituted. Examples of such substituents include cyclic aliphatic
groups such as cyclohexyl, cyclohexenyl, cyclooctenyl, or ring
alkyl or aryl substituted derivatives thereof, tert-butyl or
norbomyl. Most preferred sterically hindered aliphatic or
cycloaliphatic vinyl or vinylidene compounds are the various
isomeric vinyl-ring substituted derivatives of cyclohexene and
substituted cyclohexenes, and 5-ethylidene-2-norbomene. Especially
suitable are 1-, 3-, and 4-vinylcyclohexene.
[0073] The substantially random ethylene/styrene interpolymer
usually contains from about 5 to about 65, preferably from about 5
to about 55, more preferably from about 10 to about 50 mole percent
of at least one vinyl or vinylidene aromatic monomer; or sterically
hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer;
or both; and from about 35 to about 95, preferably from about 45 to
about 95, more preferably from about 50 to about 90 mole percent of
at least one aliphatic .alpha.-olefin having from about 2 to about
20 carbon atoms.
[0074] Other optional polymerizable ethylenically unsaturated
monomer(s) for substantially random ethylene/styrene interpolymers
include strained ring olefins such as norbomene and
C.sub.1-C.sub.10-alkyl or C.sub.6-C.sub.10-aryl substituted
norbornenes, with an exemplary substantially random interpolymer
being ethylene/styrene/norbornene.
[0075] A preferred polymeric material for blending with a flexible
hydrogenated block copolymer is a polyolefin elastomer or plastomer
characterized as having a DSC crystallinity of less than 45 weight
percent, preferably less than 30 weight percent, more preferably
less than or equal to 20 weight percent, and most preferably less
than or equal 16 percent.
[0076] The polyolefin elastomer or plastomer will typically be
characterized as having a melt index of less than 1000 g/10
minutes, preferably less than 500 g/10 minutes, most preferably
less than or equal to 50 g/10 minutes, as determined in accordance
with ASTM D-1238, Condition 190.degree. C./2.16 kilogram (kg).
However, in certain embodiments, it will be desirable to utilize an
ultra-low molecular weight polyolefin elastomer or plastomer. In
particular, ultra-low molecular weight ethylene polymers, such as
are disclosed in US-A-6,054,544, may find utility in the practice
of the claimed invention.
[0077] The ultra-low molecular weight ethylene polymers useful in
the practice of the invention will be characterized as having a
melt viscosity at 350.degree. F. of less than 8200, preferably less
than 6000, with melt viscosities at 350.degree. F. of less than 600
centipoise being easily attained. The melt viscosity will be chosen
based on the desired result. In particular, the lower the melt
viscosity of the ultra-low molecular weight ethylene polymer, the
more it will tend to reduce the overall viscosity of the
compositions of the invention.
[0078] Melt viscosity is determined in accordance with the
following procedure using a Brookfield Laboratories DVII+
Viscometer in disposable aluminum sample chambers. The spindle used
is a SC-31 hot-melt spindle, suitable for measuring viscosities in
the range of from 10 to 100,000 centipoise. A cutting blade is
employed to cut samples into pieces small enough to fit into the 1
inch wide, 5 inches long sample chamber. The sample is placed in
the chamber, which is in turn inserted into a Brookfield Thermosel
and locked into place with bent needle-nose pliers. The sample
chamber has a notch on the bottom that fits the bottom of the
Brookfield Thermosel to ensure that the chamber is not allowed to
turn when the spindle is inserted and spinning. The sample is
heated to 350.degree. F., with additional sample being added until
the melted sample is about 1 inch below the top of the sample
chamber. The viscometer apparatus is lowered and the spindle
submerged into the sample chamber. Lowering is continued until
brackets on the viscometer align on the Thermosel. The viscometer
is turned on, and set to a shear rate which leads to a torque
reading in the range of 30 to 60 percent. Readings are taken every
minute for about 15 minutes, or until the values stabilize, which
final reading is recorded.
[0079] When an ultra-low molecular weight ethylene polymer is
utilized, it will typically have a density of from 0.850 to 0.970
g/cm.sup.3. The density employed will be a function of the end use
application contemplated. For instance, when the ultra-low
molecular weight ethylene polymer is intended as a wax substitute,
densities greater than 0.910, preferably greater than 0.920
g/cm.sup.3 will be appropriate. In contrast, when the polymer is
intended as to impart some elastomeric characteristics to the
composition, densities less than 0.900 g/cm.sup.3, preferably less
than 0.895 g/cm.sup.3 will be appropriate. When the ultra-low
molecular weight ethylene polymer is an interpolymer of ethylene
and an aromatic comonomer, such as styrene, the density of the
interpolymer will be less than 1.10 g/cm.sup.3.
[0080] Also, preferably the polymeric material used for blending
with the flexible hydrogenated block copolymer is characterized as
having a percent permanent set of less than 75 at 23.degree. C.,
preferably less than or equal 60 at 23.degree. C., more preferably
less than or equal to 30 at 23.degree. C. and most preferably less
than or equal to 15 at 23.degree. C. and 38.degree. C. and 200
percent strain when measured at a 2 mil thickness using an Instron
tensiometer; or preferably a percent set elongation of less than or
equal to 25, more preferably 20, most preferably 15 at 23.degree.
C. and 100 percent strain.
[0081] The term "polymer", as used herein, refers to a polymeric
compound prepared by polymerizing monomers, whether of the same or
a different type. As used herein, generic term "polymer" embraces
the terms "homopolymer," "copolymer," "terpolymer" as well as
"interpolymer."
[0082] The term "interpolymer", as used herein refers to polymers
prepared by the polymerization of at least two different types of
monomers. As used herein the generic term "interpolymer" includes
the term "copolymers" (which is usually employed to refer to
polymers prepared from two different monomers) as well as the term
"terpolymers" (which is usually employed to refer to polymers
prepared from three different types of monomers).
[0083] The term "homogeneously branched ethylene polymer" is used
herein in the conventional sense to refer to an ethylene
interpolymer in which the comonomer is randomly distributed within
a given polymer molecule and wherein substantially all of the
polymer molecules have the same ethylene to comonomer molar ratio.
The term refers to an ethylene interpolymer that are manufactured
using so-called homogeneous or single-site catalyst systems known
in the art such Ziegler vanadium, hafnium and zirconium catalyst
systems and metallocene catalyst systems e.g., a constrained
geometry catalyst systems which is further described herein
below.
[0084] Homogeneously branched ethylene polymers for use in the
present invention can be also described as having less than 15
weight percent, preferably less than 10 weight percent, more
preferably less than 5 weight percent and most preferably zero (0)
weight percent of the polymer with a degree of short chain
branching less than or equal to 10 methyls/1000 carbons. That is,
the polymer contains no measurable high density polymer fraction
(e.g., there is no fraction having a density of equal to or greater
than 0.94 g/cm.sup.3), as determined, for example, using a
temperature rising elution fractionation (TREF) technique and
infrared or 13C nuclear magnetic resonance (NMR) analysis.
[0085] Preferably, the homogeneously branched ethylene polymer is
characterized as having a narrow, essentially single melting TREF
profile/curve and essentially lacking a measurable high density
polymer portion, as determined using a temperature rising elution
fractionation technique (abbreviated herein as "TREF").
[0086] The composition distribution of an ethylene interpolymer can
be readily determined from TREF as described, for example, by Wild
et al., Journal of Polymer Science, Poly. Phys. Ed., Vol. 20, p.
441 (1982), or in U.S. Pat. Nos. 4,798,081; 5,008,204; or by L. D.
Cady, "The Role of Comonomer Type and Distribution in LLDPE Product
Performance," SPE Regional Technical Conference, Quaker Square
Hilton, Akron, Ohio, October 1-2, pp. 107-119 (1985).
[0087] The composition (monomer) distribution of the interpolymer
can also be determined using .sup.13C NMR analysis in accordance
with techniques described in U.S. Pat. No. 5,292,845; U.S. Pat. No.
4,798,081; U.S. Pat. No. 5,089,321, incorporated here in by
reference, and by J. C. Randall, Rev. Macromol. Chem. Phys., C29,
pp. 201-317 (1989).
[0088] In analytical temperature rising elution fractionation
analysis (as described in U.S. Pat. No. 4,798,081 and abbreviated
herein as "ATREF"), the film or composition to be analyzed is
dissolved in a suitable hot solvent (e.g., trichlorobenzene) and
allowed to crystallized in a column containing an inert support
(stainless steel shot) by slowly reducing the temperature. The
column is equipped with both a refractive index detector and a
differential viscometer (DV) detector. An ATREF-DV chromatogram
curve is then generated by eluting the crystallized polymer sample
from the column by slowly increasing the temperature of the eluting
solvent (trichlorobenzene). The ATREF curve is also frequently
called the short chain branching distribution (SCBD) or composition
distribution (CD) curve, since it indicates how evenly the
comonomer (e.g., octene) is distributed throughout the sample in
that as elution temperature decreases, comonomer content increases.
The refractive index detector provides the short chain distribution
information and the differential viscometer detector provides an
estimate of the viscosity average molecular weight. The composition
distribution and other compositional information can also be
determined using crystallization analysis fractionation such as the
CRYSTAF fractionalysis package available commercially from
PolymerChar, Valencia, Spain.
[0089] Preferred homogeneously branched ethylene polymers (such as,
but not limited to, substantially linear ethylene polymers) have a
single melting peak between -30 and 150.degree. C., as determined
using differential scanning calorimetry (DSC), as opposed to
traditional Ziegler polymerized heterogeneously branched ethylene
polymers (e.g., LLDPE and ULDPE or VLDPE) which have two or more
melting points.
[0090] The single melting peak is determined using a differential
scanning calorimeter standardized with indium and deionized water.
The method involves about 5-7 mg sample sizes, a "first heat" to
about 180.degree. C. which is held for 4 minutes, a cool down at
10C/min. to -30.degree. C. which is held for 3 minutes, and heat up
at 10.degree. C./min. to 150.degree. C. to provide a "second heat"
heat flow vs. temperature curve from which the melting peak(s) is
obtained. Total heat of fusion of the polymer is calculated from
the area under the curve.
[0091] The homogeneously branched ethylene polymers for use in the
invention can be either a substantially linear ethylene polymer or
a homogeneously branched linear ethylene polymer.
[0092] The term "linear" as used herein means that the ethylene
polymer does not have long chain branching. That is, the polymer
chains comprising the bulk linear ethylene polymer have an absence
of long chain branching, as in the case of traditional linear low
density polyethylene polymers or linear high density polyethylene
polymers made using Ziegler polymerization processes (e.g., U.S.
Pat. No. 4,076,698 (Anderson et al.)), sometimes called
heterogeneous polymers. The term "linear" does not refer to bulk
high pressure branched polyethylene, ethylene/vinyl acetate
copolymers, or ethylene/vinyl alcohol copolymers which are known to
those skilled in the art to have numerous long chain branches.
[0093] The term "homogeneously branched linear ethylene polymer"
refers to polymers having a narrow short chain branching
distribution and an absence of long chain branching. Such "linear"
uniformly branched or homogeneous polymers include those made as
described in U.S. Pat. No. 3,645,992 (Elston) and those made using
so-called single site catalysts in a batch reactor having
relatively high ethylene concentrations (as described in U.S. Pat.
No. 5,026,798 (Canich) or in U.S. Pat. No. 5,055,438 (Canich)) or
those made using constrained geometry catalysts in a batch reactor
also having relatively high olefin concentrations (as described in
U.S. Pat. No. 5,064,802 (Stevens et al.) or in EP 0 416 815 A2
(Stevens et al.)).
[0094] Typically, homogeneously branched linear ethylene polymers
are ethylene/.alpha.-olefin interpolymers, wherein the
.alpha.-olefin is at least one C.sub.3-C.sub.20 .alpha.-olefin
(e.g., propylene, 1-butene, 1-pentene, 4-methyl-1-pentene,
1-hexene, 1-octene and the like) and preferably the at least one
C.sub.3-C.sub.20 .alpha.-olefin is 1-butene, 1-hexene or 1-octene.
Most preferably, the ethylene/.alpha.-olefin interpolymer is a
copolymer of ethylene and a C.sub.3-C.sub.20 .alpha.-olefin, and
especially an ethylene/C.sub.4-C.sub.8 .alpha.-olefin copolymer
such as an ethylene/1-octene copolymer, ethylene/1-butene
copolymer, ethylene/1-pentene copolymer or ethylene/1-hexene
copolymer.
[0095] Suitable homogeneously branched linear ethylene polymers for
use in the invention are sold under the designation of TAFMER.TM.
by Mitsui Chemical Corporation and under the designations of
EXACT.TM. and EXCEED.TM. resins by Exxon Chemical Company.
[0096] The term "substantially linear ethylene polymer" as used
herein means that the bulk ethylene polymer is substituted, on
average, with about 0.01 long chain branches/1000 total carbons to
about 3 long chain branches/1000 total carbons (wherein "total
carbons" includes both backbone and branch carbons). Preferred
polymers are substituted with about 0.01 long chain branches/1000
total carbons to about 1 long chain branches/1000 total carbons,
more preferably from about 0.05 long chain branches/1000 total
carbons to about 1 long chain branched/1000 total carbons, and
especially from about 0.3 long chain branches/1000 total carbons to
about 1 long chain branches/1000 total carbons.
[0097] As used herein, the term "backbone" refers to a discrete
molecule, and the term "polymer" or "bulk polymer" refers, in the
conventional sense, to the polymer as formed in a reactor. For the
polymer to be a "substantially linear ethylene polymer", the
polymer must have at least enough molecules with long chain
branching such that the average long chain branching in the bulk
polymer is at least an average of from about 0.01/1000 total
carbons to about 3 long chain branches/1000 total carbons.
[0098] The term "bulk polymer" as used herein means the polymer
which results from the polymerization process as a mixture of
polymer molecules and, for substantially linear ethylene polymers,
includes molecules having an absence of long chain branching as
well as molecules having long chain branching. Thus a "bulk
polymer" includes all molecules formed during polymerization. It is
understood that, for the substantially linear polymers, not all
molecules have long chain branching, but a sufficient amount do
such that the average long chain branching content of the bulk
polymer positively affects the melt rheology (i.e., the shear
viscosity and melt fracture properties) as described herein below
and elsewhere in the literature.
[0099] Long chain branching (LCB) is defined herein as a chain
length of at least one (1) carbon less than the number of carbons
in the comonomer, whereas short chain branching (SCB) is defined
herein as a chain length of the same number of carbons in the
residue of the comonomer after it is incorporated into the polymer
molecule backbone. For example, a substantially linear
ethylene/1-octene polymer has backbones with long chain branches of
at least seven (7) carbons in length, but it also has short chain
branches of only six (6) carbons in length.
[0100] Long chain branching can be distinguished from short chain
branching by using .sup.13C nuclear magnetic resonance (NMR)
spectroscopy and to a limited extent, e.g. for ethylene
homopolymers, it can be quantified using the method of Randall,
(Rev. Macromol. Chem. Phys., C29 (2&3), p. 285-297 (1989)).
However as a practical matter, current .sup.13C nuclear magnetic
resonance spectroscopy cannot determine the length of a long chain
branch in excess of about six (6) carbon atoms and as such, this
analytical technique cannot distinguish between a seven (7) carbon
branch and a seventy (70) carbon branch. The long chain branch can
be as long as about the same length as the length of the polymer
backbone.
[0101] Although conventional .sup.13C nuclear magnetic resonance
spectroscopy cannot determine the length of a long chain branch in
excess of six carbon atoms, there are other known techniques useful
for quantifying or determining the presence of long chain branches
in ethylene polymers, including ethylene/1-octene interpolymers.
For example, U.S. Pat. No. 4,500,648, incorporated herein by
reference, teaches that long chain branching frequency (LCB) can be
represented by the equation LCB=b/M.sub.w wherein b is the weight
average number of long chain branches per molecule and M.sub.w is
the weight average molecular weight. The molecular weight averages
and the long chain branching characteristics are determined by gel
permeation chromatography and intrinsic viscosity methods,
respectively.
[0102] Two other useful methods for quantifying or determining the
presence of long chain branches in ethylene polymers, including
ethylene/1-octene interpolymers are gel permeation chromatography
coupled with a low angle laser light scattering detector
(GPC-LALLS) and gel permeation chromatography coupled with a
differential viscometer detector (GPC-DV). The use of these
techniques for long chain branch detection and the underlying
theories have been well documented in the literature. See, e.g.,
Zimm, G. H. and Stockmayer, W. H., J. Chem. Phys., 17, 1301 (1949)
and Rudin, A., Modem Methods of Polymer Characterization, John
Wiley & Sons, New York (1991) pp. 103-112.
[0103] A. Willem deGroot and P. Steve Chum, both of The Dow
Chemical Company, at the Oct. 4, 1994 conference of the Federation
of Analytical Chemistry and Spectroscopy Society (FACSS) in St.
Louis, Mo., presented data demonstrating that GPC-DV is indeed a
useful technique for quantifying the presence of long chain
branches in substantially linear ethylene polymers. In particular,
deGroot and Chum found that the level of long chain branches in
substantially linear ethylene homopolymer samples measured using
the Zimm-Stockmayer equation correlated well with the level of long
chain branches measured using .sup.13C NMR.
[0104] Further, deGroot and Chum found that the presence of octene
does not change the hydrodynamic volume of the polyethylene samples
in solution and, as such, one can account for the molecular weight
increase attributable to octene short chain branches by knowing the
mole percent octene in the sample. By deconvoluting the
contribution to molecular weight increase attributable to 1-octene
short chain branches, deGroot and Chum showed that GPC-DV may be
used to quantify the level of long chain branches in substantially
linear ethylene/octene copolymers.
[0105] DeGroot and Chum also showed that a plot of Log(I.sub.2,
melt index) as a function of Log(GPC Weight Average Molecular
Weight) as determined by GPC-DV illustrates that the long chain
branching aspects (but not the extent of long branching) of
substantially linear ethylene polymers are comparable to that of
high pressure, highly branched low density polyethylene (LDPE) and
are clearly distinct from ethylene polymers produced using
Ziegler-type catalysts such as titanium complexes and ordinary
homogeneous catalysts such as hafnium and vanadium complexes.
[0106] For substantially linear ethylene polymers, the empirical
effect of the presence of long chain branching is manifested as
enhanced rheological properties which are quantified and expressed
in terms of gas extrusion rheometry (GER) results and/or melt flow,
I.sub.10/I.sub.2, increases.
[0107] The substantially linear ethylene polymers used in the
present invention are a unique class of compounds that are further
defined in U.S. Pat. No. 5,272,236, application Ser. No.
07/776,130, filed Oct. 15, 1991; U.S. Pat. No. 5,278,272,
application Ser. No. 07/939,281, filed Sep. 2, 1992; and U.S. Pat.
No. 5,665,800, application Ser. No. 08/730,766, filed Oct. 16,
1996, each of which is incorporated herein by reference.
[0108] Substantially linear ethylene polymers differ significantly
from the class of polymers conventionally known as homogeneously
branched linear ethylene polymers described above and, for example,
by Elston in U.S. Pat. No. 3,645,992. As an important distinction,
substantially linear ethylene polymers do not have a linear polymer
backbone in the conventional sense of the term "linear" as is the
case for homogeneously branched linear ethylene polymers.
[0109] Substantially linear ethylene polymers also differ
significantly from the class of polymers known conventionally as
heterogeneously branched traditional Ziegler polymerized linear
ethylene interpolymers (for example, ultra low density
polyethylene, linear low density polyethylene or high density
polyethylene made, for example, using the technique disclosed by
Anderson et al. in U.S. Pat. No. 4,076,698) in that substantially
linear ethylene interpolymers are homogeneously branched polymers.
Further, substantially linear ethylene polymers also differ from
the class of heterogeneously branched ethylene polymers in that
substantially linear ethylene polymers are characterized as
essentially lacking a measurable high density or crystalline
polymer fraction as determined using a temperature rising elution
fractionation technique.
[0110] The substantially linear ethylene elastomers and plastomers
for use in the present invention is characterized as having
[0111] (a) melt flow ratio, I.sub.10/I.sub.2.gtoreq.5.63,
[0112] (b) a molecular weight distribution, M.sub.w/M.sub.n, as
determined by gel permeation chromatography and defined by the
equation:
(M.sub.w/M.sub.n).ltoreq.(I.sub.10/I.sub.2)-4.63,
[0113] (c) a gas extrusion rheology such that the critical shear
rate at onset of surface melt fracture for the substantially linear
ethylene polymer is at least 50 percent greater than the critical
shear rate at the onset of surface melt fracture for a linear
ethylene polymer, wherein the substantially linear ethylene polymer
and the linear ethylene polymer comprise the same comonomer or
comonomers, the linear ethylene polymer has an 12 and
M.sub.w/M.sub.n within ten percent of the substantially linear
ethylene polymer and wherein the respective critical shear rates of
the substantially linear ethylene polymer and the linear ethylene
polymer are measured at the same melt temperature using a gas
extrusion rheometer,
[0114] (d) a single differential scanning calorimetry, DSC, melting
peak between -30.degree. and 150.degree. C., and
[0115] (e) a density less than or equal to 0.865 g/cm.sup.3.
[0116] Determination of the critical shear rate and critical shear
stress in regards to melt fracture as well as other rheology
properties such as "Theological processing index" (PI), is
performed using a gas extrusion rheometer (GER). The gas extrusion
rheometer is described by M. Shida, R. N. Shroff and L. V. Cancio
in Polymer Engineering Science, Vol. 17, No. 11, p. 770 (1977) and
in Rheometers for Molten Plastics by John Dealy, published by Van
Nostrand Reinhold Co. (1982) on pp. 97-99.
[0117] The processing index (PI) is measured at a temperature of
190.degree. C., at nitrogen pressure of 2500 psig (17.2 MPa) using
a 0.0296 inch (752 micrometers) diameter (preferably a 0.0143 inch
diameter die for high flow polymers, e.g. 50-100 12 melt index or
greater), 20:1 L/D die having an entrance angle of 180.degree.. The
GER processing index is calculated in millipoise units from the
following equation:
PI=2.15.times.10.sup.6 dyne/cm.sup.2/(1000.times.shear rate),
[0118] where: 2.15.times.10.sup.6 dyne/cm.sup.2 is the shear stress
at 2500 psi (17.2 MPa), and the shear rate is the shear rate at the
wall as represented by the following equation:
32Q'/(60 sec/min)(0.745)(Diameter.times.2.54 cm/in).sup.3,
where:
[0119] Q' is the extrusion rate (gms/min),
[0120] 0.745 is the melt density of polyethylene (gm/cm.sup.3),
and
[0121] Diameter is the orifice diameter of the capillary
(inches).
[0122] The PI is the apparent viscosity of a material measured at
apparent shear stress of 2.15.times.10.sup.6 dyne/cm.sup.2.
[0123] For substantially linear ethylene polymers, the PI is less
than or equal to 70 percent of that of a conventional linear
ethylene polymer having an I.sub.2, M.sub.w/M.sub.n and density
each within ten percent of the substantially linear ethylene
polymer.
[0124] An apparent shear stress vs. apparent shear rate plot is
used to identify the melt fracture phenomena over a range of
nitrogen pressures from 5250 to 500 psig (36 to 3.4 MPa) using the
die or GER test apparatus previously described. According to
Ramamurthy in Journal of Rheology, 30(2), 337-357, 1986, above a
certain critical flow rate, the observed extrudate irregularities
may be broadly classified into two main types: surface melt
fracture and gross melt fracture.
[0125] Surface melt fracture occurs under apparently steady flow
conditions and ranges in detail from loss of specular gloss to the
more severe form of "sharkskin". In this disclosure, the onset of
surface melt fracture is characterized at the beginning of losing
extrudate gloss at which the surface roughness of extrudate can
only be detected by 40.times. magnification. The critical shear
rate at onset of surface melt fracture for the substantially linear
ethylene polymers is at least 50 percent greater than the critical
shear rate at the onset of surface melt fracture of a linear
ethylene polymer having about the same I.sub.2 and M.sub.w/M.sub.n.
Preferably, the critical shear stress at onset of surface melt
fracture for the substantially linear ethylene polymers of the
invention is greater than about 2.8.times.10.sup.6
dyne/cm.sup.2.
[0126] Gross melt fracture occurs at unsteady flow conditions and
ranges in detail from regular (alternating rough and smooth,
helical, etc.) to random distortions. For commercial acceptability,
(e.g., in blown film products), surface defects should be minimal,
if not absent. The critical shear rate at onset of surface melt
fracture (OSMF) and critical shear stress at onset of gross melt
fracture (OGMF) will be used herein based on the changes of surface
roughness and configurations of the extrudates extruded by a GER.
For the substantially linear ethylene polymers used in the
invention, the critical shear stress at onset of gross melt
fracture is preferably greater than about 4.times.10.sup.6
dyne/cm.sup.2.
[0127] For the processing index determination and for the GER melt
fracture determination, substantially linear ethylene polymers are
tested without inorganic fillers and do not have more than 20 ppm
(parts per million) aluminum catalyst residue. Preferably, however,
for the processing index and melt fracture tests, substantially
linear ethylene polymers do contain antioxidants such as phenols,
hindered phenols, phosphites or phosphonites, preferably a
combination of a phenol or hindered phenol and a phosphite or a
phosphonite.
[0128] The molecular weights and molecular weight distributions are
determined by gel permeation chromatography (GPC). A suitable unit
is a Waters 150.degree. C. high temperature chromatographic unit
equipped with a differential refractometer and three columns of
mixed porosity where columns are supplied by Polymer Laboratories
and are commonly packed with pore sizes of 10.sup.3, 10.sup.4,
10.sup.5 and 10.sup.6 .ANG.. For ethylene polymers, the unit
operating temperature is about 140.degree. C. and the solvent is
1,2,4-trichlorobenzene, from which about 0.3 percent by weight
solutions of the samples are prepared for injection. Conversely,
for the flexible hydrogenated block copolymers, the unit operating
temperature is about 25.degree. C. and tetrahydrofuran is used as
the solvent. A suitable flow rate is about 1.0 milliliters/minute
and the injection size is typically about 100 microliters.
[0129] For the ethylene polymers where used in the present
invention, the molecular weight determination with respect to the
polymer backbone is deduced by using narrow molecular weight
distribution polystyrene standards (from Polymer Laboratories) in
conjunction with their elution volumes. The equivalent polyethylene
molecular weights are determined by using appropriate Mark-Houwink
coefficients for polyethylene and polystyrene (as described by
Williams and Ward in Journal of Polymer Science, Polymer Letters,
Vol. 6, p. 621, 1968) to derive the following equation:
M.sub.polyethylene=a*(M.sub.polystyrene).sup.b.
[0130] In this equation, a=0.4316 and b=1.0. Weight average
molecular weight, M.sub.w, is calculated in the usual manner
according to the following formula:
Mj=(.SIGMA.w.sub.i(M.sup.i.sup.j).sup.j. Where wi is the weight
fraction of the molecules with molecular weight M.sub.i eluting
from the GPC column in fraction i and j=1 when calculating M.sub.w
and j =-1 when calculating M.sub.n.
[0131] For the at least one homogeneously branched ethylene polymer
used in the present invention, the M.sub.w/M.sub.n is preferably
less than 3.5, more preferably less than 3.0, most preferably less
than 2.5, and especially in the range of from about 1.5 to about
2.5 and most especially in the range from about 1.8 to about
2.3.
[0132] Substantially linear ethylene polymers are known to have
excellent processability, despite having a relatively narrow
molecular weight distribution (that is, the M.sub.w/M.sub.n ratio
is typically less than about 3.5). Surprisingly, unlike
homogeneously and heterogeneously branched linear ethylene
polymers, the melt flow ratio (I.sub.10/I.sub.2) of substantially
linear ethylene polymers can be varied essentially independently of
the molecular weight distribution, M.sub.w/M.sub.n. Accordingly,
especially when good extrusion processability is desired, the
preferred ethylene polymer for use in the present invention is a
homogeneously branched substantially linear ethylene
interpolymer.
[0133] Suitable constrained geometry catalysts for use
manufacturing substantially linear ethylene polymers include
constrained geometry catalysts as disclosed in U.S. application
Ser. No. 07/545,403, filed Jul. 3, 1990; U.S. application Ser. No.
07/758,654, filed Sep. 12, 1991; U.S. Pat. No. 5,132,380
(application Ser. No. 07/758,654); U.S. Pat. No. 5,064,802
(application number 07/547,728); U.S. Pat. No. 5,470,993
(application Ser. No. 08/241,523); U.S. Pat. No. 5,453,410
(application Ser. No. 08/108,693); U.S. Pat. No. 5,374,696
(application Ser. No. 08/08,003); U.S. Pat. No. 5,532,394
(application Ser. No. 08/295,768); U.S. Pat. No. 5,494,874
(application Ser. No. 08/294,469); and U.S. Pat. No. 5,189,192
(application Ser. No. 07/647,111), the teachings of all of which
are incorporated herein by reference.
[0134] Suitable catalyst complexes may also be prepared according
to the teachings of WO 93/08199, and the Patents issuing therefrom,
all of which are incorporated herein by reference. Further, the
monocyclopentadienyl transition metal olefin polymerization
catalysts taught in U.S. Pat. No. 5,026,798, which is incorporated
herein by reference, are also believed to be suitable for use in
preparing the polymers of the present invention, so long as the
polymerization conditions substantially conform to those described
in U.S. Pat. No. 5,272,236; U.S. Pat. No. 5,278,272 and U.S. Pat.
No. 5,665,800, especially with strict attention to the requirement
of continuous polymerization. Such polymerization methods are also
described in PCT/U.S. 92/08812 (filed Oct. 15, 1992).
[0135] The foregoing catalysts may be further described as
comprising a metal coordination complex comprising a metal of
groups 3-10 or the Lanthanide series of the Periodic Table of the
Elements and a delocalize .beta.-bonded moiety substituted with a
constrain-inducing moiety, said complex having a constrained
geometry about the metal atom such that the angle at the metal
between the centroid of the delocalized, substituted pi-bonded
moiety and the center of at least one remaining substituent is less
than such angle in a similar complex containing a similar pi-bonded
moiety lacking in such constrain-inducing substituent, and provided
further that for such complexes comprising more than one
delocalized, substituted pi-bonded moiety, only one thereof for
each metal atom of the complex is a cyclic, delocalized,
substituted pi-bonded moiety. The catalyst further comprises an
activating cocatalyst.
[0136] Suitable cocatalysts for use herein include polymeric or
oligomeric aluminoxanes, especially methyl aluminoxane, as well as
inert, compatible, noncoordinating, ion forming compounds.
So-called modified methyl aluminoxane (MMAO) is also suitable for
use as a cocatalyst. One technique for preparing such modified
aluminoxane is disclosed in U.S. Pat. No. 5,041,584, the disclosure
of which is incorporated herein by reference. Aluminoxanes can also
be made as disclosed in U.S. Pat. No. 5,218,071; U.S. Pat. No.
5,086,024; U.S. Pat. No. 5,041,585; U.S. Pat. No. 5,041,583; U.S.
Pat. No. 5,015,749; U.S. Pat. No. 4,960,878; and U.S. Pat. No.
4,544,762, the disclosures of all of which are incorporated herein
by reference.
[0137] Aluminoxanes, including modified methyl aluminoxanes, when
used in the polymerization, are preferably used such that the
catalyst residue remaining in the (finished) polymer is preferably
in the range of from about 0 to about 20 ppm aluminum, especially
from about 0 to about 10 ppm aluminum, and more preferably from
about 0 to about 5 ppm aluminum. In order to measure the bulk
polymer properties (e.g. PI or melt fracture), aqueous HCl is used
to extract the aluminoxane from the polymer. Preferred cocatalysts,
however, are inert, noncoordinating, boron compounds such as those
described in EP 520732.
[0138] Substantially linear ethylene are produced via a continuous
(as opposed to a batch) controlled polymerization process using at
least one reactor (e.g., as disclosed in WO 93/07187, WO 93/07188,
and WO 93/07189), but can also be produced using multiple reactors
(e.g., using a multiple reactor configuration as described in U.S.
Pat. No. 3,914,342, the disclosure of which is incorporated herein
by reference) at a polymerization temperature and pressure
sufficient to produce the interpolymers having the desired
properties. The multiple reactors can be operated in series or in
parallel, with at least one constrained geometry catalyst employed
in at least one of the reactors.
[0139] Substantially linear ethylene polymers can be prepared via
the continuous solution, slurry, or gas phase polymerization in the
presence of a constrained geometry catalyst, such as the method
disclosed in EP 416,815-A. The polymerization can generally be
performed in any reactor system known in the art including, but not
limited to, a tank reactor(s), a sphere reactor(s), a recycling
loop reactor(s) or combinations thereof and the like, any reactor
or all reactors operated partially or completely adiabatically,
nonadiabatically or a combination of both and the like. Preferably,
a continuous loop-reactor solution polymerization process is used
to manufacture the substantially linear ethylene polymer used in
the present invention.
[0140] In general, the continuous polymerization required to
manufacture substantially linear ethylene polymers may be
accomplished at conditions well known in the prior art for
Ziegler-Natta or Kaminsky-Sinn type polymerization reactions, that
is, temperatures from 0 to 250.degree. C. and pressures from
atmospheric to 1000 atmospheres (100 MPa). Suspension, solution,
slurry, gas phase or other process conditions may be employed if
desired.
[0141] A support may be employed in the polymerization, but
preferably the catalysts are used in a homogeneous (i.e., soluble)
manner. It will, of course, be appreciated that the active catalyst
system forms in situ if the catalyst and the cocatalyst components
thereof are added directly to the polymerization process and a
suitable solvent or diluent, including condensed monomer, is used
in said polymerization process. It is, however, preferred to form
the active catalyst in a separate step in a suitable solvent prior
to adding the same to the polymerization mixture.
[0142] The substantially linear ethylene polymers used in the
present invention are interpolymers of ethylene with at least one
C.sub.3-C.sub.20 .alpha.-olefin and/or C.sub.4-C.sub.18 diolefin.
Copolymers of ethylene and an .alpha.-olefin of C.sub.3-C.sub.20
carbon atoms are especially preferred. The term "interpolymer" as
discussed above is used herein to indicate a copolymer, or a
terpolymer, or the like, where, at least one other comonomer is
polymerized with ethylene or propylene to make the
interpolymer.
[0143] Suitable unsaturated comonomers useful for polymerizing with
ethylene include, for example, ethylenically unsaturated monomers,
conjugated or non-conjugated dienes, polyenes, etc. Examples of
such comonomers include C.sub.3-C.sub.20 .alpha.-olefins such as
propylene, isobutylene, 1-butene, 1-hexene, 1-pentene,
4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and
the like. Preferred comonomers include propylene, 1-butene,
1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene,
and 1-octene is especially preferred. Other suitable monomers
include styrene, halo- or alkyl-substituted styrenes,
vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and
naphthenics (e.g., cyclopentene, cyclohexene and cyclooctene).
[0144] In one embodiment, the composition used in the present
invention comprises at least one hydrogenated block polymer and at
least one polypropylene polymer. Suitable polypropylene polymers
for use in the invention, including random block propylene ethylene
polymers, are available from a number of manufacturers, such as,
for example, Montell Polyolefins and Exxon Chemical Company. At
Exxon, suitable polypropylene polymers are supplied under the
designations ESCORENE.TM. and ACHIEVE.TM..
[0145] Suitable poly lactic acid (PLA) polymers for use in the
invention are well known in the literature (e.g., see D. M. Bigg et
al., "Effect of Copolymer Ratio on the Crystallinity and Properties
of Polylactic Acid Copolymers", ANTEC '96, pp. 2028-2039; WO
90/01521; EP 0 515203A; and EP 0 748846A2, the disclosures of each
of which are incorporated herein by reference). Suitable poly
lactic acid polymers are supplied commercially by Cargill Dow under
the designation EcoPLA.TM..
[0146] Suitable thermoplastic polyurethane polymers for use in the
invention are commercially available from The Dow Chemical Company
under the designation PELLATHANE.TM..
[0147] Suitable polyolefin carbon monoxide interpolymers can be
manufactured using well known high pressure free-radical
polymerization methods. However, they may also be manufactured
using traditional Ziegler-Natta catalysis and even with the use of
so-called homogeneous catalyst systems such as those described and
referenced herein above.
[0148] Suitable free-radical initiated high pressure
carbonyl-containing ethylene polymers such as ethylene acrylic acid
interpolymers can be manufactured by any technique known in the art
including the methods taught by Thomson and Waples in U.S. Pat. No.
3,520,861 and by McKinney et al. in U.S. Pat. Nos. 4,988,781;
4,599,392; and 5,384,373, the disclosures of which are incorporated
herein by reference.
[0149] Suitable ethylene vinyl acetate interpolymers for use in the
invention are commercially available from various suppliers,
including Exxon Chemical Company and E.I. du Pont de Nemours and
Company.
[0150] Suitable ethylene/alkyl acrylate interpolymers are
commercially available from various suppliers. Suitable
ethylene/acrylic acid interpolymers are commercially available from
The Dow Chemical Company under the designation PRIMACOR.TM..
Suitable ethylene/methacrylic acid interpolymers are commercially
available from E.I. du Pont de Nemours and Company under the
designation NUCREL.TM..
[0151] Suitable polyethylene terephthalate polymers include
LIGHTER.TM. available from The Dow Chemical Company.
[0152] Chlorinated polyethylene (CPE), especially chlorinated
substantially linear ethylene polymers, can be prepared by
chlorinating polyethylene in accordance with well known techniques.
Preferably, chlorinated polyethylene comprises equal to or greater
than 30 weight percent chlorine. Suitable chlorinated polyethylenes
for use in the invention are commercially supplied by Dupont Dow
Elastomers L.L.C. under the designation TYRIN.RTM..
[0153] Suitable polycarbonates are commercially available from
various suppliers, including The Dow Chemical Company under the
designation CALIBRE.RTM..
[0154] Suitable polyamids, such as nylon are commercially available
from various suppliers, including ZYTEL.TM. available from DuPont,
CAPRON.TM. available from Allied and ULTAMID.TM. available from
BASF.
[0155] Suitable polyethers are commercially available from various
suppliers, including ULTEM.TM. available from GE Plastics.
[0156] Suitable poly/vinyl choride polymers are commercially
available from various suppliers, including ALPHA DURAL.TM. AND
ALPHA available from Alpha Chemical and Plastics, UNICHEM.TM.
available from Colorite Plastics, GEON.TM. available from B.F.
Goodrich.
[0157] Suitable poly/vinylidene chloride polymers are commercially
available from various suppliers, including SARAN.TM. available
from The Dow Chemical Company.
[0158] Suitable polyesters are commercially available from various
suppliers, including FIBERCORE.TM. available from American
Cyanamid; AROPOL.TM. available from Ashland Chemical Company and
COREZYN.TM. available from Interplastic.
[0159] Suitable non-hydrogenated styrene-butadiene block copolymers
are commercially available from various suppliers, including Dexco
under the designation Vector.TM.. Additionally, partially
hydrogenated block copolymers can also be used and are well known
in the art. Such polymers are easily prepared using hydrogenation
catalysts well known in the art. Partially hydrogenated block
copolymers include block copolymers having up to 100 percent diene
unsaturation and 0 to less than 90 percent aromatic
hydrogenation.
[0160] Suitable styrenic polymers include syndiotactic and atactic
polystyrenes and high impact polystyrene resins which are
commercially available from various suppliers, including
QUESTRA.RTM., STYRON.RTM. and STYRON-A-TECH.RTM.. available from
The Dow Chemical Company.
[0161] Suitable ABS resins are commercially available from various
suppliers, including MAGNUM.RTM. available from The Dow Chemical
Company.
[0162] Suitable ABS/PC compositions are commercially available from
various suppliers, including PULSE.RTM. available from The Dow
Chemical Company.
[0163] Suitable SAN copolymers are commercially available from
various suppliers, including TYRIL.RTM. available from The Dow
Chemical Company.
[0164] Suitable ethylene vinyl alcohol copolymers are commercially
available from various suppliers, including-ELVANOL.TM. which is
available from DuPont and EVA polymers available from Eval Company
of America.
[0165] Suitable epoxy resins are commercially available from
various suppliers, including D.E.R. resins and D.E.N. resins
available from The Dow Chemical Company.
[0166] Suitable cyclic-olefin-polymers and copolymers are
polymerized cycloolefin monomers exemplified by norbomene-type
polymers such as are described in U.S. Pat. Nos. 5,115,041,
5,142,007, 5,143,979, all of which are incorporated herein by
reference. The cycloolefin moiety may be substituted or
unsubstituted. Suitable cycloolefin monomers include substituted
and unsubstituted norbornenes, dicyclopentadienes,
dihydrodicyclopentadienes, trimers of cyclopentadiene,
tetracyclododecenes, hexacycloheptadecenes, ethylidenyl norbornenes
and vinylnorbomenes. Substituents on the cycloolefin monomers
include hydrogen, alkyl alkenyl, and aryl groups of 1 to 20 carbon
atoms and saturated and unsaturated cyclic groups of 3 to 12 carbon
atoms which can be formed with one or more, preferably two, ring
carbon atoms. The substituents on the cycloolefin monomers can be
any which do not poison or deactivate the polymerization catalyst.
Examples of preferred monomers include but are not limited to
dicyclopentadiene, methyltetracyclo-dodece- ne, 2-norbomene, and
other norbomene monomers such as 5-methyl-2-norbornene,
5,6-dimethyl-2-norbomene, 5-ethyl-2-norbomene,
5-ethylidenyl-2-norbomene, 5-butyl-2-norbomene,
5-hexyl-2-norbomene, 5-octyl-2-norbomene, 5-phenyl-2-norbomene,
5-dodecyl-2-norbomene, 5-isobutyl-2-norbomene,
5-octadecyl-2-norbomene, 5-isopropyl-2-norbomene,
5-p-toluyl-2-norbornene, 5-a-naphthyl-2-norbornene,
5-cyclohexyl-2-norbornene, 5-isopropenyl-2-norbomene,
5-vinyl-2-norbomene, 5,5-dimethyl-2-norbomene, tricyclopentadiene
(or cyclopentadiene trimer), tetracyclopentadiene (or
cyclopentadiene tetramer), dihydrodicyclopentadiene (or
cyclopentene-cyclopentadiene co-dimer), methyl-cyclopentadiene
dimer, ethyl-cyclopentadiene dimer, tetracyclododecene
9-methyl-tetracyclo[6,2,1,13,6O2,7]dodecene-4, (or
methyl-tetracyclododecene),
9-ethyl-tetracyclo[6,2,1,13,6O2,7]dodecene-4, (or
ethyl-tetracyclododecene),
9-hexyl-tetracyclo-[6,2,1,13,6O2,7]dodecen-
e-4,9-decyl-tetracyclo[6,2,1,13,6O2,7]dodecene-4,9-decyl-tetracyclo[6,2,1,-
13,6O2,7]dodecene-4,
9,10-dimethyl-tetracyclo[6,2,1,13,6O2,7]dodecene-4,9--
methyl-10-ethyl-tetracyclo[6,2,1,13,6O2,7]dodecene-4,9-cyclohexyl-tetracyc-
lo [6,2,1,13,6O2,7]dodecene-4,9-chloro-tetracyclo[6,2, 1,13
6O2,7]dodecene-4,9-bromo-tetracyclo[6,2,1,13,6O2,7]-dodecene-4,9-fluoro-t-
etracyclo[6,2,1,13,6O2,7]dodecene-4,9-isobutyl-tetracyclo-[6,2,1,13,6O2,7]-
dodecene-4, and
9,10-dichlorotetracyclo[6,2,1,13,6O2,7]-dodecene-4.
[0167] Polymers comprising two or more different types of cyclic
olefin monomeric units are also suitable. For example, copolymers
of methyltetracyclododecane (MTD) and methylnorbomene (MNB) are
especially suitable. More preferably, the polymers comprise three
or more different types of monomeric unites, e.g., terpolymers,
including MTD, MNB and dicyclopentadiene (DCPD).
[0168] Additionally, hydrogenated vinyl aromatic homopolymers can
be used in combination with the hydrogenated block copolymers.
Hydrogenated vinyl aromatic homopolymers typically have high
aromatic hydrogenation levels as well (greater than 80, preferably
greater than 90 percent). Other hydrogenated vinyl
aromatic/conjugated diene block copolymers can also be used,
provided that it is a different polymer than the hydrogenated block
copolymer selected in I).
[0169] Any polymeric material which will enhance the properties of
a hydrogenated block copolymer or be enhanced by the presence of a
hydrogenated block copolymer is useful in the compositions utilized
in the present invention.
[0170] Optionally, compatibilizers may also be used in the polymer
blend of the present invention. A compatibilizer typically contains
a functional group which is compatible with the flexible
hydrogenated block copolymer and an additional functional group
which is compatible with the other synthetic or natural polymer.
Compatibilizers are well known in the art and one skilled in the
art would easily be able to recognize the type of compatibilizer
suitable for the desired compositions, if needed. For example, a
blend of a flexible hydrogenated block copolymer with a
styrene-butadiene-styrene block copolymer or other styrenic polymer
may additionally comprise a styrene-ethylenebutene-styrene block
copolymer as a compatibilizer. Additionally, a blend of a flexible
hydrogenated block copolymer with a polycarbonate may additionally
comprise a polyamide-maleic anhydride grafted polyethylene as a
compatibilizer The polymer blend composition typically contain from
0.5, generally from 1, preferably from 3, more preferably from 5
and most preferably from 10 to 99.5, generally to 99, preferably to
97, more preferably to 95 and most preferably to 90 weight percent
of the flexible hydrogenated block copolymer, based on the total
weight of the composition.
[0171] In one embodiment, the additional polymer comprises from 5,
typically from 10, generally from 15, preferably from 25, more
preferably from 30 and most preferably from 40 to 95, typically to
90, generally to 85, preferably to 75, more preferably to 70 and
most preferably to 60 weight percent of the composition comprising
the hydrogenated block copolymer.
[0172] In one embodiment of the present invention, the composition
comprises more than one hydrogenated block copolymer. The
composition may comprise a rigid hydrogenated block copolymer or
another flexible hydrogenated block copolymer. A rigid hydrogenated
block copolymer is defined as having at least two distinct blocks
of hydrogenated vinyl aromatic polymer, and at least one block of
hydrogenated conjugated diene polymer, and is further characterized
by:
[0173] a) a weight ratio of hydrogenated conjugated diene polymer
block to hydrogenated vinyl aromatic polymer block of 40:60 or
less;
[0174] b) a total number average molecular weight (Mn.sub.t) of
from 30,000 to 150,000, wherein each hydrogenated vinyl aromatic
polymer block (A) has a Mn.sub.a of from 6,000 to 60,000 and each
hydrogenated conjugated diene polymer block (B) has a Mn.sub.b of
from 3,000 to 30,000; and
[0175] c) a hydrogenation level such that each hydrogenated vinyl
aromatic polymer block has a hydrogenation level of greater than 90
percent and each hydrogenated conjugated diene polymer block has a
hydrogenation level of greater than 95 percent.
[0176] The compositions of flexible hydrogenated block copolymer
and additional polymeric material may be prepared by any suitable
means known in the art such as, but not limited to, dry blending in
a pelletized form in the desired proportions followed by melt
blending in a screw extruder, Banbury mixer or the like. The dry
blended pellets may be directly melt processed into a final solid
state article by, for example, injection molding. Additionally, the
compositions may be prepared by solution mixing the individual
polymeric components.
[0177] Additives such as antioxidants (for example, hindered
phenols such as, for example, Irganox.RTM. 1010), phosphites (for
example, Irgafos.RTM. 168)), U. V. stabilizers, cling additives
(for example, polyisobutylene), antiblock additives, slip agents,
colorants, pigments, fillers, fire retardants, light and heat
stabilizers, extension oils and the like, can also be included in
the compositions of the present invention, to the extent that they
do not interfere with the enhanced properties discovered by
applicants. In-process additives, e.g. calcium stearate, water, and
fluoropolymers may also be used for purposes such as for the
deactivation of residual catalyst or for further improved
processability.
[0178] In another aspect of the present invention, flexible
hydrogenated block copolymers, or blends thereof can also be used
in the form of aqueous dispersions for use in coatings and dipped
articles. Such dispersions will comprised the hydrogenated block
copolymer, optional blended polymers, water and surfactant(s). Such
dispersions can be produced using conventional batch or continuous
processes such as phase inversion or direct dispersion techniques,
known to those skilled in the art.
[0179] Additionally, high internal phase ratio (HIPR)emulsions, as
described in U.S. Pat. No. 5,539,021, incorporated herein by
reference, can be produced by continuously merging into a
disperser, in the presence of an emulsifying and a stabilizing
amount of a surfactant, a continuous phase liquid stream having a
flow rate R1, and a disperse phase liquid stream having a flow rate
R2; mixing the merged streams with a sufficient amount of shear,
with R2:R1 sufficiently constant, to form the HIPR emulsion without
phase inversion or stepwise distribution of an internal phase into
an external phase; wherein R2:R1 is in a range where the
polydispersity of the high internal phase ratio emulsion is less
than 2.
[0180] The continuous phase and disperse phase liquid streams are
sufficiently immiscible with each other to be emulsifiable. In one
aspect R2:R1 is defined by a range where the polydispersity of the
particles of the HIPR emulsion is less than 2. The term
polydispersity is used to denote the ratio of the volume average
diameter and the number average diameter of the particles, or
D.sub.v/D.sub.n.
[0181] Preferably R2:R1 is such that the polydispersity is less
than 1.5, more preferably less than 1.2, and most preferably not
greater than 1.1. The allowable variance of the rates of each
stream depends, in part, on the nature of the disperse and
continuous phases, and the dispe4rswers used to make the HIPR
emulsion. Preferably this variance is not greater than 10, more
preferably not greater than 5, and most preferably less than 1
percent. Preferably, the average particle size of the HIPR emulsion
is less than about 2 microns, more preferably, less than 1
micron.
[0182] The continuous phase and the disperse phase are liquids that
are sufficiently immiscible to form a stable emulsion in the
presence of a sufficient quantity of a surfactant. The liquid may
be neat, molten, or a solid or unpumpable liquid dissolved in a
solvent.
[0183] Preferably, the continuous phase is aqueous and the disperse
phase comprises the hydrogenated block copolymer, and optionally a
solvent. Suitable solvents include those used in the production of
the hydrogenation block copolymer as taught herein.
[0184] Suitable surfactants include anionic, cationic, nonionic, or
combinations thereof. Generally, higher surfactant concentrations
result in smaller diameter particles, but surfactant concentrations
that are too high tend to deleteriously affect the properties of
the final product made from the emulsion. Typically surfactant
concentrations are in the range of 0.1, more preferably 0.5, and
most preferably 2, to about 15, preferably to about 8, more
preferably to about 6 and most preferably about 4 weight percent,
based on the weight of the dispersed polymer. The surfactant may be
added initially to either the continuous phase or the disperse
phase prior to mixing of the two phases, or added separately to the
mixing device as a third stream. The surfactant is preferably added
initially with the disperse phase prior to mixing of the two
phases.
[0185] Of particular interest are the class of surfactants
comprising the alkali or amine fatty acid salts such as alkali
metal oleates (sodium oleate), and stearates; polyoxyethylene
nonionics; alkali metal lauryl sulfates, quaternary ammonium
surfactants; alkali metal alkylbenzene sulfonates, such as sodium
dodecylbenzene sulfonate; and alkali metal soaps of modified
resins.
[0186] Typically the dispersion produced contains a concentration
of dispersed phase in amounts up to about 60 percent solids in
order to have viscosities that are reasonable for processing.
Continuous processes, such as in U.S. Pat. No. 5,539,021 will
produce higher solids concentrations, but are typically diluted
before use.
[0187] Examples of continuous processes suitable for the formation
of these aqueous dispersions include U.S. Pat. Nos. 4,123,403;
5,539,021 and 5,688,842, all of which are incorporated herein by
reference.
[0188] A latex is prepared from an HIPR emulsion by combining the
emulsion with a suitable amount of the liquid which constitutes the
continuous phase liquid, or a liquid which is compatible with the
continuous phase, but which does not interfere with the integrity
of the particles. Where water is the continuous phase, the latex is
prepared by adding water to the HIPR emulsion. More preferably, the
latex is made in a continuous fashion by directing the HIPR
emulsion and water through any suitable dilution unit, such as a
centrifugal pump-head.
[0189] Flexible hydrogenated block copolymer compositions have
various advantages including high strength, low modulus, and
elastic recovery. The following end-use applications advantageously
utilize such flexible hydrogenated block copolymers and blends
thereof.
[0190] One embodiment of the present invention is related to films
produced from a composition comprising a flexible hydrogenated
block copolymer. The film typically has a thickness of less than 20
mils. Films include, but are not limited to mono and multilayer
films as well as uniaxial, biaxial and multiaxial oriented films.
Films can be made by a variety of methods including, but not
limited to casting, blowing, laminating, solution casting,
extruding, co-extruding with or without tie layers, calendering and
from aqueous or cast dispersions. Such films include, but are not
limited to, cast films such as those used in producing automotive
lumbar bags, a transdermal patch, backing layer films, labels,
medical bags, e.g. IV solution bags, blood bags and dialysis bags,
and pharmaceutical blister packaging, glass laminate films; blown
films such as those used in producing food packaging, e.g.
meat-wrap films, and fabric laminates; solvent cast films or films
from aqueous dispersions or emulsions, such as those used to
produce medical gloves and the like.
[0191] Methods of producing films from polymeric materials are well
known in the art and described in Plastics Engineering Handbook of
the Society of the Plastics Industry, Inc., Fourth Edition, 1976,
pages 156, 174, 180 and 183.
[0192] Another aspect of the present invention is related to sheet
produced from a composition comprising a flexible hydrogenated
block copolymer. Sheet typically has a thickness of 20 mils or
more. Flexible hydrogenated block copolymer sheet can be used to
produce products which include, but are not limited to, membranes,
skins for automotive instrument and door panels or seats, roofing,
geo-membranes, pond and pool liners, molded sheet such as
rotational/slush molded sheet, laminated, extruded or coextruded
sheet, mono or multi-layer sheet, coated sheet, capped sheet,
structural sheet, multi-wall sheet, calendered sheet, and the
like.
[0193] Methods of producing sheet from polymeric materials are well
known in the art and include extrusion, and calendering, all of
which are described in Plastics Engineering Handbook of the Society
of the Plastics Industry, Inc., Fourth Edition, 1976, on pages 183,
348 and 357.
[0194] Additional applications for films and sheet include
packaging, cap liners, disposable diapers, adult incontinent
products and feminine napkins and hygiene products, single-use
surgical gowns, drapes and covers, barrier films, specialty tapes,
label and envelope applications, pond liners, grain storage,
sandbags, vapor barriers, air infiltration barrier, house-wrap,
concrete curing covers, abatement products, outdoor storage covers,
export crate liners, in-plant partitions, salt and sand pile
covers, barricade and warning tapes, flagging tapes, fumigation
covers, steam sterilization film, shade and bloom control film,
pipe wrap, geo-membrane liners and covers, manufactured housing
films, oil field pit liners, enclosure films, transportation films,
remediation liners and covers, under-slab vapor barriers, pond
liners, erosion control covers, radon retarder films, floor and
carpet films, daily and interim landfill covers, divider curtains,
lead and asbestos abatement films, RV under-siding films, landfill
caps, cap layers, outdoor covering, grain covers, fumigation
covers, silage and hay covers, ceilings, stock pile covers, waste
disposal liners, rail car covers, textile backsheet, surgical
drapes, pouches and bags, stretch wrapping, signage such as vehicle
graphics, bill boards and point of purchase displays, and other
durable, long-term applications, graphic films, grocery and trash
bags, medical films, artificial leather, flexible flooring
components such as a calendered layer in a flooring application,
food wraps, toothpaste tubes auto safety glass interlayer film,
safety glass laminate film, medical packaging, retort packaging,
oriented shrink film, soft shrink films, standup pouches, elastic
masking films, reflective window films, tapes with directional
properties, elastic medical drape films, tourniquets, cling layers
in stretch cling films, scratch resistance films, biaxially
oriented films, fringed headliners, greenhouse films, heavy gauge
insulation bags, hot fill packaging applications, overhead
transparency films, produce packaging, computer screen protection
films, flat plate displacement panels, weather balloons and the
like.
[0195] The films and sheet may be monolayer or multilayer in
structure. Additional layers may be other polymeric materials
including, but not limited to those polymers listed as possible
polymers for blending with the flexible hydrogenated block
copolymers.
[0196] Another aspect of the present invention is related to
extruded, coextruded or laminated profiles produced from a
composition comprising a flexible hydrogenated block copolymer.
Such profiles include, but are not limited to, automotive profiles,
weather-stripping, window profiles, gaskets, hoses, tubing
(industrial, medical, automotive, food process and the like),
pipes, wires, cable profiles, weather stripping, sliding door
runners, edge protectors, packaging and transit protection, window
systems, furniture (functional and decorative profiles), windows
(ornamental transoms for optical design, wall-joining profiles,
facing profiles), plastic lumber, siding (interior or exterior
residential, commercial, vinyl siding replacement and other
building and construction applications) sealing strips, medical
tubing, hot water pipe, industrial pipe, rod, high heat wire and
cable jacketing, belts and the like.
[0197] Methods of producing profiles from polymeric materials are
well known in the art and described in Plastics Engineering
Handbook of the Society of the Plastics Industry, Inc., Fourth
Edition, 1976, page 191.
[0198] Another aspect of the present invention is related to coated
articles produced using coatings comprising a flexible hydrogenated
block copolymer. Flexible hydrogenated block copolymer coatings can
be used to produce products which include, but are not limited to,
coated polymeric materials, coated fabric, coated inorganic
materials such as concrete, glass and the like, coated paper or
cardboard, coated wood products, and coated metal products.
Examples include carpet backing, awnings, shading fabric, indoor
and outdoor sun screens, wall coverings, food packaging,
microporous waterproof wovens, tent fabrics, and caravan
extensions, garden furniture garments, safety and protective
wovens, films, fibers, apparel, bandages, coated lenses, coated
soft touch table tops and the like. The flexible hydrogenated block
copolymer can also be used in paint formulations. Alternatively,
coating products can be produced using a spin coating process,
wherein the flexible hydrogenated block copolymer is spin coated
onto a mold to produce an article; such as spin coating an optical
media disc or spin coating onto an optical media disc.
Additionally, dipped products can also be made using coatings of
the hydrogenated block copolymer. In particular, dipped goods can
be produced using aqueous dispersions of the hydrogenated block
copolymer or blends thereof. Dipped goods include gloves, condoms,
medical bags, angioplasty balloons, medical bellows, face masks,
blood pressure cuffs, catheters, medical tubing, gaskets and
o-rings, non-medical gloves, swim caps, tool handle grips,
industrial caps and plugs, windshield wiper boots, toy balloons,
toys, electrical parts, covers and gaskets."
[0199] Methods of coating with polymeric materials are well known
in the art and include extrusion, solvent casting, and coating from
aqueous dispersion/emulsions, all of which are described in
Plastics Engineering Handbook of the Society of the Plastics
Industry, Inc., Fourth Edition, 1976, on pages 185, and spin
coating as described in U.S. Pat. Nos. 5,635,114; 5,468,324; and
5,663,016, which are incorporated herein by reference.
[0200] Another aspect of the present invention is related to
injection molded articles produced from a composition comprising a
flexible hydrogenated block copolymer. Injection molded articles
include, but are not limited to, automotive articles such as bumper
systems, exterior trim, gaskets and seals, interior trim,
industrial rubber goods, thin wall injection molded articles,
co-injection molded or over-molded articles such as dual durometer
items, e.g. brushes, handles and automotive interior components.
Co-injection refers to the simultaneous injection of at least two
polymeric materials. In the present invention, the co-injected
materials typically include a rigid hydrogenated block copolymer,
or other olefin, in combination with the flexible hydrogenated
block copolymer. Other injection molded applications include major
appliances (cavity seals, sumps, motor mounts, bumpers, vibration
dampers, gaskets, seals, cushions, direct-drive wheels, fill tube
connectors, door seals), portable and small appliances (bumpers,
feet, handles, grips, motor mounts, vibration dampers, wheels,
casters, rollers, seals, grommets, caps, plugs, gaskets, spacers,
stops), business and electronic equipment (bumpers, feet, cushions,
supports, rollers, paper feed systems, platens, gaskets, protective
covers, grommets, mounts, bellows, vibration isolators), footwear
(molded-on soles, heels, and combination sole/heels), sporting
goods (handles, grips, cushions, spacers, air supply components,
washers, seals, cable hangers), toys, action figures, mechanical
dolls (gears, cams, flexing components), hardware (wheels, treads,
rollers, motor mounts, handles, shields, grips, pedals, pads,
vibration dampers, accessory holders, tubing covers, isolators,
nozzles), industrial equipment (wheels, casters, rollers, handles,
connectors, grips, bellows, gaskets, bumpers, protective covers),
oil and gas production (injection line components, gaskets, wipers,
seals, packers), fluid delivery (emitters, caps, seals, gaskets,
diaphragms, o-rings, pipe isolators, vibration dampers),
architectural glazing (setting blocks, spacers, wedge gaskets, leaf
seals, finned bulb seals, glazing bead systems, bulbs, weather
strips), construction (road expansion joints, pipe seals, line
connectors, pipe isolators), automotive (fascia, bumper end caps,
rub strips, bumper covers, air dams, air deflectors, shelf mats,
boots, body side molding, lens gaskets, sound deadeners, grommets,
seals, washers, poppets, bellows, radio and accessory knobs),
medical (stoppers, valves, syringes, closures, bottles, labware,
gaskets), electrical (pressure switches, cable junction covers,
transformer encapsulation, plugs, grommets, connectors, and
cabinetry), plumbing, industrial, consumer goods, bushings,
absorption pads, bumpers, wear stripping, shoe soles, belting, wear
strips, cutting surfaces, gaskets, seals, bumpers, gears, scraper
blades, mounts, holding fixtures, drive rolls, pinch rolls, lifter
pads, sporting goods, valves and fittings (gaskets, butterfly
liners, coated ball valves, coated gate valves, check valves,
flappers, diaphragms, valve seat discs,), railroad (mounts,
bumpers, vibration dampers, gaskets, check valves, seals caps),
pumps (impellers, gaskets, liners, seals), face masks, diving
equipment, housings, trays, breathing masks, lenses (contact) and
the like.
[0201] Methods of injection molding with polymeric materials are
well known in the art and are described in Plastics Engineering
Handbook of the Society of the Plastics Industry, Inc., Fourth
Edition, 1976, on page 83 and in Injection Molding Handbook by
Rosato and Rosato, 1986, page 9.
[0202] Another aspect of the present invention is related to blow
molded articles produced from a composition comprising a flexible
hydrogenated block copolymer. Blow molded articles include, but are
not limited to injection(stretch) or extrusion blow molded
articles, automotive bellows and boots, water tank bladders,
industrial bellows and boots, shoe bladders, containers of all
kinds for the food, beverage, cosmetic, medical, pharmaceutical,
and home products industries, toys, business machine panels,
computers and business equipment, hollow industrial parts, boats,
bumpers, bumper fascias, seat backs, center consoles, armrest and
headrest skins, covers, door shells, housings, casings, or other
type of enclosures for the machine and furniture industry, pressure
vessels, dash boards, ducting, fluid reservoirs, automotive
instrument panels, custom cases, toys, carboys, holding tanks,
reservoirs, wheels, contour packaging, tool holders, spoilers and
bumpers, floor heating elements, surf boards, motorbike carrier
boxes, car-top carriers, air ducts, stadium seating, structural
covers for copiers and duplicators, guards, double wall panels,
coolant overflow jars for trucks and automobiles, drinking water
storage tanks, flexible bellows, hoses, boots, sprayer tanks, toys,
and tool cases.
[0203] Methods of blow molding with polymeric materials are well
known in the art and are described in Plastics Engineering Handbook
of the Society of the Plastics Industry, Inc., Fourth Edition,
1976, on page 326.
[0204] Another aspect of the present invention is related to
rotational molded articles, which include playground equipment,
storage and feed tanks, door liners, automotive interior covers
(instrument panel skins and the like), gearshift covers, shipping
containers, business and recreational furniture, planters, trash
containers, whirlpool tubs, light globes, boats, canoes, camper
tops, toys (hobbyhorses, dolls, sandboxes, small swimming pools,
and athletic balls), advertising display signs, racks, mannequins
and the like, produced from a composition comprising a flexible
hydrogenated block copolymer.
[0205] Methods of rotational molding and rotational/slush molding
are described in Plastics Engineering Handbook of the Society of
the Plastics Industry, Inc., Fourth Edition, 1976, page 348.
[0206] Another aspect of the present invention is related to
pultruded articles produced from a composition comprising a
flexible hydrogenated block copolymer. Pultruded articles are
continuous, cross-sectional, composite, extruded profiles produced
by extruding a polymer melt and continuous fiber, simultaneously,
through the same profile die. Examples include, but are not limited
to structural beams, reinforcement bar, barricades, composite pipe,
automotive bumper moldings, concrete reinforcement, window/door
lineals, wood reinforcement, glulam (laminated joists), electrical
laminates and the like.
[0207] Methods of pultrusion with polymeric materials are well
known in the art and are described in Plastics Engineering Handbook
of the Society of the Plastics Industry, Inc., Fourth Edition,
1976, on page 47.
[0208] All end-use applications can be provided as monolayer or
multilayer articles, wherein any layer comprises the hydrogenated
block copolymer as described herein. Additional layers may be other
polymeric materials including, but not limited to those polymers
listed as possible polymers for blending with the flexible
hydrogenated block copolymers.
[0209] Surprisingly, these highly hydrogenated flexible block
copolymers are capable of making a wide range of transparent
(translucent or opaque with colorants), low color, flexible films;
profiles; sheets; coated, injection molded, blow molded and
pultruded articles having excellent properties at standard and
elevated temperatures. Flexibility is achieved without the use of
plasticizers, and the copolymers offer low residuals and
extractables, high strength, good thermal, radiation, and light
resistance, resistance to polar chemicals, acids, and bases,
retention of properties at elevated temperatures, and puncture
resistance. By using more elastic copolymers, manufacturing can be
achieved with very low moduli, high elongations, and low levels of
permanent deformation. In addition, all of these copolymers can be
processed without drying, are compatible with other polyolefins,
and have low health, environmental and safety concerns.
[0210] The following examples are provided to further illustrate
and illuminate the present invention but are not intended to limit
the invention to the specific embodiments set forth.
EXAMPLES 1-9
[0211] In one evaluation, the effect of blending a flexible
hydrogenated block polymer (HBCP) and a partially hydrogenated
block polymer into an ethylene polymer is investigated. Table 1
lists the various blends investigated in this evaluation and
includes the block polymer weight percentages and example
designations. The ethylene polymer is a substantially linear
ethylene interpolymer supplied by Dupont-Dow Elastomers under the
designation ENGAGE.TM. EG8200. Lycra is also included in this
evaluation as a control material. The various blends and control
samples are tested for percent elongation and percent set strain by
measuring the percent permanent set after a five-cycles at various
levels of strain. To determine the percent permanent set, samples
of 2 inch (5.1 cm) gauge length of Inventive Example 1 and
comparative run 8 are tested using an Instron tensiometer. A
cross-head speed of 10 inches(25.4 cm)/minute is used to provide a
strain rate of 5 min-1. Each sample is stretched to a predefined
strain (that is, stretched five elongations from 100% to 400%
strain at 100% increments using a new sample for each increment)
level and then unloaded by reversing the crosshead movement without
any hold time in between the stretching and unloading. After five
repeats of the same cycle (with no hold time in between the
stretching and the unloading), each sample is loaded for a sixth
time. The strain at which the load rises above zero is recorded as
set strain. In this evaluation, except for Lycra which is tested at
140 denier, 70 denier fiber is used for the testing. The 70 denier
fiber for each sample is made using a capillary rheometer as
described above. Notably, fiber cannot be spun at 40 wt. % Kraton
G1652.
[0212] The fibers were made from the blends under following
conditions using a variable speed take-up roll:
[0213] INSTRON Capillary Rheometer for extrusion
[0214] Die diameter=1000 microns, L/D=20
[0215] Output rate=about 0.4 gm/min
[0216] Melt temperature=250-255.degree. C.
[0217] fiber denier =about 70
[0218] Addition of the 20% HBCP into EG8200 did not significantly
improve tenacity at break or elastic recovery of EG8200. However,
addition of the 40% HBCP into EG8200 significantly improved
tenacity at break and elastic recovery of EG8200. The difference in
improvement between 20% and 40% addition of the HBCP resin is very
significant which could not be predicted using a blending rule.
[0219] FIGS. 1-3 show the results of this blend evaluation.
Additive weight percent calculations from the results in these
figures indicate that at 200%-300% strain, ethylene polymer blends
containing greater than or equal to 40 weight percent hydrogenated
block copolymer(HBCP) exhibit surprisingly better elasticity than
is predictable from additive weight percent calculations. Also, the
improvement in elasticity at greater than or equal to 40 weight
percent is substantially better than is predictable from results at
lower blend levels or from results at equivalent blend levels with
partially hydrogenated block polymers(PHBCP).
[0220] All HBCP have an aromatic hydrogenation level of at least
95%.
1TABLE 1 Example Wt. % HBCP.sup.1 Wt. % EG8200 Wt. % PHBCP.sup.2 1*
100 0 0 2 60 40 0 3 40 60 0 4 20 80 0 5* 0 100 0 6* Lycra .TM. 100%
0 0 0 7* (PHBCP = 0 80 20 Kraton .TM.G1657) 8* (PHBCP = 0 80 20
Kraton .TM.G1652) 9* (PHBCP = 0 60 40 Kraton .TM.G1657)
*Comparative examples .sup.1HBCP is hydrogenated block copolymer
(hydrogenated Styrene-butadiene-styrene) block copolymer having
66,000 Mn, 32 wt. % hydrogenated styrene, greater than 95% aromatic
hydrogenation. .sup.2PHBCP is partially hydrogenated block
copolymer (diene only hydrogenated).
EXAMPLES 10-18
[0221] The following compositions are compounded on a twin screw
extruder and pelletized.
Example 10
[0222] 90% Co-PP (703-35)(Propylene-ethylene copolymer available
from The Dow Chemical Company) and 10% HBCP (triblock SBS of 90,000
Mn, 32 wt. % hydrogenated polystyrene and 40% 1,2 butadiene
content.
Example 11
[0223] 70% Co-PP (703-35) and 30% HBCP (triblock SBS of 90,000 Mn,
32 wt. % hydrogenated polystyrene and 40% 1,2 butadiene
content.
Example 12
[0224] 90% HDPE M6030 (high density polyethylene available from The
Dow Chemical Company) and 10% HBCP (triblock SBS of 90,000 Mn, 32
wt. % hydrogenated polystyrene and 40% 1,2 butadiene content.
Example 13
[0225] 70% HDPE M6030 30% HBCP (triblock SBS of 90,000 Mn, 32 wt. %
hydrogenated polystyrene and 40% 1,2 butadiene content.
Example 14
[0226] 70% LDPE 4005 (low density polyethylene available from The
Dow Chemical Company) and 30% HBCP (triblock SBS of 90,000 Mn, 32
wt. % hydrogenated polystyrene and 40% 1,2 butadiene content.
Example 15
[0227] 30% Engage.TM. 81-80(polyethylene elastomer available from
The Dow Chemical Company) and 70% HBCP (triblock SBS of 90,000 Mn,
32 wt. % hydrogenated polystyrene and 40% 1,2 butadiene
content.
Example 16
[0228] 10% Engage.TM. 81-80 and 90% HBCP (triblock SBS of 90,000
Mn, 32 wt. % hydrogenated polystyrene and 40% 1,2 butadiene
content.
Example 17
[0229] 90% COC Topas.TM. 5013 (cyclic olefin copolymer available
from Ticona)and 10% HBCP (triblock SBS of 90,000 Mn, 32 wt. %
hydrogenated polystyrene and 40% 1,2 butadiene content.
Example 18
[0230] 70% COC Topas.TM. 5013 and 30% HBCP (triblock SBS of 90,000
Mn, 32 wt. % hydrogenated polystyrene and 40% 1,2 butadiene
content.
[0231] Testing samples are injection molded. Properties are listed
in TABLES 2,3 and 4. The following methods are used:
[0232] DTUL (Deflection temperature under load) is measured
according to ASTM D648-82.
[0233] Vicat is measured according to ASTM D1525-87.
[0234] Flexural properties are measured according to ASTM
D790-90.
[0235] ID(Instrumented Dart) is measured according to ASTM
D3763-86.
[0236] Tensile properties are measured according to ASTM
D638-90.
2TABLE 2 DTUL DTUL Flex: CLTE cm/cm/.degree. C. @ 264 @ 66 Mod
Flex: Str. (.times.10-6) Ex. Hardness .degree. C. .degree. C. Vicat
MPa MPa (-30 to 30.degree. C.) 10 58.7 50 79 143 1030 31 203 11
58.2 43 64 123 630 19 231 12 65.9 38 58 127 580 20 296 13 60.7 34
48 116 360 14 330 14 47.7 46 81 120 5 386 15 25.8 56 3 16 28.2 120
5 17 114.4 114 130 144 2810 98 112 18 87.7 108 128 143 2150 71
113
[0237]
3TABLE 3 ID (-40):Total ID (-20):Total ID (0):Total ID (73):Total
Energy Energy Energy Energy Ex. J J J J 10 4 8 12 28 11 41 45 42 29
12 39 38 40 33 13 40 44 43 36 14 39 36 35 24 15 65 16 58 17 3 3 3 5
18 12 38 47 54
[0238]
4TABLE 4 Tensile: Tensile: Izod Izod Tensile: Ultimate Ultimate
Tensile: Unnotched Notched- Yield Strength Elongation Modulus
Nonbreak Nonbreak Ex. MPa MPa % MPa J/m J/m 10 21 15 4.6 1140 1551
0 11 14 20 6.5 660 1071 682 12 21 19 9.9 770 1396 986 13 14 20 12.1
430 901 768 14 6 13 14.7 120 373 330 15 2 6 478 48 0 69 16 4 6 426
250 0 101 17 52 51 2.8 2640 0 0 18 42 31 3.5 1940 1034 0
[0239] Compositions of hydrogenated block copolymers and other
polymeric materials show excellent balance of physical
properties.
EXAMPLES 19-21
[0240] Pellets of polymer as listed in TABLE 5 are mixed
mechanically and compounded at a temperature of 250.degree. C. on a
Warner Pfleiderer 30 mm compounding extruder. The blends are then
injection molded on a 28.5 metric tonne Arburg injection molding
machine at a temperature of 210.degree. C. and a mold temperature
of 50.degree. C. Tensile bars and discs are tested under ASTM
methods as listed below:
[0241] DTUL@66.degree. C. D648
[0242] Vicat D1525
[0243] CLTE D696
[0244] Instrumented Impact D3763
[0245] Izod D256
[0246] Stress Relax and Set D4649-87
[0247] Shore A D2240(1 sec delay)
[0248] Haze D 1003
5TABLE 5 Comparative Polymer Example 19 Example 20 Example 21
.sup.1Topas .TM. 50131 100 90 70 (wt. %) .sup.2HBCP (wt. %) 0 10 30
Properties DTUL (.degree. C.) 130 130 128 Vicat (.degree. C.) 144
144 143 CLTE (cm/cm/.degree. C.) .times. 10 - 6 104 112 113
Instrumented Impact (J) @ (-40) 1.8 2.6 11.6 (-20) 2.3 3.1 37.6 (0)
2.7 3.4 47.2 (73) 2.7 4.5 53.8 Izod (J/m) 165 593 -- (Unnotched)
.sup.1Topas .TM. 5013 is a cyclic olefin copolymer available from
Ticona. .sup.2Hydrogenated block copolymer is a hydrogenated
styrene-butadiene block copolymer of 90,000 Mn, 32 percent styrene
block content, and 40 percent of butadiene is 1,2
configuration.
[0249] Blends of hydrogenated block copolymers show improved impact
and izod properties.
EXAMPLES 22-30
[0250] For mixed blends, parts by weight of polymer as listed in
TABLE 6 are mixed mechanically at 21 0C in a batch mixer (Haake
Rheocord 90 torque rheometer with Rheomix 600 bowl, approximately
60 ml polymer volume) for approximately 10 minutes at 50 rpm rotor
speed. For single component samples, samples are melt-homogenized
on a Farrel 3 inch (7.62 cm) by 7 inch (17.8 cm) lab mill (steam
heated at 155.degree. C.) for 90 seconds and removed as a sheet.
Test specimens are made by compression molding into thin sheets
using a PHI hydraulic press set at 210.degree. C. Specimens are 76
mm diameter circles of approximately 3.2 mm thickness for hardness
and haze testing. Transmission is determined directly through a
single layer. Specimens are cut in half and used as two layers for
Shore A hardness testing. For physical strength and elasticity
tests, specimens are approximately 75 mm wide by 115 m high by 0.94
mm thick. Results are listed in TABLE 6. Tests are completed
according to ASTM methods listed previously.
6TABLE 6 Cycle 1 Force Ult. % Stress at Tensile elong. Relaxation
Cycle 100% EG PHB Shore A strength at (% of peak 1 Set Elong. % EX.
8200 HBCP.sup.1 CP.sup.2 Hardness (MPa) break value) (%) (MPa) Haze
22* 100 0 0 64.7 15.1 919 13.7 52.6 2.71 42.5 23 75 25 0 68.2 25.6
706 12.8 30.8 2.64 44.0 24 50 50 0 69 28.3 544 12.0 16.8 2.96 39.7
25 25 75 0 71.2 31.0 538 11.4 10.2 2.70 34.7 26* 0 100 0 81.0 41.5
481 11.3 10.6 2.92 20.4 27* 75 0 25 69.7 22.9 738 13.5 34.9 2.76
99.4 28* 50 0 50 70.3 31.7 638 13.1 22.3 2.96 99.4 29* 25 0 75 75
39.2 588 12.5 14.1 2.66 91.6 30* 0 0 100 78 47.3 494 14 9.5 3.79
18.8 *Comparative Examples .sup.1HBCP is hydrogenated block
copolymer (hydrogenated Styrene-butadiene-styrene) block copolymer
having 63,000 Mn, 32 wt. % hydrogenated styrene, 40 percent of
butadiene is 1,2 configuration .sup.2PHBCP = Kraton .TM. G1652
[0251] The blends of hydrogenated block copolymer have improved set
and relaxation compared to the blends with partially hydrogenated
block copolymer. The set and relaxation values are surprising in
view of the lower values for the partially hydrogenated block
copolymer neat sample compared to the hydrogenated block copolymer
neat sample.
EXAMPLE 31
[0252] Preparation of Aqueous Dispersion
[0253] The hydrogenated block copolymer of
styrene-butadiene-styrene (MW of 90,000, 32 wt. percent styrene, 40
percent 1,2 butadiene configuration) in the form of a solution of
40% solids in cyclohexane is warmed to 65.degree. C. The heated
sample is then transferred and loaded into a preheated disperser
tank (65.degree. C.). This solution is the disperse phase. The
disperse phase is pumped from the tank continuously through an arm
of a 0.5" (1.27 cm) i.d. stainless steel tube fitted to a T, at a
constant rate of 31 g/min. Concurrently, surfactant, sodium oleate
(43 weight % in a solution of 2:1 (v/v) Ethanol/Water) is pumped
through an arm of 0.125" (0.32 cm) stainless steel tubing fitted to
the T, at a constant rate of at 1.1 ml/min. Upon exiting, the
merged streams are mixed through a 0.5" (1.27 cm) diameter static
mixer. The mixed stream is combined with water at flow rates
ranging from 0.9-5.0 mL/min. through a second T fitting. The
combined disperse phase, surfactant, and water are mixed together
under conditions of shear using an in-line stator rotor mixer (E.T.
Oakes) operating at 500-800 rpm. This concentrated emulsion is
diluted with additional water in a second inline mixer and the
particle size and polydispersity are measured using a Coulter
LS-230 light scattering particle size analyzer. The solvent is
removed from the resultant dispersion by rotary evaporation, and
particle size and polydispersity are measured again, showing
substantially the same results. The solids content is adjusted to
approximately 50-55% by the removal of water in vacuo. The final
volume average particle size of a 51% solids dispersion is 0.377
.mu.m (polydispersity, D.sub.v/D.sub.n=1.17).
7 TABLE 7 Particle % Sample Size(.mu.m) Solids A 0.377 51.3 B 0.377
51.4
EXAMPLE 32
Preparation of Coagulated Film
[0254] A film is prepared by a coagulation process by heating a
steel/porcelain (or etched glass) plate (7".times.7".times.1/16")
(17.8.times.17.8.times.0.16 cm) in an oven until it reaches a
temperature between 100 to 120.degree. F. (38-49.degree. C.). The
plate is then dipped into a 20 percent solution of calcium nitrate
in 1:1 by weight of water and methanol which also includes about 1
wt % of a ethoxylated octylphenol surfactant. The plate is then
placed into an oven at 230.degree. F. (110.degree. C.) for
approximately 15 minutes to form a very thin film of calcium
nitrate on the plate. The plate is allowed to cool to 105.degree.
F. (40.degree. C.) and then dipped into the polymer dispersion of
Sample A diluted to 25% solids with deionized water and removed
(total dwell time is approximately 15 to 20 sec). The plate is held
for 5 minutes at room temperature to allow the film to generate
enough gel strength, followed by leaching in a water bath at
115.degree. F. (46.degree. C.) for 10 minutes. Both sides of the
plate are then sprayed with water at 115.degree. F. (40.degree. C.)
for two additional minutes. The plate is then kept in a forced air
oven at 230.degree. F. (110.degree. C.) for 5 to 10 minutes and
then annealed 302.degree. F. (150.degree. C.) for 15 minutes,
followed by cooling to ambient temperature. A continuous polymer
film is peeled from the substrate with an overall length=4.5" (11.4
cm), width of narrow section=0.25" (0.64 cm), and gauge
length=1.31" (3.3cm).
EXAMPLE 33
[0255] Preparation of Glove
[0256] A glove is manufactured using a ceramic glove mold, baths
containing calcium nitrate, an aqueous dispersion, and distilled
water, and a small laboratory oven. The material used was a 20%
aqueous dispersion of a fully hydrogenated
styrene-butadiene-styrene copolymer with a molecular weight of
100,000 (10,000 polystyrene end blocks and 80,000 butadiene
mid-block) and low levels of crystallinity in the mid-block. To
manufacture the films, the ceramic glove mold is dipped in a 30%
calcium nitrate bath, followed by a bath containing the aqueous
dispersion bath, and then the distilled water bath. The glove mold
is placed in an oven at 140.degree. C. for 10 minutes, allowed to
cool, and the glove removed from the mold. The glove produced is
elastomeric, transparent, with high tensile strength and
elongation, and low set.
EXAMPLE 34
[0257] Elastomeric tubing is successfully extruded using a 1.5"
(3.8 cm) Killion single screw extruder with 24/1 L/D Barr ET screw,
a gear pump, and an 8 mm OD mandrel (6 mm ID) die. The material
extruded is a fully hydrogenated styrene-butadiene-styrene
copolymer with a molecular weight of 100,000 (10,000 polystyrene
end blocks and 80,000 butadiene mid-block) and little crystallinity
in the mid-block. The tubing produced is elastomeric, transparent,
kink resistant, with high tensile strength, good thermal properties
and low set.
EXAMPLE 35
[0258] Slush molded films are successfully produced using a small
vacuum drying oven and an aluminum plate. The material that is
slush molded is a fully hydrogenated styrene-butadiene-styrene
copolymer with a molecular weight of 66,000 (10,500 polystyrene end
blocks and 45,000 butadiene mid-block) with little crystallinity in
the mid-block. The polymer is first ground to a powder, then placed
on the metal plate, and inserted into the oven at a temperature of
220.degree. C. for a period of 10 minutes. The plate is removed
from the oven, allowed to cool, and the film is removed. The films
produced are elastomeric, transparent, abrasion resistant, with
high tensile strength, good thermal properties and low set.
EXAMPLE 36
[0259] A hydrogenated polymer having a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic block
of 25:75 and having a block structure of SBS and where the total
average molecular weight (Mn.sub.t) is 55,000 is blended with a
hydrogenated polymer having a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic block
of 68:32 and having a block structure of SBS and where the total
average molecular weight (Mn.sub.t) is 66,000 in a Brabender
Plasticoder at 220.degree. C. for 1 to 2 minutes and the resulting
blend is pressed into film using a Platen Press at a temperature of
230.degree. C. for not more than 1 minute and cooled.
[0260] The properties of the Platen Pressed films are shown in
TABLE 8.
8TABLE 8 Ultimate Tensile 1% Secant 2% Secant Polymer Polymer
Tensile Yield Tensile % Toughness Modulus Modulus 25:75 68:32 (MPa)
(MPa) Elong. (MPa) (MPa) (MPa) 100 0 To brittle To brittle To
brittle To brittle To brittle To brittle 62.5 37.5 20.7 30.0 303
59.9 863.9 787.4 50 50 15.2 24.9 299 50.5 672.3 608.5 37.5 62.5
11.2 25.0 314 46.7 531.0 462.4 25 75 6.5 32.4 411 49.6 439.2 317.2
0 100 2.0 22.5 430.6 23.8 36.3 35.7
[0261] The resulting Platen Pressed films are optically clear and
have good balance of toughness and modulus.
EXAMPLE 37
[0262] A hydrogenated polymer having a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic block
of 20:80 and having a block structure of SBSBS and where the total
average molecular weight (Mn.sub.t) is 75,000 is blended with a
hydrogenated polymer having a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic block
of 68:32 and having a block structure of SBS and where the total
average molecular weight (Mn.sub.t) is 66,000 in a Brabender
Plasticoder at 220.degree. C. for approximately 1 to 2 minutes and
the resulting blend is pressed into film using a Platen Press at a
temperature of 230.degree. C. for not more than 1 minute and
cooled.
[0263] The properties of the Platen Pressed films are shown in
TABLE 9.
9TABLE 9 Ultimate Tensile 1% Secant 2% Secant Polymer Polymer
Tensile Yield Tensile Toughness Modulus Modulus 20:80 68:32 (MPa)
(MPa) % Elong. (MPa) (MPa) (MPa) 100 0 10.8 25.9 4.13 0.54 924.5
868.5 75 25 18.9 26.0 5.436 0.93 866.2 811.1 68.75 31.25 21.4 18.3
8.3 1.43 709.9 689.2 62.5 37.5 22.3 9.8 13.829 2.07 740.0 716.9 50
50 16.6 20.6 291.0 44.7 581.7 555.1 37.5 62.5 11.5 26.8 358.7 50.4
473.8 455.6 31.25 68.75 9.9 32.4 413.5 58.1 475.2 434.4 25 75 8.2
23.0 355.7 40.7 336.4 297.7 0 100 2.0 22.5 430.6 23.8 36.3 35.7
[0264] The resulting Platen Pressed films are optically clear and
have good balance of toughness and modulus.
EXAMPLE 38
[0265] A hydrogenated polymer having a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic block
of 20:80 and having a block structure of SBSBS and where the total
average molecular weight (Mn.sub.t) is 75,000 is blended with a
hydrogenated polymer having a weight ratio of hydrogenated
conjugated diene polymer block to hydrogenated vinyl aromatic block
of 68:32 and having a block structure of SBS and where the total
average molecular weight (Mn.sub.t) is 66,000 on a WP ZSK-30 twin
screw extruder, where the temperatures are set at 230.degree. C.
and where the resulting blend is cast into film on a cast film
process where the temperatures are set at 230.degree. C. and the
casting roll and chill roll temperatures are set at 110.degree. C.
and the draw rate ranges from 1 to 10 fpm (30.5 to 305 cm/min).
[0266] The properties of the cast film are shown in TABLE 10.
10 TABLE 10 50%/50% 60%/40% Polymer 20:80/ Polymer 20:80/ Polymer
68:32 Polymer 68:32 Tensile Yield (MPa) 17.2 13.8 22.1 17.2
Ultimate Tensile (MPa) 35.2 34.4 14.5 23.4 % Elongation 378 359 107
270 Tensile Toughness (MPa) 70.6 65.9 22.7 48.5 1% Secant Modulus
(MPa) 786.0 599.8 1006.6 848.0 2% Secant Modulus (MPa) 730.8 551.6
930.8 758.4
[0267] The resulting films are optically clear and have a good
balance of toughness and modulus.
* * * * *