Note: Descriptions are shown in the official language in which they were submitted.
CA 02557217 2006-08-24
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CURING BLADDERS CONTAINING A PEROXIDE CURABLE RUBBER
COMPOUND
FIELD OF THE INVENTION
The present invention relates to a curring bladder containing a peroxide
curable
rubber compound prepared with a peroxide curing system, and a polymer having a
Mooney viscosity of at least 25 Mooney-units and a gel content of less than 15
wt.%
containing repeating units derived from at least one isoolefin monomer, more
than 4.1
mol% of repeating units derived from at least one multiolefin monomer, as well
as
optionally further copolymerizable monomers, and repeating units derived from
at least
one multiolefin cross-linking agent containing no transition metal compounds
and no
organic nitro compounds.
BACKGROUND OF THE INVENTION
Butyl rubber is understood to be a copolymer of an isoolefin and one or more,
preferably conjugated, multiolefins as comonomers. Commercial butyl comprise a
major portion of isoolefin and a minor amount, not more than 2.5 mol %, of a
conjugated
multiolefin. The preferred isoolefin is isobutylene. However, this invention
also covers
polymers optionally comprising additional copolymerizable co-monomers.
Butyl rubber or butyl polymer is generally prepared in a slurry process using
methyl chloride as a vehicle and a Friedel-Crafts catalyst as part of the
polymerization
initiator. The methyl chloride offers the advantage that AIC13, a relatively
inexpensive
Friedel-Crafts catalyst, is soluble in it, as are the isobutylene and isoprene
comonomers. Additionally, the butyl rubber polymer is insoluble in the methyl
chloride
and precipitates out of solution as fine particles. The polymerization is
generally carried
out at temperatures of about -90°C to -100°C. See U.S. Patent
No. 2,356,128 and
Ullmanns Encyclopedia of Industrial Chemistry, volume A 23, 1993, pages 288-
295.
The low polymerization temperatures are required in order to achieve molecular
weights
which are sufficiently high for rubber applications.
1
' CA 02557217 2006-08-24
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Peroxide curable butyl rubber compounds offer several advantages over
conventional, sulfur-curing, systems. Typically, these compounds display
extremely fast
cure rates and the resulting cured articles tend to possess excellent heat
resistance. In
addition, peroxide-curable formulations are considered to be "clean" in that
they do not
contain any extractable inorganic impurities (e.g. sulfur). The clean rubber
articles can
therefore be used, for example, in condenser caps, biomedical devices,
pharmaceutical
devices (stoppers in medicine-containing vials, plungers in syringes) and
possibly in
seals for fuel cells.
It is well accepted that polyisobutylene and butyl rubber decompose under the
action of organic peroxides. Furthermore, US 3,862,265 and US 4,749,505 teach
us
that copolymers of a C4 to C~ isomonoolefin with up to 10 wt. % isoprene or up
to 20 wt.
para-alkylstyrene undergo a molecular weight decrease when subjected to high
shear mixing. This effect is enhanced in the presence of free radical
initiators.
One approach to obtaining a peroxide-curable butyl-based formulation lies in
the
use of conventional butyl rubber in conjunction with a vinyl aromatic compound
like DVB
and an organic peroxide (see JP-A-107738/1994). In place of DVB, an electron-
withdrawing group-containing polyfunctional monomer (ethylene dimethacrylate,
trimethylolpropane triacrylate, N,N'-m-phenylene dimaleimide) can also be used
(see
JP-A-172547/1994).
A commercially available terpolymer based on IB, IP, and DVB, Bayer XL-10000,
is curable with peroxides alone. However, this material does possess some
significant
disadvantages. For example, the presence of significant levels of free DVB can
present
serious safety concerns. In addition, since the DVB is incorporated during the
polymerization process a significant amount of crosslinking occurs during
manufacturing. The resulting high Mooney (ca. 60-75 MU, M~1+8@125 °C)
and
presence of gel particles make this material extremely difficult to process.
For these
reasons, it would be desirable to have an isobutylene based polymer which is
peroxide
curable, completely soluble (i.e. gel free) and contains no, or trace amounts
of,
divinylbenzene in its composition.
2
CA 02557217 2006-08-24
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U.S. Patent No. 5,578.682 claims a process for obtaining a polymer with a
bimodal molecular weight distribution derived from a polymer that originally
possessed a
monomodal molecular weight distribution. The polymer, e.g., polyisobutylene, a
butyl
rubber or a copolymer of isobutylene and para-methylstyrene, was mixed with a
polyunsaturated crosslinking agent (and, optionally, a free radical initiator)
and
subjected to high shearing mixing conditions in the presence of organic
peroxide. This
bimodalization was a consequence of the coupling of some of the free-radical
degraded
polymer chains at the unsaturation present in the crosslinking co-agent. It is
important
to note that this patent was silent about any filled compounds of such
modified polymers
or the cure state of such compounds.
U.S. Patent No. 5,994,465 discloses a method for curing regular butyl, with
isoprene contents ranging from 0.5 to 2.5 mol %, by treatment with a peroxide
and a
bismaleimide species.
Co-Pending application CA 2,418,884 discloses a continuous process for
producing polymers having a Mooney viscosity of at least 25 Mooney-units and a
gel
content of less than 15 wt. % comprising repeating units derived from at least
one isoolefin
monomer, more than 4.1 mol % of repeating units derived from at least one
multiolefin
monomer and optionally further copolymerizable monomers in the presence of
AIC13 and a
proton source and/or cationogen capable of initiating the polymerization
process and at
least one multiolefin cross-linking agent wherein the process is conducted in
the
absence of transition metal compounds. These polymers are well suited for the
inventive rubber formulations of this invention and with regards to
jurisdictions allowing
for this method are enclosed by reference herein.
Co-Pending application CA 2,458,741 discloses a peroxide curable rubber
compound containing polymers with a Mooney viscosity of at least 25 Mooney-
units and a
gel content of less than 15 wt.% comprising repeating units derived from at
least one
isoolefin monomer, more than 4.1 mol% of repeating units derived from at least
one
multiolefin monomer, as well as optionally further copolymerizable monomers,
and
repeating units derived from at least one multiolefin cross-linking agent
containing no
transition metal compounds and no organic nitro compounds.
3
CA 02557217 2006-08-24
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Conventional resin curing systems are difficult to use in making a curing
bladder.
The result is a curing bladder with inferior physical properties due to
incomplete cure.
An ultimate elongation of less than 700% is desirable, with lower ultimate
elongation
values being indicative of more complete curing. It would further be desirable
to
achieve more complete curing using an alternate curing system that does not
impart
extractable impurities to the curing bladder.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a curing bladder comprising a
peroxide curable rubber compound preferably prepared with polymers having a
Mooney
viscosity of at least 25 Mooney-units and a gel content of less than 15 wt.%
containing
repeating units derived from at least one isoolefin monomer, more than 4.1
mol% of
repeating units derived from at least one multiolefin monomer, as well as
optionally further
copolymerizable monomers, and repeating units derived from at least one
multiolefin
cross-linking agent containing no transition metal compounds and no organic
nitro
compounds.
In another aspect, the present invention provides a curing bladder made by:
providing a peroxide curable rubber compound comprising repeating units
derived from
at least one isoolefin monomer, at least 4.1 mol% of repeating units derived
from at
least one multiolefin monomer, and repeating units derived from at least one
multiolefin
cross-linking agent; adding a peroxide curing system to the compound
comprising at
least a thermally activated peroxide and a peroxide curing co-agent; forming
the curing
bladder from the peroxide curable rubber compound with the added peroxide
curing
system; and, peroxide curing the curing bladder.
The curing bladder preferably has a greater degree of cure than that obtained
using resin based curing systems. Preferably, the curing bladder exhibits an
ultimate
elongation of less than 700%.
Further features of the invention will now be described in greater detail with
reference to preferred embodiments of the invention.
4
CA 02557217 2006-08-24
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The Mooney viscosity of a polymer suitable for use in rubber compounds for
curing bladders can be determined using ASTM test D1646 using a large rotor at
125
°C, a preheat phase of 1 min, and an analysis phase of 8 min (ML1+8 @
125 °C).
The polymer used in preparing the peroxide curable rubber compound preferabl
has a multiolefin content of greater than 4.1 mol%, and a gel content of less
than 10
wt.% and have been produced at conversions ranging from 70 % to 95%.
Preferably,
suitble polymers for use in curing bladder rubber compounds have a Mooney
viscosity
in the range of from 25-70 MU, more preferably 30-60 MU, even more preferably
30-55
MU.
The isoolefin of the polymer suitable in the present invention is not limited
to a
special isoolefin. However, isoolefins within the range of from 4 to 16 carbon
atoms,
preferably 4-7 carbon atoms, such as isobutene, 2-methyl-1-butene, 3-methyl-1-
butene,
2-methyl-2-butene, 4-methyl-1-pentene and mixtures thereof are preferred. Most
preferred is isobutene.
Likewise the multiolefin of the polymer suitable in the present invention is
not
limited to a special multiolefin. Every multiolefin copolymerizable with the
isoolefin
known by the skilled in the art can be used. However, multiolefins within the
range of
from 4-14 carbon atoms, such as isoprene, butadiene, 2-methylbutadiene, 2,4-
dimethylbutadiene, piperyline, 3-methyl-1,3-pentadiene, 2,4-hexadiene, 2-
neopentylbutadiene, 2-methyl-1,5-hexadiene, 2,5-dimethyl-2,4-hexadiene, 2-
methyl-1,4-
pentadiene, 2-methyl-1,6-heptadiene, cyclopentadiene, methylcyclopentadiene,
cyclohexadiene, 1-vinyl-cyclohexadiene and mixtures thereof, in particular
conjugated
dienes, are preferred. Isoprene is most preferred.
In the present invention, ~3-pinene can also be used as a co-monomer for the
isoolefin.
As optional monomers every monomer copolymerizable with the isoolefins and/or
dienes known by the skilled in the art can be used. a-methyl styrene, p-methyl
styrene,
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CA 02557217 2006-08-24
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chlorostyrene, cyclopentadiene and methylcyclopentadiene are preferred. Indene
and
other styrene derivatives may also be used in the present invention.
The multiolefin content of suitable polymers for using the curing bladder
rubber
compounds is at least greater than 4.1 mol%, more preferably greater than 5.0
mol%,
even more preferably greater than 6.0 mol%, yet even more preferably greater
than 7.0
mol%.
Preferably, the monomer mixture for the polymer suitable in the present
invention
contains in the range of from 80% to 95% by weight of at least one isoolefin
monomer
and in the range of from 4.0% to 20% by weight of at least one multiolefin
monomer and
in the range of from 0.01 % to 1 % by weight of at least one multiolefin cross-
linking
agent. More preferably, the monomer mixture contians in the range of from 83%
to 94%
by weight of at least one isoolefin monomer and in the range of from 5.0% to
17% by
weight of a multiolefin monomer and in the range of from 0.01 % to 1 % by
weight of at
least one multiolefin cross-linking agent. Most preferably, the monomer
mixture
contains in the range of from 85% to 93% by weight of at least one isoolefin
monomer
and in the range of from 6.0% to 15% by weight of at least one multiolefin
monomer and
in the range of from 0.01 % to 1 % by weight of at least one multiolefin cross-
linking
agent.
The weight average molecular weight, MW, is preferably greater than 240
kg/mol,
more preferably greater than 300 kg/mol, even more preferably greater than 500
kg/mol,
yet even more preferably greater than 600 kg/mol.
In connection with the present invention the term "gel" is understood to
denote a
fraction of the polymer insoluble for 60 min in cyclohexane boiling under
reflux. The gel
content is preferably less than 10 wt.%, more preferably less than 5 wt%, even
more
preferably less than 3 wt%, yet even more preferably less than 1 wt%.
There are no organic nitro compounds or transition metals present in the butyl
polymer for the rubber compounds for curing bladders of the present invention.
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The butyl polymer may further contain units derived from one or more
multiolefin
cross-linking agents. The term cross-linking agent is known to those skilled
in the art
and is understood to denote a compound that causes chemical cross-linking
between
the polymer chains in opposition to a monomer that will add to the chain. Some
easy
preliminary tests will reveal if a compound will act as a monomer or a cross-
linking
agent. The choice of the cross-linking agent is not particularly restricted.
Preferably,
the cross-linking agent contains a multiolefinic hydrocarbon compound.
Examples
include norbornadiene, 2-isopropenylnorbornene, 2-vinyl-norbornene, 1,3,5-
hexatriene,
2-phenyl-1,3-butadiene, divinylbenzene, diisopropenylbenzene, divinyltoluene,
divinylxylene and C~ to C2o alkyl-substituted derivatives thereof. More
preferably, the
multiolefin crosslinking agent is divinylbenzene, diisopropenylbenzene,
divinyltoluene,
divinyl-xylene and C~ to C2o alkyl substituted derivatives thereof, and or
mixtures of the
compounds given. Most preferably the multiolefin crosslinking agent contains
divinylbenzene and diisopropenylbenzene.
The polymerization preferably is performed in a continuous process in slurry
(suspension), in a suitable diluent, such as chloroalkanes as described in
U.S. Patent
No. 5,417,930.
The monomers are generally polymerized cationically, preferably at
temperatures
in the range from -120°C to +20°C, preferably in the range from -
100°C to -20°C, and
pressures in the range from 0.1 to 4 bar.
The use of a continuous reactor as opposed to a batch reactor seems to have a
positive effect on the polymer. Preferably, the process is conducted in at
least one
continuos reactor having a volume of between 0.1 m3 and 100 m3, more
preferable
between 1 m3 and 10 m3.
Inert solvents or diluents known to the person skilled in the art for butyl
polymerization may be considered as the solvents or diluents (reaction
medium). These
comprise alkanes, chloroalkanes, cycloalkanes or aromatics, which are
frequently also
mono- or polysubstituted with halogens. Hexane/chloroalkane mixtures, methyl
chloride,
dichloromethane or the mixtures thereof may be mentioned in particular.
Chloroalkanes
are preferably used in the process according to the present invention.
7
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Said polymers with a Mooney viscosity of at least 25 Mooney-units and a gel
content of less than 15 wt.% containing repeating units derived from at least
one isoolefin
monomer, more than 4.1 mol% of repeating units derived from at least one
multiolefin
monomer, as well as optionally further copolymerizable monomers, and repeating
units
derived from at least one multiolefin cross-linking agent containing no
transition metal
compounds and no organic nitro compounds may be partially or fully chlorinated
or
brominated.
Bromination or chlorination can be performed according to the procedures known
to
those skilled in the art, such as as described in Rubber Technology, 3~d Ed.,
Edited by
Maurice Morton, Kluwer Academic Publishers, pp. 297 - 300 and references cited
within
this reference.
The rubber compounds for cutting bladders according to the present invention
may contain other rubbers, such as NR, BR, HNBR, NBR, SBR, EPDM or
fluororubbers.
The preparation of rubber compounds is known to those skilled in the art. In
most cases carbon black is added as filler and a peroxide based curing system
is used.
Suitable compounding and vulcanization processes are known to those skilled in
the
art, such as the process disclosed in Encyclopedia of Polymer Science and
Engineering, Vol. 4, S. 66 et seq. (Compounding) and Vol. 17, S. 666 et seq.
(Vulcanization).
The present invention is not limited to a special peroxide curing system. For
example, inorganic or organic peroxides are suitable. Preferably, the
peroxides are
thermally activated. Preferred are organic peroxides such as dialkylperoxides,
ketalperoxides, aralkylperoxides, peroxide ethers, peroxide esters, such as di-
tert.-
butylperoxide, bis-(tert.-butylperoxyisopropyl)-benzol, dicumylperoxide, 2,5-
dimethyl-
2,5-di(tert.-butylperoxy)-hexane, 2,5-dimethyl-2,5-di(tert.-butylperoxy)-
hexene-(3), 1,1-
bis-(tert.-butylperoxy)-3,3,5-trimethyl-cyclohexane, benzoylperoxide, tert.-
butylcumyl-
peroxide and tert.-butylperbenzoate. Usually the amount of peroxide in the
compound
is in the range of from 1 to 10 phr (= per hundred rubber), preferably from 1
to 5 phr.
Subsequent curing is usually performed at a temperature in the range of from
100 to
8
CA 02557217 2006-08-24
POS 1199 FF
200°C, preferably 130 to 180°C. Peroxides might be applied
advantageously in a
polymer-bound form. Suitable systems are commercially available, such as Poly-
dispersion T(VC) D-40 P from Rhein Chemie Rheinau GmbH, D (= polymerbound di-
tert.-butylperoxy-isopropylbenzene).
The peroxide curing system may further comprise one or more peroxide curing
co-agents. The co-agent may include bis dieneophiles. Suitable bis
dieneophiles
include m-phenyl-bis-maleinimide and m-phenylene-bis-maleimide. The co-agent
may
include triallyl isocyanurate (TAIC), commercially available under the
trademark DIAK~
7 from DuPont, or N,N'-m-phenylene dimaleimide, known as HVA-2 (DuPont Dow),
triallyl cyanurate (TAC) or liquid polybutadiene known as Ricon~ D 153
(supplied by
Ricon Resins). Other suitable compounds that are known to cure halobutyl
elastomers
include phenolic resins, amines, amino acids, peroxides, zinc oxide and the
like.
Combinations of the aforementioned curatives may also be used. The rubber
compounds may further contain a co-agent such as zinc diacrylate. Amounts can
be
equivalent to the peroxide curative or less. Particulary suitable co-agents
include the
commercially available co-agents HVA-2, SR-633, or combinations thereof.
An antioxidant may also be included in the compound, suitably in an amount up
to 4 phr, preferably about 2 phr. Examples of suitable antioxidants include p-
dicumyl
diphenylamine (Naugard~ 445), Vulkanox~ DDA (a diphenylamine derivative),
Vulkanox~ ZMB2 (zinc salt of methylmercapto benzimidazole), Vulkanox~ HS
(polymerized 1,2-dihydro-2,2,4-trimethyl quinoline) and Irganox~ 1035
(thiodiethylene
bis(3,5-di-tert.-butyl-4-hydroxy) hydrocinnamate or thiodiethylene bis(3-(3,5-
di-tert.-
butyl-4-hydroxyphenyl)propionate supplied by Ciba-Geigy. Vulkanox is a
trademark of
Lanxess Inc.
The rubber compound according to the present invention can contain further
auxiliary products for rubbers, such as reaction accelerators, vulcanizing
agents,
vulcanizing accelerators, vulcanizing acceleration auxiliaries, antioxidants,
foaming
agents, anti-aging agents, heat stabilizers, light stabilizers, ozone
stabilizers, processing
aids, resins, plasticizers, tackifiers, blowing agents, dyestuffs, pigments,
waxes,
extenders, organic acids, inhibitors, metal oxides, and activators such as
triethanolamine, polyethylene glycol, hexanetriol, etc., which are known to
the rubber
9
CA 02557217 2006-08-24
POS 1199 FF
industry. The rubber aids are used in conventional amounts, which depend inter
alia on
the intended use. Conventional amounts are e.g. from 0.1 to 50 wt.%, based on
rubber.
Preferably the compound furthermore contains in the range of 0.1 to 20 phr of
an
organic fatty acid, preferably a unsaturated fatty acid having one, two or
more carbon
double bonds in the molecule which more preferably includes 10% by weight or
more of
a conjugated diene acid having at least one conjugated carbon-carbon double
bond in
its molecule. Preferably those fatty acids have in the range of from 8- 22
carbon atoms,
more preferably 12-18. Examples include stearic acid, palmic acid and oleic
acid and
their calcium-, zinc-, magnesium-, potassium- and ammonium salts.
The ingredients of the final compound can be mixed together, suitably at an
elevated temperature that may range from 25 °C to 200 °C.
Normally the mixing time
does not exceed one hour and a time in the range from 2 to 30 minutes is
usually
adequate. The mixing is suitably carried out in an internal mixer such as a
Banbury
mixer, or a Haake or Brabender miniature internal mixer. A two roll mill mixer
also
provides a good dispersion of the additives within the elastomer. An extruder
also
provides good mixing, and permits shorter mixing times. It is possible to
carry out the
mixing in two or more stages, and the mixing can be done in different
apparatus, for
example one stage in an internal mixer and one stage in an extruder. However,
it
should be taken care that no unwanted pre-crosslinking (= scorch) occurs
during the
mixing stage.
A curing bladder is made from the compound by first providing the peroxide
curable rubber compound, incorporating the components of the peroxide curing
system
to the compound, forming the bladder using a mold or other suitable means and
peroxide curing the curing bladder. The bladder may be peroxide cured by
elevating
the temperature of the bladder to a temperature sufficient to thermally
activate the
peroxide. The curing temperature of the curing bladder is typically in the
range of 100
to 200 °C, preferably 130 to 180 °C.
The following Examples are provided to further illustrate the present
invention
and are meant to be construed in a non-limiting sense.
CA 02557217 2006-08-24
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EXAMPLES
The Inventive Example compounds of the present invention are compared to a
standard resin cure recipe (Comprative Compound). The standard cure formuation
is
disclosed in Table 1. Mixing was accomplished with the use of an internal
mixer (black
Banbury), consisting of a drive unit (Plasticorder~ Type PL-V151 ) and a data
interface
module. Cure characteristics were determined with a Moving Die Rheometer (MDR)
test
carried out according to ASTM standard D-5289 on a Monsanto MDR 200(E). The
upper disc oscillated though a small arc of 1 degree. Curing was achieved with
the use
of an electric Press equipped with an Allan-Bradley Programmable Controller.
Table 1: Comparative Compound
Butyl Rubber (LANXESS Butyl RB30195 phr
)
Chloroprene (Baypren~ 116) 5 phr
Carbon black (N330 Vulcan 3) 47 phr
castor oil 5 phr
Pentalyn~ A 3 phr
Stearic Acid 0.5
phr
Resin SP-1045 8 phr
Zn0 6 phr
Preparation of Polymers 1 and 2
Polymer 1
The monomer feed composition was comprised of 2.55 wt. % of isoprene and
27.5 wt. % of isobutene. The monomer feed was introduced into the continuous
polymerization reactor at a rate of 5900 kg/hour. In additon, DVB was
introduced into
the reactor at a rate of 5.4 to 6kg/hour. Polymerization was initiated via the
introduction
of an AIC13/MeCI solution (0.23 wt. % of AICI3 in MeCI) at a rate of 204 to
227 kg/hour.
The internal temperature of the continuous reaction was mainted between -95
and -
100 °C through the use of an evaporative cooling process. Following
suffecient
residence within the reactor, the newly formed polymer crumb was separated
from the
11
CA 02557217 2006-08-24
POS 1199 FF
MeCI diluent with the use of an aqeous flash tank. At this point, ca. 1 wt. %
of stearic
acid was introduced into the polymer crumb. Prior to drying, 0.1 wt. % of
Irganox~ 1010
was added to the polymer. Drying of the resulting material was accomplished
with the
use of a conveyor oven.
Polymer 2
The monomer feed composition was comprised of 4.40 wt. % of isoprene and
25.7 wt. % of isobutene. The monomer feed was introduced into the continuous
polymerization reactor at a rate of 5900 kg/hour. In additon, DVB was
introduced into
the reactor at a rate of 5.4 to 6 kg/hour. Polymerization was initiated via
the introduction
of an AICI3/MeCI solution (0.23 wt. % of AICI3 in MeCI) at a rate of 204 to
227 kg/hour.
The internal temperature of the continuous reaction was mainted between -95
and -
100 °C through the use of an evaporative cooling process. Following
suffecient
residence within the reactor, the newly formed polymer crumb was separated
from the
MeCI diluent with the use of an aqeous flash tank. At this point, ca. 1 wt. %
of stearic
acid was introduced into the polymer crumb. Prior to drying, 0.1 wt. % of
Irganox~ 1010
was added to the polymer. Drying of the resulting material was accomplished
with the
use of a conveyor oven.
Inventive Compounds
The formulations for Inventive Compounds in Examples 1, 2, 3 and 4 are
disclosed in Tables, 2, 3, 4 and 5. Mixing was accomplished with the use of a
miniature
internal mixer (Brabender MIM) from C. W. Brabender, consisting of a drive
unit
(Plasticorder~ Type PL-V151 ) and a data interface module as disclosed in
Tables 2-5.
Cure characteristics were determined with a Moving Die Rheometer (MDR) test
carried
out according to ASTM standard D-5289 on a Monsanto MDR 200(E). The upper disc
oscillated though a small arc of 1 degree. Curing was achieved with the use of
an
electric Press equipped with an Allan-Bradley Programmable Controller.
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POS 1199 FF
Table 2: Example 1 (Inventive Compound 1~
Polymer 1 (5.0 mol % IP) 100 phr (0
min)
Carbon black (N330 Vulcan~47 phr (1 min)
3)
Peroxide (DI-CUP 40 C) 4 phr (4 min)
Co-agent (HVA-2) 2.5 phr (4
min)
Table 3: Example 2 (Inventive Compound 2~
Polymer 1 (5.0 mol % IP) 100 phr (0 min)
Pentalyn~ A 3 phr (1 min)
stearic acid 0.5 phr (1 min)
Carbon black (N330 Vulcan~ 47 phr (1 min)
3)
Peroxide (DI-CUP 40 C) 4 phr (4 min)
Co-agent (SR-633) 14 phr (4 min)
Table 4: Example 3 Inventive Compound 3~
Polymer 1 (4.2 mol % IP) 100 phr (0 min)
Carbon black (N330 Vulcan~50 phr (1 min)
3)
Peroxide (DI-CUP 40 C) 4 phr (4 min)
Co-agent (HVA-2) 2 phr (4 min)
Table 5: Example 5 Inventive Compound 5~
Polymer 2 (7.5 mol % 100 phr (0
IP) min)
Carbon black (N550) 50 phr (4
min)
carnauba wax 2 phr (8 min)
Vulkanox~ 4020 LG (6PPD 1 phr (8 min)
Vulkanox~ ZMB-2/C5 (ZMMBI)1 phr (8 min)
Peroxide (DI-CUP 40 C) 4 phr (9 min)
13
' CA 02557217 2006-08-24
POS 1199 FF
Co-agent (HVA-2) 3 phr (10 min)
Table 6: Results
Example ts1 ts2 t'90 4(MH-ML)Ult. Ult. M200 M300 M300/
[min][min] [min] [dN.m] Ten. Elong [MPa] [MPa] M100
[MPa] [%]
Comparativ3.66 6.72 45.61 8.68 11.21 825 2.34 3.42 2.19
a
Example 0.72 0.96 3.76 9.35 5.69 289 3.69 - -
1
Example 216 2.88 6.03 6.07 3.20 695 1.42 1.98 2.14
2
Example 0.90 1.38 4,90 8.05 8.10 442 2.82 5.43 4.72
3
Example 1.44 2.28 20.49 14.21 9.45 291 6.58
4
Compared to a typical resin cure recipe (Comparative), Examples 1-4 show much
faster cure properties. Example 4 is slower in cure properties than the 3
other
examples. Given that this seems to be induced by the addition of anti-oxidants
(Vulkanox 4020LG, Vulkanox ZMB-2 C5), this provides an additional handle by
which
one can influence compound cure reactivity.
In addition to faster cure properties, peroxide cure systems have the benefit
of
not requiring the use of resins, which are inherently difficult to incorporate
into the
formulation.
The examples containing HVA-2 as a co-agent, i.e. Examples 1, 3 and 4, appear
to present a superior degree of reinforcement, by evidence of M200 and
M300/M100,
when compared to the standard compound (Comparative).
Example 3 contains SR633 as a co-agent. The addition of SR633 seems to result
in an increased ultimate elongation and a comparable degree of reinforcement
(M300/M100), when compared to the standard.
These results indicate that using a mixture of co-agents might result in
superior
degree of reinforcement and ultimate elongation.
14
CA 02557217 2006-08-24
POS 1199 FF
Further aspects or sub-combinations of the present invention will be evident
to
persons skilled in the art and are meant to be encompassed by the following
claims.
