U.S. patent application number 09/813439 was filed with the patent office on 2001-11-01 for elastomeric compounds incorporating silicon-treated carbon blacks.
Invention is credited to Belmont, James A., Francis, Robert A., Mahmud, Khaled, Wang, Meng-Jiao.
Application Number | 20010036995 09/813439 |
Document ID | / |
Family ID | 46203687 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010036995 |
Kind Code |
A1 |
Mahmud, Khaled ; et
al. |
November 1, 2001 |
Elastomeric compounds incorporating silicon-treated carbon
blacks
Abstract
Disclosed are elastomeric compounds including an elastomer and a
silicon-treated carbon black, and optionally including a coupling
agent. The elastomeric compound exhibits poorer abrasion resistance
in the absence of a coupling agent, lower hysteresis at high
temperature and comparable or increased hysteresis at low
temperature compared to an elastomer containing an untreated carbon
black. A variety of elastomers and formulations employing such
elastomers are contemplated and disclosed. Elastomeric compounds
incorporating an elastomer and an oxidized, silicon-treated carbon
black are also disclosed. Also disclosed are methods for preparing
elastomers compounded with the treated carbon black.
Inventors: |
Mahmud, Khaled; (Tyngsboro,
MA) ; Wang, Meng-Jiao; (Lexington, MA) ;
Francis, Robert A.; (Park Orchards, AU) ; Belmont,
James A.; (Acton, MA) |
Correspondence
Address: |
Martha Ann Finnegan, Esq.
Cabot Corporation
157 Concord Road
Billerica
MA
01821-7001
US
|
Family ID: |
46203687 |
Appl. No.: |
09/813439 |
Filed: |
March 21, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09813439 |
Mar 21, 2001 |
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09392803 |
Sep 9, 1999 |
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09392803 |
Sep 9, 1999 |
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08750017 |
Aug 14, 1997 |
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6028137 |
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08750017 |
Aug 14, 1997 |
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08446141 |
May 22, 1995 |
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5830930 |
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08750017 |
Aug 14, 1997 |
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08446142 |
May 22, 1995 |
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5877238 |
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08750017 |
Aug 14, 1997 |
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08528895 |
Sep 15, 1995 |
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08750017 |
Aug 14, 1997 |
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PCT/US96/07310 |
Sep 15, 1995 |
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Current U.S.
Class: |
524/495 ;
523/216; 524/492 |
Current CPC
Class: |
C08K 5/5406 20130101;
C09C 1/56 20130101; C08K 9/06 20130101; C08K 5/5406 20130101; C09C
1/50 20130101; C01P 2006/12 20130101; C08L 21/00 20130101; C01P
2002/88 20130101; C08L 21/00 20130101; C01P 2004/04 20130101; C09C
1/565 20130101; C08K 9/06 20130101; C01P 2006/19 20130101 |
Class at
Publication: |
524/495 ;
524/492; 523/216 |
International
Class: |
C08K 009/00; C08K
003/04; C08K 003/34 |
Claims
What is claimed is:
1. An elastomeric compound comprising an elastomer and a
silicon-treated carbon black, wherein said silicon-treated carbon
black imparts to the elastomer poorer abrasion resistance,
comparable or higher loss tangent at low temperature and a lower
loss tangent at high temperature, compared to an untreated carbon
black.
2. The elastomeric compound of claim 1, further comprising a
coupling agent.
3. The elastomeric compound of claim 1, wherein said
silicon-treated carbon black includes silicon-containing regions
primarily at the surface of the carbon black aggregate.
4. The elastomeric compound of claim 1, wherein said
silicon-treated carbon black includes silicon-containing regions
distributed throughout the carbon black aggregate.
5. The elastomeric compound of claim 1, wherein said
silicon-treated carbon black is oxidized.
6. The elastomeric compound of claim 1, wherein said elastomer is
selected from the group consisting of solution SBR, natural rubber,
functional solution SBR, emulsion SBR, polybutadiene, polyisoprene,
and blends of any of the foregoing.
7. The elastomeric compound of claim 1, further comprising
silica.
8. The elastomeric compound of claim 1, further comprising carbon
black, silica, carbon black having an organic group attached
thereto, or combinations thereof.
9. The elastomeric compound of claim 1, wherein at least a portion
of said silicon-treated carbon black has an organic group attached
thereto, and optionally treated with a silane coupling agent.
10. The elastomeric compound of claim 1, wherein said organic group
is an aromatic sulfide represented by the formulas Ar--Sn--Ar' or
Ar--Sn--Ar", wherein Ar and Ar' are independently arylene groups,
Ar" is an aryl group and n is 1 to 8.
11. The elastomeric compound of claim 1, further comprising a
carbon black having an organic group attached thereto.
12. The elastomeric compound of claim 1, further comprising carbon
black.
13. The elastomeric compound of claim 1, wherein a portion of said
silicon-treated carbon black has an organic group attached thereto
and said elastomeric compound further comprises a carbon black
having an organic group attached thereto, silica, carbon black, or
mixtures thereof.
14. The elastomeric compound of claim 1 wherein said
silicon-treated carbon black contains between about 0.1% and about
25% silicon, by weight.
15. The elastomeric compound of claim 14 wherein said
silicon-treated carbon black contains between about 0.5% and about
10% silicon, by weight.
16. The elastomeric compound of claim 15 wherein said
silicon-treated carbon black contains between about 2% and about 6%
silicon, by weight.
17. The elastomeric compound of claim 2, wherein said coupling
agent is selected from the group consisting of silane coupling
agents, zirconate coupling agents, titanate coupling agents, nitro
coupling agents and mixtures of the foregoing.
18. The elastomeric compound of claim 2, wherein said coupling
agent is selected from the group consisting of
bis(3-triethoxysilylpropyl)tetrasul- fane,
3-thiocyanatopropyl-triethoxysilane,
.gamma.-mercaptopropyl-trimetho- xysilane, zirconium
dineoalkanolatodi(3-mercapto) propionato-O,
N,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane and mixtures of
the foregoing.
19. The elastomeric compound of claim 2 wherein said coupling agent
is present in an amount of from about 0.1 to 15 parts per hundred
of elastomer.
20. An elastomeric compound comprising an elastomer and
silicon-treated carbon black, wherein said elastomer is ethylene
propylene diene monomer rubber, poly chloroprene, natural rubber,
hydrogenated nitrile butadiene rubber, nitrile butadiene rubber,
chlororinated polyethylene, styrene butadiene rubber, butyl rubber,
polyacrylic rubber, polyepichlorohydrin, ethylene vinyl acetate or
blends of the foregoing.
21. The elastomeric compound of claim 20 wherein said
silicon-treated carbon black is present in an amount of from
between about 10 and 300 parts per hundred parts of said
elastomer.
22. The elastomeric compound of claim 21 wherein said
silicon-treated carbon black is present in an amount of from
between about 100 and 200 parts per hundred parts of said
elastomer.
23. The elastomeric compound of claim 22 wherein said
silicon-treated carbon black is present in an amount of from
between about 10 and 150 parts per hundred parts of said
elastomer.
24. The elastomeric compound of claim 23 wherein said
silicon-treated carbon black is present in an amount of from
between about 20 and 80 parts per hundred parts of said
elastomer.
25. An article of manufacture formed from the elastomeric compound
of claim 20.
26. The article of claim 25 wherein said elastomeric compound is
formed into weatherstripping.
27. The article of claim 25 wherein said elastomeric compound is
formed into coolant hose.
28. The article of claim 25 wherein said elastomeric compound is
formed into hydraulic hose.
29. The article of claim 25 wherein said elastomeric compound is
formed into fuel hose.
30. The article of claim 25 wherein said elastomeric compound is
formed into an engine mount.
31. The article of claim 25 wherein said elastomeric compound is
formed into a bushing.
32. The article of claim 25 wherein said elastomeric compound is
formed into a power belt.
33. The article of claim 25 wherein said elastomeric compound is
formed into a conveyor belt.
34. The article of claim 25 wherein said elastomeric compound is
formed into a power transmission belt.
35. The article of claim 25 wherein said elastomeric compound is
formed into a seal.
36. The article of claim 25 wherein said elastomeric compound is
formed into a gasket.
37. A method for improving the hysteresis of an elastomeric
compound comprising compounding an elastomer with a silicon treated
carbon black and optionally a coupling agent, wherein said
silicon-treated carbon black imparts to the elastomer poorer
abrasion resistance, comparable or higher loss tangent at low
temperature and a lower loss tangent at high temperature, compared
to an untreated carbon black.
38. The method of claim 37, wherein said silicon-treated carbon
black includes silicon-containing regions primarily at the
aggregate surface of the carbon black.
39. The method of claim 37, wherein said silicon-treated carbon
black includes silicon-containing regions distributed throughout
the carbon black aggregate.
40. The method of claim 37, wherein said silicon-treated carbon
black is oxidized.
41. The method of claim 37, wherein said elastomer is selected from
the group consisting of solution SBR, natural rubber, functional
solution SBR, emulsion SBR, polybutadiene, polyisoprene, and blends
of any of the foregoing.
42. The method of claim 37 wherein said silicon-treated carbon
black contains between about 0.1% and about 25% silicon, by
weight.
43. The method of claim 42 wherein said silicon-treated carbon
black contains between about 0.5% and about 10% silicon, by
weight.
44. The method of claim 43 wherein said silicon-treated carbon
black contains between about 2% and about 6% silicon, by
weight.
45. The method of claim 37, wherein said coupling agent is selected
from the group consisting of silane coupling agents, zirconate
coupling agents, titanate coupling agents, nitro coupling agents
and mixtures of the foregoing.
46. The method, of claim 37, wherein said coupling agent is
selected from the group consisting of
bis(3-triethoxysilylpropyl)tetrasulfane,
3-thiocyanatopropyl-triethoxy silane,
.gamma.-mercaptopropyl-trimethoxy silane, zirconium
dineoalkanolatodi(3-mercapto) propionato-O,
N,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane and mixtures of
the foregoing.
47. The method of claim 37, wherein said coupling agent is present
in an amount of from about 0.1 to 15 parts per hundred of
elastomer.
48. A method of preparing an elastomeric compound, comprising:
masticating in a mixer, silicon-treated carbon black and an
elastomer, and optionally a coupling agent, for a time and
temperature sufficient to form a masterbatch; milling said
masterbatch; cooling said masterbatch to facilitate the addition of
a curing additive and avoid substantial premature cross-linking;
masticating in a mixer a mixture comprising the masterbatch and a
curing additive, and optionally a coupling agent, for a time and
temperature sufficient to form said elastomeric compound.
49. The method of claim 48, wherein said silicon-treated carbon
black includes silicon-containing regions primarily at the
aggregate surface of the carbon black.
50. The method of claim 48, wherein said silicon-treated carbon
black includes silicon-containing regions distributed throughout
the carbon black aggregate.
51. The method of claim 48, wherein said silicon-treated carbon
black is oxidized.
52. The method of claim 48, wherein said elastomer is selected from
the group consisting of solution SBR, natural rubber, functional
solution SBR, emulsion SBR, polybutadiene, polyisoprene, and blends
of any of the foregoing.
53. The method of claim 48 wherein said silicon-treated carbon
black contains between about 0.1% and about 25% silicon, by
weight.
54. The method of claim 53 wherein said silicon-treated carbon
black contains between about 0.5% and about 10% silicon, by
weight.
55. The method of claim 54 wherein said silicon-treated carbon
black contains between about 2% and about 6% silicon, by
weight.
56. The method of claim 48, wherein said coupling agent is selected
from the group consisting of silane coupling agents, zirconate
coupling agents, titanate coupling agents, nitro coupling agents
and mixtures of the foregoing.
57. The method of claim 48, wherein said coupling agent is selected
from the group consisting of
bis(3-triethoxysilylpropyl)tetrasulfane,
3-thiocyanatopropyl-triethoxy silane,
.gamma.-mercaptopropyl-trimethoxy silane, zirconium
dineoalkanolatodi(3-mercapto) propionato-O,
N,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane and mixtures of
the foregoing.
58. The method of claim 57 wherein said coupling agent is present
in an amount of from between about 0.1 to 15 parts per hundred of
elastomer.
59. Silicon-treated carbon black, which when compounded with an
elastomer imparts to the elastomer poorer abrasion resistance,
comparable or higher loss tangent at low temperature arid a lower
loss tangent at high temperature, compared to an untreated carbon
black.
60. The silicon-treated carbon black of claim 59 including
silicon-containing regions primarily at the surface of the carbon
black aggregate.
61. The silicon-treated carbon black of claim 59 including
silicon-containing regions distributed throughout the carbon black
aggregate.
62. The silicon-treated carbon black of claim 59, wherein said
silicon-treated carbon black is oxidized.
63. The silicon-treated carbon black of claim 59 wherein said
silicon-treated carbon black contains between about 0.1% and about
25% silicon, by weight.
64. The silicon-treated carbon black of claim 63 wherein said
silicon-treated carbon black contains between about 0.5% and about
10% silicon, by weight.
65. The silicon-treated carbon black of claim 64 wherein said
silicon-treated carbon black contains between about 2% and about 6%
silicon, by weight.
66. A reinforcing agent, comprising: silio-treated carbon black,
which when compounded with an elastomer imparts to the elastomer
poorer abrasion resistance, comparable or higher loss tangent at
low temperature and a lower loss tangent at high temperature,
compared to an untreated carbon black; and a coupling agent.
67. The elastomeric compound of claim 2 wherein said coupling agent
is present in an amount of between about 0.1 and 6 parts per
hundred of elastomer.
68. The elastomeric compound of claim 37 wherein said coupling
agent is present in an amount of between about 0.1 and 6 parts per
hundred of elastomer.
69. The elastomeric compound of claim 58 wherein said coupling
agent is present in an amount of between about 0.1 and 6 parts per
hundred of elastomer.
70. An elastomeric compound comprising: an elastomer; and a
silicon-treated carbon black, wherein said silicon-treated carbon
black imparts improved cut-chip resistance and heat build-up
properties to the elastomer.
71. A method of improving cut-chip resistance in an elastomer
comprising adding an effective amount of a silicon-treated carbon
black to the elastomer.
72. An elastomeric compound comprising: an elastomer; and a
silicon-treated carbon black, wherein said silicon-treated carbon
black imparts to the elastomer improved adhesion to a tire
cord.
73. A method of improving adhesion of an elastomer to a tire cord
comprising adding an effective amount of a silicon-treated carbon
black to the elastomer.
74. A method of increasing electric resistivity in an elastomer
comprising adding an effective amount of a silicon-treated carbon
black to the elastomer.
75. A method of lowering spring rates for a given tan .delta. in an
elastomer comprising adding an effective amount of a
silicon-treated carbon black to the elastomer.
76. A method of improving tensile strength, elongation at break, or
tear strength in an elastomer comprising adding an effective amount
of a silicon-treated carbon black to the elastomer.
77. A method for increasing the CDBP of carbon black comprising
introducing into said carbon black process a silicon containing
compound to form a carbon black having silicon-containing
regions.
78. A formulation for making an elastomeric composition comprising
an elastomer and a silicon-treated carbon black.
79. The formulation of claim 78, further comprising a coupling
agent.
80. The formulation of claim 79, wherein said coupling agent is
APDS.
81. The elastomeric compound of claim 1, wherein said elastomer is
a homopolymer, a copolymer, or terpolymer.
82. The elastomeric composition of claim 1, wherein said elastomer
has a glass transition point, as measured by DSC, of less than
20.degree. C.
83. The elastomeric composition of claim 82, wherein said elastomer
has a glass transition point, as measured by DSC, of between
-120.degree. C. and 0.degree. C.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to novel elastomeric compounds
exhibiting improved hysteresis properties. More particularly, the
invention relates to novel elastomeric compounds incorporating
silicon-treated carbon blacks and products manufactured from such
compounds.
BACKGROUND OF THE INVENTION
[0002] Carbon blacks are widely used as pigments, fillers and
reinforcing agents in the compounding and preparation of rubber and
other elastomeric compounds. Carbon blacks are particularly useful
as reinforcing agents in the preparation of elastomeric compounds
used in the manufacture of tires.
[0003] Carbon blacks are generally produced in a furnace-type
reactor by pyrolyzing a hydrocarbon feedstock with hot combustion
gases to produce combustion products containing particulate carbon
black. Carbon black exists in the form of aggregates. The
aggregates, in turn are formed of carbon black particles. However,
carbon black particles do not generally exist independently of the
carbon black aggregate. Carbon blacks are generally characterized
on the basis of analytical properties, including, but not limited
to particle size and specific surface area; aggregate size, shape,
and distribution; and chemical and physical properties of the
surface. The properties of carbon blacks are analytically
determined by tests known to the art. For example, nitrogen
adsorption surface area (measured by ASTM test procedure D3037-
Method A) and cetyl-trimethyl ammonium bromide adsorption value
(CTAB) (measured by ASTM test procedure D3765 [09.01]), are
measures of specific surface area. Dibutylphthalate absorption of
the crushed (CDBP) (measured by ASTM test procedure D3493-86) and
uncrushed (DBP) carbon black (measured by ASTM test procedure
D2414-93), relates to the aggregate structure. The bound rubber
value relates to the surface activity of the carbon black. The
properties of a given carbon black depend upon the conditions of
manufacture and may be modified, e.g., by altering temperature,
pressure, feedstock, residence time, quench temperature,
throughput, and other parameters.
[0004] It is generally desirable in the production of tires to
employ carbon black-containing compounds when constructing the
tread and other portions of the tire. For example, a suitable tread
compound will employ an elastomer compounded to provide high
abrasion resistance and good hysteresis balance at different
temperatures. A tire having high abrasion resistance is desirable
because abrasion resistance is proportional to tire life. The
physical properties of the carbon black directly influence the
abrasion resistance and hysteresis of the tread compound.
Generally, a carbon black with a high surface area and small
particle size will impart a high abrasion resistance and high
hysteresis to the tread compound. Carbon black loading also affects
the abrasion resistance of the elastomeric compounds. Abrasion
resistance increases with increased loading, at least to an optimum
point, beyond which abrasion resistance actually decreases.
[0005] The hysteresis of an elastomeric compound relates to the
energy dissipated under cyclic deformation. In other words, the
hysteresis of an elastomeric composition relates to the difference
between the energy applied to deform the elastomeric composition
and the energy released as the elastomeric composition recovers to
its initial undeformed state. Hysteresis is characterized by a loss
tangent, tan .delta., which is a ratio of the loss modulus to the
storage modulus (that is, viscous modulus to elastic modulus).
Tires made with a tire tread compound having a lower hysteresis
measured at higher temperatures, such as 40.degree. C. or higher,
will have reduced rolling resistance, which in turn, results in
reduced fuel consumption by the vehicle using the tire. At the same
time, a tire tread with a higher hysteresis value measured at low
temperature, such as 0.degree. C. or lower, will result in a tire
with high wet traction and skid resistance which will increase
driving safety. Thus, a tire tread compound demonstrating low
hysteresis at high temperatures and high hysteresis at low
temperatures can be said to have a good hysteresis balance.
[0006] There are many other applications where it is useful to
provide an elastomer exhibiting a good hysteresis balance but where
the abrasion resistance is not an important factor. Such
applications include but are not limited to tire components such as
undertread, wedge compounds, sidewall, carcass, apex, bead filler
and wire skim; engine mounts; and base compounds used in industrial
drive and automotive belts.
[0007] Silica is also used as a reinforcing agent (or filler) for
elastomers. However, using silica alone as a reinforcing agent for
elastomer leads to poor performance compared to the results
obtained with carbon black alone as the reinforcing agent. It is
theorized that strong filler-filler interaction and poor
filler-elastomer interaction accounts for the poor performance of
silica. The silica-elastomer interaction can be improved by
chemically bonding the two with a chemical coupling agent, such as
bis (3-triethoxysilylpropyl) tetra-sulfane, commercially available
as Si-69 from Degussa AG, Germany. Coupling agents such as Si-69
create a chemical linkage between the elastomer and the silica,
thereby coupling the silica to the elastomer.
[0008] When the silica is chemically coupled to the elastomer,
certain performance characteristics of the resulting elastomeric
composition are enhanced. When incorporated into vehicle tires,
such elastomeric compounds provide improved hysteresis balance.
However, elastomer compounds containing silica as the primary
reinforcing agent exhibit low thermal conductivity, high electrical
resistivity, high density and poor processability.
[0009] When carbon black alone is used as a reinforcing agent in
elastomeric compositions, it does not chemically couple to the
elastomer but the carbon black surface provides many sites for
interacting with the elastomer. While the use of a coupling agent
with carbon black might provide some improvement in performance to
an elastomeric composition, the improvement is not comparable to
that obtained when using a coupling agent with silica.
[0010] It is an object of the present invention to provide novel
elastomeric compounds exhibiting improved hysteresis balance. It is
another object to provide an elastomeric compound incorporating
silicon-treated carbon blacks. It is yet another object of the
present invention to provide an elastomeric compound incorporating
silicon-treated carbon blacks, wherein the carbon black may be
efficiently coupled to the elastomer with a coupling agent. Such a
carbon black may be employed for example, in tire compounds,
industrial rubber products and other rubber goods. It is a further
object of the present invention to provide silicon-treated carbon
black/elastomeric formulations using a variety of elastomers useful
in a variety of product applications. Other objects of the present
invention will become apparent from the following description and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic view of a portion of one type of
carbon black reactor which may be used to produce the treated
carbon blacks of the present invention.
[0012] FIG. 2 is a graph demonstrating the results of a bound
rubber test carried out on elastomeric compositions of the present
invention.
[0013] FIGS. 3a, 3b and 3c are graphs demonstrating hysteresis
values measured at different temperatures and strains on
elastomeric compositions of the present invention.
[0014] FIGS. 4a-4d are photomicrographs comparing carbon blacks
useful in the present invention and prior art carbon blacks.
SUMMARY OF THE INVENTION
[0015] The present invention is directed to an elastomeric compound
including an elastomer and a silicon-treated carbon black, and
optionally including a coupling agent. A variety of elastomers and
formulations employing such elastomers are contemplated and
disclosed. The silicon-treated carbon black imparts to the
elastomer poorer abrasion resistance, lower hysteresis at high
temperature and comparable or increased hysteresis at low
temperature compared to an untreated carbon black. Elastomeric
compounds incorporating an elastomer and an oxidized,
silicon-treated carbon black are also disclosed. Also disclosed are
methods for preparing elastomeric compounds with the
silicon-treated carbon blacks and products manufactured from such
compounds.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The present inventors have discovered that elastomeric
compounds having desirable hysteresis and other properties may be
obtained by compounding an elastomer with a silicon-treated carbon
black. In the silicon-treated carbon black a silicon-containing
species, including but not limited to, oxides and carbides of
silicon, may be distributed through at least a portion of the
carbon black aggregate as an intrinsic part of the carbon
black.
[0017] In an elastomeric compound including an elastomer and a
silicon-treated carbon black, the silicon-treated carbon black
imparts to the elastomer poorer abrasion resistance, comparable or
higher loss tangent at low temperature and a lower loss tangent at
high temperature, compared to an untreated carbon black.
[0018] Silicon-treated carbon black aggregates do not represent a
mixture of discrete carbon black aggregates and discrete silica
aggregates. Rather, the silicon-treated carbon black aggregates of
the present invention include at least one silicon-containing
region either at the surface of or within the carbon black
aggregate.
[0019] When the silicon-treated carbon black is examined under
STEM-EDX, the silicon signal corresponding to the
silicon-containing species is found to be present in individual
carbon black aggregates. By comparison, for example, in a physical
mixture of silica and carbon black, STEM-EDX examination reveals
distinctly separate silica and carbon black aggregates.
[0020] The silicon-treated carbon blacks may be obtained by
manufacturing the carbon black in the presence of volatizable
silicon-containing compounds. Such carbon blacks are preferably
produced in a modular or "staged," furnace carbon black reactor as
depicted in FIG. 1. The furnace carbon black reactor has a
combustion zone 1, with a zone of converging diameter 2; a
feedstock injection zone with restricted diameter 3; and a reaction
zone 4.
[0021] To produce carbon blacks with the reactor described above,
hot combustion gases are generated in combustion zone 1 by
contacting a liquid or gaseous fuel with a suitable oxidant stream
such as air, oxygen, or mixtures of air and oxygen. Among the fuels
suitable for use in contacting the oxidant stream in combustion
zone 1, to generate the hot combustion gases, are included any
readily combustible gas, vapor or liquid streams such as natural
gas, hydrogen, methane, acetylene, alcohols, or kerosene. It is
generally preferred, however, to use fuels having a high content of
carbon-containing components and in particular, hydrocarbons. The
ratio of air to fuel varies with the type of fuel utilized. When
natural gas is used to produce the carbon blacks of the present
invention, the ratio of air to fuel may be from about 10:1 to about
1000:1. To facilitate the generation of hot combustion gases, the
oxidant stream may be pre-heated.
[0022] The hot combustion gas stream flows downstream from zones 1
and 2 into zones 3 and 4. The direction of the flow of hot
combustion gases is shown in FIG. 1 by the arrow. Carbon black
feedstock, 6, is introduced at point 7 into the feedstock injection
zone 3. The feedstock is injected into the gas stream through
nozzles designed for optimal distribution of the oil in the gas
stream. Such nozzles may be either single or bi-fluid. Bi-fluid
nozzles may use steam or air to atomize the fuel. Single-fluid
nozzles may be pressure atomized or the feedstock can be directly
injected into the gas-stream. In the latter instance, atomization
occurs by the force of the gas-stream.
[0023] Carbon blacks can be produced by the pyrolysis or partial
combustion of any liquid or gaseous hydrocarbon. Preferred carbon
black feedstocks include petroleum refinery sources such as
decanted oils from catalytic cracking operations, as well as the
by-products from coking operations and olefin manufacturing
operations.
[0024] The mixture of carbon black-yielding feedstock and hot
combustion gases flows downstream through zone 3 and 4. In the
reaction zone portion of the reactor, the feedstock is pyrolyzed to
carbon black. The reaction is arrested in the quench zone of the
reactor. Quench 8 is located downstream of the reaction zone and
sprays a quenching fluid, generally water, into the stream of newly
formed carbon black particles. The quench serves to cool the carbon
black particles and to reduce the temperature of the gaseous stream
and decrease the reaction rate. Q is the distance from the
beginning of reaction zone 4 to quench point 8, and will vary
according to the position of the quench. Optionally, quenching may
be staged, or take place at several points in the reactor.
[0025] After the carbon black is quenched, the cooled gases and
carbon black pass downstream into any conventional cooling and
separating means whereby the carbon black is recovered. The
separation of the carbon black from the gas stream is readily
accomplished by conventional means such as a precipitator, cyclone
separator, bag filter or other means known to those skilled in the
art. After the carbon black has been separated from the gas stream,
it is optionally subjected to a pelletization step.
[0026] The silicon treated carbon blacks of the present invention
may be made by introducing a volatilizable silicon containing
compound into the carbon black reactor at a point upstream of the
quench zone. Useful volatilizable compounds include any compound,
which is volatilizable at carbon black reactor temperatures.
Examples include, but are not limited to, silicates such as
tetraethoxy orthosilicate (TEOS) and tetramethoxy orthosilicate,
silanes such as, tetrachloro silane, and trichloro methylsilane;
and volatile silicone polymers such as octamethylcyclotetrasiloxane
(OMTS). The flow rate of the volatilizable compound will determine
the weight percent of silicon in the treated carbon black. The
weight percent of silicon in the treated carbon black should range
from about 0.1% to 25%, and preferably about 0.5% to about 10%, and
most preferably about 2% to about 6%. It has been found that
injecting silicon containing compound into the carbon black reactor
results in an increase in the structure (e.g., CDBP) of the
product. This is desirable in many applications of carbon
black.
[0027] The volatilizable compound may be premixed with the carbon
black-forming feedstock and introduced with the feedstock into the
reaction zone. Alternatively, the volatilizable compound may be
introduced to the reaction zone separately from the feedstock
injection point. Such introduction may be upstream or downstream
from the feedstock injection point, provided the volatilizable
compound is introduced upstream from the quench zone. For example,
referring to FIG. 1, the volatilizable compound may be introduced
to zone Q at point 12 or any other point in the zone. Upon
volatilization and exposure to high temperatures in the reactor,
the compound decomposes, and reacts with other species in the
reaction zone, yielding silicon treated carbon black, such that the
silicon, or silicon containing species, becomes an intrinsic part
of the carbon black. An example of a silicon-containing species is
silica. Besides volatalizable compounds, decomposible compounds
which are not necessarily volatilizable can also be used to yield
the silicon-treated carbon black.
[0028] As discussed in further detail below, if the volatilizable
compound is introduced substantially simultaneously with the
feedstock, the silicon-treated regions are distributed throughout
at least a portion of the carbon black aggregate.
[0029] In a second embodiment of the present invention, the
volatilizable compound is introduced to the reaction zone at a
point after carbon black formation has commenced but before the
reaction stream has been subjected to the quench. In this
embodiment, silicon-treated carbon black aggregates are obtained in
which a silicon containing species is present primarily at or near
the surface of the carbon black aggregate.
[0030] It has been found by the present inventors that the
elastomeric compounds incorporating a treated carbon black may be
additionally compounded with one or more coupling agents to further
enhance the properties of the elastomeric compound. Coupling
agents, as used herein, include, but are not limited to, compounds
that are capable of coupling fillers such as carbon black or silica
to an elastomer. Coupling agents useful for coupling silica or
carbon black to an elastomer, are expected to be useful with the
silicon-treated carbon blacks. Useful coupling agents include, but
are not limited to, silane coupling agents such as
bis(3-triethoxysilylpropyl)tetrasulfane (Si-69),
3-thiocyanatopropyl-trie- thoxy silane (Si-264, from Degussa AG,
Germany), .gamma.-mercaptopropyl-tr- imethoxy silane (A189, from
Union Carbide Corp., Danbury, Conn.); zirconate coupling agents,
such as zirconium dineoalkanolatodi(3-mercapto- ) propionato-O (NZ
66A, from Kenrich Petrochemicals, Inc., of Bayonne, N.J.); titanate
coupling agents; nitro coupling agents such as
N,N'-bis(2-methyl-2-nitropropyl)-1,6-diaminohexane (Sumifine 1162,
from Sumitomo Chemical Co., Japan); and mixtures of any of the
foregoing. The coupling agents may be provided as a mixture with a
suitable carrier, for example X50-S which is a mixture of Si-69 and
N330 carbon black, available from Degussa AG.
[0031] The silicon-treated carbon black incorporated in the
elastomeric compound of the present invention may be oxidized
and/or combined with a coupling agent. Suitable oxidizing agents
include, but are not limited to, nitric acid and ozone. Coupling
agents which may be used with the oxidized carbon blacks include,
but are not limited to, any of the coupling agents set forth
above.
[0032] The silicon-treated carbon blacks of the present invention
may have an organic group attached.
[0033] One process for attaching an organic group to the carbon
black involves the reaction of at least one diazonium salt with a
carbon black in the absence of an externally applied current
sufficient to reduce the diazonium salt. That is, the reaction
between the diazonium salt and the carbon black proceeds without an
external source of electrons sufficient to reduce the diazonium
salt. Mixtures of different diazonium salts may be used in the
process of the invention. This process can be carried out under a
variety of reaction conditions and in any type of reaction medium,
including both protic and aprotic solvent systems or slurries.
[0034] In another process, at least one diazonium salt reacts with
a carbon black in a protic reaction medium. Mixtures of different
diazonium salts may be used in this process of the invention. This
process can also be carried out under a variety of reaction
conditions.
[0035] Preferably, in both processes, the diazonium salt is formed
in situ. If desired, in either process, the carbon black product
can be isolated and dried by means known in the art. Furthermore,
the resultant carbon black product can be treated to remove
impurities by known techniques. The various preferred embodiments
of these processes are discussed below.
[0036] These processes can be carried out under a wide variety of
conditions and in general are not limited by any particular
condition. The reaction conditions must be such that the particular
diazonium salt is sufficiently stable to allow it to react with the
carbon black. Thus, the processes can be carried out under reaction
conditions where the diazonium salt is short lived. The reaction
between the diazonium salt and the carbon black occurs, for
example, over a wide range of pH and temperature. The processes can
be carried out at acidic, neutral, and basic pH. Preferably, the pH
ranges from about 1 to 9. The reaction temperature may preferably
range from 0.degree. C. to 100.degree. C.
[0037] Diazonium salts, as known in the art, may be formed for
example by the reaction of primary amines with aqueous solutions of
nitrous acid. A general discussion of diazonium salts and methods
for their preparation is found in Morrison and Boyd, Organic
Chemistry. 5th Ed., pp. 973-983, (Allyn and Bacon, Inc. 1987) and
March, Advanced Organic Chemistry: Reactions, Mechanisms, and
Structures, 4th Ed., (Wiley, 1992). According to this invention, a
diazonium salt is an organic compound having one or more diazonium
groups.
[0038] The diazonium salt may be prepared prior to reaction with
the carbon black or, more preferably, generated in situ using
techniques known in the art. In situ generation also allows the use
of unstable diazonium salts such as alkyl diazonium salts and
avoids unnecessary handling or manipulation of the diazonium salt.
In particularly preferred processes, both the nitrous acid and the
diazonium salt are generated in situ.
[0039] A diazonium salt, as is known in the art, may be generated
by reacting a primary amine, a nitrite and an acid. The nitrite may
be any metal nitrite, preferably lithium nitrite, sodium nitrite,
potassium nitrite, or zinc nitrite, or any organic nitrite such as
for example isoamylnitrite or ethylnitrite. The acid may be any
acid, inorganic or organic, which is effective in the generation of
the diazonium salt. Preferred acids include nitric acid, HNO.sub.3,
hydrochloric acid, HCl, and sulfuric acid, H.sub.2SO.sub.4.
[0040] The diazonium salt may also be generated by reacting the
primary amine with an aqueous solution of nitrogen dioxide. The
aqueous solution of nitrogen dioxide, NO.sub.2/H.sub.2O, provides
the nitrous acid needed to generate the diazonium salt.
[0041] Generating the diazonium salt in the presence of excess HCl
may be less preferred than other alternatives because HCl is
corrosive to stainless steel. Generation of the diazonium salt with
NO.sub.2/H.sub.2O has the additional advantage of being less
corrosive to stainless steel or other metals commonly used for
reaction vessels. Generation using H.sub.2SO.sub.4/NaNO.sub.2 or
HNO.sub.3/NaNO.sub.2 are also relatively non-corrosive.
[0042] In general, generating a diazonium salt from a primary
amine, a nitrite, and an acid requires two equivalents of acid
based on the amount of amine used. In an in situ process, the
diazonium salt can be generated using one equivalent of the acid.
When the primary amine contains a strong acid group, adding a
separate acid may not be necessary. The acid group or groups of the
primary amine can supply one or both of the needed equivalents of
acid. When the primary amine contains a strong acid group,
preferably either no additional acid or up to one equivalent of
additional acid is added to a process of the invention to generate
the diazonium salt in situ. A slight excess of additional acid may
be used. One example of such a primary amine is
para-aminobenzenesulfonic acid (sulfanilic acid).
[0043] In general, diazonium salts are thermally unstable. They are
typically prepared in solution at low temperatures, such as
0-5.degree. C., and used without isolation of the salt. Heating
solutions of some diazonium salts may liberate nitrogen and form
either the corresponding alcohols in acidic media or the organic
free radicals in basic media.
[0044] However, the diazonium salt need only be sufficiently stable
to allow reaction with the carbon black. Thus, the processes can be
carried out with some diazonium salts otherwise considered to be
unstable and subject to decomposition. Some decomposition processes
may compete with the reaction between the carbon black and the
diazonium salt and may reduce the total number of organic groups
attached to the carbon black. Further, the reaction may be carried
out at elevated temperatures where many diazonium salts may be
susceptible to decomposition. Elevated temperatures may also
advantageously increase the solubility of the diazonium salt in the
reaction medium and improve its handling during the process.
However, elevated temperatures may result in some loss of the
diazonium salt due to other decomposition processes.
[0045] Reagents can be added to form the diazonium salt in situ, to
a suspension of carbon black in the reaction medium, for example,
water. Thus, a carbon black suspension to be used may already
contain one or more reagents to generate the diazonium salt and the
process accomplished by adding the remaining reagents.
[0046] Reactions to form a diazonium salt are compatible with a
large variety of functional groups commonly found on organic
compounds. Thus, only the availability of a diazonium salt for
reaction with a carbon black limits the processes of the
invention.
[0047] The processes can be carried out in any reaction medium
which allows the reaction between the diazonium salt and the carbon
black to proceed. Preferably, the reaction medium is a
solvent-based system. The solvent may be a protic solvent, an
aprotic solvent, or a mixture of solvents. Protic solvents are
solvents, like water or methanol, containing a hydrogen attached to
an oxygen or nitrogen and thus are sufficiently acidic to form
hydrogen bonds. Aprotic solvents are solvents which do not contain
an acidic hydrogen as defined above. Aprotic solvents include, for
example, solvents such as hexanes, tetrahydrofuran (THF),
acetonitrile, and benzonitrile. For a discussion of protic and
aprotic solvents see Morrison and Boyd, Organic Chemistry 5th Ed.,
pp. 228-231, (Allyn and Bacon, Inc. 1987).
[0048] The processes are preferably carried out in a protic
reaction medium, that is, in a protic solvent alone or a mixture of
solvents which contains at least one protic solvent. Preferred
protic media include, but are not limited to water, aqueous media
containing water and other solvents, alcohols, and any media
containing an alcohol, or mixtures of such media.
[0049] The reaction between a diazonium salt and a carbon black can
take place with any type of carbon black, for example, in fluffy or
pelleted form. In one embodiment designed to reduce production
costs, the reaction occurs during a process for forming carbon
black pellets. For example, a carbon black product of the invention
can be prepared in a dry drum by spraying a solution or slurry of a
diazonium salt onto a carbon black. Alternatively, the carbon black
product can be prepared by pelletizing a carbon black in the
presence of a solvent system, such as water, containing the
diazonium salt or the reagents to generate the diazonium salt in
situ. Aqueous solvent systems are preferred. Accordingly, another
embodiment provides a process for forming a pelletized carbon black
comprising the steps of. introducing a carbon black and an aqueous
slurry or solution of a diazonium salt into a pelletizer, reacting
the diazonium salt with the carbon black to attach an organic group
to the carbon black, and pelletizing the resulting carbon black
having an attached organic group. The pelletized carbon black
product may then be dried using conventional techniques.
[0050] In general, the processes produce inorganic by-products,
such as salts. In some end uses, such as those discussed below,
these by-products may be undesirable. Several possible ways to
produce a carbon black product without unwanted inorganic
by-products or salts are as follows:
[0051] First, the diazonium salt can be purified before use by
removing the unwanted inorganic by-product using means known in the
art. Second, the diazonium salt can be generated with the use of an
organic nitrite as the diazotization agent yielding the I
corresponding alcohol rather than an inorganic salt. Third, when
the diazonium salt is generated from an amine having an acid group
and aqueous NO.sub.2, no inorganic salts are formed. Other ways may
be known to those of skill in the art.
[0052] In addition to the inorganic by-products, a process may also
produce organic by-products. They can be removed, for example, by
extraction with organic solvents. Other ways of obtaining products
without unwanted organic by-products may be known to those of skill
in the art and include washing or removal of ions by reverse
osmosis.
[0053] The reaction between a diazonium salt and a carbon black
forms a carbon black product having an organic group attached to
the carbon black. The diazonium salt may contain the organic group
to be attached to the carbon black. It may be possible to produce
the carbon black products of this invention by other means known to
those skilled in the art.
[0054] The organic group may be an aliphatic group, a cyclic
organic group, or an organic compound having an aliphatic portion
and a cyclic portion. As discussed above, the diazonium salt
employed in the processes can be derived from a primary amine
having one of these groups and being capable of forming, even
transiently, a diazonium salt. The organic group may be substituted
or unsubstituted, branched or unbranched. Aliphatic groups include,
for example, groups derived from alkanes, alkenes, alcohols,
ethers, aldehydes, ketones, carboxylic acids, and carbohydrates.
Cyclic organic groups include, but are not limited to, alicyclic
hydrocarbon groups (for example, cycloalkyls, cycloalkenyls),
heterocyclic hydrocarbon groups (for example, pyrrolidinyl,
pyrrolinyl, piperidinyl, morpholinyl, and the like), aryl groups
(for example, phenyl, naphthyl, anthracenyl, and the like), and
heteroaryl groups (imidazolyl, pyrazolyl, pyridinyl, thienyl,
thiazolyl, furyl, indolyl, and the like). As the steric hinderance
of a substituted organic group increases, the number of organic
groups attached to the carbon black from the reaction between the
diazonium salt and the carbon black may be diminished.
[0055] When the organic group is substituted, it may contain any
functional group compatible with the formation of a diazonium salt.
Preferred functional groups include, but are not limited to, R, OR,
COR, COOR, OCOR, carboxylate salts such as COOLi, COONa, COOK,
COO.sup.-NR.sub.4.sup.+, halogen, CN, NR.sub.2, SO.sub.3H,
sulfonate salts such as SO.sub.3Li, SO.sub.3Na, SO.sub.3K,
SO.sub.3.sup.-NR.sub.4.s- up.+, OSO.sub.3H, OSO.sub.3.sup.- salts,
NR(COR), CONR.sub.2, NO.sub.2, PO.sub.3H.sub.2, phosphonate salts
such as PO.sub.3HNa and PO.sub.3Na.sub.2, phosphate salts such as
OPO.sub.3HNa and OPO.sub.3Na.sub.2, N.dbd.NR,
NR.sub.3.sup.+X.sup.-, PR.sub.3.sup.+X.sup.-, S.sub.kR, SSO.sub.3H,
SSO.sub.3.sup.- salts, SO.sub.2NRR', SO.sub.2SR, SNRR', SNQ,
SO.sub.2NQ, CO.sub.2NQ, S-(1,4-piperazinediyl)-SR,
2-(1,3-dithianyl) 2-(1,3-dithiolanyl), SOR, and SO.sub.2R. R and
R', which can be the same or different, are independently hydrogen,
branched or unbranched C.sub.1-C.sub.20 substituted or
unsubstituted, saturated or unsaturated hydrocarbon, e.g., alkyl,
alkenyl, alkynyl, substituted or unsubstituted aryl, substituted or
unsubstituted heteroaryl, substituted or unsubstituted alkylaryl,
or substituted or unsubstituted arylalkyl. The integer k ranges
from 1-8 and preferably from 2-4. The anion X.sup.- is a halide or
an anion derived from a mineral or organic acid. Q is
(CH.sub.2).sub.w, (CH.sub.2).sub.xO(CH.sub.2).sub.z,
(CH.sub.2).sub.xNR(CH.sub.2).sub.z, or
(CH.sub.2).sub.xS(CH.sub.2).sub.z, where w is an integer from 2 to
6 and x and z are integers from 1 to 6.
[0056] A preferred organic group is an aromatic group of the
formula A.sub.yAr--, which corresponds to a primary amine of the
formula A.sub.yArNH.sub.2. In this formula, the variables have the
following meanings: Ar is an aromatic radical such as an aryl or
heteroaryl group. Preferably, Ar is selected from the group
consisting of phenyl, naphthyl, anthracenyl, phenanthrenyl,
biphenyl, pyridinyl, benzothiadiazolyl, and benzothiazolyl; A is a
substituent on the aromatic radical independently selected from a
preferred functional group described above or A is a linear,
branched or cyclic hydrocarbon radical (preferably containing 1 to
20 carbon atoms), unsubstituted or substituted with one or more of
those functional groups; and y is an integer from 1 to the total
number of --CH radicals in the aromatic radical. For instance, y is
an integer from 1 to 5 when Ar is phenyl, 1 to 7 when Ar is
naphthyl, 1 to 9 when Ar is anthracenyl, phenanthrenyl, or
biphenyl, or 1 to 4 when Ar is pyridinyl. In the above formula,
specific examples of R and R' are NH.sub.2--C.sub.6H.sub.4--,
CH.sub.2CH.sub.2--C.sub.6H.sub.4--NH.sub.2,
CH.sub.2--C.sub.6H.sub.4--NH.sub.2, and C.sub.6H.sub.5.
[0057] Another preferred set of organic groups which may be
attached to the carbon black are organic groups substituted with an
ionic or an ionizable group as a functional group. An ionizable
group is one which is capable of forming an ionic group in the
medium of use. The ionic group may be an anionic group or a
cationic group and the ionizable group may form an anion or a
cation.
[0058] Ionizable functional groups forming anions include, for
example, acidic groups or salts of acidic groups. The organic
groups, therefore, include groups derived from organic acids.
Preferably, when it contains an ionizable group forming an anion,
such an organic group has a) an aromatic group and b) at least one
acidic group having a pKa of less than 11, or at least one salt of
an acidic group having a pKa of less than 11, or a mixture of at
least one acidic group having a pKa of less than 11 and at least
one salt of an acidic group having a pKa of less than 11. The pKa
of the acidic group refers to the pKa of the organic group as a
whole, not just the acidic substituent. More preferably, the pKa is
less than 10 and most preferably less than 9. Preferably, the
aromatic group of the organic group is directly attached to the
carbon black. The aromatic group may be further substituted or
unsubstituted, for example, with alkyl groups. More preferably, the
organic group is a phenyl or a naphthyl group and the acidic group
is a sulfonic acid group, a sulfinic acid group, a phosphonic acid
group, or a carboxylic acid group. Examples of these acidic groups
and their salts are discussed above. Most preferably, the organic
group is a substituted or unsubstituted sulfophenyl group or a salt
thereof; a substituted or unsubstituted (polysulfo)phenyl group or
a salt thereof; a substituted or unsubstituted sulfonaphthyl group
or a salt thereof; or a substituted or unsubstituted
(polysulfo)naphthyl group or a salt thereof. A preferred
substituted sulfophenyl group is hydroxysulfophenyl group or a salt
thereof.
[0059] Specific organic groups having an ionizable functional group
forming an anion (and their corresponding primary amines) are
p-sulfophenyl (p-sulfanilic acid), 4-hydroxy-3-sulfophenyl
(2-hydroxy-5-amino-benzenesulfonic acid), and 2-sulfoethyl
(2-aminoethanesulfonic acid). Other organic groups having ionizable
functional groups forming anions can also be used.
[0060] Amines represent examples of ionizable functional groups
that form cationic groups. For example, amines may be protonated to
form ammonium groups in acidic media. Preferably, an organic group
having an amine substituent has a pKb of less than 5. Quaternary
ammonium groups (--NR.sub.3.sup.+) and quaternary phosphonium
groups (--PR.sub.3.sup.+) also represent examples of cationic
groups. Preferably, the organic group contains an aromatic group
such as a phenyl or a naphthyl group and a quaternary ammonium or a
quaternary phosphonium group. The aromatic group is preferably
directly attached to the carbon black. Quaternized cyclic amines,
and even quaternized aromatic amines, can also be used as the
organic group. Thus, N-substituted pyridinium compounds, such as
N-methyl-pyridyl, can be used in this regard. Examples of organic
groups include, but are not limited to,
(C.sub.5H.sub.4N)C.sub.2H.sub.5.sup.+,
C.sub.6H.sub.4(NC.sub.5H.sub.5).sup.+,
C.sub.6H.sub.4COCH.sub.2N(CH.sub.3- ).sub.3.sup.+,
C.sub.6H.sub.4COCH.sub.2(NC.sub.5H.sub.5).sup.+,
(C.sub.5H.sub.4N)CH.sub.3.sup.+, and
C.sub.6H.sub.4CH.sub.2N(CH.sub.3).su- b.3.sup.+.
[0061] An advantage of the carbon black products having an attached
organic group substituted with an ionic or an ionizable group is
that the carbon black product may have increased water
dispersibility relative to the corresponding untreated carbon
black. Water dispersibility of a carbon black product increases
with the number of organic groups attached to the carbon black
having an ionizable group or the number of ionizable groups
attached to a given organic group. Thus, increasing the number of
ionizable groups associated with the carbon black product should
increase its water dispersibility and permits control of the water
dispersibility to a desired level. It can be noted that the water
dispersibility of a carbon black product containing an amine as the
organic group attached to the carbon black may be increased by
acidifying the aqueous medium.
[0062] Because the water dispersibility of the carbon black
products depends to some extent on charge stabilization, it is
preferable that the ionic strength of the aqueous medium be less
than 0.1 molar. More preferably, the ionic strength is less than
0.01 molar.
[0063] When such a water dispersible carbon black product is
prepared, it is preferred that the ionic or ionizable groups be
ionized in the reaction medium. The resulting product solution or
slurry may be used as is or diluted prior to use. Alternatively,
the carbon black product may be dried by techniques used for
conventional carbon blacks. These techniques include, but are not
limited to, drying in ovens and rotary kilns. Overdrying, however,
may cause a loss in the degree of water dispersibility.
[0064] In addition to their water dispersibility, carbon black
products having an organic group substituted with an ionic or an
ionizable group may also be dispersible in polar organic solvents
such as dimethylsulfoxide (DMSO), and formamide. In alcohols such
as methanol or ethanol, use of complexing agents such as crown
ethers increases the dispersibility of carbon black products having
an organic group containing a metal salt of an acidic group.
[0065] Aromatic sulfides encompass another group of preferred
organic groups. Carbon black products having aromatic sulfide
groups are particularly useful in rubber compositions. These
aromatic sulfides can be represented by the formulas
Ar(CH.sub.2).sub.qS.sub.k(CH.sub.2).sub.rA- r' or
A--(CH.sub.2).sub.qS.sub.k(CH.sub.2).sub.rAr" wherein Ar and Ar'
are independently substituted or unsubstituted arylene or
heteroarylene groups, Ar" is an aryl or heteroaryl group, k is 1 to
8 and q and r are 0-4. Substituted aryl groups would include
substituted alkylaryl groups. Preferred arylene groups include
phenylene groups, particularly p-phenylene groups, or
benzothiazolylene groups. Preferred aryl groups include phenyl,
naphthyl and benzothiazolyl. The number of sulfurs present, defined
by k preferably ranges from 2 to 4. Preferred carbon black products
are those having an attached aromatic sulfide organic group of the
formula --(C.sub.6H.sub.4)--S.sub.k--(C.sub.6H.sub.4)--, where k is
an integer from 1 to 8, and more preferably where k ranges from 2
to 4. Particularly preferred aromatic sulfide groups are
bis-para-(C.sub.6H.sub.4)--S.sub.2--(C.sub.6H.sub.4)-- and
para-(C.sub.6H.sub.4)--S.sub.2--(C.sub.6H.sub.5). The diazonium
salts of these aromatic sulfide groups may be conveniently prepared
from their corresponding primary amines,
H.sub.2N--Ar--S.sub.k--Ar'--NH.sub.2 or H.sub.2N--Ar--S.sub.k--Ar".
Preferred groups include dithiodi-4,1-phenylene,
tetrathiodi-4,1-phenylene, phenyldithiophenyl ene,
dithiodi-4,1-(3-chlorophenylene),
--(4-C.sub.6H.sub.4)--S--S--(2-C.s- ub.7H.sub.4NS),
--(4-C.sub.6H.sub.4)--S--S--(4-C.sub.6H.sub.4)--OH,
-6-(2-C.sub.7H.sub.3NS)--SH,
--(4-C.sub.6H.sub.4)--CH.sub.2CH.sub.2--S--S-
--CH.sub.2CH.sub.2--(4-C.sub.6H.sub.4)--,
--(4-C.sub.6H.sub.4)--CH.sub.2CH-
.sub.2--S--S--S--CH.sub.2CH.sub.2--(4-C.sub.6H.sub.4)--,
--(2-C.sub.6H.sub.4)--S--S--(2-C.sub.6H.sub.4)--,
--(3-C.sub.6H.sub.4)--S- --S--(3-C.sub.6H.sub.4)--,
-6-(C.sub.6H.sub.3N.sub.2S), -6-(2-C.sub.7H.sub.3NS)--S--NRR' where
RR' is --CH.sub.2CH.sub.2OCH.sub.2- CH.sub.2--,
--(4-C.sub.6H.sub.4)--S--S--S--S--(4-C.sub.6H.sub.4)--,
--(4-C.sub.6H.sub.4)--CH.dbd.CH.sub.2,
--(4-C.sub.6H.sub.4)--S--SO.sub.3H- ,
--(4-C.sub.6H.sub.4)--SO.sub.2NH--(4-C.sub.6H.sub.4)--S--S--(4-C.sub.6H.-
sub.4)--NHSO.sub.2--(4-C.sub.6H.sub.4)--,
-6-(2-C.sub.7H.sub.3NS)--S--S-2-- (6-C.sub.7H.sub.3NS)--,
--(4-C.sub.6H.sub.4)--S--CH.sub.2--(4-C.sub.6H.sub- .4)--,
--(4-C.sub.6H.sub.4)--SO.sub.2--S--(4-C.sub.6H.sub.4)--,
--(4-C.sub.6H.sub.4)--CH.sub.2--S--CH.sub.2--(4-C.sub.6H.sub.4)--,
--(3-C.sub.6H.sub.4)--CH.sub.2--S--CH.sub.2--(3-C.sub.6H.sub.4)--,
--(4-C.sub.6H.sub.4)--CH.sub.2--S--S--CH.sub.2--(4-C.sub.6H.sub.4)--,
--(3-C.sub.6H.sub.4)--CH.sub.2--S--S--CH.sub.2--(3-C.sub.6H.sub.4)--,
--(4-C.sub.6H.sub.4)--S--NRR' where RR' is
--CH.sub.2CH.sub.2OCH.sub.2CH.- sub.2--,
--(4-C.sub.6H.sub.4)--SO.sub.2NH--CH.sub.2CH.sub.2--S--S--CH.sub.-
2CH.sub.2--NHSO.sub.2--(4-C.sub.6H.sub.4)--,
--(4-C.sub.6H.sub.4)-2-(1,3-d- ithianyl;), and
--(4-C.sub.6H.sub.4)--S--(1,4-piperizinediyl)-S--(4-C.sub.-
6H.sub.4)--.
[0066] Another preferred set of organic groups which may be
attached to the carbon black are organic groups having an
aminophenyl, such as (C.sub.6H.sub.4)--NH.sub.2,
(C.sub.6H.sub.4)--CH.sub.2--(C.sub.6H.sub.4)-- -NH.sub.2,
(C.sub.6H.sub.4)--SO.sub.2--(C.sub.6H.sub.4)--NH.sub.2. Preferred
organic groups also include aromatic sulfides, represented by the
formulas Ar--Se--Ar' or Ar--Sc--Ar", wherein Ar and Art are
independently arylene groups, Ar" is an aryl and n is 1 to 8.
Methods for attaching such organic groups to carbon black are
discussed in U.S. patent applications Ser. Nos. 08/356,660,
08/572,525, and 08/356,459, the disclosures of which are fully
incorporated by reference herein.
[0067] As stated earlier, the silicon-treated carbon black may also
be modified to have at least one organic group attached to the
silicon-treated carbon black. Alternatively, a mixture of
silicon-treated carbon black and a modified carbon black having at
least one attached organic group may be used.
[0068] Furthermore, it is within the bounds of this application to
also use a mixture of silica and silicon-treated carbon black.
Also, any combination of additional components with the
silicon-treated carbon black may be used such as one or more of the
following:
[0069] a) silicon-treated carbon black with an attached organic
group optionally treated with silane coupling agents;
[0070] b) modified carbon black having an attached organic
group;
[0071] c) silica;
[0072] d) modified silica, for example, having an attached organic
group, and/or
[0073] e) carbon black. Examples of silica include, but are not
limited to, silica, precipitated silica, amorphous silica, vitreous
silica, fumed silica, fused silica, silicates (e.g., alumino
silicates) and other Si containing fillers such as clay, talc,
wollastonite, etc. Silicas are commercially available from such
sources as Cabot Corporation under the Cab-O-Sil.RTM. tradename;
PPG Industries under the Hi-Sil and Ceptane tradenames;
Rhone-Poulenc under the Zeosil tradename; and Degussa AG under the
Ultrasil and Coupsil tradenames.
[0074] The elastomeric compounds of the present invention may be
prepared from the treated carbon blacks by compounding with any
elastomer including those useful for compounding a carbon
black.
[0075] Any suitable elastomer may be compounded with the treated
carbon blacks to provide the elastomeric compounds of the present
invention. Such elastomers include, but are not limited to,
rubbers, homo- or co-polymers of 1,3-butadiene, styrene, isoprene,
isobutylene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene,
and propylene Preferably, the elastomer has a glass transition
temperature (Tg) as measured by differential scanning colorimetry
(DSC) ranging from about -120.degree. C. to about 0.degree. C.
Examples include, but are not limited, styrene-butadiene rubber
(SBR), natural rubber, polybutadiene, polyisoprene, and their
oil-extended derivatives. Blends of any of the foregoing may also
be used.
[0076] Among the rubbers suitable for use with the present
invention are natural rubber and its derivatives such as
chlorinated rubber. The silicon-treated carbon black products of
the invention may also be used with synthetic rubbers such as:
copolymers of from about 10 to about 70 percent by weight of
styrene and from about 90 to about 30 percent by weight of
butadiene such as copolymer of 19 parts styrene and 81 parts
butadiene, a copolymer of 30 parts styrene and 70 parts butadiene,
a copolymer of 43 parts styrene and 57 parts butadiene and a
copolymer of 50 parts styrene and 50 parts butadiene; polymers and
copolymers of conjugated dienes such as polybutadiene,
polyisoprene, polychloroprene, and the like, and copolymers of such
conjugated dienes with an ethylenic group-containing monomer
copolymerizable therewith such as styrene, methyl styrene,
chlorostyrene, acrylonitrile, 2-vinyl-pyridine, 5-methyl
2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine,
alkyl-substituted acrylates, vinyl ketone, methyl isopropenyl
ketone, methyl vinyl either, alphamethylene carboxylic acids and
the esters and amides thereof such as acrylic acid and
dialkylacrylic acid amide; also suitable for use herein are
copolymers of ethylene and other high alpha olefins such as
propylene, butene-1 and pentene-1.
[0077] The rubber compositions of the present invention can
therefore contain an elastomer, curing agents, reinforcing filler,
a coupling agent, and, optionally, various processing aids, oil
extenders, and antidegradents. In addition to the examples
mentioned above, the elastomer can be, but is not limited to,
polymers (e.g., homopolymers, copolymers, and terpolymers)
manufactured from 1,3 butadiene, styrene, isoprene, isobutylene,
2,3-dimethyl-1,3 butadiene, acrylonitrile, ethylene, propylene, and
the like. It is preferred that these elastomers have a glass
transition point (Tg), as measured by DSC, between -120.degree. C.
and 0.degree. C. Examples of such elastomers include
poly(butadiene), poly(styrene-co-butadiene), and
poly(isoprene).
[0078] Elastomeric compositions also include vulcanized
compositions (VR), thermoplastic vulcanizates (TPV), thermoplastic
elastomers (TPE) and thermoplastic polyolefins (TPO). TPV, TPE, and
TPO materials are further classified by their ability to be
extruded and molded several times without loss of performance
characteristics.
[0079] In making the elastomeric compositions, one or more curing
agents such as, for example, sulfur, sulfur donors, activators,
accelerators, peroxides, and other systems used to effect
vulcanization of the elastomer composition may be used.
[0080] Formulation of the silicon-treated carbon blacks of the
present invention with elastomers are contemplated to have
advantages not realized when such elastomers are formulated with
conventional carbon blacks. Set forth below in Table 1A is a list
of certain of the elastomers which are particularly useful for
industrial rubber applications; and preferred loading ratios with
the silicon-treated carbon blacks of the present invention,
designated as parts of carbon black per hundred parts of elastomer
(PHR); contemplated benefits obtained by such composition compared
to the same composition employing a conventional carbon black; and
useful industrial applications for each composition corresponding,
where applicable, to the contemplated benefit obtained with such
composition.
1TABLE 1A FIELD OF POLYMER LOADING BENEFITS UPON FORMING
APPLICATION Ethylene Propylele 50-250 PHR INCREASED UHF HEATING
RATES WEATHERSTRIP Diene Monomer 100-200 PHR INCREASED TEAR
STRENGTH WEATHERSTRIP (EPDM) REDUCED IRIDESCENCE WEATHERSTRIP
IMPROVED HEAT AGING RESISTANCE HOSE HIGHER ELECTRICAL RESISTIVITY
HOSE INCREASED ELONGATION @ GIVEN HOSE HARDNESS LONGER FATIGUE LIFE
ENGINE MOUNTS LOWER SPRING RATIO FOR A GIVEN ENGINE MOUNTS TAN
.delta. IMPROVED RESILENCE ENGINE MOUNTS Poly-Chloroprene 10-150
phr LOWER SPRING RATIO FOR A GIVEN ENGINE MOUNTS (NEOPRENE) 20-80
phr TAN .delta. IMPROVED GLYCOL RESISTANCE SEALS IMPROVED RESILENCE
SEALS, HOSE LOWER HEAT BUILD-UP BELTS Natural Rubber 10-150 phr
LOWER SPRING RATIO FOR A GIVEN ENGINE MOUNTS (NR) 20-80 phr TAN
.delta. HIGHER CUT/CHIP RESISTANCE BELTS Hydrogenated 10-150 phr
LOWER SPRING RATIO FOR A GIVEN ENGINE MOUNTS Nitrile Butadiene
20-80 phr TAN .delta. Rubber INCREASED HIGH TEMP TEAR MOUNTS, SEALS
(HNBR) RESISTANCE IMPROVED RESILIENCE SEALS, HOSE LOWER HEAT
BUILD-UP BELTS Styrene Butadiene 10-150 phr HIGHER CUT/CHIP
RESISTANCE BELTS Rubber (SBR) Ethylene Vinyl 10-150 phr IMPROVED
PHYSICAL PROPERTIES HOSE Acetate (EVA)
[0081] It has been found that in certain tire usages, cut-chip
resistance is a necessary property, especially with regard to
trucks, for instance, travelling between pavements and dirt
surfaces. In particular, after travelling on a pavement, the tires
build up heat, which, upon entering a job site, can result in
excess cutting and chipping of the tire on a rough terrain. It has
been discovered that when the silicon-treated carbon black of the
present invention is incorporated into a tire tread compound (or
other parts of the tire including sidewalls), the heat build-up of
the tire tread characterized by tan .delta. (delta) at 70.degree.,
can be reduced, tear strength can be increased, and elongation
properties can be increased, while maintaining acceptable tensile
strength of the tread compound. With an improvement in these
properties, the cut-chip resistance of the tread can improve
substantially, resulting in a longer lasting, better performing
tire tread.
[0082] In order to improve the above-described properties, thereby
obtaining improved cut-chip resistance, the silicon-treated carbon
black of the present invention may be used in a blend with other
fillers such as silica and carbon black, as well as with a coupling
agent.
[0083] The silicon-treated carbon blacks of the present invention
can also be used in a wire breaker compound in tires. With the use
of wire breaker compounds containing the silicon-treated carbon
blacks, excellent adhesion can be obtained to the steel cord.
Additionally, it is also possible to reduce heat buildup in this
component of the tire.
[0084] The contemplated benefits obtained with the compositions set
forth in Table 1A are characterized by expected properties compared
to the same composition made with conventional
(non-silicon-treated) carbon black. Evaluation of these properties
for a given silicon-treated carbon black/elastomer composition is
done by conducting comparative tests. Most of the properties set
forth in Table 1A are determined by routine tests known to those
skilled in the art. Other tests are briefly described below:
[0085] Hardness refers to Shore A Hardness, which is determined
according to the procedure set forth in ASTM D-2240-86.
[0086] Resilience may be determined according to the procedure set
forth in ASTM D1054, utilizing a ZWICK Rebound Resilience Tester,
Model 5109, manufactured by Zwick of America, Inc., Post Office Box
997, East Windsor, Conn. 06088.
[0087] The UHF microwave receptivity may be measured by a
Dielecmetre (supplied by Total Elastomers in France). The UHF
microwave receptivity is characterized by a coefficient, .alpha.,
which is defined as
.alpha.=(150.degree. C.-80.degree. C.)/(t.sub.150-t.sub.80)
[.degree.C/s]
[0088] where t.sub.150 and t.sub.80 are the times needed for
samples to reach 150.degree. C. and 80.degree. C. respectively. a
is the heating rate between temperatures 80.degree. and 150.degree.
C.
[0089] The electrical resistivity of the composition may be
measured by painting samples 2 inches wide by 6 inches long by
0.085 inch thick with a half inch width of silver paint. The sample
is then conditioned to produce a stable reading by cycling from
room temperature to 100.degree. C. and back to room temperature,
followed by aging at 90.degree. C. for 24 hours.
[0090] The stabilized resistivity was measured at the end of the
aging cycle, and once again after the sample was allowed to cool
back to room temperature.
[0091] The resultant elastomeric compounds containing treated
carbon black and optionally containing one or more coupling agents
may be used for various elastomeric products such as treads for
vehicle tires, industrial rubber products, seals, timing belts,
power transmission belting, and other rubber goods. When utilized
in tires, the elastomeric compounds may be used in the tread or in
other components of the tire, for example, the carcass and
sidewall.
[0092] Tread compounds produced with the present elastomeric
compounds incorporating a silicon-treated carbon black but without
a coupling agent, provide improved dynamic hysteresis
characteristics. However, elastomeric compounds incorporating a
silicon-treated carbon black and a coupling agent demonstrate
further improved characteristics when tested for dynamic hysteresis
at different temperatures and resistance to abrasion. Therefore, a
tire incorporating a tread compound manufactured with an
elastomeric compound of the present invention, incorporating both a
silicon-treated carbon black and a coupling agent will demonstrate
even lower rolling resistance, good traction and better wear
resistance when compared with a tire made with a tread compound
incorporating the treated carbon black but lacking the coupling
agent.
[0093] The following examples illustrate the invention without
limitation.
EXAMPLES
Example 1
[0094] Silicon-treated carbon blacks according to the present
invention were prepared using a pilot scale reactor generally as
described above, and as depicted in FIG. 1 and having the
dimensions set forth below: D.sub.1=4 inches, D.sub.2=2 inches,
D.sub.3=5 inches, L.sub.1=4 inches, L.sub.2=5 inches, L.sub.3=7
inches, L.sub.4=1 foot and Q=4.5 feet. The reaction conditions set
forth in Table 1 below, were employed.
[0095] These conditions result in the formation of a carbon black
identified by the ASTM designation N234. A commercially available
example of N234 is Vulcan .RTM. 7H from Cabot Corporation, Boston,
Mass. These conditions were altered by adding a volatilizable
silicon-containing compound into the reactor, to obtain a
silicon-treated carbon black. The flow rate of the volatilizable
compound was adjusted to alter the weight percent of silicon in the
treated carbon black. The weight percent of silicon in the treated
carbon black was determined by the ashing test, conducted according
to ASTM procedure D-1506.
[0096] One such new treated carbon black was made by injecting an
organo-silicon compound, namely octamethyl-cyclotetrasiloxane
(OMTS), into the hydrocarbon feedstock. This compound is sold as
"D4" by Dow Coming Corporation, Midland, Mich. The resultant
silicon-treated carbon black is identified herein as OMTS-CB. A
different silicon-treated carbon black (TEOS-CB) was prepared by
introducing a second silicon-containing volatilizable compound,
tetraethoxy silane, (sold as TEOS, by Huls America, Piscataway,
N.J.), into the hydrocarbon feedstock.
[0097] Since changes in reactor temperature are known to alter the
surface area of the carbon black, and reactor temperature is very
sensitive to the total flow rate of the feedstock in the injection
zone (zone 3 in FIG. 1), the feedstock flow rate was adjusted
downward to approximately compensate for the introduction of the
volatilizable silicon-containing compound, such that a constant
reactor temperature was maintained. This results in an
approximately constant external surface area (as measured by t
area) for the resultant carbon blacks. All other conditions were
maintained as necessary for manufacturing N234 carbon black. A
structure control additive (potassium acetate solution) was
injected into the feedstock to maintain the specification structure
of the N234 carbon black. The flow rate of this additive was
maintained constant in making the silicon-treated carbon blacks
described throughout the following examples.
[0098] The external surface area (t-area) was measured following
the sample preparation and measurement procedure described in ASTM
D3037-Method A for Nitrogen surface area. For this measurement, the
nitrogen adsorption isotherm was extended up to 0.55 relative
pressure. The relative pressure is the pressure (P) divided by the
saturation pressure (P.sub.0) (the pressure at which the nitrogen
condenses). The adsorption layer thickness (t.sub.1) was then
calculated using the relation: 1 t 1 = 13.99 0.034 - log ( P / P 0
) ]
[0099] The volume (V) of nitrogen adsorbed was then plotted against
t.sub.1. A straight line was then fitted through the data points
for t.sub.1 values between 3.9 and 6.2 Angstroms. The t-area was
then obtained from the slope of this line as follows:
t-area, m.sup.2/gm=15.47.times.slope
2TABLE 1 Carbon Black Conditions N234 TEOS-CB OMTS-CB Air Rate,
kscfh 12.8 12.8 12.8 Gas Rate, kscfh 0.94 0.94 0.94 feedstock rate,
lbs/hr 166 139 155 Si compound rate, lbs/hr 0 16 5
[0100] The resultant carbon blacks were analyzed for surface area
and silicon content. These values are set forth in Table 2
below:
3TABLE 2 Carbon Black Properties N234 TEOS-CB OMTS-CB % Silicon in
Carbon Black 0.02 2.85 2.08 DBP, cc/100 g 125.0 114.0 115.0 CDBP,
cc/100 g 101.5 104.1 103.5 t-Area, m.sup.2/g 117.0 121.0 121.0
N.sub.2 area, m.sup.2/g 120.4 136.0 133.0
Example 2
[0101] A scanning transmission electron microscope (STEM) coupled
to an energy dispersive X-ray analyzer, was used to further
characterize the silicon-treated carbon black. The following Table
3 compares N234, OMTS-CB (prepared according to Example 1) and N234
to which 3.7% by weight silica (L90, sold as CAB-O-SIL.RTM. L90, by
Cabot Corporation, Boston, Mass.) was added to form a mixture. As
described below, the STEM system may be used to examine an
individual aggregate of carbon black for elemental composition. A
physical mixture of carbon black and silica will result in the
identification of silica aggregates which show mostly silicon
signal and little or background carbon signal. Thus, when multiple
aggregates are examined in a mixture, some of the aggregates will
show a high Si/C signal ratio, corresponding to aggregates of
silica.
[0102] Five mg of carbon black was dispersed into 20 ml of
chloroform and subjected to ultrasonic energy using a probe
sonicator (W-385Heat Systems Ultra Sonicator). A 2 ml aliquot was
then dispersed into 15 ml of chloroform using a probe sonicator for
three minutes. The resulting dispersion was placed on a 200 mesh
nickel grid with aluminum substrate. The grid was then placed under
a Fisons EB501 Scanning Transmission Electron Microscope (Fisons,
West Sussex, England) equipped with an Oxford Link AN10000 Energy
Dispersive X-ray Analyzer (Oxford Link, Concord, Mass.).
[0103] Initially the grid was scanned for potential silica
aggregates at low magnification (less than 200,000.times.). This
was done by searching for aggregates that had a Si/C count ratio
greater than unity. After this initial scan, typically thirty
aggregates were selected for detailed analysis at higher
magnification (from between 200,000.times. and 2,000,000.times.).
The selected aggregates included all of the aggregates which
contained Si/C count ratios greater than unity, as identified by
the initial scan. The highest ratios of Si/C counts thus determined
are set forth in Table 3 for N234, OMTS-CB and a mixture of N234
and silica.
4TABLE 3 Ratio of Si/C Signal Measured with STEM Highest Ratio of %
Si in Si/C Counts per Modified Sample Aggregate N234 0 0.02 OMTS-CB
3.28 0.27 N234 + 3.7% silica (L90) 1.7 49
[0104] Thus, a well dispersed mixture of carbon black and silica
having the same silicon content as the OMTS-CB shows 180 times
higher peak Si/C counts. This data shows that the OMTS-CB carbon
black is not a simple physical mixture of silica and carbon black,
but rather that the silicon is a part of the intrinsic chemical
nature of the carbon black.
Example 3
[0105] HF Treatment
[0106] Hydrofluoric acid (HF) is able to dissolve silicon compounds
but does not react with carbon. Thus, if either a conventional
(untreated) carbon black or a mixture of silica and carbon black is
treated with HF, the surface and surface area of the carbon black
will remain unchanged, because it is unaffected by the dissolution
of the silicon compounds removed from the mixture. However, if
silicon containing species are distributed throughout at least a
portion, including the surface, of the carbon black aggregate, the
surface area will markedly increase as micropores are formed as the
silicon compound is dissolved out of the carbon black
structure.
[0107] Five grams of the carbon black to be tested were extracted
with 100 ml of 10% v/v hydrofluoric acid for 1 hour. The silicon
content and nitrogen surface area were measured before and after
the HF treatment. The results are shown in Table 4.
5TABLE 4 HF Treatment % Si % Si N.sub.2SA N.sub.2SA Before HF After
HF Before HF After HF Treatment Treatment Treatment Treatment N234
0.02 0.05 123 123 OMTS-CB 3.3 0.3 138 180
[0108] Photomicrographs were taken of the carbon black samples
before and after HF treatment. The photomicrographs are shown in
FIGS. 4a-4d. These photographs show that the silicon-treated carbon
blacks have a rougher surface, consistent with increased
microporosity after the HF treatment, compared to the untreated
carbon black.
Example 3A
[0109] Another silicon-treated carbon black was made by injecting
TEOS into the reaction zone of the reactor immediately (one foot)
downstream from the hydrocarbon feedstock injection plane, as
indicated at injection point 12 in FIG. 1. All other reaction
conditions were maintained as required for manufacturing N234
black, as described in Example 1. The TEOS flow rate was adjusted
to 17.6 lbs per hour.
[0110] The resultant black was analyzed for silicon content and
surface area, before and after HF extraction as described in
Example 3. The results are described in Table 4A.
6TABLE 4A TEOS-CB' - manufactured by injection of TEOS into
reaction zone % Si N.sub.2Area Before HF 2.27 127.7 After HF 0.04
125.8
[0111] Thus, no increase in N.sub.2 surface area was seen after HF
extraction of the TEOS-CB'. Analysis of the aggregates by the STEM
procedure described in Example 2 also showed silicon to be present
in the aggregates and not as independent silica entities. These
results show that in this case the silicon-containing species of
the silicon-treated carbon blacks are primarily located near the
surface.
Example 4
[0112] Preparation of Elastomeric Compositions
[0113] The carbon blacks of the previous Examples were used to make
elastomeric compounds. Elastomeric compositions incorporating the
silicon-treated carbon blacks discussed above, were prepared using
the following elastomers: solution SBR (Duradene 715 and Cariflex
S-1215, from Firestone Synthetic Rubber & Latex Co., Akron,
Ohio), functionalized solution SBR (NS 114 and NS 116 from Nippon
Zeon Co., SL 574 and T0589 from Japan Synthetic Rubber Co.),
emulsion SBR (SBR 1500, from Copolymer Rubber & Chemicals,
Corp., Baton Rouge, La.), and natural rubber (SMR5, from
Malaysia).
[0114] The elastomeric compositions were prepared according to the
following formulation:
7 TABLE 5 Ingredient Parts by weight elastomer 100 carbon black 50
zinc oxide 3 stearic acid 2 Flexzone 7P .RTM. 1 Durax .RTM. 1.25
Captax .RTM. 0.2 sulfur 1.75 Si-69 (optional) 3 or 4
[0115] Flexzone 7P.RTM., N-(1,3-dimethyl
butyl)-N'-phenyl-p-phenylene diamine, is an anti-oxidant available
from Uniroyal Chemical Co., Middlebury, Conn. Durax.RTM.,
N-cyclohexane-2 -benzothiazole sulphenamide, is an accelerator
available from R.T. Vanderbilt Co., of Norwalk, Conn., and
Captax.RTM., 2-mercaptobenzothiazole, is an accelerator available
from R.T. Vanderbilt Co.
[0116] The elastomeric compounds were prepared using a two-stage
mixing procedure. The internal mixer used for preparing the
compounds was a Plasti-Corder EPL-V (obtained from C.W. Brabender,
South-Hackensack, N.J.) equipped with a cam-type mixing head
(capacity 600 ml). In the first stage, the mixer was set at
80.degree. C., and the rotor speed was set at 60 rpm. After the
mixer was conditioned to 100.degree. C. by heating the chamber with
a dummy mixture, the elastomer was loaded and masticated for 1
minute. Carbon black, pre-blended with zinc oxide (obtained from
New Jersey Zinc Co., New Jersey), and optionally a coupling agent,
was then added. After three minutes, stearic acid (obtained from
Emery Chemicals, Cincinnati, Ohio) and anti-oxidant were added.
Mixing was continued for an additional two minutes. The stage 1
masterbatch was then dumped from the mixer at five minutes total.
This was then passed through an open mill (four inch, two-roll
mill, obtained from C.W. Brabender, South Hackensack, N.J.) three
times and stored at room temperature for two hours.
[0117] In the second stage, the mixing chamber temperature was set
to 80.degree. C. and the rotor speed was set to 35 rpm. After the
mixer was conditioned the masterbatch from stage one was loaded and
mixed for one minute. The curative package (including sulfur, Durax
and Captax) was then added. The material was dumped from the mixer
at two minutes and passed through the open mill three times.
[0118] Batches of the compounds were prepared as described for the
carbon blacks in the previous Examples. The same grade of
conventional carbon black was used as a control. For each carbon
black, two batches were prepared. The first batch was made using
Si-69 as the coupling agent. The second batch was made without a
coupling agent. After mixing, each of the elastomeric compositions
was cured at 145.degree. C. to an optimum cure state according to
measurements made with a Monsanto ODR Rheometer.
[0119] Elastomeric compounds employing the elastomers set forth in
Table 1A may be formulated by following the foregoing
procedure.
Example 5
[0120] Bound Rubber Test
[0121] The bound rubber content of an elastomeric compound
incorporating carbon black can be taken as a measure of the surface
activity of the carbon black. The higher the bound rubber content,
the higher the surface activity of the carbon black.
[0122] Bound rubber was determined by extraction of an elastomeric
compound with toluene at room temperature. The bound rubber is the
elastomer remaining after extraction by the solvent. The elastomer
used was solution SBR (SSBR) Duradene 715 without a coupling agent,
as described above in Example 4.
[0123] As seen in FIG. 2, the bound rubber was determined for a
series of blends of silica and carbon black, which serve as a
reference against which to compare the bound rubber of the
silicon-treated carbon black. The results of the bound rubber
measurements for the two sets of compounds are plotted against
their equivalent silica content in FIG. 2. For the treated carbon
blacks, the equivalent silica content is a theoretical value
calculated from the total silicon as measured by ashing. It is seen
that silicon-treated carbon blacks yield a higher bound rubber than
their conventional counterparts. This suggests that the treated
carbon black surface is relatively more active. Moreover, as shown
in FIG. 2, the bound rubber content of treated carbon black-filled
compounds lie well above the reference line generated from the
blends of carbon black and silica. This confirms that the treated
carbon black is not a physical mixture of silica and carbon
black.
Example 6
[0124] Dynamic Hysteresis and Abrasion Resistance
[0125] The dynamic hysteresis and abrasion resistance rates were
measured for the elastomeric compositions produced according to
Example 4 above.
[0126] Abrasion resistance was determined using an abrader, which
is based on a Lamboum-type machine as described in U.S. Pat. No.
4,995,197, hereby incorporated by reference. The tests were carried
out at 14% slip. The percentage slip is determined based on the
relative velocities of a sample wheel and a grindstone wheel. The
abrasion resistance index is calculated from the mass loss of the
elastomeric compound. Dynamic properties were determined using a
Rheometrics Dynamic Spectrometer II (RDS II, Rheometrics, Inc.,
N.J.) with strain sweep. The measurements were made at 0 and
70.degree. C. with strain sweeps over a range of double strain
amplitude (DSA) from 0.2 to 120%. The maximum tan .delta. values on
the strain sweep curves were taken for comparing the hysteresis
among elastomeric compounds as can be seen in FIGS. 3a and 3b.
Alternatively, hysteresis measurements were made by means of
temperature sweeps at a DSA of 5% and a frequency of 10 Hz. The
temperature range was from -60.degree. C. to 100.degree. C., as
seen in FIG. 3c.
8TABLE 6 Dynamic Hysteresis Data tan .delta. tan .delta. abrasion
at SSBR Composition.sup.a Si-69 at 0.degree. C. at 70.degree. C.
14% slip N234 0 0.400 0.189 100 N234 3 0.429 0.170 103.5 OMTS-CB 0
0.391 0.175 84.4 OMTS-CB 3 0.435 0.152 110.5 TEOS-CB 0 0.400 0.167
78.1 TEOS-CB 3 0.433 0.142 97.2 .sup.aDuradene 715; two stage
mixing.
[0127] As seen in Table 6 above, tan .delta. at 70.degree. C.
values were reduced by 7%, tan .delta. at 0.degree. C. values
reduced by 2.3% and the wear resistance was reduced by 15%, for the
SSBR samples when OMTS-CB was substituted for N234.However, when
the Si-69 coupling agent was incorporated into the composition, the
wear resistance for the OMTS-CB sample improved to 110% of the
value for N234. The tan .delta. at 70.degree. C. values decreased
by 19.6% compared to N234 without coupling agent and 10.5% compared
to N234 with coupling agent. The tan .delta. at 0.degree. C. values
increased by 11% when the coupling agent was added to the OMTS-CB,
compared to OMTS-CB without coupling agent. Similarly, for TEOS-CB,
the tan .delta. at 70.degree. C. value is reduced by 11.6%, the tan
.delta. at 0.degree. C. value is unchanged and the wear is reduced
by 21.9%. When compounded with the coupling agent, the tan .delta.
at 70.degree. C. value is reduced by 24.9%, the tan .delta. at
0.degree. C. value is increased by 8.3% and the wear decreased by
only 2.8%.
[0128] It was determined that employing the treated carbon blacks
and an elastomer in an elastomeric composition of the present
invention generally resulted in poor abrasion resistance, compared
to an elastomeric composition including the same elastomer and N234
carbon black. However, as seen in Table 6, when Si-69 coupling
agent was incorporated into the composition, abrasion resistance
returned to approximately the same values as obtained with
untreated carbon black.
[0129] As used herein, "untreated carbon black" means a carbon
black prepared by a process similar to that used to prepare the
corresponding treated black, but without the volatizable silicon
compound and by making suitable adjustments to the process
conditions to achieve a carbon black with an external surface area
approximately equal to that of the treated black.
Example 6A
[0130] The dynamic hysteresis and abrasion properties of a black
made by following the procedure of Example 3A (and containing 1.91%
Si) were measured as in Example 6. As seen in Table 6A below, tan
.delta. at 70.degree. C. values were reduced by 14%, tan .delta. at
0.degree. C. values were reduced by 6% and the wear resistance was
reduced by 22%, for the SSBR samples when TEOS-CB was substituted
for N234.However, when Si69 coupling agent was incorporated into
the composition, the wear resistance for the TEOS-CB sample
improved to 108% of the value for N234. The tan .delta. at
70.degree. C. values decreased by 18% compared to N234 without
coupling agent and 7% compared to N234 with coupling agent. The tan
.delta. at 0.degree. C. values decreased by only 1.5% when the
coupling agent was added to TEOS-CB, compared to N234 with coupling
agent.
9TABLE 6A Dynamic Hysteresis Data SSBR Abrasion Composition.sup.a
Si 69 tan .delta. @ 0.degree. C. tan .delta. @ 70.degree. C. @ 14%
Slip N234 0 0.428 0.184 100 N234 4 0.394 0.162 94 TEOS-CB 0 0.402
0.158 78 TEOS-CB 4 0.388 0.151 108 .sup.aCariflex S-1215; two stage
mixing
Example 7
[0131] Improvement in Hysteresis by Three Stage Compounding
[0132] The beneficial properties obtained using the treated carbon
blacks with the elastomeric compounds of the present invention may
be further enhanced by using an additional mixing stage during the
compounding process. The procedure for two stage mixing used in the
previous compounding examples, is described above in Example 4.
[0133] For three stage mixing, the stage 1 mixer was set at
80.degree. C. and 60 rpm. After conditioning to 100.degree. C. by
heating the chamber with a dummy mixture, the elastomer was
introduced to the mixer at 100.degree. C. and masticated for one
minute. The carbon black was added to the elastomer and mixing
continued for an additional three minutes. In some cases, a
coupling agent was also added with the carbon black, at a rate of 3
to 4 parts per hundred of elastomer. The stage 1 masterbatch was
then dumped and passed through an open mill three times and stored
at room temperature for 2 hours. The second stage chamber
temperature was also set at 80.degree. C. and 60 rpm. After
conditioning to 100.degree. C., the masterbatch was introduced to
the mixer, masticated for one minute, and the antioxidant was then
added. At four minutes or when a temperature of 160.degree. C. is
reached, the stage 2 masterbatch was dumped and passed through the
open mill 3 times and stored at room temperature for 2 hours. The
third stage chamber temperature was set at 80.degree. C. and 35
rpm. The masterbatch from stage 2 was then added to the mixer and
masticated for 1 minute. The curing package was then added and the
stage 3 material was dumped at 2 minutes and passed through an open
mill 3 times.
[0134] Table 7 below compares hysteresis and abrasion
characteristics for elastomers compounded with TEOS-CB using two
and three stage mixing. As can be seen from the Table, three stage
mixing results in higher tan .delta. at 0.degree. C. and lower tan
.delta. at 70.degree. C. Elastomeric compounds employing the
elastomer set forth in Table 1A may be formulated by following the
foregoing procedure.
10TABLE 7 Dynamic Hysteresis Data - 2 Stage v. 3 Stage Mixing tan
.delta. tan .delta. abrasion at Carbon Black Si-69 at 0.degree. C.
at 70.degree. C. 14% slip Duradene 715 Two Stage Mixing N234 0
0.458 0.189 100 N234 3 0.439 0.170 103.5 TEOS-CB 0 0.434 0.150 78.1
TEOS-CB 3 0.436 0.131 97.2 Duradene 715 Three Stage Mixing N234 0
0.471 0.165 100 N234 3 0.456 0.146 98.4 TEOS-CB 0 0.446 0.139 57.6
TEOS-CB 3 0.461 0.113 101.8
Example 8
[0135] Oxidized Carbon Black
[0136] In another aspect of the present invention, it was
determined by the present inventors that oxidation of the
silicon-treated carbon black can lead to elastomeric compositions
with enhanced hysteresis. For a black made using the conditions of
Table 1, but with OMTS as the volatilizable silicon-containing
compound, and 2.74% silicon in the final black, the improvement
obtained with oxidation is illustrated in the following Table. The
hysteresis performance with the oxidized black is further enhanced
by incorporating a coupling agent into the elastomeric
compound.
[0137] The oxidized carbon black was prepared by treating the black
with nitric acid. A small stainless steel drum was loaded with
carbon black and rotated. During rotation a 65% nitric acid
solution is sprayed onto the carbon black, until 15 parts per
hundred carbon black had been added. After a soak period of 5
minutes, the drum was heated to about 80.degree. C. to initiate the
oxidation reaction. During the oxidation reaction, the temperature
increased to about 100-120.degree. C. This temperature was held
until the reaction was completed. The treated black was then heated
to 200.degree. C. to remove residual acid. The treated black was
then dried overnight at 115.degree. C. in a vacuum oven. Table 8
below compares hysteresis characteristics for elastomers compounded
with OMRS-CB and oxidized OMTS-CB, with and without a coupling
agent. Additional elastomeric compounds employing the elastomers
set forth in Table 1A may be formulated by following the foregoing
procedure.
11TABLE 8 Dynamic Hysteresis Data - oxidized, treated carbon black
Carbon Black tan .delta. tan .delta. Duradene 715 - 2 stage Si-69
at 0.degree. C. at 70.degree. C. N234 0 0.513 0.186 N234 3 0.463
0.176 OMTS-CB 0 0.501 0.166 OMTS-CB 3 0.467 0.135 oxidized OMTS-CB
0 0.487 0.154 oxidized OMTS-CB 3 0.467 0.133
Example 9
[0138] Hysteresis and Abrasion Resistance for a Variety of
Elastomers
[0139] Hysteresis and abrasion resistance was compared for
elastomeric compounds prepared with treated carbon blacks
compounded with different elastomers, compounded with and without a
coupling agent. Conventional carbon black was used as a control.
The results are set forth in the Table 9 below.
[0140] These data show hysteresis improvement for all five
elastomer systems tested. For example, the tan .delta. at
70.degree. C. is reduced by between 10.5 and 38.3% without a
coupling agent, and by between 11.7 and 28.2% with a coupling
agent, compared to the corresponding control.
[0141] It can also be seen that in all cases abrasion resistance
for the treated carbon black compound compared to the untreated
control decreases when no coupling agent is used. Abrasion
resistance is substantially improved when the coupling agent is
used. It can also be seen that the hysteresis balance is improved
with treated carbon black (with or without coupling agent),
compared to control carbon black.
12TABLE 9 Hysteresis and Abrasion Resistance - 3 Stage Mixing tan
.delta. tan .delta. wear at Carbon Black Si-69 at 0.degree. C. at
70.degree. C. 14% slip Solution SBR 116/NS 114-80/20 blend N234 0
0.689 0.151 100.0 N234 3 0.750 0.131 123.1 TEOS-CB 0 0.721 0.115
86.3 TEOS-CB 3 0.751 0.094 115.4 Solution SBR SL 574 N234 0 0.286
0.118 100.0 N234 3 0.260 0.108 96.4 TEOS-CB 0 0.246 0.101 58.0
TEOS-CB 3 0.258 0.093 86.8 Solution SBR PAT589 N234 0 0.676 0.190
100.0 N234 3 0.686 0.182 99.1 TEOS-CB 0 0.698 0.170 82.4 TEOS-CB 3
0.726 0.150 134.2 Emulsion SBR 1500 N234 0 0.299 0.176 100.0 N234 3
0.285 0.137 87.9 TEOS-CB 0 0.280 0.156 60.1 TEOS-CB 3 0.270 0.121
88.1 Natural Rubber SMR 5 N234 0 0.253 0.128 100.0 N234 3 0.202
0.088 85.8 TEOS-CB 0 0.190 0.079 60.9 TEOS-CB 3 0.173 0.069
88.6
Example 10
[0142] Cut Chip Resistance
[0143] A carbon black made as described earlier is used to make a
truck-tire tread compound. The properties of the OMTS-CB are
described in Table 10. The elastomeric composition is described in
Table 11. The mixing procedure is similar to Example 4 except that
ZnO and Circo Light Oil (obtained from Natrochem Inc., Savannah,
Ga.) were added with the stearic acid, anti-oxidants (Flexzone
7P.RTM. and AgeRite Resin D (obtained from R.T. Vanderbilt Co.,
Norwalk, Conn.)) and the wax, Sunproof Improved (obtained from
Uniroyal Chemical Co., Middlebury, Conn.).
[0144] The tensile strength and elongation at break were measured
using the method described in ASTM D-412. The tearing strength was
measured using the method described in ASTM D-624. As can be seen
from Table 12, OMTS-CB gave a 19% improvement in tear strength, a
13% improvement in elongation at break, and a 36% reduction in tan
6 at 70.degree. C. at comparable tensile strength. This shows that
the cut-chip resistance and heat build-up properties are improved
with OMTS-CB.
13 TABLE 10 OMTS-CB % Si in Carbon Black 4.62 DBP, cc/100 g 106.3
CDBP, cc/100 g 100.1 t-Area, m.sup.2/g 121.0
[0145]
14 TABLE 11 Parts By Parts By INGREDIENT Weight Weight NR (SMR5)
100 100 N234 50 -- OMTS-CB -- 50 Circo Light Oil 5.0 5.0 Zinc Oxide
5.0 5.0 Stearic Acid 3.0 3.0 Flexzone 7P .RTM. 1.5 1.5 AgeRite
Resin D 1.5 1.5 Sunproof Improved 1.5 1.5 Durax .RTM. 1.2 1.2
Sulfur 1.8 1.8
[0146]
15 TABLE 12 Tensile Strength, Elongation @ Tear Strength tan
.delta. mPa Break, % Index, % @ 70.degree. C. N234 27.2 552 100
0.133 OMTS-CB 26.9 624 119 0.086
Example 11
[0147] To evaluate the use of the silicon-treated carbon blacks of
the present invention in a wire breaker compound, the following
experiment was conducted.
[0148] Nine compounds were prepared using N 326, N 231 and the
OMTS-CB described in the previous example. The analytical
properties of these carbon blacks are described in Table 13.
16TABLE 13 CARBON BLACK ANALYTICAL PROPERTIES N326 N231 OMTS-CB
CTAB, m.sup.2/g 81 108 125 DPB absorption, cc/100 g 72 92 104 CDBP,
cc/100 g 67 86 101
[0149] Generally, heat build-up, as measured by tan .delta. at
60.degree. C., and adhesion, increases with increase in surface
area and structure.
[0150] The compound formulations are shown in Table 14. NR is SMR
CV60 (obtained from Malaysia). Silica is Hi-Sil 233 (obtained from
PPG Industries, Inc., Pittsburgh, Pa.). Naphthenic oil is a
processing agent (obtained from Harwick Chemical Corporation,
Akron, Ohio). Resorcinol is a bonding agent (obtained from Indspec
Chemical, Pittsburgh, Pa.). Cobalt naphthenate is a bonding agent
(Cobalt content 6%, obtained from the Shepard Chemical Co.,
Cincinnati, Ohio). Hexa is hexamethylenetetramine, a bonding agent
(obtained from Harwick Chemical Corporation, Akron, Ohio).
17 TABLE 14 Ingredients Parts Per Hundred NR 100 100 100 Carbon
Black 55 55 40 Precipitated Silica -- -- 15 Napthenic Oil 5 5 5 ZnO
10 10 10 Stearic Acid 2 2 2 Resorcinol -- -- 2.5 Hexa -- -- 1.6
Cobalt Naphthalene (6% Co) -- 2 -- Santocure MDR 0.8 0.8 0.8 Sulfur
4 4 4
[0151]
18TABLE 15 BONDING AGENT N326 N231 OMTS-CB SYSTEMS* CTL Co HRH CTL
Co HRH CTL Co HRH Tensile Strength, MPa 26.3 27.1 26.6 27.4 28.5
26.9 26.4 25.2 27.6 Elongation at Break, % 498 527 494 534 527 500
409 490 474 Hardness, Shore A 67 67 74 71 71 78 65 70 74 Adhesion
Strength, lb. 68 95 45 94 106 45 90 107 91 Wire Adhesion G G F G G
F G G F Appearance Rating** tan .delta. at 60.degree. C. 0.137
0.145 0.116 0.166 0.170 0.133 0.134 0.152 0.120 *Ctl-Control,
without bonding agent, Co-cobalt containing bonding agent,
HRH-silica-resorcinol-hexamethylene tetramine containing bonding
agent. **G = good covering; F = fair covering.
[0152] In the experiment, a passenger tire steel cord wire,
2.times.2.times.0.25 mm, was coated with a bran plate with 63.5% by
weight copper. The adhesion rating was made using ASTM D-2229. This
rating has two components: the force required to remove the cord
from the adhesion compound and the appearance of the removed wire.
In general, the higher the force required and the higher the rating
of the appearance, the better the adhesion.
[0153] It is seen that the OMTS-CB shows the favorable heat
build-up properties of N326 and at the same time the favorable
adhesion properties of N231.
Example 12
[0154] Generally, in the production of carbon black, alkali metal
salt additives are used to control carbon black structure, for
example CDBP. An increase in the amount of alkali metal salt added
leads to a decrease in the structure of the carbon black. Two
carbon blacks were made using the method described in Example 1.
The conditions of manufacture were:
19 TABLE 16 CONDITIONS N234 TEOS-CB Air Rate, kscfh 12.8 12.8 Gas
rate, kscfh 0.94 0.94 Feedstock Rate, lbs/hr 166 140.2 Si Compound
Rate, lbs/hr 0 17 K+ Rate, gms/hr.sup.a 0.547 0.604 .sup.aK.sup.+
injected as a Potassium Acetate solution.
[0155] The resultant carbon blacks were analyzed for surface area,
structure, and silicon content. These values are set forth in Table
17 below.
20 TABLE 17 PROPERTIES N234 TEOS-CB % Silicon in Carbon Black 0.02
3.28 CDBP, cc/100 g 103 110 t-area, m.sup.2/g 119.2 121.3
N.sub.2-area, m.sup.2/g 122.7 137.4
[0156] Thus, in this case the CDBP is found to increase by 7
points, even though the K+ rate is slightly higher in the
reactor.
Example 13
[0157] Attachment of Organic Groups
[0158] OMTS-CB was made as described in Example 1, but having the
following properties.
21 TABLE 18 % Silicon in Carbon Black 4.7 DBP, cc/100 g 103.2 CDBP,
cc/100 g 101.1 t-Area, m.sup.2/g 123 N.sub.2 Area, m.sup.2/g
164.7
[0159] The carbon black was treated with 0.15 mmol of
4-aminodiphenyldisulfide (APDS) per gram of black to attach an
organic group based on the preferred procedure described earlier.
The OMTS-CB was then compounded according to the following
formulation.
22 TABLE 19 Parts by Ingredient Weight Elastomer (Duradene 715) 75
Elastomer (Tacktene 1203) 25 Carbon Black 75 Si-69 4.5 Oil (Sundex
8125) 25 Zinc Oxide 3.5 Stearic Acid 2 Flexzone 7P .RTM. 1.5
Sunproof Improved 1.5 Durax .RTM. 1.5 Vanax DPG 1 TMTD 0.4 Sulfur
1.4
[0160] Tacktene 1203 is an elastomer obtained from Polysar Rubber
Corporation, Canada Vanax DPG and tetramethyl thiuran disulfide
(TMTD) are accelerators obtained from R.T. Vanderbilt Co., Norwalk,
Conn., and Akrochem Co., Akron, Ohio, respectively.
[0161] The mixing procedure described in Example 7 was used. The
oil and Si-69 were added in the first mixing stage. The performance
of the compounds is described in Table 20.
23 TABLE 20 tan .delta. tan .delta. Abrasion @ 0.degree. C. @
70.degree. C. @ 14% Slip OMTS-CB 0.385 0.158 100 OMTS-CB APDS 0.307
0.108 69
[0162] As shown in Table 20, attaching APDS to OMTS--CB results in
a 31% reduction in tan .delta.@70.degree. C. with a 20% reduction
in tan .delta.@0.degree. C.
Example 14
[0163]
24 TABLE 21 A B C Carbon Black Silicon Content (5%) 0 2.1 4.0
N.sub.2SA t-area (m.sup.2/g) 54 52 54 DBPA (ml/100 g) 71 68 70
Physical Properties Recipe 1 2 3 Hardness (Shore A) 66 65 66
Tensile (MPa) 15.5 17.8 19.4 Elongation (%) 276 271 300 Tear, Die C
(kN/m) 23.6 24.2 25.4 D E F Carbon Black Silicon Content (%) 0 1.6
4.1 N.sub.2SA t-Area (m.sup.2/g) 54 51 52 DBPA (ml/100 g) 105 98
102 Physical Properties Recipe 1 2 3 Hardness (Shore A) 64 68 66
Tensile (MPa) 16.2 19.4 18.6 Elongation (%) 255 265 276 Tear, Die C
(kN/m) 22.9 24.3 26.3
[0164]
25TABLE 22 RECIPES Ingredient (Parts by Weight) 1 2 3 Royalene 509
EPDM 100 100 100 AZO-66 Zinc Oxide 4 4 4 Hystrene Stearic Acid 1 1
1 Carbon Black 60 60 60 Sunpar 2280 Paraffinic Oil 25 25 25
Rubbermakers Sulfur 2.5 2.5 2.5 Methyl Tuads 1 1 1 Rhenogram MBT-75
(75% active) 2 2 2 Si-69 Polysulfidic Silane 0 1.2 2.4 TOTALS 195.5
196.7 197.9
[0165]
26 SUPPLIERS OF INGREDIENTS: Royalene 509 EPDM Uniroyal Chemical
Co., CT AZO-66 Zinc Oxide Asarco, Inc., OH Hystrene Stearic Acid
Humko Chemical Co., TN Sunpar 2280 Paraffinic Oil Sun Refining and
Marketing, PA Rubbermakers Sulfur R. E. Carroll, NJ Methyl Tuads R.
T. Vanderbilt, CT Rhenogran MBT-75 (75% active) Rhein-Chemie Corp.,
NJ Si-69 Polysulfidic Silane Struktol, OH
[0166] As seen from the above EPDM examples, the use of
silicon-treated carbon black substantially improves tensile,
elongation, and tear strength at comparable hardness levels. These
improvements in physical properties would provide advantages in
useful lifetimes of seals, boots, and general molded rubber parts.
Similar advantages for the silicon-treated carbon blacks would be
envisaged in peroxide cured elastomers which, for example, do not
contain unsaturated double bonds such as EPDM, or which may not
need additional coupling agents to achieve their desirable
properties.
[0167] Advantages for the silicon-treated carbon blacks would also
be expected in elastomers containing elements other than carbon and
hydrogen which would give additional interactions with the
silicon-containing domains in the carbon blacks. Examples of
elastomers containing non-hydrocarbon groups would include but not
be limited to NBR (acrylonitrile-butadiene rubber), XNBR
(carboxylic-acrylonitrile-butadien- e rubber), HNBR
(hydrogenated-acrylonitrile-butadiene rubber), CR (chloroprene
rubber), ECO (ethylene oxide-chloromethyl oxirane), GPO
(polypropylene oxide-allyl glycidyl ether), PPO (polypropylene
oxide), CSM (chloro-sulfonyl-polyethylene), CM
(chloro-polyethylene), BIIR (bromo-isobutene-isoprene rubber), CIIR
(chloro-isobutene-isoprene rubber), ACM (copolymers of ethyl or
other acrylate and small amount of vulcanizable co-monomer), and
AEM (copolymers of ethyl or other acrylate and ethylene).
[0168] All patents, patent applications, test methods, and
publications mentioned herein are incorporated by reference.
[0169] Many variations of the present invention will suggest
themselves to those skilled in the art in light of the above
detailed disclosure. For example, the compositions of the present
invention may include other reinforcing agents, other fillers, oil
extenders, antidegradants, and the like. All such modifications are
within the full intended scope of the claims.
* * * * *