Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 93/09178 PCI'/EP92/01030
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Tire and Belt Compositions
The present invention relates to tires and belts which have improved
properties as compared to standard tire and belt compositions. The
inventors have found that tire and belt compositions having a reduced
heat buildup exhibit improved properties9 especially when subjected to
environments which lead to ageing of the rubber compositions.
The importance of heat buildup is recognized in the article, "Carbon
Black in NR/BR Blends for Truck Tires,'l Rubber Chemistr~ and
Technology, Vol. 58, pp. 350-36B (1985), wherein it is stated that
treadwear, heat buildup, resistance to cutting and chipping and fuel
economy are important to heavy duty truck tire performance.
Accordingly, there is a need in the art for tire and belt products
which exhibit a low heat buildup. since such products exhibit a better
performance as well as having, in many`cases, a longer service life.
Many attempts have been made to produce products with a low heat
buildup. ~or example~ European Patent application 0 314 271 discloses
the use of an improved processing aid to improve handling, durability
and rolling resistance of tires, as well as reducing heat buildup.
European Patent application 0 451 603 relates to the use of an anionic
polymerization initiator for curing elastomers to improve their
hysteresis. ~mproved hysteresis leads to tires having a lower rolling
resistance. One aspect of hysteresis is heat buildup.
PCT patent application WO 91/05821 discloses a tire sidewall
composition comprising a particular polymer which leads to sidewalls
having a desirable reduced internal heat buildup and improved adhesion
to adjacent rubber carcass and tread portions of the tire.
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Finally, the publication, "Natural Rubber Compounds for Truck Tires,"
NR Technology, Vol. 16, Part 1 (1985) suggests the use of additional
stearic acid activator in order to reduce the heat generation, among
other properties, in truck tires.
However, all of these solutions fall short of the goal of providing
tires and belts with longer service life, better ageing
characteristics, lower rolling resistance and better fuel economy.
The present inventors have surprisingly found that tire and belt
compositions having a particular heat buildup exhibit several improved
properties, particularly when the tires and belts are subjected to
service conditions.
More specifically, the present invention relates, in one aspect to a
tire wherein at least one of the tread, steel-cord skim stock,
sidewall and carcass portions contains a rubber composition formed by
curing a blend of at least:
50-100 weight percent of natural rubber, polyisoprene or a mixture
thereof,
0-50 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
20-65 phr, based on the total rubber content, of carbon black,
0.5-4.0 phr of activator,
1.0-10.0 phr of zinc oxide,
1.0-10.0 phr of sulfur or a sulfur donor, and
0.5-5.0 phr of curing accelerator,
. . .
characterized in that said rubber composition has a heat buildup of
20-35C. These tires exhibit one or more improvements in a wide
variety of properties such as abrasion resistance, rolling resistance,
ageing resistance, adhesion to steel, cutting and chipping resistance
and service life.
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In a second aspect, the present invention relates to a belt which
contains a rubber composition formed by curing a blend of at least:
50-100 weight percent of natural rubber, polyisoprene or a mixture
thereof,
0-50 weight percent of butadiene rubber~ styrene-butadiene rubber or a
mixture thereof,
20-65 phr, based on the total rubber content, of carbon black,
0.5-4.0 phr of activator,
1.0-10.0 phr of zinc oxide,
1.0-10.0 phr of sulfur or a sulfur donor, and
0.1-5.0 phr of curing accelerator,
characterized in that said rubber composition has a heat buildup of
10-25C. These belts exhibit one or more improv~ments in a variety of
properties including tear strength, tensile strength, service life and
ageing resistance.
The low heat buildup rubber compositions of the present invention can
be used in tire treads for truck tires and off-the-road tires, in
particular, for sidewalls, for tire carcasses and for steel-cord skim
stocks. In belts, the rubber compositions of the present invention
are particularly useful for conveyor belts and V-belts which are
subjected to high loading and abrasion in service.
2g
A typical truck tire tread composition in accordance with the present
invention comprises the cured product of a blend containing:
50-100 we-ight percent of natural rubber~ polyisoprene or a mixture
30 thereof,
0 50 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
45-65 phr, based on the total rubber content, of carbon black,
1.0-3.0 phr of activator,
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1.0~10.0 phr of zinc oxide,
1.0-5.0 phr of sulfur or a sulfur donor, and
0.5-5.0 phr of curing accelerator.
Of course, these truck tire treads may contain other conventional
additives such as 0-20 phr silica, 2-10 phr tackifier, 5-50 phr of
processing oil, 1-5 phr waxes, 1-5 phr antioxidant and 1-5 phr
antiozonants.
Important properties for truck tire treads include abrasion
resistance, rolling resistance, resistance. to cracking, thermal and
oxidative stability and durability.
A typical steel-cord skim stock composition in accordance with the
present invention is the cured product of a blend comprising:
85-100 weight percent of natural rubber, polyisoprene or a mixture
thereof,
0-15 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
45-65 phr, based on the total rubber content, of carbon black having
an average particle size of 10-30 nm,
0.5-2.0 phr of activator,
1.0-10.0 phr of zinc oxide,
4.0-8.0 phr of sulfur or a sulfur donor, and
0.5-1.5 phr of curing accelerator.
These steel-cord skim stocks may also contain 0-20 phr silica, 0-2.0
phr of a cobalt salt and 1-3 phr of antidegradants. Adhesion to steel
is an important property for this portion of the tire.
A typical carcass portion of a tire in accordance with the present
invention is the cured product of a blend comprising:
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50-80 weight percent of natural rubber, polyisopr~ne or a mixture
thereof,
20-50 weight percent of butadiene rubber~ styrene-butadiene rubber or
a mixture thereof,
20-50 phr, based on the total rubber content, of carbon black having
an average particle size of 45 70 nm,
1.0-3.0 phr of activator,
1.0-10.0 phr of zinc oxide,
2.0-5.0 phr of sulfur or a sulfur donor, and
0.5-5.0 phr of curing accelerator.
These carcass portions may a~so contain 1-3 phr antioxidant and 2-8
phr processing oil, if desired. Important properties fcr the carcass
portion are the thermal resistance and the rebound resilience.
A typical sidewall portion of a tire in accordance with the present
invention is the cured product of a blend comprising:
50-100 weight percent of natural rubber, polyisoprene or a mixture
thereof,
0-50 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
40-60 phr, based on the total rubber content, of carbon btack having
an average particle size of 20-70 nm,
1.0-4.0 phr of activator,
2.0-6.0 phr of zinc oxide,
1.0-3.0 phr of sulfur or a sulfur donor, and
0.5-1.5 phr of curing accelerator.
These sidewall portions may also contain from 5-10 phr of whitening.
Important properties for the sidewall portion are fatigue resistance,
ozone resistance, cutting and chipping resistance and reversion
resistance.
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A typical off-the-road tire tread in accordance with the present
invention is the cured product of a blend which comprises:
80-100 weight percent of natural rubber, polyisoprene or a mixture
thereof,
0-20 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
20-50 phr, based on the total rubber content, of carbon black having
an average particle size of 10-30 nm,
1.0-3.0 phr of activator,
1.0-10.0 phr of zinc oxide,
10-25 phr of silica having a surface area of 100-200 m2/g,
1.0-2.0 phr of sulfur or a sulfur donor, and
1.0-2.0 phr of curing accelerator.
Off-the-road tîre treads may also include 5-50 phr of processing oil,
0-5 phr of resin, 0-2 phr wax, 1-4 phr antio~onants and 0.5-2.0 phr
antioxidants. Important properties for off-the-road tire treads are
tread wear, cutting and chipping resistance and hysteresis.
A typical conveyor belt in accordance with the present invention is
the cured product of a blend comprising:
95-100 weight percent of natural rubber~ polyisoprene or a mixture
thereof,
0-5 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
30-50 phr, based on the total rubber content, of carbon black having
an average particle size of 20-40 nm.,
0.5-4.0 phr of activator,
1.0-lO.O phr of zinc oxide,
1.0-10.0 phr of sulfur or a sulfur donor, and
0.1-5.0 phr of curing accelerator.
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Other additives such as 1-4 phr antiozonants, may be employed.
Important properties for conveyor belts are fatigue resistance,
abrasion resistance and tear strength.
A typical V-belt in accordance with the present invention is the cured
product of a blend comprising:
SO-100 weight percent of natural rubber, polyisoprene or a mixture
thereof,
0-50 weight percent of butadiene rubber, styrene-butadiene rubber or a
mixture thereof,
30-65 phr, based on the total rubber content, of carbon black having
an average particle size of 20-100 nm,
0.5-4.0 phr of activator,
1.0-10.0 phr of zinc oxide,
1.0-10.0 phr of sulfur or a sulfur donor, and
0.1-5.0 phr of curing accelerator.
Other additives such as 1-4 phr antiozonants, may be employed.
Important properties for V-belts are fatigue resistance and service
life.
Examples of sulfur which may be used in the present invention include
various types of sulfur such as powdered sulfur, precipitated sulfur
and insoluble sulfur. Also, sulfur donors may be used in place of, or
-~ in addition to sulfur in order to provide the required level of sulfur
during the vulcanization process. Examples of such sulfur donors
include, but are not limited to, tetramethylthiuram disulfide,
tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipen-
tamethylene thiuram hexasulfide, dipentamethylene thiuram
tetrasulfide, dithiodimorpholine, caprolactam disulfide and mixtures
thereof.
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In this text, references to sulfur shall include sulfur donors and
mixtures of sulfur and sulfur donors. Further, references to the
quantity of sulfur employed in the vulcanization, when applied to
sulfur donors, refer to a quantity of sulfur donor which is required
to provide the equivalent amount of sulfur that is specified.
In most circumstances it is also desirable to have a vulcanization
accelerator in the rubber compound. Conventional, known vulcanization
accelerators may be employed. The preferred vulcanization accelera-
tors include mercaptobenzothiazole, 2,2'-mercaptobenzothiazole
disulfide, sulfenamide accelerators including
N-cyclohexyl-2-benzothiazole sulfenamide,
N-tertiary-butyl-2-benzothiazole sulfenamide,
N,N'-dicyclohexyl-2-benzothiazole sulfenamide, and
2-(morpholinothio)benzothiazole; thiophosphoric acid derivative
accelerators, thiurams, dithiocarbamates, diphenyl guanidine, diortho-
tolyl guanidine, dithiocarbamylsulfenamides, xanthates, triazine acce-
lerators and mixtures thereof.
Other rubber additives may also be employed in their usual amounts.
For example, reinforcing agents such as carbon black9 silica, clay,
whiting and other mineral fillers, as well as mixtures of fillers, may
be included in the rubber composition. Other additives such as
process oils, tackifiers, waxes, antioxidants, antiozonants, pigments,
resins, plasticizers, process aids, factice, compounding agents and
activators such as stearic acid and oleic acid, and zinc oxide may be
included in the listed amounts. For a more complete listing of rubber
additives which may be used in combination with the present invention
see, W. Hofmann, ~Rubber Technology Handbook", Chapter 4, Rubber
Chemicals and Additives, pp. 217-353, Hanser Publishers, Munich 1989.
Further, scorch retarders such as phthalic anhydride, pyromellitic
anhydride, benzene hexacarboxylic trianhydride, 4-methylphthalic
anhydride, trimellitic anhydride, ~-chlorophthalic anhydride, N-
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cyclohexyl-thic~halimides salicylic acid, benzoic acid, maleic
anhydride and N-nitrosodiphenylamine may also be included in the
rubber composition in conventional, known amounts. Finally, in speci-
fic applications it may also be desirable to include steel-cord adhe-
sion promoters such as cobalt salts and dithiosulfates in conven-
tional, known quantities.
The process of curing the blends of the present invention is
preferably carried out at a temperature of 110-220C over a period of
up to 24 hours. More preferably, the process is carried out at a
temperature of 120-190C over a period of up to 8 hours. All of the
additives mentioned above with respect to the rubber composition may
also be present during the vulcanization process.
In a more preferred embodiment of the vulcanization process, the
vulcanization is carried out at a temperature of 120-190~C over a
period of up to 8 hours and in the presence of at least one vulca-
nization accelerator. The best heat buildup in accordance with the
present invention is found when vulcanization is carried out at a
temperature above 160C and~or for a period exceeding tgo.
The tire and belt products of the present invention have reduced heat
buildup. With respect to the tire products, they exhibit a heat
buildup of 20-35C whereas the belt products exhibit a heat buildup of
from 10-35C.
Heat buildup, for the purposes of the present specification, was
measured using ASTM 623 A at a starting temperature of 100C. The
actual heat buildup is the temperature rise from 100C to the
temperature at which equilibrium was reached. Equilibrium temperature
is when the temperature stabilizes and does not rise any further.
Note that for some prior art products, the temperature never
stabilizes.
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One way to produce products in accordance with the present invention
is to carry out the curing of the blend in the presence of 0.1-5.0
parts by weight of a coagent represented by the general formula A:
Q1-D-(Q2)n (A);
wherein D, optionally containing one or more heteroatoms or groups
selected from nitrogen, oxygen, silicon, phosphorus, boron, sulphone
and sulphoxy, is a monomeric or oligomeric divalent, trivalent or
tetravalent group, n is an integer selected from 1, 2 or 3, Q1 and Q2
are independently selected from the formulas I and II:
B 11
C~ C-C-H
/ l
-N R2 (I)
C~ C-R3
20 and;
B R
Il /
C----------------C=C
\
-N R2 (II)
1l _ _ l-R3
B~ H
wherein R1, R2 and R3 are independently selected from hydrogen, C1-C1g
alkyl groups, C3-C1g cycloalkyl groups, C6-C1g aryl groups, C7-C30
aralkyl groups and C7-C30 alkaryl groups and R2 and R3 may combine to
form a ring when R1 is hydrogen; B and B~ are independently selected
from the following hetero atoms: oxygen and sulfur.
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These imides are, in general, known compounds and may be prepared by
the methods disclosed in, "The synthesis of Biscitraconimides and
Polybiscitraconimides~" Galanti, A.V. and Scola, D.A., Journ. of Poly.
- Sci.: Polymer Chemistry Edition, Vol. 19, pp. 451-475, (1981), and
"The Synthesis of Bisitaconamic Acids, Isomeric Bisimide Monomers9"
Galanti, A.V. et al., Journ. Poly. Sci.: Polymer Chemistry Edition,
Vol. 20, pp. 233-239 (1982) and Hartford, S.L., Subramanian, S. and
Parker, J.A., Journ. Poly. Sci.: Polymer Chemistry Edition, Vol. 16,
p. 137, 1982, the disclosures of which are hereby incorporated by
reference. Particularly useful imide compounds are disclosed in PCT
patent application PCT/EP 91/02048.
The invention is further illustrated by the following examples which
are not to be construed as limiting the invention in any way. The
scope of the invention is to be determined from the claims appended
hereto.
EXPE~IMENTAL METHODS USED IN THE EXAMPLES
Compounding, Vulcanization and Characterization of Compounds
In the following examples, rubber compounding, vulcanization and
testing was carried out according to standard methods except as
otherwise stated:
Base compounds were mixed in a Farrel Bridge BR 1.6 liter Banbury type
internal mixer (preheating at 50C, rotor speed 77 rpm, mixing time 6
min with ~ull cooling).
~ulcanization ingredients and coagents were addded to the compounds on
a Schwabenthan Polymix 150L two-roll mill (friction 1:1.22,
temperature 70C, 3 min).
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.
Optimum cure time (tgo) is the time- to 90% of delta torque above
minimum, reversion time (tr2) is the time to 2% of delta torque below
maximum torque. Final torque (Tf) is the torque measured after the
overcure time.
Sheets and test specimens were vulcanized by compression molding in a
Fontyne TP-400 press.
Tensile measurements were carried out using a Zwick 1445 tensile
tester (ISO-2 dumbbells, tensile properties according to ASTM D
412-87, tear strength according to ASTM D 624-86).
Hardness was determined according to DIN 53505, and ISO 48 (IRHD).
Rebound resilience was measured at room temperature (RT) according to
ASTM D 1054-87.
Compression set was determined after 24 h at 70C or 72 h at 23C
according to ASTM D 395-89.
Heat build-up temperature rise and compression set after dynamic
loading were determined using a Goodrich Flexometer (load 1 MPa,
stroke 0.445 cm, frequency 30 Hz, start temperature 100C, running
time 30 min; ASTM D 623-78). Blow out time was determined according to
ASTM D 623-78 ~load 2 MPa, stroke 0.645 cm, frequency 30 Hz, start
temperature 100C).
Abrasion was determined using a Zwick abrasion tester as volume loss
per 40 m path traYelled (DIN 53516~.
Ageing of test specimens was carried out in a ventilated air oven at
70C or 100C for periods up to 14 days (ISO 188)
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Examples 1 3 and Comparative Example A
- Examples 1-3 and Comparative Example A are formulations for truck tire
treads. The components of each formulation are given in Table 1 and
the physical and mechanical properties for different curing conditions
are given in Tables 2a-2d. The heat buildup and permanent set are
given for di~ferent curing conditions in Tables 3a-3b.
TABLE 1: Compound composition
Ingredient _ _ _ 1 2 3
NR SMR 20 80 80 80 80
BR Buna C3 10 20 20 20 20
Carbon Black N-375 55 -55 55 55
Stearic Acid 2 2 2 2
ZnO RS 4 4 4 4
Ar.Oil Dutrex 729HP 8 8 8 8
Permanax 6PPD (R) 2 2 2 2
Perkacit CBS c 1.2 1.2 1.2 1.2
Sulphur 1.2 1.2 1.2 1.2
Coagent BCI-MX* _ _ 0.75 1 1.25
* BCI-MX = N,N'-m-xylene-bis-citraconic imide
TABLE 2a: Physical and mechanical properties of the vulcanizates cured
at 150C for tgo
Test A 1 2 3
Density g/cm3 1.12 1.12 1.12 1.12
Hardness IRHD 69 69 68 69
Tensile strength MPa 25.6 26.2 23~9 26.1
Elongation ~ 533 535 502 545
Modulus 50% MPa 1.4 1.3 1.3 1.3
Modulus 100~ MPa 2.6 2.4 2.4 2.3
Modulus 300~ MPa 13.1 12.9 12.5 12.5
Rebound res~lience ~ 32 33 32 32
Abrasion mm3 87 100 __ _ _
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TABLE 2b: Physical and mechanical properties of the vulcanizates cured
at 150C for 60 min
Test A 1 2 3
Density g/cm3 1 .12 1.12 1.12 1.12
Hardness IRHD 65 69 68 68
Tensile strength MPa 23.7 23. 7 22.5 23.6
Elongation % 534 536 498 506
Modulus 50% MPa 1.3 1.4 1.4 1.4
Modulus 100~ MPa 2. 2 2.3 2.4 2.3
Modulus 300% MPa 11.4 11.8 12.0 12.3
Rebound resilience %_ _ 30 32 31 32
TABLE 2c: Physical and mechanical properties of the vulcanizates cured
at 170~C for tgo
Test A 1 2 3
Density g/cm3 1.12 1.12 1.12 1.12
Hardness IRHD 68 66 67 67
Tensile strength MPa 25. 3 25.6 24.5 24.5
Elongation ~ 541 557 548 532
Modulus 50% MPa 1.3 1.3 1.2 1.2
Modulus 100% MPa 2.3 2.1 2.2 2.1
Modulus 300% MPa 12.4 11.6 11.8 11.7
Rebound resilience % 32 33 31 32
TABLE 2d: Physical and mechanical properties of the vulcanizates cured
at 170C for 30 min
Test A 1 2 3
Density g/cm3 1.12 1.12 1.12 1.12
Hardness IRHD 62 66 66 67
Tensile strength MPa 18.4 21.2 20.4 22.3
Elongation % 511 510 482 502
Modulus 50% MPa 1.1 1.2 1.2 1.3
Modulus 100% MPa 1. 7 2.0 2.1 2.2
Modulus 300% MPa 8.9 10.7 10.9 11.5
Rebound resilience % 29 30 31 31
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TABLE 3a: Heat build up and Permanent set of the vulcanizates cured at
170C for 30 min
ITest I A 1 1 1 2 1 3
Heat build up C 51 34 33 34
Permanen~ set % 18.0 10.2 9.5 7.9 _
TABLE 3b: Hsat build up and Permanent set of the vulcanizates cured at
150C for 2 x tgo
Test A 1 2
Heat build up C 48 34 32 34
Permanent set _ % 17.8 13.0 11.0 13.4
Example 4 and Comparative Example B
Example 4 and Comparative Example B are also formulations for truck
tire treads. The components of each formulation are given in Table 4
and the physical and mechanical properties for different curing
ccnditions are given in Tables 5a-5b. The heat buildup and permanent
set are given for different curing conditions in Tables 6a-6b.
TABLE 4: Compound composition
_ Recipes
Ingredients ~ B 4
NR SMR 20 80.00 80.00
BR Buna CB 10 20.00 20.00
Carbon Black N-375 55.00 55.00
Stearic Acid 2 . 00 2 . 00
Zinc Oxide RS 4.00 4.00
Ar.Oil Dutrex 729HP 8.00 8.00
Permanax 6PPD 2.00 2.00
Perkacit CBS c 1.20 1.20
Sulphur 1.20 1.20
BCI-MX _ _ ___ _ 1.00
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TABLE 5a: Mechanical properties of the vulcanization cured at 150C
for tgo times
. _ Recipes
Properties _ _ 4
Modulus, MPa
50~ 1.16 1.20
(1.06) (1.20)
100% (1 97) 2 08
300% 11 .52 11 .40
(9.37) (10.87)
Tensile strength, 26.60 27.23
MPa (22 .20) (22 .87)
Elongation,% 565 580
Tear strength, 94.5 100
kN/m (8~) (84)
Rebound resilience, % (32) (32)
Hardness, Shore A (54) (58)
* Values in the parentheses designate the properties of the
vulcantizates cured at 150C for 60 min.
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TABLE 5b: Mechanical properties of the vulcanization cured at 170C
for tgo times
Recipes
Properties B 4
Modulus, MPa
50% 1.11 1.09
(0-93) (1.16)
100~ 1.79 1.7~
(1-~7) (1.90)
300% 9.73 10.06
(6.95) (10.19)
Tensile strength, 24.50 25.63
MPa (16.49) t22.56)
Elongation,~ 576 579
(522) (540)
Tear strength, 110 105
kN/m (49) (69)
Rebound resilience, % 57 58
~ ss, Shore A (53) ¦ ~
* values in the parentheses designate the relevant properties of the
vulcanizates cured at 170C for 30 min.
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Table 6a: Heat build up and permanent set properties (at 100C) of the
vulcanizates cured at 150C for tgo*2 and 60 minutes
Stro~e 4.45 mm, Load: 11 kg, Freqùency: 30Hz
Start Temp.: 100C, Duration: 25 minutes
UNAGED
Sample HBU,C Permanent Set,%
B 45 18 68
4 34 14.06
(27) (8.20)
AGED, 7d/70C
B 55 18.08
(65) (25.39)
4 25 9.52
(27) (6.61)
AGED, 14d/70C
B 56 20.47
(100) (Blown out)
_ (227) (86 88)
*values in the parentheses designate the properties of the
. vulcanizates cured at 150C for 60 minutes
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Table 6b: Heat build up and permanent set properties (at 100C) of the
vulcanizates cured at 170C for tgo*2 and 30 minutes
Stroke: 4.45 mm, Load- 11 kg, Frequency: 30Hz
Start Temp.: 100C, Duration: 25 minutes
UNAGED
Sample HBU,C Permanent Set,%
~ 47 ~1.54
(52) (18.05)
4 34 1~.75
(~8) (7.43)
AGED, 7d/70C
B 46 19.78
(83) (30.27)
4 27 11.02
(29~ (7-31)
AGED,_14d/70C
B (112) (Blown out)
4 26 8.58
(30) (6.93)
. _
*values in the parentheses designate the properties of the
vulcanizates cured at 170C for 30 minutes
Examples 5-7 and Comparative Examples C-D
Examples 5-7 and Comparative Examp~es C-D are formulations for off-
the-road tire treads. The components of each formulation are given in
Table 7 and the physical and mechanical properties for different
curing conditions are given in Tables 8a-8d. The heat buildup and
permanent set are given for different curing conditions in Tables
9-10.
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TABLE 7: Compound composition
Ingredients _ _ C 5 6 7 D
NR SMR 20 100 100 100 100 100
Carbon Black N-220 40 40 40 40 40
Perkasil KS 404 Gr 20 20 20 20 20
Zinc Oxide RS 5 5 5 5 5
Steari c Acid 2 2 2 2 2
Ar.Oil Dutrex 729HP 3 3 3 3 3
Resin Cumar. 3 3 3 3 3
Si-69 3 3 3 3 3
Permanax TQ 1.5 1.5 1.5 1.5 1.5
Permanax 6PPD 2.5 2.5 2.5 2.5 2.5
Wax Sunolite 240 1 1 1 1
Perkacit CBS c 1.41 1.41 1.41 1.41 1.41
Sulfur 1.43 1.43 1.43 1.43 1.43
BCI-MP* 1.0 _ _
BCI-MX 1.0
BCI-ES2** 1.0
Duralink HTS __ 1.0
* BCI-MP = N,N'-m-phenylene-bis-citraconic imide
** BCI-ES2 = bis(2-citraconimidoethyl)disulfide
TABLE 8a: Physical and mechanical properties of vulcanizates cured at
150C for tgo
Test ~ 5 6 7 D
Density g/cm3 1.16 1.16 1.16 j 1.16 1.16
Hardness IRHD 70 74 70 68 67
Tensile strength MPa 23.7 23.1 23.8 23.5 22.5
Elongation % 507 494 522 495 503
Modulus 50% MPa 1.3 1.4 1.3 1.4 1.3
Modulus 100% MPa 2.6 2.7 2.5 2.6 2.3
Modulus 300% MPa 12.8 12.9 12.2 12.9 11.5
Rebound resilience % 29 28 29 30 31
Tear Strength kN/m 128 108 100 114 92
Compr.set 3 days 23C % 14 15 16 15 16
Compr.set 1 day 70C % 32 29 31 28 33
~UBSTITUTE SHEET
WO 93/09178 PCI/EP92/01030
212~3~ 7
TABLE 8b: Physical and mechanical properties of vulcanizates cured at
150C for 60 min
Test _ 5 6 7 D .
Density ~ lcm3 1.16 1.161.16 1.16 1.16
Hardness IRHD 70 74 72 73 69
Tensile strength MPa 20.9 24.1 23.5 25.0 19.7
Elongation % 458 441 457 475 436
Modulus 50% MPa 1.4 1.7 1.6 1.7 1.3
Modulus 100% MPa 2.8 3.6 3.2 3.5 2.6
Modulus 300~ MPa 13.2 16.6 15.4 15.7 12.6
Rebound resilience % 26 29 30 28 28
Tear Strength kN/m 51.2 84.8 ~80.1 71.9 52.6
Compr.set 3 days 23C % 16 15 15 13 15
Compr.set 1 day 70C % l_ 24 23 22 22 24
TABLE 8c: Physical and mechanical properties of the vulcanizates cured
at 170C for tgo
Test C 5 6 7 D
Density g/cm' 1.16 1.161.16 1.16 1.16
Hardness IRHD 67 73 67 73 67
Tensile strength MPa 21.9 22.3 20.2 21.2 20.6
Fl ongation % 522 476 508 462 502
Modulus 50~ MPa 1.2 1.5 1.2 1.5 1.2
Modulus 100% MPa 2.2 2.7 2.1 2.6 2.1
Modulus 300~ MPa 11.0 12.5 10~2 12.5 10.4
Rebound resilience % 29 27 28 27 28
Tear Strength kN/m 96 65 - 76 67 82
, Compr.set 3 days 23C % 16 16 18 17 18
Compr.set 1 day 70C % 36 26 37 ~ 25 38
.
~UBSTITUTE SHEET
WO 93/09178 P~/EP92/01030
21~2347
22
TABLE 8d: Physical and mechanical properties of the vulcanizates cured
at 170C for 30 min
Test - C r 5 7 D
Density -- 97 cm3 i.16 1.16 1.16 1.161.16
Hardness IRHD 69 75 74 74 69
Tensile strength MPa 17.2 21.0 21.6 22.3 17.5
Elongation % 433 415 446 416 451
Modulus 50% MPa 1.3 1.6 1.5 1.7 103
Modulus 100% MPa 2.3 3.0 2.9 3.4 2.2
Modulus 300% MPa 10.8 14.4 13.4 15.6 10.6
Rebound resilience % 29 27 27 27 26
Tear Strength kN/m 75 75 60 59 27
Compr.set 3 days 23C % 20 15 17 16 19
Compr.set 1 day ?oC % 27 22 24 22 _ 27
TABLE 9: Dynamic properties of the vulcanizates oured at 150C for
tgo*2
Compounds Control BCI-MP BCI-MX BCI-ES2 Dura.HTS
(C) (5) (6) (7) (D)
PPHR -- 1.0 1.0 1.0 1.0
GOODRICH FLEXOMETER
Stroke: 4.45mm, Temp.: 100C, Frequency: 30 Hz, Duration: 25 min
Heat Build-up,C 48 24 28 24 48
(46) (24) (~3) (25) (46)
Set,% 23.1 7.2 11.7 8.9 22.5
t15.2) t5.2) (5.0) (6.3~ (17.6)
Stroke- 6.45mm,_Temp.: 100C~ Frequency: 30Hz
Blow out times 3.5 7.2 4.5 7.0 4.2
minutes (3~ (9.3) (8.0)~ (6.0) (4.0)
Values in the parentheses are those for the vulcanizates at 150C for
60 minutes
3~
~3UBSTITUTE SHEET
WO 93/09178 PCI'/EP92/01030
212~3 17
23
TABLE 10: Dynamic properties of the vulcanizates cured at 170C for
tgo*2
Compounds Control BCI-MP BCI-MX BCI-ES2 Dura.HTS
(C) (5) (6) (7) (D)
PPHR -- 1,0 1.0 1.0 1.0
~OODRICH FLEXOMETER
Stroke: 4.45mm, Temp.:_100C, Frequency: 30 Hz, Duration: 25 min
Heat Build-up,C 49 24 34 24 49
(47) (24) (25) (27) (46)
10Set,% 27.9 2.9 17.0 5.5 29.6
(15.7) (4.8) ~5.8~ (6.0) (16.5)
Stroke: 6.45 mm, Temp.: 100C, Frequency-. 30Hz
B ow out times 4.0 10.0 4.5 10.0 3.5
minutes (4.0) (11.0) (8.0) (9.0)_ (3.75)
Values in the parentheses designate the values obtained for the vulcanizates cured at 170C for 30 minutes
Example 8 and Comparative Examples E-F
Example 8 and Comparative Examples E-F are formulations for conveyor
belts. The components of each formulation are given in Table 11 and
the physical and mechanical properties for different curing conditions
are given in Tables 12a-12b. The heat buildup and permanent set are
given for different curing conditions in Table 13.
TABLE 11: Compound composition
Ingredient E F
NR SMR 20 100 100 100
Black N-330 45 45 45
Dutrex 729 H 4 4 4
ZnO RS 5 5 5
Stearic Acid 2 2 2
6PPD 1 1
Sulfur 2.5 2,5 2.5
Perkacit CBS - 0.5 0.5 0.5
BCI-MX _ 1.0
HVA-2 _ _ __ 1.0
SUBSTITUTE SHEET
WO 93/09178 PCIJEP92/01030
2122347
24
TABLE 12a: Mechanical properties (vulcanization 150C, tgo)
Test E 8 F
S Hardness ~ I~HD 69 71 71
Tensile strength MPa 26.4 25.8 25.6
Elongation % ?75 465 470
Modulus 50% MPa 1.6 1.6 1.5
Modulus 100% MPa 3.4 3.1 3.2
Modulus 300% MPa 15.4 14.5 14.8
Rebound resilience % 38 37 37
Tear strength kN/m 73 91 81
Abrasion mm3 124 128 136
Compr.set 72h/23C % 9 10 10
Density g/cc 1.12 1.12 1.12
Compr.set 24h/70C % 23 24 23
Heat build up C 25 17 25
Permanent set % 8.6 5.8 _7.4
TABLE 12b: Mechanical properties (vulcanization 170C, 30 min)
Test E 8 F
Hardness IRHD 59 68 64
Tensile strength MPa 14.1 19.8 17.0
Elongation % 415 415 445
Modulus 50% MPa 1.1 1.5 1.2
Modulus 100% MPa 1.9 2.8 2.2
Modulus 300% MPa 8.8 13.0 10.1
Rebound resilience % 32 35 33
Tear strength kN/m 20 29 21
. Abrasion mm3 ~ _ __ __
Compr.set 72h/23C % 20 11 19
Density g/cc 1.12 1.12 1.12
Compr.set 24h/70C % 30 19 27
Heat build up C 46 20 ~3
Permanent set % _16.4 3.2 9.3
. .
SUBSTITUTE SHEET
WO 93/09178 21 2 2 3 4 7 PCl'/EP92/01030
TABLE 13: Ageing properties (vulcanization 150C, tgo)
Test E 8 F
Ageing medium air air air
Ageing temperature C 100 100 100
Ageing time day(s) 3 3 3
Hardness IRHD 73 76 74
Change in Hardn. IRHD + 4 + 5 + 3
Tensile strength MPa 13.7 16.2 14.9
Change in T.S. % -48 -37 -42
Elongation % 230 225 230
Change in Elong. % -52 -52 -51
Modulus 50% MPa 2.3 2.5 2.4
Change in M50% % +44 +56 +50
Modulus 100% MPa 5.0 5.5 5.3
Change in M100~ % +47 +77 +66
~3UBSTITlJTE SHEET
