Curable composition comprising elastomeric terpolymer of carbon monoxide

Terpolymers having 1,4-diketo functionalities and a carbonyl group concentration of about 5-20% of polymer weight can be conveniently cured by heating with an aromatic primary diamine or its precursor and a catalytic amount of an acid having a pKa of at most about 3. Cured polymers have good physical properties and are suitable in such applications as, for example hose, tubing, wire coatings, gaskets, and seals.

BACKGROUND OF THE INVENTION 
This invention relates to certain novel curing systems for copolymers of 
ethylene with carbon monoxide as well as to curable compositions 
comprising such copolymers together with a curing system of the type 
disclosed hereafter and to cured polymers obtained by heating the above 
curable compositions to their cure temperature. 
Dipolymers of carbon monoxide with ethylene and terpolymers with ethylene 
and another ethylenically unsaturated monomer such as, for example, methyl 
acrylate, or vinyl acetate are well known. Such copolymers are known to 
contain 1,4-diketo functions arising from CO/unsaturated monomer/CO 
triads. Although such polymers can be cured by known free radical 
techniques, for example, in the presence of peroxides, free radical curing 
suffers from various shortcomings. Thus, for example, because of the 
inherently non-discriminating nature of peroxide cures, various customary 
additives, which could be adversely affected by the peroxide (for example, 
certain fillers, and plasticizers), cannot be used. Furthermore, peroxides 
have a deleterious effect on commonly used antioxidants and processing 
oils. 
It is, therefore, desirable to have available a non-peroxide curing system 
for ethylene/carbon monoxide copolymers. 
SUMMARY OF THE INVENTION 
According to this invention, there is provided a curing system for 
elastomeric terpolymers of ethylene with another ethylenically unsaturated 
monomer and carbon monoxide, in which the ketone carbonyl concentration is 
about 5-20 weight percent of the polymer, said curing system consisting 
essentially of about 0.15 to 8.0 mole % of an aromatic primary diamine 
based on the ketone carbonyl groups of the terpolymer or of a precursor 
which will liberate a free aromatic primary diamine under the cure 
conditions, and a catalytic amount of an acid having a pKa of at most 
about 3 or a precursor capable of liberating such acid under the cure 
conditions. 
There also are provided curable polymer compositions comprising a 
terpolymer of ethylene with another ethylenically unsaturated monomer and 
with carbon monoxide and the above diamine/acid curing system. 
Finally, there also is provided a process for curing polymers by heating 
the above curable compositions to a temperature at which curing takes 
place.

DETAILED DESCRIPTION OF THE INVENTION 
Unless the CO group content is at least about 5% of the copolymer weight, 
the statistical distribution of CO groups throughout the molecule may 
result in a number of CO/ethylenic monomer/CO triads which is too small 
for effective crosslinking. The preferred ketone CO group concentration is 
8-12 weight percent of the polymer weight. A typical terpolymer which can 
be successfully cured according to the process of the present invention 
contains about 35% of ethylene, 55% of methyl acrylate, and 10% of carbon 
monoxide. High CO group concentrations, above about 20 weight percent, 
result in stiff, nonelastomeric cured polymers. For the purpose of this 
disclosure, an elastomer is defined as a polymer which, when stretched to 
twice its length and released, at room temperature, returns with force to 
its original length. 
The carbon monoxide concentration of ethylene/unsaturated monomer/carbon 
monoxide terpolymers can be determined by nuclear magnetic resonance (nmr) 
analysis. Pertinent structural assignments are as follows: 
For CH.sub.3 of methyl acrylate .delta.=3.59 ppm. For ethylene CH.sub.2 in 
.alpha.-position to CO in 1:1 ethylene/CO structural units 
.delta.=3.00-2.40 ppm. 
For CH.sub.2 in .alpha.-position to CO in other structural units and for CH 
of 
##STR1## 
where R' and R" are alkyl groups .delta.=2.40-2.00 ppm. For CH.sub.2 in 
.beta.-position to CO .delta.=1.55 ppm. 
Those terpolymers normally fall in the following structural types: 
##STR2## 
where E stands for the ethylene group, and R stands for an alkyl group. The 
starred groups are those containing protons used in the calculations. 
The amount of ethylenically unsaturated monomer X in E/X/CO terpolymers is 
calculated from the areas of the nmr peaks corresponding to the starred 
groups. Corrections for other protons associated with monomer X can then 
be made in the spectrum. 
The monomer composition of an ethylene/methyl acrylate/carbon monoxide 
terpolymer is calculated as shown below to illustrate the practical 
application of the nmr method. In the following discussion MA stands for 
methyl acrylate. Circled numbers correspond to those shown in the drawing. 
Regardless of its environment, the MA methyl has one resonance (line 
.circle.1 ) at 3.59 ppm. 
##EQU1## 
.alpha.-methylenes of E/CO in 1,4 dione or 1:1 units, lines .circle.2 
and .circle.3 . 
##EQU2## 
.alpha.-methylenes of E/CO in (2 or more):1 units, line .circle.4 . 
##EQU3## 
All the remaining lines .circle.5 , .circle.6 , .circle.7 
##EQU4## 
Carbon monoxide 
B+C=F the number of units due to one mole of CO. 
Total ethylene 
##EQU5## 
Analysis of similar CO-containing terpolymers by nmr spectroscopy is 
discussed, for example, in Chapter 4 (J. E. McGrath et al) of Applications 
of Polymer Spectroscopy, edited by E. G. Brame, Jr., Academic Press, New 
York, 1978, pp. 42-55. 
Typical copolymerizable ethylenically unsaturated monomers X in the 
terpolymers include, .alpha.,.beta.-unsaturated C.sub.3 -C.sub.20 mono- 
and dicarboxylic acids, vinyl esters of saturated C.sub.1 -C.sub.18 
carboxylic acids, alkyl esters of .alpha.,.beta.-unsaturated C.sub.3 
-C.sub.20 mono- and dicarboxylic acids, vinyl C.sub.1 -C.sub.18 alkyl 
ethers, acrylonitrile, methacrylonitrile, copolymerizable unsaturated 
hydrocarbons such as C.sub.3 -C.sub.12 .alpha.-olefins, cyclic 
hydrocarbons such as norbornene, and vinyl aromatic compounds such as 
styrene. 
The reaction of 1,4-diketo groups with primary aromatic amines is believed 
to result in the formation of a stable pyrrole structure, as shown in the 
equation below: 
##STR3## 
wherein R stands for an aromatic divalent organic radical, and the wavy 
lines represent polymer chains. 
The primary aromatic diamine, H.sub.2 N--R--NH.sub.2 can be any diamine, 
including diamines in which R contains heteroatoms, such as, for example, 
N, S, or O. Suitable diamines include, for example, 
p,p'-methylenedianiline, p-phenylenediamine, p,p'-oxydianiline, 
p-toluidine, and 2,4-toluenediamine. Polymers cured with such diamines 
have very good thermal and hydrolytic stability. 
Methylenebis(o-chloroaniline) also can be used, although this chemical has 
been designated as a potential carcinogen and is no longer commercially 
available from the Du Pont Company; it is still available, however, from 
other manufacturers. 
Free diamines may react quite fast with 1,4-diketo copolymers and therefore 
form scorchy compositions. The most suitable diamine components of the 
compositions of the present invention are blocked diamines, which 
decompose under the cure conditions, thus releasing the free diamine in 
situ. A typical blocking group is the carbamate. Blocked diamines provide 
excellent processing safety. Aliphatic diamines are very scorchy, even in 
precursor form, such as, for example, hexamethylenediamine carbamate. 
Further, reactions with aliphatic diamines appear to be reversible. For 
these reasons, aliphatic diamines are not suitable in the compositions of 
the present invention. 
For the purpose of the present disclosure, the term "aromatic" means that 
there is present at least one cyclic structure having a system of 
conjugated double bonds, as, e.g., in benzene or naphthalene. 
The diamine or diamine precursor concentration is fairly critical in that 
effective crosslinking will not be obtained below the lower limit of the 
above recited range, while above the upper limit reaction of the cure 
sites (1,4-diketo groups) with one amine group of the diamine will result 
in a polymer containing amine-terminated pendant groups, rather than in a 
crosslinked polymer. 
The crosslinking reaction according to the present invention is catalyzed 
by acids, which may be inorganic or organic, so long as their pKa is no 
more than about 3. In addition to normal inorganic acids such as, for 
example, sulfuric, phosphorous, phosphoric, or hydrochloric, various 
organophosphonous and organophosphonic acids, sulfonic acids, chloroacetic 
acids, salicylic acid, and malonic acid are suitable catalysts. It is 
practical to use acid precursors, which form the free acids under cure 
conditions, thus further increasing the processing safety of the 
compositions of this invention. Typical such precursors are, for example 
various acid esters, which decompose to liberate the acids. Such 
precursors include various alkyl tosylates, which are known to undergo 
pyrolysis to p-toluenesulfonic acid (pKa=0.70) and the corresponding 
alkene, as shown below: 
##STR4## 
A commercial antioxidant, tri(mixed mono- and dinonyl phenyl)phosphite, 
sold by Uniroyal under the name "Polygard", proved to be an effective cure 
catalyst. This material is known to slowly hydrolyze in the presence of 
moisture to liberate phosphorous acid, which always is present in a small 
amount in the commercial material. The pKa is about 2. A sample of 
"Polygard" was found to contain about 1.1 weight percent (0.013 mole/100 
g) of phosphorous acid. 
The maximum cure rates are obtained when the molar ratio of the acid 
catalyst to the diamine curing agent is close to 0.1. Acceptable rates are 
still obtained when this ratio is as low as 0.03 or as high as 1. No 
significant improvement can be expected above that latter ratio, while a 
large amount of a strong acid could cause polymer degradation. 
The use of blocked diamine or polyamine curing agent and/or blocked acid 
catalyst (that is, precursors of the diamine or polyamine and of the acid) 
improves the processing safety of the polymer compound. The cure 
temperature preferably should be the same for the curing system of the 
present invention as normally is employed for polymer cures, so that no 
equipment or operating procedure modifications will be required. The usual 
industrial cure temperature of about 177.degree. C. is suitable in the 
present process. Naturally, when a protected curing agent or acid catalyst 
is employed, it must be so chosen that its thermal decomposition to the 
free amine and/or free acid occurs at the cure temperature at a 
satisfactory rate. 
Polymer compounds containing the curing agent and acid catalyst are 
prepared by standard mixing techniques, for example, in a rubber mill or 
an internal mixer. 
Curing carbonyl group-containing terpolymers according to this invention 
gives products which have good physical properties and are suitable in 
such applications as, for example, hose, tubing, wire coating, gaskets, 
seals, coated fabrics, and sheet goods. 
This invention is now illustrated by examples of certain preferred 
embodiments thereof, where all parts, proportions, and percentages are by 
weight unless indicated otherwise, except that curing agent and catalyst 
concentrations are also expressed as mole % based on ketone carbonyl 
groups. For methylenedianiline complexes with alkali metal chlorides the 
mole % concentration is calculated on the basis of free 
methylenedianiline. The abbreviation "phr" means "parts per 100 parts of 
polymer". All the cured polymeric compositions of this invention were 
elastomeric. 
EXAMPLE 1 
Polymer Preparation 
An ethylene/methyl acrylate/carbon monoxide (E/MA/CO) 35/55/10 terpolymer 
is prepared according to the general processes of U.S. Pat. Nos. 2,495,286 
to Brubaker and 3,780,140 to Hammer in a continuous, stirred, high 
pressure 725 mL polymerization reactor at 190.degree. C. and 186 MPa. In a 
typical run, the feed stream compositions, flow rates and polymer 
composition are as follows: 
______________________________________ 
Feed Composition (parts) 
Rate, (kg/hr) 
______________________________________ 
Ethylene ethylene (100) 6.36 
Comonomer 1 
methyl acrylate (100) 
1.19.sup.1 
monoethyl ether 
of hydroquinone (100 ppm) 
2,6-di-t-butyl- 
4-methyl phenol (220 ppm) 
Comonomer 2 
CO (100) 0.30 
Solvent methanol (25) 0.27.sup.2 
t-butyl alcohol (75) 
Catalyst 2-t-butylazo-2- 0.5.sup.3 
Solution cyano-4-methoxy- 
methylpentane (1512 ppm) 
methanol (25) 
t-butyl alcohol (75) 
Telogen acetone (100) 0.45 
______________________________________ 
.sup.1 Total Comonomer 1 composition feed rate 
.sup.2 Total solvent feed rate 
.sup.3 Total catalyst solution feed rate 
Other E/MA/CO polymer compositions are prepared by variations in the 
reaction paramters such as comonomer solution composition, relative feed 
rates of the monomer streams, temperature, pressure, and monomer 
conversion. 
EXAMPLE 2 
Curing of an E/MA/CO terpolymer with a complex of methylenedianiline with 
lithium chloride 
A terpolymer having a composition of 53% E, 37% MA, and 10% CO, 100 parts, 
was compounded on a water-cooled, two-roll rubber mill with 50 parts of 
SRF (N774) carbon black, 1 part of substituted diphenylamine antioxidant 
("Naugard" 445, Uniroyal), 1 part tri(mixed mono- and dinonyl 
phenyl)phosphite ("Polygard", Uniroyal) and various quantities of lithium 
chloride complex of methylenedianiline. (MDA).sub.3 LiCl. 
Slabs for specimens for the determination of tensile properties and pellets 
for compression set measurements were cured in presses at about 4.5 MPa 
pressure and 177.degree. C. Molds were loaded and unloaded hot. The 
stress-strain properties--M.sub.100 (100% modulus), M.sub.200 (200% 
modulus), T.sub.B (tensile strength at break), and E.sub.B (percent 
elongation at break)-were measured by ASTM method D-412. Compression set 
(Comp. Set B) of the cured pellets was measured by ASTM method D-395. 
Table I shows the results obtained with press cures of 30 minutes and 60 
minutes with several concentrations of the curing agent. The acid catalyst 
required for the crosslinking reaction is supplied by the acid impurities 
known to be present in the "Polygard" antioxidant. The omission of 
"Polygard" in these stocks without the inclusion of some other acid 
catalyst fails to produce a vulcanized polymer under the same press cure 
conditions. 
TABLE I 
______________________________________ 
VULCANIZATE PROPERTIES OF (MDA).sub.3 LiCl-CURED 
E/MA/CO TERPOLYMER* 
Cure Time 
60 min 30 min 
A B C D 
______________________________________ 
(MDA).sub.3 LiCl, phr 
1.22 2.01 2.80 1.50 
mole % 1.64 2.69 3.72 2.08 
M.sub.100 (MPa) 
2.8 6.8 9.0 7.5 
M.sub.200 (MPa) 
9.1 -- -- -- 
T.sub.B (MPa) 
15.5 13.6 15.2 15.9 
E.sub.B (%) 290 160 145 190 
Shore A, Hardness 
55 60 66 57 
Compression Set B 
23 26 29 12 
70 hr/100.degree. C. 
Compression Set B 
34 30 32 24 
70 hr/150.degree. C. 
______________________________________ 
*Recipe: 
E/MA/CO terpolymer (100) 
Carbon Black (50) 
"Polygard" (1) 
"Naugard" 445 (1) 
(MDA).sub.3 LiCl (as shown) 
EXAMPLE 3 
Vulcanizate properties of E/MA/CO terpolymers cured with (MDA).sub.3 LiCl 
complex 
Four E/MA/CO terpolymers having different proportions of monomers were 
individually compounded as described in Example 1. Table II shows the 
properties of vulcanizates obtained after a one-hour cure at 177.degree. 
C. followed by a post-cure of four hours at 150.degree. C. As in Example 
2, "Polygard" functions as the required acid catalyst. 
TABLE II 
______________________________________ 
VULCANIZATE PROPERTIES OF (MDA).sub.3 LiCl-CURED 
E/MA/CO TERPOLYMER 
A B C D 
______________________________________ 
Polymer* 100 100 100 100 
(MDA).sub.3 LiCl, phr 
2.6 2.6 2.6 2.6 
mole % 5.0 4.5 4.2 3.9 
M.sub.100 (MPa) 
5.0 6.6 7.1 6.6 
M.sub.200 (MPa) 
16.0 19.0 -- 19.1 
T.sub.B (MPa) 
17.9 20.3 20.3 20.5 
E.sub.B (%) 207 203 200 203 
______________________________________ 
*A -- 43.8% E/49.1% MA/7.1% CO 
B -- 41.0% E/51.2% MA/7.8% CO 
C -- 37.6% E/53.9% MA/8.5% CO 
D -- 38.1% E/53.0% MA/8.9% CO 
EXAMPLE 4 
Stocks were compounded on a water-cooled, two-roll rubber mill. Oscillating 
Disk Rheometer (ODR) measurements were obtained on the uncured stocks at 
177.degree. C. by ASTM Method D-2705. The cure rates were determined by 
measuring the maximum slope of the ODR traces. 
Table III shows cure rates obtained with the following diamines; 
methylenedianiline, methylenedianiline-sodium chloride complex, 
p-phenylenediamine, m-phenylenediamine, 4-aminophenyl ether and 
4,4'-diaminodiphenyl disulfide as curing agents with "Polygard" 
functioning as the required acid catalyst. In stocks B, C, E, F, and G 
cyclohexyl tosylate also was added as a precursor of p-toluenesulfonic 
acid. 
The ODR data for stock A compared with stocks B and C, and similarly stock 
D compared with E clearly demonstrate the very large rate enhancements, 
evidenced by increases of maximum slope, obtained by the inclusion of this 
additional acid catalyst. 
TABLE III 
__________________________________________________________________________ 
A B C D E F G H I 
__________________________________________________________________________ 
Polymer (1)* 100 100 100 100 100 100 100 
Polymer (2)** 100 100 
SRF (N774) Carbon 
50 50 50 50 50 50 50 50 50 
Black 
"Naugard" 445 
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 
Curing agent 
MDA, phr 1.25 
1.25 
1.50 
mole % 1.84 
1.84 
2.22 
(MDA).sub.3 NaCl, phr 2.00 
2.00 
mole % 2.67 
2.67 
p-phenylenediamine, phr 1.09 
mole % 2.9 
m-phenylenediamine, phr 1.09 
mole % 2.9 
4-aminophenyl ether, phr 1.49 
mole % 2.6 
4,4'-diaminodiphenyl 
disulfide, 
phr 1.87 
mole % 2.6 
Acid Catalyst 
"Polygard", phr 
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 
cyclohexyl tosylate, phr 
1.20 
0.96 1.20 
0.20 
0.20 
mole % 1.34 
1.67 1.34 
0.23 
0.23 
ODR at 177.degree. C. 
Minimum torque, N .multidot. m 
0.15 
0.23 
0.41 
0.42 
0.38 
0.43 
0.50 
0.25 
0.38 
Maximum torque (at 
3.45 
5.68 
5.06 
5.14 
6.10 
5.65 
5.50 
2.99 
1.83 
60 minutes), N .multidot. m 
Maximum slope, 
0.48 
2.85 
1.93 
0.62 
2.09 
1.16 
0.98 
0.24 
0.11 
N .multidot. m/min 
__________________________________________________________________________ 
*Polymer (1) -- 52.8% E/37.3% MA/9.9% CO 
**Polymer (2) -- 54.5% E/37.5% MA/8.0% CO 
EXAMPLE 5 
Evaluation of acid catalysts 
Stocks were compounded as shown in Table IV. Cure rates at 177.degree. C. 
were measured as in Example 13. Acid strength is given as pKa at 
25.degree. C. in water. The data in Table IV show the cure rates obtained 
with the lithium chloride complex of methylenedianiline as the curing 
agent and different acid catalysts. The (MDA) LiCL complex was used in all 
runs at the level of 1.59 phr (2.9 mole %). It will be noted that the cure 
rates increase with acid strength. For example, in the presence of 
2,6-dihydroxybenzoic acid (pKa=1.22) the cure is 6.8 times faster than in 
the presence of 2,4-dihydroxybenzoic acid (pKa=3.29). Acids with pKa in 
range of 4 to 5 give low rates of cure, while acids with pKa in the range 
of 2.5 to 3.0 give moderate rates of cure, and acids with pKa of less than 
2.0 give fast rates of cure. 
TABLE IV 
__________________________________________________________________________ 
A B C D E F G H I 
__________________________________________________________________________ 
Polymer (1)* 100 100 100 100 
Polymer (2)** 100 100 100 100 100 
SRF (N774) Carbon 
50 50 50 50 50 50 50 50 50 
Black 
(MDA).sub.3 LiCl, phr 
1.59 
1.59 
1.59 
1.59 
1.59 
1.59 
1.59 
1.59 
1.59 
mole % 2.87 
2.87 
2.87 
2.87 
2.87 
2.33 
2.33 
2.87 
2.87 
Acid Catalyst (pKa) 
Trimethylacetic acid 
(5.03), phr 0.42 
mole % 1.60 
Benzoic Acid (4.19), phr 
0.50 
mole % 1.60 
Diethylmalonic acid 
(3.15), phr 0.22 
mole % 0.53 
Cyanoacetic acid (2.45), phr 
0.14 
mole % 0.63 
2,4-Dihydroxybenzoic acid 
(3.29), phr 2.20 
mole % 0.49 
2,5-Dihydroxybenzoic acid 
(Unknown but believed 
to be about 3.3), phr 0.20 
mole % 0.49 
2,6-Dihydroxybenzoic acid 
(1.22), phr 0.20 
mole % 0.49 
p-Methoxyphenylphosphonic acid 
(&lt; 2), phr 0.78 
mole % 1.35 
p-Methoxyphenylphosphinic acid 
(&lt;2), phr 0.72 
mole % 1.35 
ODR at 177.degree. C. 
Minimum torque, N .multidot. m 
0.17 
0.23 
0.28 
0.53 
0.15 
0.18 
0.51 
0.28 
0.45 
Maximum torque (at 
0.90 
2.30 
2.00 
3.16 
1.56 
2.97 
3.49 
4.60 
4.40 
60 minutes), N .multidot. m 
Maximum slope, 0.03 
0.06 
0.289 
0.41 
0.108 
0.194 
0.739 
1.06 
1.14 
N .multidot. m/min 
__________________________________________________________________________ 
*Polymer (1) -- 38.4% E/54.3% MA/7.3% CO 
**Polymer (2) -- 36.2% E/54.8% MA/9.0% CO 
EXAMPLE 6 
An E/MA/CO 38.4/54.3/7.3% terpolymer, 100 parts, was compounded by the 
technique used in the previous examples with 50 parts of SRF (N-774) 
carbon black and 1.5 parts (2.87 mole %) of methylenedianiline (MDA) as 
the curing agent. Cyclohexyl tosylate was the acid catalyst, but its 
concentration, based on 100 parts of the compounded rubber, was varied as 
shown in Table V. 
The data presented in Table V show that cyclohexyl tosylate in 
concentrations as low as 0.06 part is an effective accelerator for the MDA 
cure of this E/MA/CO terpolymer, and that very fast rates are obtained 
with concentrations above 0.15 part. 
TABLE V 
______________________________________ 
A B C D E F 
______________________________________ 
Compounded Rubber 
100 100 100 100 100 100 
Cyclohexyl 
Tosylate, 
phr 1.19 0.90 0.60 0.30 0.15 0.06 
mole % 1.8 1.4 0.9 0.5 0.2 0.1 
ODR at 177.degree. C. 
Minimum torque, N .multidot. m 
0.09 0.10 0.11 0.12 0.08 0.11 
Maximum torque (at 
4.84 4.63 4.60 4.52 4.30 4.70 
60 minutes), N .multidot. m 
Maximum slope, 1.12 1.12 1.01 1.01 0.70 0.28 
N .multidot. m/min 
______________________________________ 
Recipe: 
Polymer E, 38.4%/MA, 54.3%/CO, 7.3% (100 parts) 
SRF (N774) Carbon Black (50 parts) 
Methylenedianiline (1.5 parts, 2.87 mole %) 
Cyclohexyl tosylate (as shown) 
EXAMPLE 7 
An E, 36.2%/MA, 54.8%/CO, 9.0% terpolymer was compounded as shown in Table 
VI. The concentration of methylenedianiline, which was the curing agent, 
was varied. 
The ODR data in Table VI show that both the cure rate (evidenced by changes 
in maximum slope) and the state of cure (evidenced by changes in maximum 
torque) rise through a maximum and then decrease as a function of 
methylenedianiline concentration, and that this maximum occurs at a 
diamine concentration of 0.01 mole/100 g of polymer. It is well known that 
this type behavior is indicative of systems in which the polymer contains 
a limited cure site concentration. For the above example this data 
indicates a cure site concentration of 0.02 mole/100 g of polymer. The 
cure sites are attributed to 1,4-diketone functionalities that arise from 
CO/ethylene/CO triads in the polymer chain. 
TABLE VI 
__________________________________________________________________________ 
A B C D E F G H 
__________________________________________________________________________ 
Polymer* 100 100 100 100 100 100 100 100 
SRF (N-774) 50 50 50 50 50 50 50 50 
Carbon Black 
Cyclohexyl Tosylate, phr 
0.33 
0.33 
0.33 
0.33 
0.33 
0.33 
0.33 
0.33 
mole % 0.40 
0.40 
0.40 
0.40 
0.40 
0.40 
0.40 
0.40 
Methylenedianiline (MDA), phr 
0.39 
0.78 
1.19 
1.58 
1.97 
2.36 
3.13 
3.94 
mole % 0.6 1.2 2.0 2.5 3.1 3.8 5.0 6.3 
ODR at 177.degree. C. 
Minimum torque, N .multidot. m 
0.24 
0.31 
0.34 
0.34 
0.28 
0.32 
0.29 
0.29 
Maximum torque (at 
1.42 
2.49 
3.51 
4.55 
3.29 
5.46 
5.38 
4.52 
60 minutes, N .multidot. m 
Maximum slope, N .multidot. m/min 
0.42 
0.86 
1.01 
1.01 
0.99 
0.90 
0.75 
0.45 
__________________________________________________________________________ 
*Polymer -- 36.2% E/54.8% MA/9.0% CO