A method for, and compositions, providing vulcanizable compounds of unsaturated polymers having an improved balance of scorch time and cure rates, ie., slow scorch times and fast cure rates, comprising adding to said vulcanizable polymers accelerating amounts of benzothiazolesulfenamides selected from the group consisting of N-oxydiethylene-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazole sulfenamide and N-cyclohexyl-2-benzothiazole sulfenamide, with N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamides wherein the alkyl radicals contain 4 to 8 carbon atoms.

BACKGROUND OF INVENTION 
N-oxydiethylene-2-benzothiazole sulfenamide (OBTS), 
N-t-butyl-2-benzothiazole sulfenamide (BBTS), and 
N-cyclohexyl-2-benzothiazole sulfenamide (CTBS) are commercially available 
and widely used accelerators for the curing and vulcanization of 
unsaturated elastomers. While the scorch time of compounds containing 
OBTS, BBTS and CTBS are generally satisfactory, the cure rates often are 
slower than is desireable for many applications. An auxiliary material to 
be used in conjunction with the N-oxydiethylene-2-benzothiazole 
sulfenamide, N-t-butyl-2-benzothiazole sulfenamide, and 
N-cyclohexyl-2-benzothiazole sulfenamide in unsaturated polymers to 
enhance the cur rate without substantially altering the scorch time would 
be a valuable addition to the compounders art. Such a system would enhance 
and expand the use of the N-oxydiethylene-2-benzothiazole sulfenamide, 
N-t-butyl-2-benzothiazole sulfenamide and N-cyclohexyl-2-benzothiazole 
sulfenamide while providing the compounder with more flexibility. 
SUMMARY OF THE INVENTION 
The cojoint use of (1) N-oxydiethylene-2-benzothiazole sulfnamide, (2) 
N-t-butyl-2-benzothiazole sulfenamide or (3) N-cyclohexyl-2-benzothiazole 
sulfenamide and N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamides, 
wherein the tertiary alkyl radicals contain 4 to 8 carbon atoms, provides 
an improved balance of scorch times and cure rates in unsaturated polymer 
compounds when they are subsequently cured or vulcanized. 
DETAILED DESCRIPTION 
The N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamides have the structural 
formula 
##STR1## 
wherein R is a t-alkyl radical containing 4 to 8 carbon atoms, i.e., 
t-butyl, t-pentyl, 2-methyl-2-pentyl, t-octyl, 2,4,4-trimethyl-2-pentyl, 
and the like. 
The N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamides are readily 
prepared in accordance with procedures described in U.S. Patent No. 
3,985,743, Taylor, 1976. A useful procedure is to react morpholine and a 
t-alkylamine in a solvent with aqueous sodium hypochlorite, and then with 
carbon disulfide. The resulting sulfenamide is recovered from the reaction 
media. Preferably the reactions are conducted in an aqueous/non-aqueous 
medium. The medium comprises water and an organic solvent, usually a 
chlorinated solvent, including for example methylene chloride, ethylene 
dichloride, chloroform, carbon tetrachloride and the like. The temperature 
of reactions range from about, preferably, -10.degree. C. to about 
40.degree. C. While an excess of amine may be used, excellent yields are 
obtained from about 1 mole of morpholine, 1 mole of t-alkyl amine, 1 mole 
of NaOCl, and 1 mole of carbon disulfide. 
The invention is useful is preparing curable and vulcanizable compounds of 
unsaturated polymers, especially the unsaturated elastomers, and other 
polymers that may be cured or vulcanized to an elastomeric state. Typical 
polymers include natural rubber; cispolyisoprene; cis-polybutadiene; 
copolymers of butadiene-1,3 and vinylidene monomers containing the 
CH.sub.2 C.dbd.ene-1,3 structure, such as styrene, acrylonitrile, alkyl 
acrylates and methacrylates, and others known to those skilled in the art; 
polychloroprene; copolymers of isobutylene and isoprene; unsaturated 
olefin polymers exemplified by ethylene-propylene diene copolymers, and 
the like known to those skilled in the art, in both solid, latex and 
liquid states. The vulcanizable polymers contain at least about one weight 
percent unsaturation and are usually cured or vulcanized with sulfur 
and/or sulfur containing compounds. 
In addition to the cojoint use of N-oxydiethylene-2-benzothiazole 
sulfenamide, N-t-butyl-2-benzothiazole sulfenamide or 
N-cyclohexyl-2-benzothiazole sulfenamide and 
N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamide, in accordance with 
this invention, the usual compounding agents will be used by the man 
skilled in the compounding art, depending on the polymer used, the 
application and the physical properties desired in the cured or vulcanized 
products. Such materials may include activators, retarders, vulcanizing 
and curing agents; protective materials including antioxidants, 
antiozonants, anti-blocking agents, antiflex cracking agents, flame 
retarders, fungicides, germicides, antistatic agents and chemical and heat 
stabilizers; processing materials including plasticizers and softeners, 
processing aids, and tackifiers; extenders, fillers and reinforcing 
materials, and the like. Standard comcompounding ingredients include zinc 
oxide, carbon black, sulfur, oil, and fatty acids. 
The amounts and ratios of the synergistic combination of 
N-oxydiethylene-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazole 
sulfenamide or N-cyclohexyl-2-benzothiazole sulfenamide with 
N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamide used may be varied by 
the man skilled in the art depending on the scorch time and cure rate or 
cure index desired. The amounts normally will be varied from about 0.5 to 
about 5 weight parts, per one hundred weight parts of polymer used, of 
N-oxydiethylene-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazole 
sulfenamide or N-cyclohexyl-2-benzothiazole sulfenamide and about 0.5 to 
about 10 weight parts of N-oxydiethylenethiocarbamyl-N'-t-alkyl 
sulfenamide. The weight ratio of N-oxydiethylene-2-benzothiazole 
sulfenamide, N-t-butyl-2-benzothiazole sulfenamide or 
N-cyclohexyl2-benzothiazole sulfenamide to 
N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamide may be from about 0.25 
to about 2. 
In evaluating the utility of the system of this invention is the following 
Examples it is assumed that the physical properties of the vulcanizates 
are about equivalent. Then the scorch and cure rates are considered. These 
are determined in accordance with ASTM Test Procedure D 1646. This test 
provides the Mooney scorch delay, t.sub.5, and the cure index. In the case 
of the scorch, longer periods of time, larger numbers, are desirable for 
flexibility in operations. As to cure index, the smaller number represents 
a faster cure and is more desirable. In other words, the best condition is 
to have a compound with a long scorch time and a small cure index. 
Another benchmark is the cure rate index, determined in the Monsanto 
Rheometer, ASTM D 2085. In the rubber industry it is generally accepted 
that as the cure rate index for a compound becomes larger, indicating a 
faster cure, the scorch time, t.sub.2 or t.sub.5 becomes less, a shorter 
time or smaller number, and thus the compounds are more scorchy and less 
desirable. 
Contrary to this and in accordance with this invention, compounds may be 
provided that have increased scorch times but are faster curing, as will 
be shown in the Examples. The structure of the 
N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamide is critical and 
essential to the successful practice of the invention and many closely 
related structures do not provide the same balance of desired cured or 
vulcanizing properties.

In the following Examples, in testing the various sulfenamides, the levels 
used are based upon an equal molar basis. Examples 1-5 demonstrate the 
advantages of the invention. Example 6 shows that other sulfenamides, even 
with similar structures, do not provide the scorch times and cure indexes 
provided by the N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamides. An 
advantage of use of the N-oxydiethylenethiocarbamyl-N'-t-alkyl sulfenamide 
is that less can be used to obtain the desired effect than that required 
for other materials. These N-oxydiethylenethiocarbamyl-N'-t-alkyl 
sulfenamides are more easily dispersed in elastomers and are very soluble 
in elastomers such as natural rubber, increasing the ease of 
incorporation, as well as preventing blooming of stocks. Further, the 
lower temperature of melting of these materials allows for desirable 
higher speed processing of compounds. 
EXAMPLE 1 
N-oxydiethylenethiocarbamyl-N'-t-butyl 
sulfenamide 
To a reactor, equipped with a stirrer and cooling bath, containing 87.12 
grams (1.0 mole) of morpholine and 73.14 grams (1.0 mole) of t-butylamine 
in 1000 ml of methylene chloride, there was added 591.3 grams of a 12.59% 
aqueous solution (1.0 mole) of sodium hypochlorite, with stirring, at a 
temperature of 0.degree.-10.degree. C. After ten minutes at this 
temperature, the mixture was allowed to warm up to 20.degree. C. by 
removing the cooling bath. At this point 76.14 grams (1.0 mole) of carbon 
disulfide was added at a rate to maintain the solution at a temperature of 
32.degree.-35.degree. C. After the addition was completed, the reaction 
mixture was stirred for an additional 15 minutes. Agitation was stopped 
and the reaction mixture allowed to separate into aqueous and organic 
phases. The phases were separated. Th eorganic phase was washed with 
water, and dried with sodium sulfate. The dried solution was heated to 
evaporate the solvent. A light yellow solid was obtained. This solid was 
slurried in 200-300 ml of hexane, filtered, rinsed with cold hexane and 
dried. 165 grams of N-oxydiethylenethiocarbamyl-N'-t-butyl sulfenamide was 
obtained. The melting point was 66-69.degree. C. The field desorption/mass 
spectrum indicated a molecular mass of 234. 
EXAMPLE 2 
To demonstrate the utility of the sulfenamide of Example 1 in combination 
with N-oxydiethylene-2-benzothiazole sulfenamide (OBTS), and in comparison 
to N-oxydiethylenethiocarbamyl-N'-oxydiethylene sulfenamide (CR-18), in 
natural rubber, a series of compounds were prepared following this general 
recipe: 
______________________________________ 
Component Weight parts 
______________________________________ 
Natural rubber 100.0 
Zinc oxide 4.5 
Stearic acid 2.0 
Carbon black (HAF) 50.0 
Paraffin wax.sup.1 1.0 
Aromatic petroleum oil.sup.2 
10.0 
Sulfur 2.0 
N--1,3-dimethylbutyl-N'--phenyl- 
1.5 
p-phenylenediamine.sup.3 
______________________________________ 
.sup.1 Sunolite 240 
.sup.2 Sundex 790 
.sup.3 Antozite 67F 
Seven compounds were prepared using varying amounts of the sulfenamide of 
Example 1, N-oxydiethylenethiocarbamyl-N'-t-butyl sulfenamide (BTOS), 
N-oxydiethylene-2-benzothiazole sulfenamide (OTBS) and 
N-oxydiethylenethiocarbamyl-N'-oxydiethylene sulfenamide and tested as 
shown in Table I. The Monsanto Rheometer data were obtained in accordance 
with ASTM Test Procedure D 2084, the Mooney scorch data were obtained in 
accordance with ASTM test procedure D 1646, and the Stress Strain data 
were obtained in accordance with ASTM test procedure D 412. These data 
clearly demonstrate the unexpected improvement in the balance of scorch 
and cure rates obtained in natural rubber when the novel combination of 
sulfenamides is employed. 
TABLE I 
__________________________________________________________________________ 
Compound 1 2 3 4 5 6 7 
__________________________________________________________________________ 
OBTS - weight parts 
0.8 0.2 
0.2 
0.2 
0.24 
CR-18 - weight parts 0.6 0.4 
BTOS - weight parts 0.6 0.4 
0.38 
0.36 
Monsanto Rheometer, 1.degree. ARC, 302.degree. F. 
Maximum torque, in lbs. 
30.4 
28.4 
28.4 
31.2 
31.5 
31.1 
34.0 
Minimum torque, in lbs. 
5.6 
5.7 
5.7 
6.2 
6.3 
6.4 
6.4 
M.sub.H -M.sub.L 24.8 
22.7 
22.7 
25.0 
25.2 
24.7 
27.6 
Scorch time (t.sub.2), min. 
5.7 
4.8 
4.6 
5.4 
4.8 
5.0 
4.9 
Cure time (t.sub.90), min. 
12.8 
12.1 
10.5 
10.7 
9.2 
9.4 
8.8 
Cure time (t.sub.95),min. 
14.5 
13.3 
11.7 
11.5 
10.0 
10.2 
9.6 
Cure rate index 14.1 
13.7 
16.9 
18.9 
22.7 
22.7 
25.6 
Mooney Scorch, ML at 250.degree. F. 
t.sub.5 (min.) 37.4 
28.3 
25.3 
32.9 
33.7 
30.6 
33.0 
t.sub.35 (min.) 42.2 
33.0 
28.9 
37.2 
36.5 
33.4 
35.4 
Cure Index 4.8 
4.7 
3.6 
4.3 
2.8 
2.8 
2.4 
Stress Strain, Opt.Cure (t.sub.95) at 302.degree. F. 
Tensile strength, psi 
4093 
4010 
3793 
4202 
4296 
4145 
4231 
Elongation, % 591 
607 
613 
598 
601 
570 
615 
300% Modulus, psi 1568 
1500 
1349 
1591 
1650 
1724 
1556 
Shore A2 hardness 58.3 
55.5 
56.7 
60.4 
61.0 
57.8 
60.7 
__________________________________________________________________________ 
EXAMPLE 3 
To demonstrate the utility of the sulfenamide of Example 1 in combination 
with N-oxydiethylene-2-benzothiazole sulfenamide (OBTS), and in comparison 
to N-oxydiethylenethiocarbamyl-N'-oxydiethylene sulfenamide (CR-18), in 
styrene-butadiene rubber, a series of compounds were prepared following 
this general recipe: 
______________________________________ 
Component Weight parts 
______________________________________ 
Ameripol 1712.sup.1 
55.0 
Ameripol 1500.sup.1 
25.0 
Taktene 1203.sup.2 
35.0 
Zinc oxide 3.0 
Stearic acid 2.0 
Carbon black (HAF) 
70.0 
Sundex 8125 20.0 
Antozite 67F 2.0 
Agerite Resin D.sup.3 
2.0 
Sulfur 2.0 
______________________________________ 
.sup.1 Styrenebutadiene rubbers, 22-24% bound styrene 
.sup.2 Polybutadiene 
.sup.3 Polymerized dihydroquinoline 
Nine compounds were prepared using varying amounts of the sulfenamide of 
Example 1, N-oxydiethylenethiocarbamyl-N'-t-butyl sulfenamide (BTOS), 
N-oxydiethylene-2-benzothiazole sulfenamide (OBTS) and 
N-oxyethylenethiocarbamyl-N'-oxydiethylene sulfenamide (CR-18) and tested 
as shown in Table II. The Monsanto Rheometer data were obtained in 
accordance with ASTM Test Procedure D 2084, the Mooney scorch data were 
obtained in accordance with ASTM test procedure D 1646, and the Stress 
Strain data were obtained in accordance with ASTM test procedure D 412. 
These data show the excellent results obtained using smaller total amounts 
of the novel combination of sulfenamides, as compared to larger amounts of 
either sulfenamide used alone. 
TABLE II 
______________________________________ 
Compound 1 2 3 
______________________________________ 
OBTS-weight parts 1.43 0.43 
CR-18-weight parts 0.64 
BTOS-weight parts 1.01 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
32.5 32.0 32.7 
Minimum torque, in lbs. 
7.0 7.0 6.7 
M.sub.H -M.sub.L 25.5 25.0 26.0 
Scorch time (t.sub.2), min. 
5.5 4.3 5.5 
Cure time (t.sub.90), min. 
10.04 8.8 11.3 
Cure time (t.sub.95), min. 
12.1 10.0 12.7 
Cure rate index 20.4 22.5 17.2 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 19.0 12.8 17.2 
t.sub.35 (min.) 21.4 14.9 20.4 
Cure Index 2.4 2.1 3.2 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 
3067 3064 3048 
Elongation, % 590 535 530 
300% Modulus, psi 1218 1476 1452 
Shore A2 hardness 63 64.8 62.9 
______________________________________ 
Compound 4 5 6 
______________________________________ 
OBTS-weight parts 0.43 0.40 0.43 
CR-18-weight parts 
BTOS-weight parts 0.64 0.60 0.60 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
32.5 32.0 32.4 
Minimum torque, in lbs. 
7.1 7.0 7.0 
M.sub.H -M.sub.L 25.4 25.0 25.4 
Scorch time (t.sub.2), min. 
5.3 5.5 5.4 
Cure time (t.sub.90), min. 
9.5 9.7 8.9 
Cure time (t.sub.95), min. 
10.6 10.7 10.9 
Cure rate index 23.8 23.8 28.6 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 18.0 19.0 18.7 
t.sub.35 (min.) 20.4 21.5 21.5 
Cure Index 2.4 2.5 2.8 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 
2966 3120 3015 
Elongation, % 508 548 518 
300% Modulus, psi 1484 1440 1486 
Shore A2 hardness 63.5 63.9 64.1 
______________________________________ 
Compound 7 8 9 
______________________________________ 
OBTS-weight parts 0.33 0.25 0.50 
CR-18-weight parts 
BTOS-weight parts 0.67 0.75 0.50 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
32.5 32.5 31.5 
Minimum torque, in lbs. 
7.4 7.5 7.2 
M.sub.H -M.sub.L 25.1 25.0 24.3 
Scorch time (t.sub.2), min. 
5.3 5.0 5.7 
Cure time (t.sub.90), min. 
9.6 9.2 10.6 
Cure time (t.sub.95), min. 
10.6 10.2 11.7 
Cure rate index 23.3 23.8 20.4 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 16.0 15.9 17.2 
t.sub.35 (min.) 18.4 18.4 20.1 
Cure Index 2.0 2.5 2.9 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 
3053 2793 2909 
Elongation, % 550 485 561 
300% Modulus, psi 1406 1499 1278 
Shore A2 hardness 66.9 67.8 68 
______________________________________ 
EXAMPLE 4 
N-oxydiethylenethiocarbamyl-N'-(2,4,4-trimethyl-2-pentyl) sulfenamide 
To a reactor, equipped with a stirrer and cooling bath, containing 8.71 
grams (0.1 mole) of morpholine and 12.92 grams (0.1 mole) of t-octylamine 
in 100 ml of hexane, there was added 55.22 grams of an 13.48% aqueous 
solution (0.1 mole) of sodium hypochlorite, with stirring, at a 
temperature of 0.degree.-10.degree. C. After ten minutes at this 
temperature, the mixture was allowed to warm up to 20.degree. C. by 
removing the cooling bath. At this point 7.61 grams (0.1 mole) of carbon 
disulfide was added at a rate to maintain the solution at a temperature of 
32.degree.-35.degree. C. After the addition was completed, the reaction 
mixture was stirred for an additional 15 minutes. Agitation was stopped 
and a solid precipitate was removed by filtration to give 13 grams of 
product. This solid was slurried in 200 ml of hexane and filtered to 
remove the solid impurity. The filtrate was heated to remove the hexane. 
Ten grams of white, flaky and crystalline 
N-oxydiethylenethiocarbamyl-N'-(2,4,4-trimethyl-2-pentyl) sulfenamide was 
obtained. The melting point was 73.degree.-75.degree. C. The field 
desorption/mass spectrum indicated a molecular mass of 290. 
The N-oxydiethylenethiocarbamyl-N'-(2,4,4-trimethyl-2-pentyl)sulfenamide 
was tested in the same recipe set forth in Example 3 in amount of 1.25 
weight parts. The resulting vulcanizate compounds had a Scorch Time, 
t.sub.2, of 5.4 min.; a Cure Time, t.sub.90, of 10.5 min.; and a Cure Rate 
Index of 19.6. The Mooney Scorch values obtained were, t.sub.5, 15.3 min,; 
with a Cure Index of 2.4. The tensile strength of the vulcanized compounds 
was 2901 psi; the percent elongation was 555; and the 300% modulus was 
1278 psi. 
EXAMPLE 5 
N-oxydiethylenethiocarbamyl-N'-t-pentyl sulfenamide 
To a reactor, equipped with a stirrer and cooling bath, containing 8.75 
grams (0.1 mole) of morpholine and 8.72 grams (0.1 mole) of t-amylamine in 
100 ml of hexane, there was added 55.22 grams of an 13.48% aqueous 
solution (0.1 mole) of sodium hypochlorite, with stirring, at a 
temperature of 0.degree.-10.degree. C. After ten minutes at this 
temperature, the mixture was allowed to warm up to 20.degree. C. by 
removing the cooling bath. At this point 7.61 grams (0.1 mole) of carbon 
disulfide was added at a rate to maintain the solution at a temperature of 
32.degree.-35.degree. C. After the addition was completed, the reaction 
mixture was stirred for an additional 15 minutes. Agitation was stopped 
and the reaction mixture allowed to separate into aqueous and organic 
phases. The phases were separated. The organic phase was washed with 
water, and dried with sodium sulfate. The dried solution was heated to 
evaporate the solvent. A yellow oil was obtained which crystallized on 
standing. This solid was recrystallized from methanol. 8.0 grams of 
N-oxydiethylenethiocarbamyl-N'-t-pentyl sulfenamide was obtained. The 
field desorption/mass spectrum indicated a molecular mass of 248. 
The N-oxydiethylenethiocarbamyl-N'-t-pentyl sulfenamide was tested in the 
same recipe set forth in Example 3, in an amount of 1.07 weight parts. The 
resulting compound had a Scorch Time, t.sub.2, of 5.0 min.; a Cure Time, 
t.sub.90, of 9.3 min.; and a Cure Rate Index of 23.3. The Mooney Scorch 
values were, a t.sub.5, of 13.0 min, and a Cure Index of 2.2. The tensile 
strength of vulcanizates of the compound was 2817 psi; elongation of 539% 
and a 300% modulus of 1301 psi. 
EXAMPLE 6 
Following the procedure and recipes of Example 3, 
N-oxybis(2-methylethylene)-thiocarbamyl-N'-t-butyl sulfenamide (2), 
structurally related to N-oxydiethylenethiocarbamyl-N'-t-alkyl 
sulfenamides, but not a part of this invention, was compared to 
N-oxydiethylenethiocarbamyl-N'-t-butyl sulfenamide (1). The amounts used 
and the results obtained are set forth in Table IV. The sulfenamides of 
the compounds are identified by the numbers above. 
TABLE III 
______________________________________ 
Compound 1 2 
______________________________________ 
Compound (1)-weight parts 
1.01 
Compound (2)-weight parts 1.13 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 32.0 27.8 
Minimum torque, in lbs. 6.9 7.2 
M.sub.H -M.sub.L 25.1 20.6 
Scorch time (t.sub.2), min. 
5.3 5.7 
Cure time (t.sub.90), min. 
9.9 14.6 
Cure time (t.sub.95), min. 
11.0 16.6 
Cure rate index 21.7 11.2 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 15.9 16.3 
t.sub.35 (min.) 18.5 20.5 
Cure Index 2.6 4.2 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 2939 3142 
Elongation, % 470 619 
300% Modulus, psi 1653 1186 
Shore A2 hardness 70 67 
______________________________________ 
Referring to Data Table III, Mooney Scorch Data, the Scorch time (t.sub.5) 
of the two compounds is substantially equivalent, the Scorch time 
(t.sub.5) of (2) being only about 2.5% longer than (1). However, the real 
and critical difference is in the Cure Index. The Cure Index of (1) is 
2.6, about 61.5% lesser, or faster, than (2) having a Cure Index of 4.2. 
EXAMPLE 7 
To demonstrate the utility of the sulfenamide of Example 1 in combination 
with N-t-butyl-2-benzothiazole sulfenamide (BBTS) and 
N-cyclohexyl-2-benzothiazole sulfenamide (CTBS) in styrene-butadiene 
rubber, a series of compounds were prepared following this general recipe: 
______________________________________ 
Component Weight parts 
______________________________________ 
Ameripol 1712.sup.1 
55.0 
Ameripol 1500 25.0 
Taktene 1203.sup.2 
35.0 
Zinc oxide 3.0 
Stearic acid 2.0 
Carbon black (HAF) 
70.0 
Sundex 8125 20.0 
Antozite 67F 2.0 
Agerite Resin D.sup.3 
2.0 
Sulfur 2.0 
______________________________________ 
.sup.1 Styrenebutadiene rubbers, 22-24% bound styrene 
.sup.2 Polybutadiene 
.sup.3 Polymerized dihydroquinoline 
Five compounds were prepared using the sulfenamide of Example 1, 
N-oxydiethylenethiocarbamyl-N'-t-butyl sulfenamide (BTOS), with (1) 
N-t-butyl-2-benzothiazole sulfenamide (BBTS) and (2) 
N-cyclohexyl-2-benzothiazole sulfenamide (CTBS), and tested as shown in 
Table IV. The Monsanto Rheometer data were obtained in accordance with 
ASTM Test Procedure D 2084, the Mooney scorch data were obtained in 
accordance with ASTM test procedure D 1646, and the Stress Strain data 
were obtained in accordance with ASTM test procedure D 412. These data 
show the excellent results obtained using the novel combination of 
sulfenamide (BTOS) and these two benzothiazole sulfenamides. The Mooney 
Scorch times (t.sub.5) are longer for the combination of 
N-oxydiethylenethiocarbamyl-N'-t-butyl sulfenamide with 
N-t-butyl-2-benzothiazole sulfenamide (BBTS) or 
N-cyclohexyl-2-benzothiazole sulfenamide (CTBS) than that obtained with 
the equivalent amount of BBTS or CTBS alone. Also the cure rates of the 
combinations are obviously faster than BBTS or CTBS alone. Thus, by means 
of the novel combinations of this invention, a desired increase in scorch 
delay is obtained with no loss, and often, a gain in cure rate. This is 
not true of the combination of N-oxydiethylenethiocarbamyl-N'-t-butyl 
sulfenamide with other commercially available benzothiazole accelerators. 
These commercially available accelerators include: 
N-dicyclohexyl-2-benzothiazole-sulfenamide (DCBS), 
N-diisopropyl-2-benzothizazolesulfenamide (DIBS), 2-mercaptobenzothiazole 
(MBT), 2-benzothiazyl disulfide (MBTS) or 4-morpholino-2-benzothiazyl 
disulfide (Morfax). This is demonstrated in the following Example 8. 
TABLE IV 
__________________________________________________________________________ 
Compound 1 2 3 4 5 
__________________________________________________________________________ 
BBTS - weight parts 1.35 0.40 
0.45 
CTBS - weight parts 1.50 
BTOS - weight parts 
1.01 0.61 
0.61 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
31.2 
32.3 
31.5 32.0 
32.1 
Minimun torque, in lbs. 
7.8 7.6 
7.1 8.1 
8.3 
M.sub.H -M.sub.L 23.4 
24.7 
24.4 23.9 
23.8 
Scorch time (t.sub.2), min. 
5.3 5.6 
5.7 6.6 
6.4 
Cure time (t.sub.90), min. 
10.1 
12.1 
10.8 11.4 
10.6 
Cure time (t.sub.95), min. 
11.2 
13.7 
12.3 12.6 
11.7 
Cure rate index 18.6 
13.9 
16.9 18.7 
20.6 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 16.9 
19.0 
17.8 22.5 
21.0 
t.sub.35 (min.) 19.2 
22.1 
19.2 24.8 
23.0 
Cure Index 2.3 3.1 
2.0 2.3 
2.0 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 
2954 
2749 
2999 2821 
2766 
Elongation, % 581 548 
583 559 
555 
300% Modulus, psi 1218 
1217 
1243 1209 
1205 
__________________________________________________________________________ 
EXAMPLE 8 
The procedure from Example 7 was followed, including using the same base 
recipe and five commercial sulfenamide accelerators. The test results are 
found in Table V. 
After an evaluation of the data it is reaily apparent that the improved 
balance of scorch times and cure rates obtained with the 
N-oxydiethylenethiocarbamyl-N'-alkyl sulfenamides of this invention in 
combination with N-oxydiethylene-2-benzothiazole sulfenamide, 
N-t-butyl-2-benzothiazole sulfenamide and N-cyclohexyl-2-benzothiazole 
sulfenamide are not obtained with other closely related benzothiazole 
accelerators as demonstrated in these tests in this Example. The 
combination of BTOS with MBTS results in a scorch delay that is about an 
average of that of the two additives of the combination. BTOS with MBT 
exhibits a scorch delay shorter than either additive alone. Although some 
increase in cure index may be noted, there is still not obtained the 
desired balance of both increased cure rates and scorch delay. This is 
also the results noted with Morfax, DIBS and DCBS with BTOS. The scorch 
times are less for the combination than for Morfax, DIBS and DCBS alone, 
thus no advantage, and although the cure rates have been increased some 
this still does not provide the desirable balance obtained in accordance 
with the invention. 
TABLE V 
______________________________________ 
Compound 1 2 3 4 
______________________________________ 
MBT 0.95 
MBTS 0.95 
Morfax 1.62 
DIBS 
DCBS 
BTOS-weight parts 1.01 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
31.2 24.8 25.8 34.0 
Minimum torque, in lbs. 
7.8 8.2 7.9 8.3 
M.sub.H -M.sub.L 23.4 16.6 17.9 25.7 
Scorch time (t.sub.2), min. 
5.3 5.9 5.1 4.3 
Cure time (t.sub.90), min. 
10.1 22.0 20.8 10.5 
Cure time (t.sub.95), min. 
11.2 25.3 24.4 12.3 
Cure rate index 18.6 3.8 6.0 14.8 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 16.9 17.2 14.0 12.5 
t.sub.35 (min.) 19.2 23.9 21.2 15.6 
Cure Index 2.3 6.7 7.2 3.1 
Stress Strain, Opt. Cure (t.sub.95)at 320.degree. F. 
Tensile strength, psi 
2954 2781 2715 3017 
Elongation, % 581 802 759 557 
300% Modulus, psi 1218 716 729 1331 
______________________________________ 
Compound 5 6 7 8 
______________________________________ 
MBT 0.28 
MBTS 0.30 
Morfax 
DIBS 1.52 
DCBS 1.97 
BTOS-weight parts 0.61 0.61 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
31.1 30.9 30.7 30.4 
Minimum torque, in lbs. 
7.6 8.3 8.2 7.4 
M.sub.H -M.sub.L 23.5 22.6 22.5 23.0 
Scorch time (t.sub.2), min. 
8.4 8.9 4.0 4.7 
Cure time (t.sub.90), min. 
18.9 19.1 8.2 9.0 
Cure time (t.sub.95), min. 
20.6 20.9 9.5 10.4 
Cure rate index 8.1 8.2 22.3 21.0 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 28.5 30.5 12.5 15.4 
t.sub.35 (min.) 35.2 37.0 14.5 17.4 
Cure Index 6.7 6.5 2.0 2.0 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 
3019 3072 2769 2803 
Elongation, % 612 650 609 604 
300% Modulus, psi 1151 1081 1030 1056 
______________________________________ 
Compound 9 10 11 
______________________________________ 
MBT 
MBTS 
Morfax 0.48 
DIBS 0.45 
DCBS 0.59 
BTOS-weight parts 0.61 0.61 0.61 
Monsanto Rheometer, 1.degree. ARC, 320.degree. F. 
Maximum torque, in lbs. 
33.4 30.5 31.2 
Minimum torque, in lbs. 
8.2 7.4 8.1 
M.sub.H -M.sub.L 25.2 23.1 23.1 
Scorch time (t.sub.2), min. 
4.2 6.2 6.1 
Cure time (t.sub.90), min. 
8.2 12.4 12.1 
Cure time (t.sub.95), min. 
9.5 13.9 13.6 
Cure rate index 22.0 14.3 14.6 
Mooney Scorch, ML at 280.degree. F. 
t.sub.5 (min.) 13.0 19.4 19.2 
t.sub.35 (min.) 15.0 22.3 22.0 
Cure Index 2.0 2.9 2.8 
Stress Strain, Opt. Cure (t.sub.95) at 320.degree. F. 
Tensile strength, psi 
2937 2946 3108 
Elongation, % 552 622 634 
300% Modulus, psi 1315 1103 1161 
______________________________________