Curable composition of halogen-containing polymer

A curable composition of halogen-containing polymer composed of PA1 (1) 100 parts by weight of a halogen-containing polymer, PA1 (2) as a crosslinking agent, about 0.1 to about 10 parts by weight of a 2,4-dithiohydantoin having the formula ##STR1## wherein R.sub.1 and R.sub.2 are identical or different and represent a member selected from the class consisting of a hydrogen atom, C.sub.1 -C.sub.8 alkyl groups, C.sub.6 -C.sub.8 cycloalkyl groups, C.sub.2 -C.sub.8 alkenyl groups, C.sub.6 -C.sub.8 aryl groups and C.sub.7 -C.sub.8 aralkyl groups, or R.sub.1 and R.sub.2 are bonded together to form a 5- or 7-membered hydrocarbon ring which may contain a nitrogen atom and have at least one lower alkyl group as a substituent, or a metal salt thereof, and PA1 (3) as an acid acceptor, about 0.5 to about 50 parts by weight of a compound of a metal of Group II of IVa of the periodic table.

BACKGROUND OF THE INVENTION 
This invention relates to a cureble composition of a halogen-containing 
polymer containing, as a crosslinking agent, a 2,4-dithiohydantoin 
compound or a metal salt thereof which can readily and effectively induce 
curing of the halogen-containing polymer. Cured articles from the 
composition have various superior properties such as a high curing 
density, good heat-aging resistance and good dynamic fatigue resistance. 
More specifically, this invention pertains to a curable composition of a 
halogen-containing polymer composed of 
(1) 100 parts by weight of a halogen-containing polymer, 
(2) as a crosslinking agent, about 0.1 to about 10 parts by weight of a 
2,4-dithiohydantoin having the formula 
##STR2## 
wherein R.sub.1 and R.sub.2 are identical or different and represent a 
member selected from the class consisting of a hydrogen atom, C.sub.1 
-C.sub.8 alkyl groups, C.sub.6 -C.sub.8 cycloalkyl groups, C.sub.2 
-C.sub.8 alkenyl groups, C.sub.6 -C.sub.8 aryl groups and C.sub.7 -C.sub.8 
aralkyl groups, or R.sub.1 and R.sub.2 are bonded together to form a 5- to 
7-membered hydrocarbon ring which may contain a nitrogen atom and have at 
least one lower alkyl group as a substituent, or a metal salt thereof, and 
(3) as an acid acceptor, about 0.5 to about 50 parts by weight of a 
compound of a metal of Group II or IVa of the periodic table. 
Halogen-containing polymers such as polychloroprene, polyepichlorohydrin, 
an epichlorohydrin/ethylene oxide copolymer, chlorine-containing acrylic 
rubber, chlorinated polyethylene, brominated butyl rubber, fluorine rubber 
and polyvinyl chloride in the cured state find extensive use as materials 
having good properties, such as superior thermal stability, oil resistance 
and chemical resistance. It has been difficult however to cure the 
halogen-containing polymers effectively because the carbon-halogen bond in 
these polymers is chemically stable. 
Numerous curing agents for halogen-containing polymers have been suggested 
heretofore, but none have shown a satisfactory curing effect. 
2-Mercaptoimidazoline, a typical curing agent now in commercial use, too, 
has the defect that it cannot cure polymers having relatively low 
reactivity, such as chlorinated polyethylene or polyvinyl chloride, at a 
feasible speed. In addition, it has been pointed out that 
2-mercaptoimidazoline may be carcinogenic (P. R. Johnson, Rubber Journal, 
pages 37-44, April 1973). 
In view of the state of the art, it has been desired to develop other 
curing agents of industrial value which can easily and effectively cure 
halogen-containing polymers having relatively low reactivity. 
SUMMARY OF THE INVENTION 
It has now been found in accordance with this invention that the 
2,4-dithiohydantoin compounds of formula (I), which have not been known 
heretofore as any crosslinking agents, much less as crosslinking agents 
for the halogen-containing polymers exemplified hereinabove, are very 
useful as crosslinking agents capable of readily and effectively exerting 
a curing action on a wide range of halogen-containing polymers including 
those of relatively low reactivity as exemplified hereinabove. 
The compounds of formula (I) and a process for their production are 
disclosed, for example, in German Laid-Open Patent Application No. 
2,814,256, French Patent No. 966,395, Chemical Abstracts 46, 7587b, 
British Patent No. 667,122, Chemical Abstracts 47, 1733c, and Chemical 
Abstracts 43, 6171e, and are known to be useful as lubricant oil 
additives. Their utility as a crosslinking agent for polymers or rubbers 
including halogen-containing polymers has been completely unknown to date. 
It has been unexpectedly found in accordance with this invention that the 
2,4-dithiohydantoin compounds of formula (I) or the metal salts thereof, 
with or without a vulcanization accelerator, exhibit superior performance 
as a crosslinking agent for a wide variety of halogen-containing polymers. 
It has also been found that cured products obtained by curing 
halogen-containing polymers with the compounds of formula (I) in the 
presence of the acid acceptor (3), with or without a vulcanization 
accelerator, have good properties, and the curing time changes little with 
a change in the amount of the crosslinking agent, thus insuring a good 
reproducibility of quality. 
It is an object of this invention therefore to provide an improved curable 
composition of a halogen-containing polymer. 
Another object of this invention is to provide a crosslinking agent useful 
for such a curable halogen-containing polymer composition.

DETAILED DESCRIPTION OF INVENTION 
The halogen-containing polymer in the curable composition of this invention 
includes a variety of polymers such as chlorinated polyethylene, a 
chlorinated ethylenepropylene copolymer, a chlorinated 
ethylene/propylene/nonconjugated diene terpolymer, chlorosulfonated 
polyethylene, polyvinyl chloride, chlorine-containing acrylic rubber, 
chlorinated butyl rubber, brominated butyl rubber, fluorine rubber, 
polychloroprene, polyepichlorohydrin, an epichlorohydrin/allyl glycidyl 
ether copolymer, an epichlorohydrin/ethylene oxide copolymer, and an 
epichlorohydrin/ethylene oxide/allyl glycidyl ether terpolymer. 
The crosslinking agent used in this invention is a 2,4-dithiohydantoin 
having the following formula (I) 
##STR3## 
wherein R.sub.1 and R.sub.2 are identical or different and represent a 
member selected from the class consisting of a hydrogen atom, C.sub.1 
-C.sub.8 alkyl groups, C.sub.6 -C.sub.8 cycloalkyl groups, C.sub.2 
-C.sub.8 alkenyl groups, C.sub.6 -C.sub.8 aryl groups and C.sub.7 -C.sub.8 
aralkyl groups, or R.sub.1 and R.sub.2 are bonded together to form a 5- to 
7-membered hydrocarbon ring which may contain a nitrogen atom and have at 
least one lower alkyl group as a substituent; or a metal salt thereof. 
Examples of the alkyl groups as R.sub.1 and R.sub.2 include methyl, ethyl, 
isopropyl, isobutyl and heptyl. Examples of the cycloalkyl groups for 
R.sub.1 and R.sub.2 are cyclohexyl and 4-methyl-cyclohexyl. Examples of 
the alkenyl groups for R.sub.1 and R.sub.2 are vinyl, allyl and 
isopropenyl. Examples of the aryl groups for R.sub.1 and R.sub.2 include 
phenyl and p-tolyl. Examples of the aralkyl groups for R.sub.1 and R.sub.2 
are benzyl and phenethyl. 
Alternatively, R.sub.1 and R.sub.2, taken together with the carbon atom to 
which they are bonded, may represent a 5- or 7-membered hydrocarbon ring 
which may contain a nitrogen atom and have at least one lower alkyl group, 
preferably having 1 to 3 carbon atoms, as a substituent. 
Examples of the hydrocarbon ring are cyclopentamethylidene, 
cyclohexamethylidene, cycloheptamethylidene, 
3-methylcyclopentamethylidene, 2-methylcyclopentamethylidene, 
2,3-dimethylcyclohexamethylidene, 4-azacyclohexamethylidene, 
4-methyl-4-azacyclohexamethylidene, 
3,3,4,5,5-pentamethyl-4-azacyclohexamethylidene, and 
3,3,5-trimethyl-4-azacyclohexamethylidene. 
The mono- or di-metal salts of the compounds of formula (I) can also be 
used in this invention. Examples of the metals in these metal salts are 
metals of Groups Ia, IIa, IIb and VIIa of the periodic table. Preferably, 
the metal is selected from the group consisting of Na, K, Mg, Ca, Ba, Zn, 
Cd and Mn. 
Typical examples of the compounds of formula (I) and their metal salts 
include the following compounds. 
2,4-Dithiohydantoin, 
5-methyl-2,4-dithiohydantoin, 
5,5-dimethyl-2,4-dithiohydantoin, 
5,5-diethyl-2,4-dithiohydantoin, 
5-isobutyl-5-methyl-2,4-dithiohydantoin, 
5-cyclohexyl-2,4-dithiohydantoin, 
5-isopropenyl-2,4-dithiohydantoin, 
5-phenyl-2,4-dithiohydantoin, 
5-benzyl-2,4-dithiohydantoin, 
5,5-cyclotetramethylene-2,4-dithiohydantoin, 
5,5-cyclopentamethylene-2,4-dithiohydantoin, 
5,5-2'-methylcyclotetramethylene-2,4-dithiohydantoin, 
5,5-1'-methylcyclopentamethylene-2,4-dithiohydantoin, 
5,5-3'-methyl-3'-azacyclopentamethylene-2,4-dithiohydantoin, 
5,5-2',2',4'-trimethyl-3'-azacyclopentamethylene-2,4-dithiohydantoin, 
a 1:1 (mole) salt of 2,4-dithiohydantoin and sodium, 
a 1:2 (mole) salt of 5-methyl-2,4-dithiohydantoin and potassium, 
a 2:1 (mole) salt of 5,5-dimethyl-2,4-dithiohydantoin and magnesium, 
a 1:1 (mole) salt of 5,5-diethyl-2,4-dithiohydantoin and calcium, 
a 2:1 (mole) salt of 5-isobutyl-5-methyl-2,4-dithiohydantoin and barium, 
a 2:1 (mole) salt of 5-cyclohexyl-2,4-dithiohydantoin, 
a 2:1 salt of 5-isopropenyl-2,4-dithiohydantoin and cadmium, 
a 2:1 (mole) salt of 5-phenyl-2,4-dithiohydantoin and manganese, 
a 1:1 (mole) salt of 5-benzyl-2,4-dithiohydantoin and sodium, 
a 1:2 (mole) salt of 5,5-cyclotetramethylene-2,4-dithiohydantoin and 
sodium, 
a 1:1 (mole) salt of 5,5-cyclopentamethylene-2,4-dithiohydantoin and 
potassium, 
a 2:1 (mole) salt of 5,5-cyclohexamethylene-2,4-dithiohydantoin and 
magnesium, 
a 2:1 (mole) salt of 5,5-2'-methylcyclotetramethylene-2,4-dithiohydantoin 
and manganese, 
a 1:2 (mole) salt of 5,5-1'-methylcyclopentamethylene-2,4-dithiohydantoin 
and sodium, 
a 1:1 (mole) salt of 
5,5-1',2'-dimethylcyclopentamethylene-2,4-dithiohydantoin and zinc, 
a 1:1 (mole) salt of 5,5-3'-azacyclopentamethylene-2,4-dithiohydantoin and 
cadmium, 
a 2:1 (mole) salt of 
5,5-3'-methyl-3'-azacyclopentamethylene-2,4-dithiohydantoin and zinc, 
a 2:1 (mole) salt of 
5,5-2',2',3',4',4'-pentamethyl-3'-azacyclopentamethylene-2,4-dithiohydanto 
in and magnesium, 
a 2:1 (mole) salt of 
5,5-2',2',4'-trimethyl-3'-azacyclopentamethylene-2,4-dithiohydantoin and 
calcium. 
The use of the compound of formula (I) in such a salt form has the further 
advantage that the occurrence of offensive odors or gases can be avoided 
during the vulcanizing operation. 
The curable composition of this invention further contains a compound of a 
metal of Group II or IVa of the periodic table as an acid acceptor. The 
metal compounds as an acid acceptor include oxides, hydroxides, 
carbonates, carboxylates, silicates, borates, and phosphites of metals of 
Group II of the periodic table, preferably Mg, Ba, Ca and Zn; and oxides, 
basic carbonates, basic carboxylates, basic phosphites, basic sulfites, 
and tribasic sulfates of metals of Group IVa of the periodic table, 
preferably Sn and Pb. Specific examples are magnesia, magnesium hydroxide, 
barium hydroxide, magnesium carbonate, barium carbonate, quick lime, 
slaked lime, calcium carbonate, calcium silicate, calcium stearate, zinc 
stearate, calcium phthalate, magnesium phosphite, calcium phosphite, zinc 
oxide, tin oxide, litharge, red lead, white lead, dibasic lead phthalate, 
dibasic lead carbonate, tin stearate, basic lead phosphite, basic tin 
phosphite, basic lead sulfite, and tribasic lead sulfate. 
The curable composition of this invention is composed of 100 parts by 
weight of the halogen-containing polymer (1), about 0.1 to about 10 parts 
by weight, preferably about 0.2 to about 6 parts by weight, of 
2,4-dithiohydantoin of formula (I) a metal salts thereof as a crosslinking 
agent, and about 0.5 to about 50 parts by weight, preferably about 1 to 
about 30 parts by weight, more preferably about 1 to about 20 parts by 
weight, of the compound of a metal of Group II or IVa of the periodic 
table as an acid acceptor. 
When the amount of the crosslinking agent (2) is too small below the 
specified limit, the crosslinking effect is insufficient, and when it far 
exceeds the upper limit specified, the resulting cured product is 
comparatively brittle. When the amount of the acid acceptor is too small 
below the specified limit, the resulting cured product has poor resistance 
to heat deterioration, and when it far exceeds the upper limit, the 
mechanical properties (such as tensile strength and elongation) of the 
resulting cured product are degraded. 
In addition to the aforesaid three essential ingredients (1), (2) and (3), 
the curable composition of this invention may further include other 
additives conventionally used in the art. 
Examples of such additives include organic or inorganic fillers such as 
calcium carbonate, clay, talc, diatomaceous earth, ferrite, mica powder, 
barium sulfate, graphite, glass fibers, cork powder and wood flour; 
reinforcing agents such as carbon black, silica, calcium silicate and 
basic magnesium carbonate; plasticizers such as dioctyl phthalate, 
diisodecyl adipate, chlorinated paraffin and process oils for rubbers; 
processing aids such as paraffin wax and stearic acid; antioxidants such 
as polymerized trimethyl dihydroquinoline, 
2,6-di-tert-butyl-4-methyl-phenol and dilauryl thiodipropionate; coloring 
agents such as titanium oxide, red iron oxide and ultramarine; and fire 
retarding agents such as antimony trioxide, aluminum hydroxide, zinc 
borate, tris(chloroethyl)phosphate and tetrabromobisphenols. 
The amounts of these additives per 100 parts by weight of the 
halogen-containing polymer are up to about 1000 parts by weight for the 
fillers; up to about 200 parts by weight for the reinforcing agent; up to 
about 100 parts by weight for the plasticizers; up to about 10 parts by 
weight for the processing aids; up to about 5 parts by weight for the 
antioxidants; up to about 50 parts by weight for the coloring agents; and 
up to about 50 parts by weight for the fire retardants. 
The composition of this invention may further include a vulcanization 
accelerator, the use of which is preferred for halogen-containing polymers 
having a relatively low reactivity such as chlorinated polyethylene, 
polyvinyl chloride, chlorinated butyl rubber and polyepichlorohydrin. 
Examples of the vulcanization accelerator are elementary sulfur, thiuram 
sulfides, dithiocarbamates, sulfenamides, aliphatic or aromatic amines, 
salts of weak acids such as 2-mercaptobenzothiazole, phthalic acid or 
benzoic acid with these amines, addition products of these amines with 
alcohols or oximes, for examples adducts with cyclohexyl alcohol, or 
cyclohexanoneoxime, and basic silicas. 
Specific examples of these vulcanization accelerators are 
dipentamethylenethiuram tetrasulfide, tetramethylthiuram disulfide, 
cadmium pentamethylenedithiocarbamate, tellurium dimethyldithiocarbamate, 
piperidine pentamethylenedithiocarbamate, cyclohexylamine, dibutylamine, 
dibutylammonium oleate, diphenyl guanidine, di-ortho-tolyl guanidine, 
acetaldehyde aniline, butylaldehyde aniline, 
N-cyclohexyl-2-benzothiazothiazyl sulfenamide, 
N,N'-dicyclohexyl-2-benzothiazyl sulfenamide, and a dicyclohexylamine salt 
of 2-mercaptobenzothiazole. 
The amount of the vulcanization accelerator is not particularly critical, 
but is preferably about 0.2 to about 6 parts by weight per 100 parts by 
weight of the halogen-containing polymer. 
In order to impart excellent processing safety in addition to rapid 
vulcanization rates, there may be incorporated a vulcanization retarder of 
the following formula 
##STR4## 
wherein R.sub.5 and R.sub.6, independently from each other, represent a 
C.sub.1 -C.sub.20 aliphatic, alicyclic or aromatic hydrocarbon group. 
Examples of the vulcanization retarder include 
N-cyclohexylthio-phthalimide, N-cyclohexylthiosuccinimide, 
N-cyclohexylthiomaleimide, N-dodecylthiophthalimide, 
N-dodecylthiosuccinimide, N-dodecylthiomaleimide, N-phenylthiophthalimide, 
N-phenylthiosuccinimide, and N-phenylthiomaleimide. The amount of the 
vulcanization retarder is, for example, about 0.1 to about 3 parts by 
weight, preferably about 0.3 to about 2 parts by weight, per 100 parts by 
weight of the halogen-containing polymer. 
The curable composition of this invention can be prepared by uniformly 
blending 100 parts by weight of the halogen-containing polymer (1), about 
0.1 to about 10 parts by weight of the 2,4-dithiohydantoin of the formula 
(I) or an acid salt thereof as a crosslinking agent (2), about 0.5 to 
about 50 parts by weight of the metal compound as an acid acceptor (3), 
and optionally the other additives exemplified hereinabove. Blending can 
be effected by using known blending devices such as a mixing roll, a 
Banbury mixer, and various kneaders such as a pressure-type kneader. The 
blending temperature that can be employed is about 50.degree. to about 
100.degree. C. for the curing agent and accelerator, and about 60.degree. 
to about 200.degree. C. for the other compounding agents. 
The composition of this invention can be cured by heating it to a 
temperature of, say, about 100.degree. to about 200.degree. C. The heating 
time can be chosen properly, and may, for example, be about 0.5 to 120 
minutes. Curing of the composition can be performed by any desired methods 
such as press-forming under heat in a mold, injection molding, and heat 
molding using a steam can, an air bath, an infrared ray, or microwaves. 
The following examples illustrate the present invention more specifically. 
In these examples, the amounts of the various components are expressed in 
parts by weight unless otherwise specified. 
EXAMPLES 1 TO 11 AND COMATIVE EXAMPLES 1 TO 3 
In each run, the ingredients shown in Tables 1 and 5 were kneaded on an 
open roll at 60.degree. to 70.degree. C. The resulting sheet was placed in 
a mold, and molded under pressure at 155.degree. C. and 80 kg/cm.sup.2 for 
30 minutes. The vulcanizate obtained was tested for the various properties 
shown in Tables 2 to 4 and 6 to 9. The results are shown in Tables 2 to 4 
and 6 to 9. 
In Comparative Example 1, 2-mercaptoimidazoline customarily used as a 
vulcanizer for an epichlorohydrin/ethylene oxide copolymer was used, and 
in Comparative Example 2, 1-phenyl-3,5-dimercapto-1,2,4-triazole which is 
disclosed in U.S. Pat. No. 4,234,705 as a vulcanizer for a 
halogen-containing polymer was used. 
Tables 2 and 6 show the basic properties of vulcanizates; Table 3 shows the 
heat-aging resistances of the vulcanizates obtained in Examples 1, 2, 3 
and 6 and Comparative Examples 1 and 2 in terms of changes from their 
basic properties; Table 7 shows the heat-aging resistances of the 
vulcanizate obtained in Examples 7 to 9 and Comparative Example 2; Tables 
4 and 8 show the results of tests for permanent compression set and oil 
resistance; and Table 9 shows the results of a dynamic fatigue test on the 
vulcanizates obtained in Examples 2, 3, 8 and 9 and Comparative Example 2. 
The dynamic fatigue test was performed by the method of ASTM D623-58A using 
a Goodrich flexometer. A cylindrical specimen was subjected to repeated 
compression under a fixed load, and after a certain period of time, the 
test specimen was examined for change. The PS values (the decrease from 
the initial height of the test specimen) in Table 9 show the superiority 
of the vulcanizates in accordance with this invention. 
The cure curves of the compounds obtained in Examples 1, 2, 6 and 8 and 
Comparative Examples 1 and 3 were determined by a JSR-type curelastometer 
at an angle of amplitude of 3.degree. and a temperature of 155.degree. C. 
The results are plotted in FIG. 1 in which curve a refers to Examples 1; 
curve b, to Example 2; curve c, to Example 6; and curve d, to Comparative 
Example 1, and in FIG. 2 in which curve e refers to Example 8, and curve 
f, to Comparative Example 3. 
TABLE 1 
__________________________________________________________________________ 
(Recipe: parts by weight) 
Example (Ex.) or Comparative 
Example (CEx.) Ex. 1 
Ex. 2 
CEx. 1 
CEx. 2 
Ex. 3 
Ex. 4 
Ex. 5 
Ex. 6 
__________________________________________________________________________ 
Polychloroprene (Neoprene W, *1) 
100 
Epichlorohydrin-ethylene oxide 
copolymer (Epichlomer C, *2) 
100 100 100 100 
Epichlorohydrin homopolymer 
(Epichlomer H, *3) 100 
Brominated butyl rubber 
(Polysar Bromobutyl X-2, *4) 100 
Chlorinated butyl rubber 
(HT-1066, *5) 100 
SRF carbon black (Seast S, *6) 20 
EEF carbon black (Seast SO, *7) 
20 40 40 40 35 40 
HAF carbon black (Seast 3, *8) 20 50 35 
Calcium carbonate (Hakuenka CC, *9) 
90 
Dioctyltin distearate (lubricant) 
1 0.5 0.5 0.5 0.5 1 0.5 
Trioctyl trimellitate (plasticizer) 
15 
Nickel dibutyldithiocarbamate 
(antioxidant) 1 1 1 1 1 
Phenyl-.beta.-naphthylamine (antioxidant) 
1 
Magnesia 2 2 2 6 10 2 
Zinc oxide 10 
Calcium hydroxide 2 3 3 3 5 3 
Barium carbonate 4 
Butyraldehyde aniline 
(Nocseller 8, *10) 2 1 
2-Mercaptobenzothiazole salt of 
dicyclohexylamine 1 
Salicylic acid 1 
2,4-Dithiohydantoin 
0.5 
5,5-Dimethyl-2,4-dithiohydantoin 
1 1 
5-Cyclohexyl-2,4-dithiohydantoin 1.2 
5-Isobutyl-5-methyl-2,4- 
dithiohydantoin 2 
5-Phenyl-2,4-dithiohydantoin 4 
2-Mercaptoimidazoline 1 
1-Phenyl-3,5-dimercapto-1,2,4-triazole 
1 
__________________________________________________________________________ 
Note to Table 1 
*1: a tradename for a product of E. I. du Pont de Nemours & Co. 
*2: a tradename for a product of Osaka Soda Co., Ltd. 
*3: a tradename for a product of Osaka Soda Co., Ltd. 
*4: a tradename for a product of Polysar Co. 
*5: a tradename for a product of Shell Chemical Co. 
*6: a tradename for a product of Tokai Carbon Co., Ltd. 
*7: a tradename for a product of Tokai Carbon Co., Ltd. 
*8: a tradename for a product of Tokai Carbon Co., Ltd. 
*9: a tradename for a product of Shiraishi Kogyo K. K. 
*10: a tradename for a product of Ouchi Shinko Kogyo K. K. 
TABLE 2 
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Basic properties 
Example (Ex.) or Comparative 
Example (CEx.) Ex. 1 
Ex. 2 
CEx. 1 
CEx. 2 
Ex. 3 
Ex. 4 
Ex. 5 
Ex. 6 
__________________________________________________________________________ 
100% Modulus (kg/cm.sup.2) 
34 36 26 30 40 24 30 41 
300% Modulus (kg/cm.sup.2) 
82 101 68 96 107 97 98 107 
Tensile strength (kg/cm.sup.2) 
169 142 125 135 151 161 141 155 
Elongation at break (%) 
440 405 830 500 390 480 405 380 
Hardness (JISA) 
66 70 63 68 71 57 67 73 
__________________________________________________________________________ 
TABLE 3 
__________________________________________________________________________ 
Heat-aging resistance (in a Geer's oven) 
Example (Ex.) or Comparative Example (CEx.) 
Ex. 1 
Ex. 2 
CEx. 1 CEx. 2 
Ex. 3 
Ex. 6 
__________________________________________________________________________ 
(3 days at 135.degree. C.) 
Change in tensile strength (%) 
-54.0 
+2.0 +4.0 -- -- -- 
Change in elongation at break (%) 
-84.0 
0 -38.0 -- -- -- 
Change in hardness (point) 
+22 +2 +4 -- -- -- 
(12 days at 150.degree. C.) 
Change in tensile strength (%) 
-- -48.5 
Unmeasurable 
-47.0 
-- -31.5 
Change in elongation at break (%) 
-- -53.0 
because the 
-60.5 
-- -47.0 
Change in hardness (point) 
-- +1 sample was 
+1 -- +3 
softened. 
(20 days at 150.degree. C.) 
Change in tensile strength (%) 
-- -81.0 
Unmeasurable 
-- -44.0 
-74.5 
Change in elongation at break (%) 
-- -59.0 
because the 
-- -62.0 
-57.0 
Change in hardness (point) 
-- -7 sample was 
-- -2 -2 
softened. 
__________________________________________________________________________ 
TABLE 4 
__________________________________________________________________________ 
Permanent compression set and oil resistance 
Example (Ex.) or Comparative 
Example (CEx.) Ex. 1 
Ex. 2 
CEx. 1 
CEx. 2 
Ex. 3 
Ex. 4 
Ex. 5 
Ex. 6 
__________________________________________________________________________ 
Permanent compression set (25% 
compression) 
100.degree. C. .times. 70 hours (%) 
41 -- -- -- -- -- 30 -- 
120.degree. C. 70 hours (%) 
54 34 71 37 27 24 -- 42 
Oil resistance (JIS No. 3 oil; 
120.degree. C. .times. 70 hours) 
Degree of volume swelling (%) 
61.7 
11.8 
17.4 
12.4 
12.0 
-- -- -- 
__________________________________________________________________________ 
TABLE 5 
__________________________________________________________________________ 
(parts by weight) 
Example (Ex.) or Comparative Example (CEx.) 
Ex. 7 
Ex. 8 
Ex. 9 
Ex. 10 
Ex. 11 
CEx. 3 
__________________________________________________________________________ 
Polychloroprene (Neoprene W) 
100 
Epichlorohydrin-ethylene oxide copolymer 
(Epichlomer C) 100 100 
Epichlorohydrin homopolymer (Epichlomer H) 
100 
Brominated butyl rubber (Polysar Bromobutyl X-2) 
100 
Chlorinated butyl rubber (HT-1066) 100 
SRF carbon black (Seast S) 20 
FEF carbon black (Seast SO) 
20 40 35 40 
HAF carbon black (Seast 3) 20 50 35 
Calcium carbonate (Hakuenka CC) 
90 
Dioctyltin distearate 1 0.5 0.5 1 0.5 
Trioctyl trimellitate 15 
Nickel dibutyldithiocarbamate 
1 1 1 
Phenyl-.beta.-naphthylamine 
1 
Magnesia 2 6 10 2 
Zinc oxide 10 
Calcium hydroxide 2 3 5 3 
Barium carbonate 4 
Butyraldehyde aniline (Nocseller 8) 2 
2-Mercaptobenzothiazole salt of dicyclohexyl- 
amine 1 
5,5-Cyclopentamethylene-2,4-dithiohydantoin 
0.3 2 
5,5-2'-methylcyclotetramethylene-2,4- 
dithiohydantoin 1 
5,5-3'-methyl-3'-azacyclopentamethylene-2,4- 
dithiohydantoin 2 3 1 
2-Mercaptoimidazoline 
__________________________________________________________________________ 
TABLE 6 
______________________________________ 
Basic properties 
Example 
(Ex.) or Compara- CEx. Ex. Ex. 
tive Example (CEx.) 
Ex. 7 Ex. 8 3 Ex. 9 
10 11 
______________________________________ 
100% modulus (kg/cm.sup.2) 
28 33 26 44 30 27 
300% modulus (kg/cm.sup.2) 
75 97 68 113 104 90 
Tensile strength (kg/cm.sup.2) 
161 137 125 152 171 144 
Elongation at break (%) 
490 440 830 340 440 430 
Hardness (JIS A) 
63 68 63 73 60 65 
______________________________________ 
TABLE 7 
__________________________________________________________________________ 
Heat-aging resistance (in a Geer's oven) 
Example (Ex.) or Comparative Example (CEx.) 
Ex. 7 
Ex. 8 
CEx. 3 Ex. 9 
__________________________________________________________________________ 
(8 days at 135.degree. C.) 
Change in tensile strength (%) 
-44.0 
+7.5 +4.0 -- 
Change in elongation at break (%) 
-87.0 
-10.0 
-38.0 -- 
Change in hardness (point) 
+24 +3 +4 -- 
(12 days at 150.degree. C.) 
Change in tensile strength (%) 
-- -40.0 
Unmeasurable 
-- 
Change in elongation at break (%) 
-- -57.0 
because the 
-- 
Change in hardness (point) 
-- +3 sample was 
-- 
softened. 
(20 days at 150.degree. C.) 
Change in tensile strength (%) 
-- -74.0 
Unmeasurable 
-45.0 
Change in elongation at break (%) 
-- -48.0 
because the 
-58.0 
Change in hardness (point) 
-- -9 sample was 
-4 
softened. 
__________________________________________________________________________ 
TABLE 8 
__________________________________________________________________________ 
Permanent compression set and oil resistance 
Example (Ex.) or Comparative Example (CEx.) 
Ex. 7 
Ex. 8 
CEx. 3 
Ex. 9 
Ex. 10 
Ex. 11 
__________________________________________________________________________ 
Permanent compression set (25% compression) 
100.degree. C. .times. 70 hours (%) 
45 -- -- -- -- 30 
120.degree. C. .times. 70 hours (%) 
57 36 71 24 25 -- 
Oil resistance (JIS No. 3 oil; 120.degree. C. .times. 70 
hours) 
Degree of volume swelling (%) 
64.3 
12.1 
17.4 
3 -- -- 
__________________________________________________________________________ 
TABLE 9 
______________________________________ 
Dynamic fatigue resistance 
Example (Ex.) or Comparative 
Example (CEx.) Ex. 2 Ex. 3 CEx. 2 
Ex. 8 
Ex. 9 
______________________________________ 
.DELTA.T (.degree.C.) 
14 14 24 14 14 
ISC (%) 12.6 13.0 15.7 12.7 13.0 
IDC (%) 4.3 6.2 7.5 4.5 6.2 
PS (%) 0.8 1.2 2.4 1.0 1.3 
______________________________________ 
Measured by the method of ASTM D623-58A (by means of a Goodrich flexometer) 
under the following conditions. 
Stroke: 0.175 inch 
Load: 25 pounds 
Vibration: 1800 cycles/min. 
Testing temperature: 100.degree. C. 
Testing time: 25 minutes 
The abbreviations used in Table 5 have the following meanings. 
.DELTA.T: heat-generating temperature 
ISC: initial static compression 
IDC: initial dynamic compression 
PS: permanent set 
EXAMPLES 12 TO 17 AND COMATIVE EXAMPLES 4 AND 5 
In each run, the ingredients shown in Table 10 was kneaded on an open roll 
at 60.degree. to 70.degree. C. The resulting sheet was vulcanized as 
described in Examples 1 to 11 and the vulcanizate obtained was tested for 
the various properties as in Examples 1 to 11. The results are shown in 
Tables 11 to 14. 
In Comparative Example 4, 2-mercaptoimidazoline was used, and in 
Comparative Example 5, 1-phenyl-3,5-dimercapto-1,2,4-triazole disclosed in 
U.S. Pat. No. 4,234,705 was used. 
FIG. 3 shows the cure curves, similar to FIGS. 1 and 2, of the compounds 
obtained in Example 13 (curve g), Example 17 (curve h) and Comparative 
Example 4 (curve i). 
TABLE 10 
__________________________________________________________________________ 
(Recipe: parts) 
Example (Ex.) or Comparative 
Example (CEx.) Ex. 12 
Ex. 13 
CEx. 4 
CEx. 5 
Ex. 14 
Ex. 15 
Ex. 16 
Ex. 17 
__________________________________________________________________________ 
Polychloroprene (Neoperene W) 
100 
Epichlorohydrin-ethylene oxide 
copolymer (Epichlomer C) 
100 100 100 100 
Epichlorohydrin homopolymer 
(Epichlomer H) 100 
Brominated butyl rubber 
(Polysar Bromobutyl X-2) 100 
Chlorinated butyl rubber 
(HT-1066) 100 
SRF carbon black (Seast S) 20 
FEF carbon black (Seast SO) 
20 40 40 40 35 40 
HAF carbon black (Seast 3) 20 50 35 
Calcium carbonate (Hakuenka 
CC) 90 
Dioctyltin distearate 
(lubricant) 1 0.5 0.5 0.5 0.5 1 0.5 
Trioctyl trimellitate 
(plasticizer) 15 
Nickel dibutyldithiocarba- 
mate (anti-oxidant) 1 1 1 1 1 
Phenyl-.beta.-naphthylamine (anti- 
oxidant) 1 
Magnesia 2 2 2 6 10 3 
Zinc oxide 10 
Calcium hydroxide 
2 3 3 3 5 3 
Barium carbonate 4 
Butyraldehyde aniline 
(Nocseller 8) 2 1 
2-Mercaptobenzothiazole salt 
of dicyclohexylamine 1 
N-cyclohexylthiophthalimide 1 
1:1 (mole) salt of 2,4- 
dithiohydantoin and sodium 
0.5 
2:1 (mole) salt of 5,5- 
dimethyl-2,4-dithiohydantoin 
and Mg 1.0 
2:1 (mole) salt of 5-cyclohexyl- 
2,4-dithiohydantoin and Zn 2.0 
1:1 (mole) salt of 5,5-cyclo- 
pentamethylene-2,4-dithio- 
hydantoin 2.5 
5,5-3'-azacyclopentamethylene- 
2,4-dithiohydantoin and Cd 4.0 
2:1 (mole) salt of 5-iso- 
butyl-2,4-dithiohydantoin 
and barium 1.0 
2-mercaptoimidazoline 1.0 
1-phenyl-3,5-dimercapto-1,2,4- 
triazole 1.0 
__________________________________________________________________________ 
TABLE 11 
______________________________________ 
Dynamic fatigue resistance 
Example (Ex.) or Compara- 
tive Example (CEx.) 
Ex. 13 CEx. 5 Ex. 14 
______________________________________ 
.DELTA.T (.degree.C.) 
15 24 15 
ISC (%) 12.9 15.7 13.0 
IDC (%) 4.5 7.5 6.1 
PS (%) 1.1 2.4 1.3 
______________________________________ 
TABLE 12 
__________________________________________________________________________ 
Basic properties 
Example (Ex.) or Comparative 
Example (CEx.) Ex. 12 
Ex. 13 
CEx. 4 
CEx. 5 
Ex. 14 
Ex. 15 
Ex. 16 
Ex. 17 
__________________________________________________________________________ 
100% Modulus (kg/cm.sup.2) 
32 33 26 30 40 25 28 40 
300% Modulus (kg/cm.sup.2) 
80 97 68 96 110 97 96 103 
Tensile strength (kg/cm.sup.2) 
164 140 125 135 150 162 144 146 
Elongation at break (%) 
470 420 830 500 370 470 410 395 
Hardness (JIS A) 
64 69 63 68 72 58 66 72 
__________________________________________________________________________ 
TABLE 13 
__________________________________________________________________________ 
Heat-aging resistance (in a Geer's oven) 
Example (Ex.) or Comparative Example 
(CEx.) Ex. 11 
Ex. 13 
CEx. 4 CEx. 5 
Ex. 14 
Ex. 17 
__________________________________________________________________________ 
(2 days at 135.degree. C.) 
Change in tensile strength (%) 
-47.0 
+4.0 +4.0 -- -- -- 
Change in elongation at break (%) 
-80.0 
+10.0 
+38.0 -- -- -- 
Change in hardness (point) 
+22 +3 +4 -- -- -- 
(12 days at 150.degree. C.) 
Change in tensile strength (%) 
-- -48.0 
Unmeasurable 
-47.0 
-- -45.0 
Change in elongation at break (%) 
-- -57.5 
because the 
-60.5 
-- -51.0 
Change in hardness (point) 
-- +2 sample was 
+1 -- +1 
softened 
(20 days at 150.degree. C.) 
Change in tensile strength (%) 
-- -77.0 
Unmeasurable 
-- -65.0 
-- 
Change in elongation in break (%) 
-- -62.0 
because the 
-- -70.5 
-- 
Change in hardness (point) 
-- -6 sample was 
-- -5 -- 
softened 
__________________________________________________________________________ 
TABLE 14 
__________________________________________________________________________ 
Permanent compression set and oil resistance 
Example (Ex.) or 
Comparative 
Example (CEx.) 
Ex. 12 
Ex. 13 
CEx. 4 
CEx. 5 
Ex. 14 
Ex. 15 
Ex. 16 
Ex. 17 
__________________________________________________________________________ 
Permanent compres- 
sion set (25% 
compression) 
100.degree. C. .times. 70 hours 
(%) 43 -- -- -- -- -- 33 -- 
120.degree. C. .times. 70 hours 
(%) 55 37 71 37 30 24 -- 39 
Oil resistance 
(JIS No. 3 oil, 
120.degree. C. .times. 70 hours) 
Degree of volume 
swelling (%) 
62.0 
12.0 
17.4 
12.4 
12.2 
-- -- -- 
__________________________________________________________________________