3,361,719 United States Patent Office Patented Jan. 2, 1968 2 chloride at a temperature of 20 C. Providing a further 3,361,719 reaction the mixture was heated to about 100 C., then VULCANIZATION AGENTS the resulting product was treated with carbon tetrachloride to separate retained sulfur. HaraldGermany, Blimel, assignors Otto Wiechulla, to Chemische and WaiterWerke Reuter,Huls Aktien Marl, gesellschaft, Marl, Germany 5 Dicyclohexanone-disulfide was obtained by reacting 2 No Drawing. Filed Jan. 22, 1964, Ser. No. 339,337 mols cyclohexanone with 1 mol disulfur-dichloride at a Claims priority, application Germany, Feb. 6, 1963, temperature of 0 to 10 C. for one hour. For further C 29,102 reaction the mixture was held at 30° C. for 3 hours, then 6 Claims. (C. 260-66) poured into benzene to remove present hydrochloric acid 10 and finally washed with diluted aqueous alkali hydroxide This invention relates to elastomer technology, partic Solution and water. ularly to vulcanization agents. Relatively small amounts of the material are used, It is known that for the vulcanization of elastomers, generally from 0.05 to 20%, and preferably 0.1 to 10% so-called vulcanization agents are used. These Vulcaniza based on the weight of the elastomers. tion agents are substances which by themselves or in com Suitable vulcanizable elastomeric mixtures comprise bination with other substances will effect a transition of e.g. natural rubber and synthetic rubber-like vulcanizable elastomers from the non-crosslinked into the cross-linked elastomers such as butadiene-styrene polymers, butadiene condition. For this purpose sulfur in its various forms is acrylonitrile copolymers, polychloroprene, polybutadiene, generally used, but use can also be made of selenium, tel polyisoprene, butyl-rubber, ethylene-propylene copolymers lurium, polysulfides and corresponding compounds of 20 in Saturated or unsaturated form, halogenated or halo selenium and tellurium, polynitroso-compounds, quinone Sulfonated polyethylene, these types of polymers being derivatives, metal oxides or mixtures of metal oxides such classified as sulfur-vulcanizable rubbers for the purpose as zinc oxide, magnesium oxide, lead oxide, calcium OX of this invention. In addition to the rubber base, there can ides, etc. be included fillers such as active or inactive carbon black, The known vulcanization accelerators can also be des active or inactive silicic acid, silicates, carbonates, sulfates, ignated as vulcanization agents. The mode of opera materials to impart resistance to light crazing, fatigue or tion of these vulvanization accelerators is that without ageing, and also waxes, fatty acids, plasticizing oils, color themselves causing any cross-linking, they cooperate with ing materials and vulcanization agents. other vulcanization agents to speed up the vulcanization These mixtures are masticated in the machines that are and to produce improved products. Vulcanization accelera 30 generally employed in the rubber industry, such as internal tors occur in many different classes of chemical com mixers (Banbury) and rubber mills. The basic mixtures pounds and are generally used in combination with sulfur, are generally produced at higher temperatures than the metal oxides, fatty acids and other substances commonly final mixtures which consist of the basic mixtures with present in vulcanizable mixtures. Known accelerators ae Vulcanizing agents added thereto to produce cross linking. e.g. various substituted amines, quanidine, toluidine, The advantage of said vulcanizing agents consists in aniline derivatives, thiuramsulfide, thiazole, dithiocarb that they are operable in extremely small concentrations aminate, sulfenamide, peroxides metal compounds of aS compared to other vulcanizing agents. Therefore the these substances, and corresponding compounds of Seleni Vulcanizing agents according to the present invention in um and tellurium volve a highly economic production of elastomeric mix The principal object of this invention is to provide new 40 tures. vulcanization agents. Without further elaboration, it is believed that one Other objects are to provide a process of vulcanization skilled in the art can, using the preceding description, as well as vulcanized and vulcanizable compositions based utilize the present invention to its fullest extent. The fol on the new vulcanization agents. lowing preferred specific embodiments are, therefore, to Upon further study of the specification and claims be construed as merely illustrative, and not limitative of other objects and advantages of the present invention will the remainder of the specification and claims in any way become apparent. whatsoever. To attain the objects of this invention it has been found that ketone-disulfides of the formulas Example I CE C3 50 In an internal mixer of 2 liter net volume operated at O O do CO 40 rp.m. and at 50 C., by means of heat transfer fluid, J. H. H. J. the following mixture is produced B. YYH, S-S- 100 parts cold rubber type 1500, specifically a copolymer S-S 55 obtained by copolymerization of 23 parts styrene and H 77 parts butadiene in an emulsifier containing aqueous H His emulsion at 5° C. ("Type 1500 refer to ASTM, Rubber World, 1960, page 107) ( D (II) 47.5 parts HAF carbon black can be advantageously used as vulcanization agents in 608 parts aromatic plasticizer oil vulcanizable mixtures. Not only the dicyclohexanone-di 1 part N-phenyl-N'-cyclohexyl-p-phenylene diamine sulfide, di-acetophenone-disulfide can be used, but also 1 part ozocerite their alkyl-, aryl- or aralkyl-substitued derivatives, e.g. The materials are mixed 10 minutes. The above-men the disulfides of methyl-, ethyl- and butyl-acetophenone, 65 tioned Vulcanization agents are then mixed therewith on phenyl-acetophenone, methyl-phenyl-acetophenone; the a laboratory rubber mill. This method of mixing and also disulfides of methyl-cyclohexanone, cyclohexyl-cyclohex the basic composition given above are used in all the fol anone, methyl-phenylcyclohexanone. lowing examples. The ketone-disulfides are obtainable by the reaction of The ring and plate shaped samples for testing which 1 to 2 mols of a disulfur-dichloride with 2 mols of a 70 were obtained by vulcanization at 150° C. in a press and ketone. For the preparation of di-acetophenone-disulfide subsequent stamping out had the following properties as 1 mol acetophenone was reacted with 1 mol disulfur-di defined by the German standardization regulations. 3,361,719
TABLE I
Modulus, kg.fcm. Elasticity Parts, ingredients in addi- Heating Tensile Expan------Perm. Resist- Hardness, Mix- per 100 tion to those listed time in Strength, Sion, expan- ance to Shore d s ture parts of in Example I min. kg.fcm. percent 300 500 Slon, tearg., 22°C., 75° C., rubber percent percent percent kg. Icm. percent percent
l------2 Sulfur, Dicyclo- 5A O 865 6 O O 2 4. 40 33 5 hexanone- 30B 66 985 16 35 63 O 49 4. 38 disulfide. 6OC 78 755 42 103 26 2. 54 43 44 20D 206 550 83 82 4. 8 59 43 49 2------5 ZnO, Sulfur, 15A. 92 735 49 3 26 22 57 39 A5 2 Dicyclohexanone- 30B 224 665 68 54 20 2. 60 39 48 disulfide. 60'C 242 600 86 9i 8 18 60 40 5. 5 i2O'D 237 540 103 26 5 61 40 52 3------5 Dicyclohexanone- 15A. 6 760 6 6 100 40 40 32 disulfide, 30B 16 1,030 6 13 100 3 45 4. 34 60C 59 90 6 35 65 O 50 42 38 120D 25 820 28 68 41 6 50 43 42
The preceding table shows that mixture number 3 is Consequently, such changes and modifications are prop Vulcanized to a significant degree without the addition of erly, equitably, and intended to be, within the full range any other vulcanizing agents except the novel agent of of equivalence of the following claims. this invention. What is claimed is: Example 2 25 1. In a process of vulcanizing rubber of the group con As the following table shows, a change in the amount sisting of natural rubber, butadiene-styrene copolymers, of the dicyclohexanone-disulfide to below 0.5 part per 100 butadiene - acrylonitrile copolymers, polychloroprene, parts of rubber has only a very slight effect on the prop polybutadiene, polyisoprene, butyl-rubber, ethylene-pro erties of the product. Even if the amount is reduced to pylene copolymers, halogenated polyethylene, and halo 0.25 part per 100 parts of rubber, the product is still 80 sulfonated polyethylene, the improvement which com useful. prises employing as a vulcanization agent 0.05-20% by
TABLE I
Parts, Modulus, kg/cm. Perm, Resist Mix- per 100 Ingredients in addition to Heating Tensile Expan- Expan- ance to Hardness, Elasticity ture parts of those listed in Example i time in Strength, Sion, Slon, tearg. Shore 22°C., rubber min. kg.fon. Percent 300 500 Percent kgfen. Percent Percent Percent
I------5 ZnO, 15A. 108 955 22 5. 65 4. 52 40 2 Sulfur, 30B 14 725 37 88 33 56 4. 0.25 Dicyclohexanonedisulfide. 60C 173 620 57 30 23 f 56 39 120D 22 630 73 66 2 4 5 39 2------5 ZnO, 5A. 5 90 24 59 50 5 53 39 2 Sulfur, 30B 73 85 40 94. 27 6 55 40 0. 5 Dicyclohexanon.edisulfide. 60C 92 670 58 32 25 5 57 39 120D 223 635 77 68 20 5 59 3. 3------5 ZnO, 5A 15 890 3. 73 44 8 54 39 2 Sulfur, 30B 172 15 47 06 27 9 56 40 Dicyclohexanonedisulfide. 60'C 205 670 64 40 17 7 58 39 120D 224 60 82 75 9 14 O 39 4------5 ZnO, 5A 80 4. 94 34 56 40 2 Sulfur, 30B 206 725 57 30 26 17 .. 5 40 2 Dicyclohexanon.edisulfide. 60C 225 655 74 63 20 5 59 40 120D 243 605 92 194 18 4. 39 5------5 ZnO, 15A. 96. 795 47 06 30 20 57 39 2 Sulfur, 30B 20. 650 68 -46 20 19 59 39 5 Dicyclohexanonedisulfide. 60C 94. 545 8. 175 4. 7 6. 39 120D 240 585 97 200, 16 16 62 39
Results similar to the preceding examples are obtained 60 weight based on the weight of the rubber, of a compound by replacing the cold rubber of Example 1 with natural Selected from the group consisting of dicyclohexanone rubber or any synthetic rubber-like vulcanizable elastomer disulfide, diacetophenone-disulfide, di-(lower alkyl) ace Such as those hereinbefore mentioned. tophenone-disulfide, diphenylacetophenone-disulfide, di Similarly, the examples can be repeated successfully (methylphenylacetophenone)-disulfide, di-(methyl-cyclo using the other generically and specifically described novel 65 hexanone) - disulfide, di-(cyclohexyl-cyclohexanone)-di Vulcanizing agents of this invention such as diacetophe Sulfide, and di-(methyl-phenylcyclohexanone)-disulfide. none-disulfide, the disulfides of methyl-, ethyl- and butyl 2. The process of claim 1, wherein the vulcanizing acetophenone, phenyl-acetophenone, methyl-phenyl-ace agent is dicyclohexanone-disulfide. tophenone; the disulfides of methyl-cyclohexanone, cyclo 3. The process of claim 1, wherein the vulcanizing hexyl-cyclohexanone, methyl-phenyl-cyclohexanone. 70 agent is diacetophenone-disulfide. From the foregoing description, one skilled in the art 4. An unvulcanized composition comprising a pre can easily ascertain the essential characteristics of this in dominant amount of a rubber selected from the group vention, and without departing from the spirit and scope consisting of natural rubber, butadiene-styrene copoly thereof, can make various changes and modifications of mers, butadiene-acrylonitrile copolymers, polychloro the invention to adapt it to various usages and conditions. 75 prene, polybutadiene, polyisoprene, butyl-rubber, ethyl 3,361,719 5 6 ene-propylene copolymers, halogenated polyethylene, and References Cited halo-sulfonated polyethylene and 0.2-20% based on the UNITED STATES PATENTS weight of the rubber of a compound selected from the group consisting of di-cyclohexanone-disulfide, diaceto 3,296,308 1/1967 Walker et al. ----- 260-79.5 phenone-disulfide, di-(lower alkyl) acetophenone-disul OTHER REFERENCES fide, diphenylacetophenone-disulfide, di-(methylphenyl acetophenone) - disulfide, di-(methyl-cyclohexanone)-di Chemical Abstracts, June 1962, vol. 56; 15330H. sulfide, di-(cyclohexyl-cyclohexanone)-disulfide, and di Milligan et al.: Chem. Soc. Jour., 1961, pt. 4 (pp. (methyl-phenylcyclohexanone)-disulfide. 4269-5564), p. 5552 relied on. 5. The composition of claim 4, wherein the compound Walker et al.: Jour. Org. Chem., vol. 28, September is dicyclohexanone-disulfide. 10 December 1963, p. 3080. 6. The composition of claim 4, wherein the compound JOSEPH L. SCHOFER, Primary Examiner. is diacetophenone-disulfide. DANIEL K. DENENBERG, Assistant Examiner.