Patiented May 27, 1947 242,352

UNITED STATES PATENT OFFICE 2,421,352 SUBSTITUTED TOCARBAMO SULFENAMOES Philip T. Paul and Byron A. Hunter, Naugatuck, Conn., assignors to United States Rubber Com pany, New York, N. Y., a corporation of New Jersey No Drawing. Original application March 9, 1944, Serial No. 525,774. Divided and this applica tion April 26, 1944, Serial No. 532,881 5 Claims. (C. 260-551) 2 . This invention relates to new chemical com phatic groups (saturated or unsaturated) such pounds which are useful as vulcanization accel as methyl, ethyl, propyl, methallyl, amyl, hexyl, erators in the Vulcanization of rubbers, both nat allyl, butyl, benzyl, lauryl, etc., exemplified by ural and synthetic, such as Hevea brasiliensis N',N'-dimethyl thiocarbamo sulfenamide, N',N'- and Various polymerS Such as butadiene-styrene 5 diethyl thiocarbamo sulfenamide, N',N'-dipropyl copolymer, butadiene - acrylonitrile copolymer, thiocarbamosulfenamide, N',N'-dimethallylthio isoprene-isobutylene copolymer, etc. carbamo sulfenamide, N',N'-diamyl thiocarbamo This application is a division of our copending sulfenamide, N',N'-dihexyl thiocarbamo Sulfen application Serial No. 525,774, filed March 9, 1944. amide, N',N'-diallyl thiocarbamo sulfenamide, The new class of rubber vulcanization accel O N',N' - dibutyl thiocarbamo sulfenamide, N'- erators are N,N'-disubstituted thiocarbamo Sul methyl N-benzyl thiocarbamo sulfenamide, N'- fenamides in which the sulfenamide nitrogen is ethyl N-benzyl thiocarbamo Sulfenamide, N',N'- directly attached to each of two carbon atoms, dibenzyl thiocarbamo sulfenamide, N',N'-dilauryl as represented by the grouping thiocarbamo sulfenamide, N'-methyl N-butyl S C s thiocarbamo sulfenamide, or carbon atoms of HN--s-N? alicyclic groups such as cyclohexyl, etc., exem N plified by N',N'-dicyclohexylthiocarbamo Sulfen Care amide, N'-methyl N'-cyclohexyl thiocarbamo where the carbon atoms C1 and Ca each belong sulfenamide, N'-ethyl N'-cyclohexylthiocarbamo to a similar or dissimilar group selected from the 20 sulfenamide, or carbon atoms of a heterocyclic aliphatic, allicyclic, or heterocyclic series. ring having the nitrogen atom as a hetero ring There is considerable confusion in the tech atom, as exemplified by N',N'-dimethylene thio nical literature concerning the nomenclature of carbamo sulfenamide, N',N'-tetramethylene thio Compounds containing the -S-N linkage. The carbamo sulfenamide, N',N'-trimethylene thio nomenclature which is proposed and followed in carbamo sulfenamide, N',N' - pentamethylene this specification considers these compounds as thiocarbamo sulfenamide, N',N' - oxydiethylene amides of the hypothetical thiocarbamo sulfenic thiocarbamo sulfenamide, N',N'-thiodiethylene acid thiocarbamo sulfenamide; or the said carbon atoms may be part of substituted groups such as HN-C-S-OH 30 in N',N'-di-b-hydroxyethyl thiocarbamo sulfen amide, N',N'-di-b-chloroethyl thiocarbamo Sull Thiocarbamosulfenic acid fenamide, N',N'-di-b-(dimethyl amino) ethyl S thiocarbamo Sulfenamide. HN-C-S-NH The chemicals of this invention are prepared by reacting a salt of a dithiocarbamic acid with Thiocarbamo sulfenamide 35 an N-halogenated secondary aliphatic amine In the formula for thiocarbamo sulfenamide Which in turn may be prepared from a hypo there are two nitrogen atoms one belonging to chlorite and a secondary amine, e.g., the thiocarbamo nucleus and the other belong ing to the Sulfenamide nucleus. These are dif (A) RNH + NaOCl - RNC1 + NaOH ferentiated by referring to the thiocarbamo nitro 40 (B) S gen as the 'N' nitrogen and the Sulfenamide NEC-S-NH -- ClNR - NHC-S-NR nitrogen as the "N' nitrogen. According to this (R2 represents dimethyl, dicyclohexyl, penta system the compound methylene, oxydiethylene, etc.). s o H 45 During the preparation of the chloramines it is advisable to maintain the pH from 7 to 10 by HN-C-S-N the addition of acidic or basic reagents as re CH3 quired. In the cases of diamyland dibutyl amines is named N',N'-dimethyl thiocarbamo sulfen the optimum pH has been found to be about 8. amide. C1 and Ca may be carbon atoms of ali 50 In this connection, buffering agents are quite 2,421,352 4. useful in controlling the pH. The ammonium able test pieces were cut and tested. In the foll dithiocarbamate may be prepared from carbon lowing table tensiles are in pounds per square disulfide and ammonia in water solution or in inch and elongations in percent. non-aqueous Solvents. The reaction between ammonium dithiocar bamate and the N-chloramine is preferably car Cure in Minutes ried out at room temperature or lower. In the preparation of the N-chloro amines, adequate precautions for ventilation and cooling should be 0. observed.The following examples, in which the parts are by weight, are given to further illustrate the in The present accelerators are also useful in con vention. junction with other accelerating agents such as Eacample 1.-Preparation of N',N'-dibutyl thio the mercapto thiazoles, mercapto aryl thiazoles, carbamo Sulfenamide 5 mercapto thiazolines, diary guanidines and their Salts, dithiocarbamates, etc. To a mixture of 97 grams technical dibutyl These chemicals are also useful as high pres amine and 550 cc. water, dilute hydrochloric acid Sure lubricant aids, gasoline antioxidants, and as is added until the pH is approximately 8. With bactericides, fungicides, and insecticides. cooling in an ice bath and stirring, a solution of 20 The term "a rubber' in the appended claims is 56 grams sodium hypochlorite in 670 cc. water is employed in a generic sense to designate rubbery gradually added. It is recommended that the materials capable of vulcanization when heated hypochlorite solution be freshly prepared. After with sulfur, and includes besides natural rubbers, stirring one hour to complete the formation of rubber isomers, and artificially-prepared rubbers the N-chlor dibutyl amine, a solution of 74 grams 25 Such as first herein referred to, and latices of any ammonium dithiocarbamate in 100 cc. water is Such materials, whether or not admixed with pig added and the stirring continued for 12 hours ments, fillers, softeners, antioxidants, other accel during which time the reaction mixture is allowed erators, etc. to warm to room temperature. The product is a The present invention is not limited to the brown oil, lighter than Water, which is separated, 30 Specific examples above set forth wherein pre washed with dilute acetic acid and dried over a ferred accelerators are employed. Other ratios suitable drying agent such as potassium car of the compounding ingredients than those men bonate. tioned in the example as well as other well-known Yield 40 grans fillers, pigments, and the like may be employed 35 in the production of various types of rubber com Analysis Theory. Found pounds as will be apparent to those skilled in the art to which this invention pertains. Per Cent Sulfur------29, 30.17 Having thus described our invention, what we claim and desire to protect by Letters Patent is: Eacample 2-Preparation of N',N'-dibutyl thio 40 1. An N'-disubstituted thiocarbamyl sulfen carbono Sulfenamide amide of the formula This material is prepared as described in Ex R. ample 1, except that, in place of the dibutyl N-C-S-N amine, 118 grams technical diamylamine are 45 Yr, used. 30 grams of N',N'-diamyl thiocarbamo Sul Where R1 and R2 each represent hydrocarbon rad fenamide is obtained as a brown oil. icals selected from the class consisting of ali phatic, aralkyl, and cycloalkyl radicals. Analysis theory Found 2. An N',N'-dibutyl thiocarbamyl sulfenamide. 50 3. An N',N'-diamyl thiocarbamyl sulfenamide. Per Cent Sulfur------26.8 22.5 4. An N',N'-di-aliphatic hydrocarbon thiocar bamylsulfenamide. Eacample 3 5. An N',N'-dialkyl thiocarbamyl sulfenamide. The above chemicals were each tested in a tread stock compounded from synthetic rubber. 55 PHILIP T. PAUL. BYRON A. HUNTER. Master Batch Parts REFERENCES CTED Butadiene-styrene copolymer------100.0 60 The following references are of record in the Refined coal tar------5.0 Carbon black.------50.0 file of this patent: Stearic acid--- 2.0 Zinc oxide------5.0 UNITED STATES PATENTS Sulfur------2.0 840 Number Name Date 65 2,318,482 Hanslick ------May 4, 1943 2,160,851 Faust ------June 6, 1939 2,285,813 Hanslick ------June 9, 1942 A. B 2,333,468 Cooper ------Nov. 2, 1943 2,381,392 Smith ------Aug. 7, 1945 Master Batch------184 N,N-dibutyl thiocarbamo sulfenamide.------0.5 ------70 FOREIGN PATENTS N,N'-diaInyl thiocarbano sulfenamide------0.5 Number Country Date The stocks A and B were prepared and vul 323,421 Great Britain ------Apr. 23, 1925 canized in a press at 45 pounds per Square inch 712,418 France ------Oct. 2, 1931 steam pressure, for 30, 45, and 60 minutes. Suit s 8,103 Australia ------1932