Patent GB-469634-A (GB)
Title: Improvements in accelerators of vulcanization
IPC: C08K5/00
Filed: 1936-08-11
Abstract: The vulcanization of rubber is accelerated by the addition to the mix of a reaction product of a mercaptoarylene thiazole or a dithiocarbamate with an imino methylene dihalide.  The accelerators so formed are in the former case of the general formula <FORM:0469634/IV/1> and in the second case of the general formula <FORM:0469634/IV/2> where R is any arylene group, R1 and R2 may be aliphatic, alicyclic, aralkyl or heteroalkyl, and R1 may also be aryl.  R1 and R2 may also be combined to form a cyclic residue, and Y may be any substituted or unsubstituted hydrocarbon residue.  The dithiocarbamates used in the present invention may be represented by Z--S--M where Z is a thiocarbamyl radical and M is a reactive radical such alkali metal or ammonium. The preferred dithio carbamates are those derived from secondary amines, but those derived from primary amines are also included. A list of amines from which suitable dithiocarbamates may be prepared is given of which the following is a typical selection: di-ethyl-, N-butyl tetrahydrofurfuryl-, N-ethyl benzyl-, di-allyl-, N-methyl hexahydrotolyl-and difurfurylamines, piperidine, and morpholine.  Mercaptoarylthiazoles, mentioned include mercaptobenzothiazoles, mercaptonaphthathiazoles, 4- or 5-nitro-1-mercaptobenzothiazole and other nitro, amino, hydroxy, alkoxy, alkyl and halogen substituted 1-mercapto arylene thiazoles. Examples of imino methylene dichlorides are those in which Y of the formula C12C = NY is phenyl, tolyl, nitrophenyl, chlorphenyl, ethoxyphenyl, allyl, naphthyl, amyl, benzyl, cyclohexyl, hexahydrotolyl, and furfuryl.  These compounds may be prepared by the chlorination at relatively low temperatures of the corresponding isothiocyanate or mustard oil. The imino methylene dichlorides are preferred to the other dihalides, but the other dihalides such as the dibromides may also be used.  In examples: (1) a toluene solution of phenyl imino-methylene dichloride is added to a suspension in toluene of sodium benzothiazyl mercaptide and the mixture refluxed for two hours to give phenyl imino-methylene bis-benzothiazyl sulphide; (2) phenyl imino-methylene dichloride is reacted with sodium diethyl dithiocarbamate in toluene to give phenyl imino-methylene bis-diethyl-dithiocarbamate.  The accelerators of the present invention may be used either alone or in conjunction with other basic nitrogen containing accelerators of which diphenyl-guanidine is the preferred example.  Specification 360,949 is referred to.ALSO:The vulcanization of rubber is accelerated by the addition to the mix of a reaction product of a mercaptoarylene thiazole or a dithiocarbamate with an imino methylene dihalide.  The accelerators so formed are in the former case of the general formula <FORM:0469634/V/1> and in the second case of the general formula <FORM:0469634/V/2> where R is an arylene group, R1 and R2 may be aliphatic, alicyclic, aralkyl or heteroalkyl, and R1 may also be aryl.  R1 and R2 may also be combined to form a cyclic residue, and Y may be any substituted or unsubstituted hydrocarbon residue.  The dithiocarbamates used in the present invention may be represented by Z-S-M where Z is a thiocarbamyl radical and M is a reactive radical such as alkali metal or ammonium.  The preferred dithio carbamates are those derived from secondary amines, but those derived from primary amines are also included.  A list of amines from which suitable dithiocarbamates may be prepared is given of which the following is a typical selection:-di-ethyl-, N-butyl tetrahydrofurfuryl-, N-ethyl benzyldi-allyl-, N-methyl hexahydrotolyl- and difurfuryl-amines, piperidine, and morpholine.  Mercaptoarylthiazoles mentioned include mercaptobenzothiazoles, mercaptonaphthathiazoles, 4- or 5-nitro-1-mercaptobenzothiazole and other nitro, amino, hydroxy, alkoxy, alkyl and halogen substituted 1-mercapto arylene thiazoles. Examples of imino methylene dichlorides are those in which Y of the formula Cl2C=NY is phenyl, tolyl, nitrophenyl, chlorphenyl, ethoxyphenyl, allyl, naphthyl, amyl, benzyl, cyclohexyl, hexahydrotolyl, and furfuryl.  These compounds may be prepared by the chlorination at relatively low temperatures of the corresponding isothiocyanate or mustard oil. The imino methylene dichlorides are preferred to the other dihalides, but the other dihalides such as the dibromides may also be used.  In examples, (1) a toluene solution of phenyl imino-methylene dichloride is added to a suspension in toluene of sodium benzothiazyl mercaptide and the mixture refluxed for two hours to give phenyl imino-methylene bis benzothiazyl sulphide; (2) phenyl imino-methylene dichloride is reacted with sodium diethyl dithiocarbamate in toluene to give phenyl imino methylene bis diethyl-dithiocarbamate.  The accelerators of the present invention may be used either alone or in conjunction with other basic nitrogen containing accelerators of which diphenyl-guanidine is the preferred example.  Specification 360,949 is referred to.