Rubber mixtures giving reversion-free vulcanizates and process of vulcanization

Claim 2

A composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with a different rubber (B) and from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, or its hydrolysate, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber mixtures contains the silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, at the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU4## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 3

A rubber mixture according to claim 1 wherein n is 0, R is alkyl of 1 to 4 carbon atoms and Alk is an alkylene group having 2 to 4 carbon atoms.

Claim 4

A rubber mixture according to claim 1 containing (1) 1 to 300 parts by weight of silicate filler, (2) from 0.1 to 150 parts by weight of carbon black filler or (3) a mixture of a silicate filler and a carbon black filler, the total amount of filler being 1 to 300 parts by weight of which 0.1 to 150 parts by weight is carbon black, all parts by weight being based on 100 parts by weight of rubber.

Claim 5

A rubber mixture according to claim 3 wherein n is 0, R is alkyl of 1 to 4 carbon atoms and Alk is an alkylene group of 2 to 4 carbon atoms.

Claim 6

A rubber mixture according to claim 4 wherein x is a number from 2.0 to 4.0.

Claim 7

A rubber mixture according to claim 3 wherein the filler consists essentially of a silicate filler.

Claim 8

A rubber mixture according to claim 3 wherein the filler consists essentially of a carbon black filler.

Claim 9

A rubber mixture according to claim 3 wherein the filler consists essentially of a mixture of a silicate filler and a carbon black filler.

Claim 10

A rubber mixture according to claim 3 wherein rubber (B) is carboxyl rubber, epoxide rubber, trans-polypentamer, halogenated butyl rubber, 2-chlorobutadiene polymer, ethylene-vinyl acetate copolymer or ethylenepropylene copolymer.

Claim 11

A rubber mixture according to claim 3 wherein rubber (A) is a natural rubber, polyisoprene rubber or a mixture thereof.

Claim 12

A rubber mixture according to claim 1 wherein the rubber mixture contains (a) bis-(3-triethoxysilylpropyl)-oligosulphide having at least 22.0 weight percent of sulphur, (b) a sulphenamide vulcanisation accelerator and (c) sulphur in a molar ratio of 1:1:1 with a deviation of not over ±0.1 for a vulcanisation temperature of 145° C. ±3° C.

Claim 13

A rubber mixture according to claim 11 wherein the silane is present in the rubber mixture in an amount of 1 to 25 parts by weight, based on 100 parts by weight of silicate filler.

Claim 14

A rubber mixture according to claim 12 including 0.05 to 5 parts by weight of a vulcanisation retarder based on 100 parts by weight of rubber.

Claim 15

A rubber mixture according to claim 13 wherein the vulcanisation retarder is N-cyclohexyl-thiophthalimide, polynitroso-2,2,4-trimethyl-1,2-dihydroquinoline or a mixture of these two retarders.

Claim 16

A rubber mixture according to claim 11 including 0.05 to 5 parts by weight of a vulcanisation retarder based on 100 parts by weight of rubber.

Claim 17

A rubber mixture according to claim 3 wherein the silane is present in the rubber mixture in an amount of 1 to 25 parts by weight, based on 100 parts by weight of silicate filler.

Claim 18

A rubber mixture according to claim 16 including 0.05 to 5 parts by weight of a vulcanisation retarder based on 100 parts by weight of rubber.

Claim 19

A rubber mixture according to claim 3 including 0.05 to 5 parts by weight of a vulcanisation retarder based on 100 parts by weight of rubber.

Claim 20

A rubber mixture according to claim 3 wherein the silane is present in the rubber mixture in an amount of 1 to 25 parts by weight, based on 100 parts by weight of silicate filler.

Claim 21

A rubber mixture according to claim 1 including 0.05 to 5 parts by weight of a vulcanisation retarder based on 100 parts by weight of rubber.

Claim 22

A rubber mixture according to claim 3 where x is 3.0 to 4.0, n is 0 and R is alkyl of 1 to 4 carbon atoms.

Claim 23

A rubber mixture according to claim 1 where the silane is bis-(3-triethoxysilylpropyl)-oligosulphide having at least 22.0 weight percent of sulphur.

Claim 24

A rubber mixture according to claim 1 where x is 3.0 to 4.0, n is 0 and R is alkyl of 1 to 4 carbon atoms.

Claim 25

A rubber mixture according to claim 1 where the silane is bis-(3-triethoxysilylpropyl)-oligosulphide having at least 22.0 weight percent of sulphur.

Claim 26

A process for vulcanising moulding composition based on a rubber (A) which still contains double bonds and which can be crosslinked with sulphur and a vulcanisation accelerator to form an elastomer or on a mixture of such a rubber (A) with a different rubber (B) using from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of a vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk represents a difunctional hydrocarbon radical containing from 1 to 10 carbon atoms and x is a number of from 2.0 to 8.0, all parts by weight being used on 100 parts by weight of rubber or its hydrolysate comprising moulding and heating a composition to the selected vulcanisation temperature, thoroughly heating at that temperature and cooling, characterised in that the molar ratio of the silane to accelerator to sulphur, expressed as S 8 , in the moulding composition is selected in such a way that, at the vulcanisation temperature, the reversion R resulting from the crosslinking isotherm (DIN 53 529) is 0 (±5%), as determined in accordance with the following formula: ##EQU5## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D max+60 min) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 27

A process for vulcanising moulding composition based on a rubber (A) which still contains double bonds and which can be crosslinked with sulphur and a vulcanisation accelerator to form an elastomer or on a mixture of such a rubber (A) with a different rubber (B) using from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of a vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk represents a difunctional hydrocarbon radical containing from 1 to 10 carbon atoms and x is a number of from 2.0 to 8.0, all parts by weight being used on 100 parts by weight of rubber or its hydrolysate comprising moulding and heating a composition to the selected vulcanisation temperature, thoroughly heating at that temperature and cooling, characterised in that the molar ratio of the silane to accelerator to sulphur, expressed as S 8 , in the moulding composition is selected in such a way that, at the vulcanisation temperature, the reversion R resulting from the crosslinking isotherm (DIN 53 529) is 0 (±5%), as determined in accordance with the following formula: ##EQU5## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D max+60 min) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 28

A process according to claim 25 wherein the rubber mixture is one containing (1) 1 to 300 parts by weight of a silicate filler, (2) from 0.1 to 150 parts by weight of a carbon black filler or (3) a mixture of a silicate filler and a carbon black filler, the total amount of filler being 1 to 300 parts by weight of which 0.1 to 150 parts by weight is carbon black, all parts by weight being based on 100 parts by weight of rubber.

Claim 29

A process as claimed in claim 26, characterised in that there is employed a mixture based on natural rubber, polyisoprene rubber or a mixture of natural rubber and polyisoprene rubber which contains (a) a silane of the formula [(C 2 H 5 O) 3 Si-(CH 2 ) 3 -] 2 S x , in which x=3.0 to 4.0, (b) a vulcanisation accelerator from the class of sulphenamide accelerator and (c) sulphur, expressed as S 8 , in a molar ratio of 1:1:1 (with a deviation of ±0.1 in each case), the rubber mixture is vulcanised at 145° C. (±3° C.) and, on completion of vulcanisation, is cooled.

Claim 30

A process according to claim 27 wherein the silane has at least 22.0 weight percent of sulphur.

Claim 31

A tire prepared by vulcanising the composition of claim 1 at a temperature where the reversion is ±5%.

Claim 32

A tire according to claim 29 wherein the vulcanisation is at 142° to 148° C.

Claim 33

A tire prepared by vulcanising the composition of claim 3 at a temperature where the reversion is ±5%.

Claim 34

A tire according to claim 31 wherein the vulcanisation is at 145° C. ±3° C.

Claim 35

A tire prepared by vulcanising the composition of claim 5 at a temperature where the reversion is 0±5%.

Claim 36

A tire according to claim 33 wherein the vulcanisation is at 142° to 148° C.

Claim 37

A tire prepared by vulcanising the composition of claim 11 at a temperature where the reversion is 0±5%.

Claim 38

A tire according to claim 35 wherein the vulcanisation is at 142° to 148° C.

Claim 39

A tire prepared by vulcanising the composition of claim 12 at a temperature where the reversion is 0±5%.

Claim 40

A tire according to claim 37 wherein the vulcanisation is at 142° to 148° C.

Claim 41

A process for vulcanising moulding composition based on a rubber (A) which still contains double bonds and which can be crosslinked with sulfur and a vulcanisation accelerator to form an elastomer or on a mixture of such a rubber (A) with a different rubber (B) using from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of a vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk represents a difunctional hydrocarbon radical containing from 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, all parts by weight being used on 100 parts by weight of rubber comprising moulding and heating the composition to a selected vulcanisation temperature, thoroughly heating at that temperature and cooling, characterised in that the molar ratio of the silane to accelerator to sulfur, expressed as S 8 , in the moulding composition is selected in such a way that, at the vulcanisation temperature, the reversion R resulting from the crosslinking isotherm (DIN 53 529) is 0 (±5%), as determined in accordance with the following formula: ##EQU6## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D max+60 min) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 42

A process for vulcanising moulding composition based on a rubber (A) which still contains double bonds and which can be crosslinked with sulfur and a vulcanisation accelerator to form an elastomer or on a mixture of such a rubber (A) with a different rubber (B) using from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of a vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk represents a difunctional hydrocarbon radical containing from 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, all parts by weight being used on 100 parts by weight of rubber comprising moulding and heating the composition to a selected vulcanisation temperature, thoroughly heating at that temperature and cooling, characterised in that the molar ratio of the silane to accelerator to sulfur, expressed as S 8 , in the moulding composition is selected in such a way that, at the vulcanisation temperature, the reversion R resulting from the crosslinking isotherm (DIN 53 529) is 0 (±5%), as determined in accordance with the following formula: ##EQU6## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D max+60 min) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 43

A process according to claim 39 wherein the vulcanisation is carried out 142° to 148° C.

Claim 44

A process according to claim 25 wherein the vulcanisation is carried out at 142° to 148° C.

Claim 45

A composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with a different rubber (B) and from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [P.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x ( 1) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber A mixture contains silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, as the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU7## in which D max is the maximum vulcameter torgue, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 46

A composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with a different rubber (B) and from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [P.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x ( 1) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber A mixture contains silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, as the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU7## in which D max is the maximum vulcameter torgue, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 47

A rubber mixture according to claim 42 wherein n is 0, R is alkyl of 1 to 4 carbon atoms and Alk is an alkylene group having 2 to 4 carbon atoms.

Claim 48

A composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with a different rubber (B) and from 0.2 to 10 parts by weiht of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represents an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing 5 to 8 carbon atoms or the phenyl radical; all the radicals; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, and also containing (1) 1 to 300 parts by weight of silicate filler, (2) from 0.1 to 150 parts by weight of carbon black filler or (3) a mixture of a silicate filler and a carbon black filler, the total amount of filler being 1 to 300 parts by weight of which 0.1 to 150 parts by weight is carbon black, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber A mixture contains the silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, as the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU8## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 49

A composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with a different rubber (B) and from 0.2 to 10 parts by weiht of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represents an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing 5 to 8 carbon atoms or the phenyl radical; all the radicals; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, and also containing (1) 1 to 300 parts by weight of silicate filler, (2) from 0.1 to 150 parts by weight of carbon black filler or (3) a mixture of a silicate filler and a carbon black filler, the total amount of filler being 1 to 300 parts by weight of which 0.1 to 150 parts by weight is carbon black, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber A mixture contains the silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, as the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU8## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 50

A rubber mixture according to claim 44 wherein n is 0, R is alkyl of 1 to 4 carbon atoms and Alk is an alkylene group of 2 to 4 carbon atoms.

Claim 51

A rubber mixture according to claim 45 wherein x is a number from 2.0 to 4.0.

Claim 52

A rubber mixture according to claim 44 wherein the filler consists essentially of a silicate filler.

Claim 53

A rubber mixture according to claim 44 wherein the filler consists essentially of a carbon black filler.

Claim 54

A rubber mixture according to claim 44 wherein the filler consists essentially of a mixture of a silicate filler and a carbon black filler.

Claim 55

A rubber mixture according to claim 44 wherein rubber (B) is carboxyl rubber, epoxide rubber, trans-polypentamer, halogenated butyl rubber, 2-chlorobutadiene polymer, ethylenevinyl acetate copolymer or ethylene-propoylene copolymer.

Claim 56

A rubber mixture according to claim 44 wherein rubber (A) is a natural rubber, polyisoprene rubber or a mixture thereof.

Claim 57

A tire prepared by vulcanizing at a temperature where the reversion is 0±5%, a composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with different rubber (B) and from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber A mixture contains the silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, as the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU9## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 58

A tire prepared by vulcanizing at a temperature where the reversion is 0±5%, a composition which is a formable and vulcanisable rubber mixture comprising a rubber (A) which still contains double bonds and which can be cross-linked with sulphur and a vulcanisation accelerator to form an elastomer or a mixture of such a rubber (A) with different rubber (B) and from 0.2 to 10 parts by weight of sulphur, from 0.2 to 10 parts by weight of at least one vulcanisation accelerator and from 1 to 10 parts by weight of a silane corresponding to the formula [R.sub.n.sup.1 (RO).sub.3-n Si-Alk-].sub.2 S.sub.x (I) in which R and R 1 represent an alkyl group containing from 1 to 4 carbon atoms, a cycloalkyl group containing from 5 to 8 carbon atoms or the phenyl radical; all the radicals R and R 1 may be the same or different in meaning, n=0, 1 or 2, Alk is a difunctional hydrocarbon radical containing 1 to 10 carbon atoms, and x is a number of from 2.0 to 8.0, all parts by weight being based on 100 parts by weight of rubber, wherein the rubber A mixture contains the silane, vulcanisation accelerator and sulphur, expressed as S 8 , in such a molar ratio that, as the vulcanisation temperature, the rubber mixture has a reversion R resulting from the cross-linking isotherm (DIN 53 529) of 0 (±5%), the reversion R being calculated in accordance with the following formula: ##EQU9## in which D max is the maximum vulcameter torque, D min is the minimum vulcameter torque, D.sub.(max+60 mins) is the vulcameter torque as measured 60 minutes after appearance of the maximum torque.

Claim 59

A tire according to claim 52 wherein the vulcanisation is at 142° to 148° C.