Blocked mercaptosilane coupling agents for filled rubbers

Abstract

Blocked mercaptosilanes are provided in which the blocking group contains an unsaturated heteroatom or carbon chemically bound directly to sulfur via a single bond. This blocking group optionally may be substituted with one or more carboxylate ester or carboxylic acid functional groups. These silanes are used in manufacture of inorganic filled rubbers, with the silanes deblocked by a deblocking agent. Synthesis of the blocked mercaptosilanes is also provided.

1 - 3 . (canceled)  
     
     
         4 . A process of manufacturing a filled rubber comprising the steps of mixing a rubber, an inorganic filler, and a blocked mercaptosilane wherein the blocked mercaptosilane has the formula:  
         [(X 3 Si) q -G] a —[Y—[S-G-SiX 3 ] b ] c    
       wherein 
 Y is a polyvalent species (Q) z A(=E) selected from the group consisting of —C(═NR)—, —SC(═NR)—; —SC(═O)—; —OC(═O)—; —S(═O)—; —S(═O) 2 —; —OS(═O) 2 —; (—NR)S(═O) 2 —; —SS(═O)—; —OS(═O)—; (—NR)S(═O)—; —SS(═O) 2 —; (—S))P(═O)—; —(—S)P(═O)—; —P(═O)(−) 2 ; (—S) 2 P(═S)—; —S)P(═S)—; —P(═S)(−) 2 ; (—NR) 2 P(═O)—; (—NR)(—S)P(═O)—; (—O)(—NR)P(═O)—; (—O)(—S)P(═O)—; (—O) 2 P(═O)—; —(—O)P(═O)—; —(—NR)P(═O)—; (—NR) 2 P(═S)—; (—NR)(—S)P(═S)—; (—O)(—NR)P(═S)—; (—O)(—S)P(═S)—; (—O) 2 P(═S)—; —(—O)P(═S)—; and —(—NR)P(═S)—: wherein the atom A, attached to the unsaturated heteroatom E, is attached to the sulfur which in turn is linked via a group G to the silicon atom;  
 each R is chosen independently from hydrogen, straight, cyclic, or branched alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, with each R containing from 1 to 18 carbon atoms;  
 each G is independently a monovalent or polyvalent group derived by substitution of alkyl, alkenyl, aryl, or aralkyl wherein G can contain from 1 to 18 carbon atoms, with the proviso that G is not such that the blocked mercaptosilane would contain an ∀,∃-unsaturated carbonyl that can undergo polymerization reactions, and if G is univalent. G can be a hydrogen atom;  
 X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—. R 2 C═NO—, R 2 NO—, R 2 N—, —R, and —(OSiR 2 ) t (OSiR 3 ) wherein each R is as above, and at least one X is not —R;  
 z is 0 to 2; q is 0 to 6; a is 0 to 7; b is 1 to 3; c is 1 to 6; t is 0 to 5; with the provisos that (I) if A is carbon, sulfur, or sulfonyl, then a+b is 2; (II) if A is phosphorus, then a+b is 3 unless both (i) c is greater than 1 and (ii) b is 1, in which case a is c+1;  
 to produce a rubber mixture;  
 mixing into the rubber mixture (i) a deblocking agent to deblock the blocked mercaptosilane, and (ii) a curing agent; and  
 allowing the rubber mixture to cure.  
 
     
     
         5 - 18 . (canceled)  
     
     
         19 . The process for the manufacture of a filled rubber of  claim 4  comprising the steps of mixing a rubber, an inorganic filler, and a blocked mercaptosilane of the formula:  
         X 3 SiGSC(═O)GC(═O)SGSiX 3    
       wherein 
 each G is independently a divalent group derived by substitution of alkyl, alkenyl, aryl, or aralkyl, wherein G can contain from 1 to 18 carbon atoms, with the proviso that G is not such that the blocked mercaptosilane would contain an ∀,∃-unsaturated carbonyl including a carbon-carbon double bond next to the thiocarbonyl group;  
 X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R 2 C═NO—, R 2 NO—, R 2 N—, —R, and —(OSiR 2 ) t (OSiR 3 ) wherein each R is chosen independently from hydrogen, straight, cyclic, or branched alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, with each R containing from 1 to 18 carbon atoms, and at least one X is not —R; and  
 t is 0 to 5;  
 to produce a rubber mixture;  
 mixing into the rubber mixture (i) a deblocking agent to deblock the blocked mercaptosilane, and (ii) a curing agent; and  
 allowing the rubber mixture to cure.  
 
     
     
         20 - 22 . (canceled)  
     
     
         23 . A filled rubber produced by a process comprising the steps of mixing a rubber, an inorganic filler and a blocked mercaptosilane wherein the blocked mercaptosilane has the formula:  
         [(X 3 Si) q -G] a —[Y—[S-G-SiX 3 ] b ] c    
       wherein 
 Y is a polyvalent species (Q) z A(=E), each wherein the atom A attached to the unsaturated heteroatom E is attached to the sulfur, which in turn is linked via a group G to the silicon atom;  
 each G is independently a monovalent or polyvalent group derived by substitution of alkyl alkenyl, aryl, or aralkyl wherein G can contain from 1 to 18 carbon atoms, with the proviso that if Y is —C(═O)—, G is not such that the blocked mercaptosilane would contain an ∀,∃-unsaturated carbonyl, and if G is univalent, G can be a hydrogen atom;  
 X is independently a group selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R 2 C═NO—, R 2 NO—, R 2 N—, —R, and —(OSiR 2 )(OSiR 3 ) wherein each R is chosen independently from hydrogen, straight, cyclic, or branched alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups with each R containing from 1 to 18 carbon atoms, and at least one X is not —R;  
 Q is oxygen, sulfur, or (—NR—);  
 A is carbon, sulfur, phosphorus, or sulfonyl;  
 E is oxygen, sulfur, or NR;  
 z is 0 to 2; q is 0 to 6; a is 0 to 7; b is 1 to 3; c is 1 to 6; t is 0 to 5; with the provisos that (A) if A is carbon, sulfur, or sulfonyl, then a+b is 2; (B) if A is phosphorus, then a+b is 3 unless both (i) c is greater than 1 and (ii) b is 1, in which case a is c+1;  
 to produce a rubber mixture;  
 mixing into the rubber mixture (i) a deblocking agent to deblock the blocked mercaptosilane, and (ii) a curing agent; and  
 allowing the rubber mixture to cure.  
 
     
     
         24 - 35 . (canceled)  
     
     
         36 . The filled rubber of  claim 23  produced by a process comprising the steps of mixing a rubber, an inorganic filler, and a blocked mercaptosilane wherein the blocked mercaptosilane has the formula:  
         [(X 3 Si) q -G] a —[Y—[S-G-SiX 3 ] b ] c    wherein    Y is —C(═O)—,    R is hydrogen or an alkyl having from one to four carbon atoms;    each G is a substituted phenyl with the proviso that G is not such that the mercaptosilane would contain an ∀,∃-unsaturated carbonyl that can undergo polymerization reactions;    X is independently a group selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R 2 C═NO—, R 2 NO—, R 2 N—, —R, and —(OSiR 2 ) t (OSiR 3 ) wherein each R and G is as above, and at least one X is not —R; and    q is 0 to 6; a is 0 to 7; b is 1 to 2; c is 1 to 6: t is 0 to 5; and a+b is 2;    to produce a rubber mixture;    mixing into the rubber mixture (i) a deblocking agent to deblock the blocked mercaptosilane, and (ii) a curing agent; and    allowing the rubber mixture to cure.    
     
     
         37 . (canceled)  
     
     
         38 . A filled rubber produced by a process comprising the steps of mixing a rubber, an inorganic filler, and a blocked mercaptosilane of the formula:  
         X 3 SiGSC(═O)GC(═O)SGSiX 3    
       wherein 
 each G is independently a divalent group derived by substitution of alkyl, alkenyl, aryl, or aralkyl, wherein G can contain from 1 to 18 carbon atoms, with the proviso that G is not such that the blocked mercaptosilane would contain an ∀,∃-unsaturated carbonyl including a carbon-carbon double bond next to the thiocarbonyl group;  
 X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, R 2 C═NO—, R 2 NO—, R 2 N—, —R, and —(OSiR 2 ) t (OSiR 3 ) wherein each R is chosen independently from hydrogen, straight, cyclic, or branched alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, with each R containing from 1 to 18 carbon atoms, and at least one X is not —R; and  
 t is 0 to 5;  
 to produce a rubber mixture;  
 mixing into the rubber mixture (i) a deblocking agent to deblock the blocked mercaptosilane, and (ii) a curing agent; and  
 allowing the rubber mixture to cure.