# US 7,745,539 B2 · Low molecular weight nitrite rubber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,745,539 B2 - Document ID: US7745539B2 - Status: Granted - Kind: B2 - Application number: 10/926,532 - Filed: 2004-08-26 - Published: 2005-02-03 - Granted: 2010-06-29 - Earliest claimed: 2001-06-29 - Assignees: LANXESS Corporation - Inventors: Frédéric Guérin; Sharon X. Guo - Web page: https://patentgrep.com/patent/US7745539B2 ## CPC - C08L 9/02: Copolymers with acrylonitrile - C08C 19/08: Depolymerisation - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - C08C: TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS ## Abstract The present invention relates to nitrile rubber polymers having lower molecular weights and narrower molecular weight distributions than those known in the art. The present invention also relates to a process for the manufacture of said nitrile rubber and the use of said nitrile rubber for the manufacture of shaped articles. ## Claims ### Claim 1 A nitrile rubber having a molecular weight (Mw) in the range of from 25,000 to 200,000 g/mol, a Mooney viscosity (ML 1+4 @ 100 deg. C.) of less than 8 and a polydispersity index of less than about 2.1. ### Claim 2 (depends on 1) A nitrile rubber according to claim 1, wherein the nitrile rubber comprises in the range of from 40–80 wt. % of repeating units derived from at least one conjugated diane and in the range of from 15–60 wt. % of repeating units derived from at least one α,β-unsaturated nitrile. ### Claim 3 (depends on 2) A nitrile rubber according to claim 2, wherein the nitrile rubber further comprises one or more further co-monomers and wherein the wt. % for the repeating units derived from diene(s) and nitrile(s) are adjusted to result in 100 wt. % in total. ### Claim 4 (depends on 3) A nitrile rubber according to claim 3, wherein the co-monomers are one or more unsaturated carboxylic acids. ### Claim 5 A shaped article comprising nitrile rubber having a molecular weight (Mw) in the range of from 25,000 to 200,000 g/mol, a Mooney viscosity (ML 1+4 @ 100 deg. C.) of less than 8 and a polydispersity index of less than about 2.1. ### Claim 6 (depends on 5) A shaped article according to claim 5, wherein the shaped article is a hose, a bearing pad, a stator, a well head seal, a valve plate, a cable sheathing, a wheel, a roller, a pipe seal or a footwear component. ### Claim 7 A nitrile rubber having a molecular weight (Mw) in the range of from 25,000 to 200,000 g/mol, a Mooney viscosity (ML 1+4 @ 100 deg. C.) of less than 8 and a polydispersity index of less than about 2.1, wherein the nitrile rubber is prepared by olefin metathesis of at least one conjugated diene, at least one α,β-unsaturated nitrile and optionally further one or more copolymerizable monomers in the presence of one or more compounds of the general formula I, II, III or IV and optionally the presence of a co-olefin and a solvent, wherein, wherein: M is Os or Ru, R and R1 are, independently, hydrogen or a hydrocardon selected from the group consisting of C2-C20 alkenyl, C2-C20 alkynyl, C1-C20 alkyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsufonyl and C1-C20 alkylsulfinyl, X and X1 are independently any anionic ligand, and L and L1 are independently any neutral ligand or any neutral carbine, optionally, L and L1 can be linked to one another to form a bidentate neutral ligand; wherein M1 is Os or Ru; R2 and R3 are, independently, hydrogen or a hydrocarbon selected from the group consisting of C2-C20 alkenyl, C2-C20 alkynyl, C1-C20alkyl, aryl, C2-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl and C2-C20 alkylsulfinyl, X2 is an anionic ligand, and L2 is a neutral π-bonded ligand, independent of whether they are mono- or polycyclic, L3 is a ligand selected from the group consisting of phosphines, sulfonated phosphines, fluorinated phosphines, functionalized phosphines bearing up to three aminoalkyl-, ammonumalkyl-, alkoxyalkyl-, alkoxylcarbonylaklyl-, hydrocycarbonylalkyl-, hydroxyalkyl- or ketoalkyl- groups, phosphites, phosphinites, phosphonites, phosphinamines, arsines, stibenes, ethers, amines, amides, imines, sulfoxides, thioethers and pyridines, Y-is a non-coordinating anion, n is an integer in the range of from 0 to 5; wherein M2 is Mo or W, R4 and R5 are, independently, hydrogen or a hydrocarbon selected from the group consisting of C2-C20 alkenyl, C2-C20 alkynl, C1-C20 alkyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl and C1-C20 alkylsulfinyl, R6 and R7 are independently selected from any unsubstituted or halo-substituted alkyl, aryl, aralkyl groups or silicon-containing analogs thereof, wherein M is Os or Ru, R and R1 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, and substituted or unsubstituted alkyl, X and X1 are independently any anionic ligand, and L and L1 are independently any neutral ligand or any neutral carbine, optionally, L and L1 can be linked to one another to form a bidentate neutral ligand.