Dynamic vulcanization of fluorocarbon elastomers

Abstract

Processable rubber compositions contain a vulcanized fluorocarbon elastomer dispersed in a matrix of a non-fluorine containing thermoplastic polymeric material. In one embodiment the matrix forms a continuous phase and the vulcanized elastomeric material is in the form of particles forming a non-continuous phase. The compositions are made by combining a curative, an uncured fluorocarbon elastomer, and a thermoplastic material, and heating the mixture at a temperature and for a time sufficient to effect vulcanization of the elastomeric material, while mechanical energy is applied to mix the mixture during the heating step. Shaped articles such as seals, gaskets, O-rings, and hoses may be readily formed from the rubber compositions according to conventional thermoplastic processes such as blow molding, injection molding, and extrusion.

1 - 11 . (canceled)  
     
     
         12 . A processable rubber composition comprising a cured fluorocarbon elastomer dispersed in a thermoplastic matrix, 
 wherein the thermoplastic matrix comprises a non-fluorine containing thermoplastic polymer, and    wherein the cured fluorocarbon elastomer is present as a discrete phase or a phase co-continuous with the matrix, and    wherein the dimensions of the elastomer phase are less than 10 μm, as measured by atomic force microscopy on cryogenically microtomed cross-sections of shaped articles formed from the processable rubber composition,    wherein the thermoplastic matrix comprises an amorphous polymer with a glass transition temperature of greater than or equal to 150° C. or a semi-crystalline polymer with a melting point greater than or equal to 150° C.    
     
     
         13 . A composition according to  claim 12 , wherein the dimensions of the elastomer phase are less than or equal to 1 μm.  
     
     
         14 . A composition according to  claim 12 , wherein the cured fluorocarbon elastomer is present at least in part as particles dispersed in a continuous thermoplastic phase.  
     
     
         15 . A composition according to  claim 12 , wherein the cured fluorocarbon elastomer is present at least in part in a dispersed phase co-continuous with the thermoplastic phase.  
     
     
         16 . A composition according to  claim 12 , wherein the cured fluorocarbon elastomer comprises repeating units derived from tetrafluoroethylene and propylene.  
     
     
         17 - 18 . (canceled)  
     
     
         19 . A composition according to  claim 12 , wherein the cured fluorocarbon elastomer comprises repeating units derived from vinylidene fluoride and hexafluoropropylene.  
     
     
         20 - 21 . (canceled)  
     
     
         22 . A composition according to  claim 12 , wherein the cured fluorocarbon elastomer comprises repeating units derived from tetrafluoroethylene and perfluoroalkylvinyl ethers, 
 wherein the perfluoroalkyl vinyl ether contains 1 to 6 carbons in the perfluoroalkyl group    
     
     
         23 - 24 . (canceled)  
     
     
         25 . A processable rubber composition made by a process comprising the step of dynamically vulcanizing a fluorocarbon elastomer in the presence of a non-fluorine-containing thermoplastic material, 
 wherein the thermoplastic material has a glass transition temperature of greater than or equal to 150° C. or a melting point greater than or equal to 150° C.    
     
     
         26 . A composition according to  claim 25 , made by a process comprising the steps of: 
 combining an uncured or partially cured fluorocarbon elastomer, a curative agent capable of reacting with the fluorocarbon elastomer to effect cure, and a non-fluorine-containing thermoplastic material;    mixing the combination; and    applying heat to the combination during the mixing step.    
     
     
         27 . A composition according to  claim 25 , made by a process comprising the steps of: 
 mixing the elastomer and thermoplastic components in the presence of the curative agent, and    heating during mixing to effect cure of the elastomeric components.    
     
     
         28 . A composition according to  claim 25  made by a process comprising the steps of: 
 mixing the elastomer material and thermoplastic material for a time and at a shear rate sufficient to form a dispersion of the elastomeric material in a continuous thermoplastic phase;    adding a curative to the dispersion while continuing the mixing; and    heating the dispersion while continuing to mix the curative, elastomeric material, and thermoplastic material.    
     
     
         29 . A composition according to  claim 25 , wherein the curative agent comprises a polyol.  
     
     
         30 . A composition according to  claim 25 , wherein the curative agent comprises a peroxide.  
     
     
         31 . A method for making a rubber composition comprising: 
 forming a mixture by combining a curative, an uncured or partially cured elastomeric material, and a thermoplastic material; and    heating the mixture at a temperature and for a time sufficient to effect vulcanization of the elastomeric material, wherein mechanical energy is applied to mix the mixture during the heating step;    wherein the elastomeric material comprises a fluorocarbon elastomer; and    wherein the thermoplastic material comprises a non-fluorine-containing polymeric material with a glass transition temperature greater than or equal to 150° C. or a melting point greater than or equal to 150° C.    
     
     
         32 . A method according to  claim 31  comprising: 
 mixing the elastomer and thermoplastic components in the presence of a curative agent, and    heating during mixing to effect cure of the elastomeric component.    
     
     
         33 . A method according to  claim 31  comprising: 
 mixing the elastomeric material and the thermoplastic material for a time and at a shear rate sufficient to form a dispersion of the elastomeric material in a continuous thermoplastic phase;    adding a curative to the dispersion while continuing the mixing; and    heating the dispersion while continuing to mix the curative, elastomeric material, and thermoplastic material.    
     
     
         34 . A method according to  claim 31 , wherein the fluorine-containing elastomer comprises repeating units derived from: 
 10-90 mole % tetrafluoroethylene;    10-90 mole % propylene; and    up to 30 mole % of an additional fluorine containing monomer.    
     
     
         35 . A method according to  claim 34 , wherein the additional monomer comprises vinylidene difluoride.  
     
     
         36 . A method according to  claim 31 , wherein the fluorocarbon elastomer comprises repeating units deriving from vinylidene fluoride and hexafluoropropylene.  
     
     
         37 . A method according to  claim 36 , wherein the fluorocarbon elastomer further comprises repeating units derived from tetrafluoroethylene.  
     
     
         38 . A method according to  claim 31 , wherein the fluorocarbon elastomer is selected from the group consisting of: 
 VDF/HFP,    VDF/HFP/TFE,    VDF/PFVE/TFE,    TFE/Pr,    TFE/Pr/VDF,    TFE/Et/PFVE/VDF,    TFE/Et/PFVE, and    TFE/PFVE.    
     
     
         39 . A method according to  claim 38 , wherein the fluorocarbon elastomer also comprises cure site monomers.  
     
     
         40 . A method according to  claim 31 , wherein the curative agent comprises an amine.  
     
     
         41 . A method according to  claim 31 , wherein the curative comprises a polyol.  
     
     
         42 . A method according to  claim 31 , wherein the curative comprises a peroxide.  
     
     
         43 . A method according to  claim 31 , wherein the thermoplastic material comprises a thermoplastic elastomer.  
     
     
         44 . A method according to  claim 43 , wherein the thermoplastic elastomer comprises blocks of polyamide and blocks of polyether.  
     
     
         45 . A method according to  claim 43 , wherein the thermoplastic elastomer comprises blocks of polyether and blocks of polyester.  
     
     
         46 . A method according to  claim 31 , wherein the thermoplastic material comprises a polyamide, a polyester, or a polyolefin.  
     
     
         47 . A method according to  claim 31 , comprising a continuous process.  
     
     
         48 . A method according to  claim 47 , carried out in a twin screw extruder.  
     
     
         49 . A method according to  claim 31 , comprising a batch process.  
     
     
         50 . A method according to  claim 31 , wherein the combination comprises at least about 35 parts by weight vulcanized elastomeric material per 100 parts of the vulcanized elastomeric material and thermoplastic material combined.  
     
     
         51 . A method according to  claim 31 , wherein the combination comprises at least about 45 parts by weight vulcanized elastomeric material per 100 parts of the vulcanized elastomeric material and thermoplastic material combined.  
     
     
         52 . A method according to  claim 31 , wherein the combination comprises at least about 50 parts by weight vulcanized elastomeric material per 100 parts of the vulcanized elastomeric material and thermoplastic material combined.  
     
     
         53 . A shaped article comprising a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein the thermoplastic material comprises a non-fluorine-containing thermoplastic polymer having a glass transition temperature greater than or equal to 150° C. or a melting point greater than or equal to 150° C.  
     
     
         54 . A shaped article according to  claim 53 , wherein the hardness of the article is Shore A 50 or greater, the tensile strength of the article is 4 MPa or greater, the modulus at 100% of the article is 4 Mpa or greater, or the elongation at break of the article is 10% or greater.  
     
     
         55 . A shaped article according to  claim 53 , wherein the cured fluorocarbon elastomer is present at a level of at least 35% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic polymer.  
     
     
         56 . A shaped article according to  claim 53  wherein the cured fluorocarbon elastomer is present at a level of at least 50% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic polymer.  
     
     
         57 - 58 . (canceled)  
     
     
         59 . An article according to  claim 53 , wherein the fluorocarbon elastomer is selected from the group consisting of: 
 VDF/HFP,    VDF/HFP/TFE,    VDF/PFVE/TFE,    TFE/Pr,    TFE/Pr/VDF,    TFE/Et/PFVE/VDF,    TFE/Et/PFVE, and    TFE/PFVE.    
     
     
         60 . An article according to  claim 53 , wherein the thermoplastic polymer comprises a thermoplastic elastomer.  
     
     
         61 . An article according to  claim 60 , wherein the thermoplastic elastomer comprises a polyamide block and a polyester block.  
     
     
         62 . An article according to  claim 60 , wherein the thermoplastic elastomer comprises a polyester block and a polyether block.  
     
     
         63 . An article according to  claim 53 , wherein the thermoplastic polymer comprises a polyamide.  
     
     
         64 . An article according to  claim 63 , wherein the polyamide comprises an aromatic polyamide.  
     
     
         65 . An article according to  claim 64 , wherein the aromatic polyamide comprises repeating units derived from a diamine containing more than 6 carbons and an aromatic diacid.  
     
     
         66 . An article according to  claim 64 , wherein the aromatic polyamide comprises repeating units derived from nonanediamine and an aromatic diacid.  
     
     
         67 . A seal according to  claim 53 .  
     
     
         68 . An O-ring according to  claim 53 .  
     
     
         69 . A gasket according to  claim 53 .  
     
     
         70 . A hose according to  claim 53 .  
     
     
         71 . A continuous process for making a processable rubber composition comprising: 
 combining a fluorocarbon elastomer, curative agent, a thermoplastic material comprising a non-fluorine containing thermoplastic polymer in a twin screw extruder,    mixing the combination in the twin screw extruder for a time and at a temperature sufficient to effect cure of the fluorocarbon elastomer, and    extruding the cured mixture wherein the thermoplastic polymer comprises an amorphous polymer with a glass transition temperature greater than or equal to 150° C. or a semi-crystalline polymer having a melting point greater than or equal to 150° C.    
     
     
         72 . A process according to  claim 71  comprising: 
 injecting a combination of the fluorocarbon elastomer and thermoplastic material into the twin screw extruder with a first feeder, and    injecting the curative agent into the screw extruder with a second feeder downstream from the first feeder.    
     
     
         73 . A process according to  claim 71 , wherein the fluorocarbon elastomer and curative agent are formulated together into a pre-compound.  
     
     
         74 . A process according to  claim 71 , wherein the fluorocarbon elastomer comprises repeating units derived from tetrafluoroethylene and propylene.  
     
     
         75 . A process according to  claim 71 , wherein the fluorocarbon elastomer comprises repeating units derived from vinylidene fluoride and hexafluoropropylene.  
     
     
         76 . A process according to  claim 71 , wherein the fluorocarbon elastomer is selected from the group consisting of: 
 VDF/HFP,    VDF/HFP/TFE,    VDF/PFVE/TFE,    TFE/Pr,    TFE/Pr/VDF,    TFE/Et/PFVE/VDF,    TFE/Et/PFVE, and    TFE/PFVE.    
     
     
         77 . A process according to  claim 71 , wherein the thermoplastic material comprises a thermoplastic elastomer.  
     
     
         78 . A process according to  claim 77 , wherein the thermoplastic elastomer comprises polyamide blocks and polyester blocks.  
     
     
         79 . A process according to  claim 77 , wherein the thermoplastic elastomer comprises blocks of polyester and blocks of polyether.  
     
     
         80 . A process according to  claim 71 , wherein the thermoplastic material comprises an aromatic polyamide.  
     
     
         81 . An process according to  claim 80 , wherein the aromatic polyamide comprises repeating units derived from a diamine containing more than 6 carbons and an aromatic diacid.  
     
     
         82 . An process according to  claim 80 , wherein the aromatic polyamide comprises repeating units derived from nonanediamine and an aromatic diacid.  
     
     
         83 . A method for reducing costs of a manufacturing process for making shaped rubber articles from a processable rubber composition, comprising 
 recycling scrap material generated during the manufacturing process to make new shaped articles comprising the processable rubber composition,    wherein the processable rubber composition is the product of dynamic vulcanization of a fluorocarbon elastomer in the presence of a thermoplastic material, wherein the thermoplastic material comprises a non-fluorine containing thermoplastic polymer.    
     
     
         84 . A method according to  claim 83 , wherein the manufacturing process comprises forming the shaped articles by a thermoplastic processing technique.  
     
     
         85 . A method according to  claim 83 , wherein the thermoplastic processing technique is selected from the group consisting of blow molding, injection molding, compression molding, and extrusion.  
     
     
         86 - 95 . (canceled)