Elastomeric compositions containing fluoropolymer blends

Abstract

Processable rubber compositions contain a vulcanized fluorocarbon elastomer dispersed in a thermoplastic matrix comprising a fully fluorinated polymer and a partially fluorinated polymer. The processing temperature is below the melting point of the fully fluorinated polymer. The compositions are made by combining a curative, uncured fluorocarbon elastomer, a fully fluorinated thermoplastic, and a partially fluorinated 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 .- 14 . (canceled)  
   
   
       15 . A processable rubber composition comprising a cured fluorocarbon elastomer dispersed in a thermoplastic matrix, wherein 
 the thermoplastic matrix comprises a fully fluorinated thermoplastic melt-processable polymer and a partially fluorinated thermoplastic melt-processable polymer;    the cured fluorocarbon elastomer is present as a discrete phase or a phase co-continuous with the matrix; and    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.    
   
   
       16 . A composition according to  claim 15 , wherein the dimensions of the elastomer phase are less than or equal to 1 μm.  
   
   
       17 . A composition according to  claim 15 , wherein the cured fluorocarbon elastomer is present at least in part as particles dispersed in a continuous thermoplastic phase.  
   
   
       18 . A composition according to  claim 15 , wherein the cured fluorocarbon elastomer is present at least in part in a dispersed phase co-continuous with the thermoplastic phase.  
   
   
       19 . A composition according to  claim 15 , wherein the composition exhibits a single melting temperature of less than 290° C.  
   
   
       20 . A composition according to  claim 15 , wherein the composition exhibits a single melting temperature of less than 250° C.  
   
   
       21 . A composition according to  claim 15 , wherein the ratio of the weight of the fully fluorinated polymer to the weight of the partially fluorinated polymer in the matrix ranges from 1:9 to 9:1.  
   
   
       22 . A composition according to  claim 21 , wherein the ratio of the weight of the fully fluorinated polymer to the weight of the partially fluorinated polymer in the matrix ranges from 1:2 to 2:1.  
   
   
       23 . A method for making a processable rubber composition comprising: 
 mixing an elastomeric component and a thermoplastic component in the presence of a curative agent, and    heating during mixing to effect cure of the elastomeric component wherein the elastomeric material comprises a fluorocarbon elastomer; and wherein the thermoplastic material is a fluoroplastic blend comprising a fully fluorinated thermoplastic melt-processable polymer and a partially fluorinated thermoplastic melt-processable polymer.    
   
   
       24 . A method according to  claim 23 , comprising forming a mixture by combining the curative, an uncured or partially cured elastomeric material, and the 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.    
   
   
       25 . A method according to  claim 23  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.  
   
   
   
       26 . A method according to  claim 23 , wherein the ratio of the weight of the fully fluorinated polymer to the weight of the partially fluorinated polymer in the matrix ranges from 1:9 to 9:1.  
   
   
       27 . A method according to  claim 26 , wherein the ratio of the weight of the fully fluorinated polymer to the weight of the partially fluorinated polymer in the matrix ranges from 1:2 to 2:1.  
   
   
       28 . A method according to  claim 23 , wherein the fluorocarbon elastomer comprises repeating units derived from vinylidene fluoride and hexafluoropropylene.  
   
   
       29 . A method according to  claim 28 , wherein the fluorocarbon elastomer further comprises repeating units derived from tetrafluoroethylene.  
   
   
       30 . A method according to  claim 23 , 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, TFE/PFVE, and mixtures thereof.  
   
   
       31 . A method according to  claim 30 , wherein the fluorocarbon elastomer also comprises cure site monomers.  
   
   
       32 . A method according to  claim 23 , wherein the curative comprises a polyol.  
   
   
       33 . A method according to  claim 23 , wherein the curative comprises a peroxide.  
   
   
       34 . A method according to  claim 23 , wherein the thermoplastic material comprises a fully fluorinated polymer selected from the group consisting of PFA, MFA and FEP, and a partially fluorinated polymer selected from the group consisting of polyvinylidene fluoride and copolymers of vinylidene fluoride.  
   
   
       35 . A method according to  claim 23 , comprising a continuous process.  
   
   
       36 . A method according to  claim 35 , carried out in a twin screw extruder.  
   
   
       37 . A method according to  claim 23 , comprising a batch process.  
   
   
       38 . A method according to  claim 23 , wherein the composition comprises at least about 35 parts by weight vulcanized elastomeric material per 100 parts of the vulcanized elastomeric material and thermoplastic material combined.  
   
   
       39 . A method according to  claim 23 , 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.  
   
   
       40 . A shaped article comprising a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein the thermoplastic material comprises from about 10 to about 90% by weight of a fully fluorinated thermoplastic melt-processable polymer and from about 10 to about 90% by weight of a partially fluorinated thermoplastic polymer.  
   
   
       41 . A shaped article according to  claim 40 , 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.  
   
   
       42 . A shaped article according to  claim 40 , 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.  
   
   
       43 . A shaped article according to  claim 40  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.  
   
   
       44 . A method according to  claim 40 , 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, TFE/PFVE, and mixtures thereof.  
   
   
       45 . A seal according to  claim 40 .  
   
   
       46 . An O-ring according to  claim 40 .  
   
   
       47 . A gasket according to  claim 40 .  
   
   
       48 . A hose according to  claim 38 .  
   
   
       49 . 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 from about 10 to about 90% by weight of a fully fluorinated thermoplastic polymer and from about 10 to about 90% by weight of a partially fluorinated thermoplastic polymer.  
   
   
       50 . A method according to  claim 49 , wherein the manufacturing process comprises forming the shaped articles by a thermoplastic processing technique.  
   
   
       51 . A method according to  claim 49 , wherein the thermoplastic processing technique is selected from the group consisting of blow molding, injection molding, compression molding, and extrusion.  
   
   
       52 . A method according to  claim 49 , wherein recycling comprises melting the scrap material at a temperature below the melting point of the fully fluorinated polymer.  
   
   
       53 . A method according to  claim 49 , wherein recycling comprising melting the scrap material at a temperature below 250° C.  
   
   
       54 . A process of manufacturing shaped plastic articles, comprising preparing a processable rubber composition by dynamically vulcanizing a fluorocarbon elastomer in the presence of a fluoroplastic blend comprising a fully fluorinated melt-processable polymer and a partially fluorinated melt-processable polymer; 
 melting the rubber composition; and    fabricating the shaped article from the molten rubber composition with a thermoplastic processing technique.    
   
   
       55 . A method according to  claim 54 , comprising melting the rubber at a temperature below the melting temperature of the fully fluorinated polymer.  
   
   
       56 . A method according to  claim 54 , comprising melting the rubber at a temperature below 280° C., wherein the fluoroplastic blend comprises more than 65% by weight fluorine.  
   
   
       57 . A method according to  claim 54 , comprising injection molding the molten rubber composition.  
   
   
       58 . A method according to  claim 54 , comprising extruding the molten rubber composition.  
   
   
       59 . A processable rubber composition comprising a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein: 
 the thermoplastic material comprises a fully fluorinated melt-processable thermoplastic polymer and a partially fluorinated melt-processable thermoplastic polymer;    the cured fluorocarbon elastomer is present at a level of greater than or equal to 35% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic material; and    the dimensions of the cured fluorocarbon elastomer 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.    
   
   
       60 . A processable rubber composition according to  claim 59 , wherein the dimensions are less than 1 μm.  
   
   
       61 . A method for making a processable rubber composition comprising: 
 mixing an elastomeric component and the thermoplastic material in the presence of a curative agent; and    heating during mixing to effect cure of the elastomeric component, wherein the elastomeric component comprises a fluorocarbon elastomer;    wherein said rubber composition comprises a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein the thermoplastic material comprises a fully fluorinated melt-processable thermoplastic polymer and a partially fluorinated melt-processable thermoplastic polymer; and the cured fluorocarbon elastomer is present at a level of greater than or equal to 35% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic material.    
   
   
       62 . A method according to  claim 61 , comprising 
 forming a mixture by combining the curative, an uncured or partially cured fluorocarbon elastomer and the thermoplastic material; and    heating the mixture at a temperature and for a time sufficient to effect vulcanization of the elastomer, wherein mechanical energy is applied to mix the mixture during the heating step.    
   
   
       63 . A method according to  claim 61 , comprising: 
 mixing the elastomeric component 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.    
   
   
       64 . A shaped article made by thermoplastic processing of a processable rubber composition comprising a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein: 
 the thermoplastic material comprises a fully fluorinated melt-processable thermoplastic polymer and a partially fluorinated melt-processable thermoplastic polymer; and the cured fluorocarbon elastomer is present at a level of greater than or equal to 35% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic material.    
   
   
       65 . A shaped article according to  claim 64 , 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.  
   
   
       66 . A shaped article according to  claim 64 , wherein the thermoplastic material comprises from about 10 to about 90% by weight of a fully fluorinated thermoplastic polymer and from about 10 to about 90% by weight of a partially fluorinated thermoplastic polymer.  
   
   
       67 . A shaped article according to  claim 64  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.  
   
   
       68 . A shaped article according to  claim 64 , 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, TFE/PFVE, and mixtures thereof.  
   
   
       69 . A seal according to  claim 64 .  
   
   
       70 . An O-ring according to  claim 64 .  
   
   
       71 . A gasket according to  claim 64 .  
   
   
       72 . A hose according to  claim 64 .  
   
   
       73 . A process of manufacturing a shaped plastic article, comprising 
 preparing a processable rubber composition by dynamically vulcanizing a fluorocarbon elastomer in the presence of the fluoroplastic material;    melting the rubber composition; and    fabricating the shaped article from the molten rubber composition with a thermoplastic processing technique; wherein said processable rubber composition comprises a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein:    the thermoplastic material comprises a fully fluorinated melt-processable thermoplastic polymer and a partially fluorinated melt-processable thermoplastic polymer; and the cured fluorocarbon elastomer is present at a level of greater than or equal to 35% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic material.    
   
   
       74 . A method according to  claim 73 , comprising melting the rubber composition at a temperature below the melting temperature of the fully fluorinated polymer.  
   
   
       75 . A method according to  claim 73 , comprising melting the rubber at a temperature below 280° C., wherein the fluoroplastic blend comprises more than 65% by weight fluorine.  
   
   
       76 . A method according to  claim 73 , comprising injection molding the molten rubber composition.  
   
   
       77 . A method according to  claim 73 , comprising extruding the molten rubber composition.  
   
   
       78 . A processable rubber composition comprising a cured fluorocarbon elastomer dispersed in a matrix comprising a thermoplastic material, wherein: 
 the thermoplastic material comprises a fully fluorinated melt-processable thermoplastic polymer and a partially fluorinated melt-processable thermoplastic polymer;    the cured fluorocarbon elastomer is present at a level of 50%-80% by weight based on the total weight of cured fluorocarbon elastomer and thermoplastic material; and    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, and    wherein the composition exhibits a single melting temperature of less than 250° C.    
   
   
       79 . A composition according to  claim 78 , wherein the ratio of the weight of the fully fluorinated polymer to the weight of the partially fluorinated polymer in the matrix ranges from 1:2 to 2:1.  
   
   
       80 . A composition according to  claim 78 , wherein the fluorocarbon elastomer comprises repeating units derived from vinylidene fluoride and hexafluoropropylene.  
   
   
       81 . A composition according to  claim 80 , wherein the fluorocarbon elastomer further comprises repeating units derived from tetrafluoroethylene.  
   
   
       82 . A composition according to  claim 78 , 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, TFE/PFVE, and mixtures thereof.  
   
   
       83 . A composition according to  claim 82 , wherein the fluorocarbon elastomer also comprises cure site monomers.  
   
   
       84 . A composition according to  claim 78 , wherein the thermoplastic material comprises a fully fluorinated polymer selected from the group consisting of PFA, MFA and FEP, and a partially fluorinated polymer selected from the group consisting of polyvinylidene fluoride and copolymers of vinylidene fluoride.