Elastomer Composition, Method for Producing Same, and Pneumatic Tire Using Same

Abstract

An elastomer composition, having an excellent flexibility and low temperature durability, a method for producing the same and a pneumatic tire using the same are provided. An elastomer composition (C) comprising a matrix of a thermoplastic resin (A), in which a dispersed phase of an elastomer component (B) is finely dispersed to form an island-in-sea structure, wherein volume ratios of the thermoplastic resin (A) and the elastomer component (B) satisfy the following formula (I): Φd/Φm>ηd/ηm   (I) wherein Φd and ηd, respectively, indicate a volume ratio and a melt viscosity of the elastomer component (B), and Φm and ηm, respectively, indicate a volume ratio and a melt viscosity of the thermoplastic resin (A)), a method for producing the same and a pneumatic tire using the same.

1 . An elastomer composition (C) characterized by comprising a matrix of a thermoplastic resin (A) in which a dispersed phase of an elastomer component (B) is finely dispersed to form an island-in-sea structure, wherein volume ratios of the thermoplastic resin (A) and the elastomer component (B) satisfy the following formula (I):
     Φd/Φm>ηd/ηm   (I)   
     where Φd and ηd, respectively, indicate a volume ratio and a melt viscosity of the elastomer component (B) and Φm and ηm, respectively, indicate a volume ratio and a melt viscosity of the thermoplastic resin (A). 
   
   
       2 . An elastomer composition (C) as claimed in  claim 1 , wherein the volume ratio of elastomer component (B) is 55 to 95%. 
   
   
       3 . An elastomer composition (C) as claimed in  claim 1 , wherein the thermoplastic resin (A) is at least one thermoplastic resin selected from the group consisting of Nylon 6, Nylon 6/66 copolymer, Nylon 11, Nylon 12, a Nylon 6/10 copolymer and a Nylon 6/12 copolymer. 
   
   
       4 . An elastomer composition (C) as claimed in  claim 1 , wherein the elastomer component (B) is at least one elastomer selected from the group consisting of a bromide of an isoprene-paramethyl styrene copolymer, a maleic anhydride-modified ethylene-α-olefin copolymer, butyl rubber, halogenated butyl rubber and polyisoprene rubber. 
   
   
       5 . A method for producing an elastomer composition (C) according to  claim 1  comprising the steps of:
 mixing and shaping a thermoplastic resin (A), an elastomer component (B) and a plasticizer (D) in a ratio satisfying the following formulae (II) and (III):
     Φd /( Φm+Φ 1)×( ηml/ηd )<1  (II) 
     ηml/ηd= 0.8−1.2  (III) 
   
     wherein Φd and ηd, respectively, indicate a volume ratio and a viscosity of the elastomer component (B), Φm indicates a volume ratio of the thermoplastic resin (A), Φ1 indicates a volume ratio of the plasticizer (D) and ηml indicates a melt viscosity of a mixture of the thermoplastic resin (A) and the plasticizer (D); and, then,
 removing the plasticizer (D) by evaporation, extraction or migration. 
 
   
   
       6 . A method for producing an elastomer composition (C) according to  claim 5 , wherein the plasticizer (D) is alkylbenzene sulfonamide. 
   
   
       7 . A pneumatic tire using an elastomer composition (C) according to  claim 1  as an inner liner. 
   
   
       8 . An elastomer composition (C) as claimed in  claim 2 , wherein the thermoplastic resin (A) is at least one thermoplastic resin selected from the group consisting of Nylon 6, Nylon 6/66 copolymer, Nylon 11, Nylon 12, a Nylon 6/10 copolymer and a Nylon 6/12 copolymer. 
   
   
       9 . An elastomer composition (C) as claimed in  claim 2 , wherein the elastomer component (B) is at least one elastomer selected from the group consisting of a bromide of an isoprene-paramethyl styrene copolymer, a maleic anhydride-modified ethylene-α-olefin copolymer, butyl rubber, halogenated butyl rubber and polyisoprene rubber. 
   
   
       10 . An elastomer composition (C) as claimed in  claim 3 , wherein the elastomer component (B) is at least one elastomer selected from the group consisting of a bromide of an isoprene-paramethyl styrene copolymer, a maleic anhydride-modified ethylene-α-olefin copolymer, butyl rubber, halogenated butyl rubber and polyisoprene rubber. 
   
   
       11 . A method for producing an elastomer composition (C) according to  claim 2  comprising the steps of:
 mixing and shaping a thermoplastic resin (A), an elastomer component (B) and a plasticizer (D) in a ratio satisfying the following formulae (II) and (III):
     Φd /( Φm+Φ 1)×( ηml/ηd )<1  (II) 
     ηml/ηd= 0.8−1.2  (III) 
   
     wherein Φd and ηd, respectively, indicate a volume ratio and a viscosity of the elastomer component (B), Φm indicates a volume ratio of the thermoplastic resin (A), Φ1 indicates a volume ratio of the plasticizer (D) and ηml indicates a melt viscosity of a mixture of the thermoplastic resin (A) and the plasticizer (D); and, then,
 removing the plasticizer (D) by evaporation, extraction or migration. 
 
   
   
       12 . A method for producing an elastomer composition (C) according to  claim 3  comprising the steps of:
 mixing and shaping a thermoplastic resin (A), an elastomer component (B) and a plasticizer (D) in a ratio satisfying the following formulae (II) and (III):
     Φd /( Φm+Φ 1)×( ηml/ηd )<1  (II) 
     ηml/ηd= 0.8−1.2  (III) 
   
     wherein Φd and ηd, respectively, indicate a volume ratio and a viscosity of the elastomer component (B), Φm indicates a volume ratio of the thermoplastic resin (A), Φ1 indicates a volume ratio of the plasticizer (D) and ηml indicates a melt viscosity of a mixture of the thermoplastic resin (A) and the plasticizer (D); and, then,
 removing the plasticizer (D) by evaporation, extraction or migration. 
 
   
   
       13 . A method for producing an elastomer composition (C) according to  claim 4  comprising the steps of:
 mixing and shaping a thermoplastic resin (A), an elastomer component (B) and a plasticizer (D) in a ratio satisfying the following formulae (II) and (III):
     Φd /( Φm+Φ 1)×( ηml/ηd )<1  (II) 
     ηml/ηd= 0.8−1.2  (III) 
   wherein Φd and ηd, respectively, indicate a volume ratio and a viscosity of the elastomer component (B), Φm indicates a volume ratio of the thermoplastic resin (A), Φ1 indicates a volume ratio of the plasticizer (D) and ηml indicates a melt viscosity of a mixture of the thermoplastic resin (A) and the plasticizer (D); and, then,   removing the plasticizer (D) by evaporation, extraction or migration.   
   
   
       14 . A pneumatic tire using an elastomer composition (C) according to  claim 2  as an inner liner. 
   
   
       15 . A pneumatic tire using an elastomer composition (C) according to  claim 3  as an inner liner. 
   
   
       16 . A pneumatic tire using an elastomer composition (C) according to  claim 4  as an inner liner. 
   
   
       17 . A method for producing an elastomer composition (C) according to  claim 11 , wherein the plasticizer (D) is alkylbenzene sulfonamide. 
   
   
       18 . A method for producing an elastomer composition (C) according to  claim 12 , wherein the plasticizer (D) is alkylbenzene sulfonamide. 
   
   
       19 . A method for producing an elastomer composition (C) according to  claim 13 , wherein the plasticizer (D) is alkylbenzene sulfonamide. 
   
   
       20 . An elastomer composition (C) as claimed in  claim 8 , wherein the elastomer component (B) is at least one elastomer selected from the group consisting of a bromide of an isoprene-paramethyl styrene copolymer, a maleic anhydride-modified ethylene-α-olefin copolymer, butyl rubber, halogenated butyl rubber and polyisoprene rubber.