Latex of the highly saturated nitrile rubber and adhesive composition

Abstract

A latex of a highly saturated nitrile rubber wherein the highly saturated nitrile rubber contains α,β-ethylenically unsaturated nitrile monomer units in a ratio of 10 to 60 wt %, has an iodine value of 120 or less, and has a weight average molecular weight of solubles in chloroform of 100,000 or less, and when removing volatiles contained in the latex and making a film of the highly saturated nitrile rubber, a loss tangent tan δ (50° C.) at 50° C. of the film is 0.3 to 0.6 and a complex torque S* at the time of 100% shear strain at 100° C. of the film is 20 dNm or less, and an adhesive composition containing the latex are provided.

1 . A latex of a highly saturated nitrile rubber wherein
 the highly saturated nitrile rubber contains α,β-ethylenically unsaturated nitrile monomer units in a ratio of 10 to 60 wt %, has an iodine value of 120 or less, and has a weight average molecular weight of solubles in chloroform of 100,000 or less, and   when removing volatiles contained in the latex and making a film of the highly saturated nitrile rubber, a loss tangent tan δ (50° C.)  at 50° C. of the film is 0.3 to 0.6 and a complex torque S* at the time of 100% shear strain at 100° C. of the film is 20 dNm or less.   
     
     
         2 . The latex of a highly saturated nitrile rubber according to  claim 1 , wherein when removing volatiles contained in the latex and making a film of the highly saturated nitrile rubber, a difference Δ tan δ=tan δ (150° C.) −tan δ (50° C.) , which is a difference of the loss tangent tan δ (50° C.)  at 50° C. and a loss tangent tan δ (150° C.)  at 150° C. of the film, is 0.35 or less. 
     
     
         3 . The latex of a highly saturated nitrile rubber according to  claim 1 , wherein when removing volatiles contained in the latex and making a film of the highly saturated nitrile rubber, a storage modulus G′ (100° C.)  at 100° C. of the film is 200 kPa or less. 
     
     
         4 . The latex of a highly saturated nitrile rubber according to  claim 1 , wherein the highly saturated nitrile rubber contains 10 to 60 wt % of α,β-ethylenically unsaturated nitrile monomer units, 0.1 to 20 wt % of acid group-containing α,β-ethylenically unsaturated monomer units, and 20 to 89.9 wt % of diene monomer units and/or α-olefin monomer units. 
     
     
         5 . The latex of a highly saturated nitrile rubber according to  claim 1 , wherein the latex of a highly saturated nitrile rubber is one obtained by emulsion polymerization of monomers forming the highly saturated nitrile rubber and
 the latex of a highly saturated nitrile rubber is one obtained through a process of not adding a molecular weight modifier at the time of start of emulsion polymerization and adding 1 to 3 parts by weight of a molecular weight modifier, after start of emulsion polymerization, with respect to 100 parts by weight of the monomers used for polymerization at the stage of a 5 to 60 wt % polymerization conversion rate.   
     
     
         6 . An adhesive composition comprising the latex of a highly saturated nitrile rubber according to  claim 1 . 
     
     
         7 . The adhesive composition according to  claim 6  further comprising a resorcinol formaldehyde resin. 
     
     
         8 . The adhesive composition according to  claim 7  wherein a content of the resorcinol formaldehyde resin is 5 to 30 parts by weight with respect to 100 parts by weight of a solid content of the latex of a highly saturated nitrile rubber. 
     
     
         9 . A fiber base material-highly saturated nitrile rubber composite obtained by bonding a fiber base material and a highly saturated nitrile rubber using the adhesive composition according to  claim 6 .