Asphalt composition containing hydrogenated conjugated diene copolymer

Abstract

An asphalt composition comprising from 0.5 to 50 parts by weight of a hydrogenated conjugated diene copolymer (a) and 100 parts by weight of asphalt (b), wherein the hydrogenated conjugated diene copolymer (a) comprises a polymer block (A) comprising vinyl aromatic monomer units and at least one hydrogenated copolymer block (B) obtained by hydrogenation of a non-hydrogenated random copolymer block comprising conjugated diene monomer units and vinyl aromatic monomer units, the hydrogenated conjugated diene copolymer (a) having the following characteristics (1) to (5): (1) the content of the vinyl aromatic monomer units is more than 30% and not more than 60% by weight per weight of the hydrogenated conjugated diene copolymer; (2) the content of the polymer block (A) is from 5% to 50% by weight per weight of the hydrogenated copolymer; (3) the weight average molecular weight is from 30,000 to 500,000; (4) the percentage of hydrogenation of the double bonds in the conjugated diene monomer units is from 60% to 100%; and (5) at least one peak of the loss tangent (tan δ) is present in the range of from −40° C. to less than −10° C. in a dynamic viscoelastic spectrum obtained with respect to the hydrogenated copolymer.

1 . An asphalt composition comprising from 0.5 to 50 parts by weight of a hydrogenated conjugated diene copolymer (a) and 100 parts by weight of asphalt (b), wherein the hydrogenated conjugated diene copolymer (a) comprises a polymer block (A) comprising vinyl aromatic monomer units and at least one hydrogenated copolymer block (B) obtained by hydrogenation of a non-hydrogenated random copolymer block comprising conjugated diene monomer units and vinyl aromatic monomer units, the hydrogenated conjugated diene copolymer (a) having the following characteristics (1) to (5): 
 (1) the content of the vinyl aromatic monomer units is more than 30% and not more than 60% by weight per weight of the hydrogenated conjugated diene copolymer;    (2) the content of the polymer block (A) is from 5% to 50% by weight per weight of the hydrogenated copolymer;    (3) the weight average molecular weight is from 30,000 to 500,000;    (4) the percentage of hydrogenation of the double bonds in the conjugated diene monomer units is from 60% to 100%; and    (5) at least one peak of the loss tangent (tan δ) is present in the range of from −40° C. to less than −10° C. in a dynamic viscoelastic spectrum obtained with respect to the hydrogenated copolymer.    
     
     
         2 . The asphalt composition according to  claim 1 , wherein said hydrogenated conjugated diene copolymer (a) does not substantially have a crystallization peak in the range of from −20° C. to S0° C. in the chart of differential scanning calorimetry (DSC).  
     
     
         3 . The asphalt composition according to  claim 1 , wherein the content of the vinyl aromatic monomer units in said hydrogenated conjugated diene copolymer (a) is more than 40% and not more than 60% by weight per weight of the hydrogenated conjugated diene copolymer (a).  
     
     
         4 . The asphalt composition according to  claim 1 , wherein the hydrogenated copolymer block in said hydrogenated conjugated diene copolymer (a) is a hydrogenated copolymer block obtained by hydrogenation of a non-hydrogenated random copolymer block with a tapered structure.  
     
     
         5 . The asphalt composition according to  claim 1 , wherein said hydrogenated conjugated diene copolymer (a) has at least two polymer blocks (A) comprising vinyl aromatic monomer units.  
     
     
         6 . The asphalt composition according to  claim 1 , wherein the hydrogenated conjugated diene copolymer (a) has a molecular weight distribution (Mw/Mn) of from 1.1 to 5.  
     
     
         7 . The asphalt composition according to  claim 1 , wherein the hydrogenated conjugated diene copolymer (a) is a modified hydrogenated copolymer to which an atomic group having a functional group is bonded.  
     
     
         8 . The asphalt composition according to  claim 1  for use in a roofing shingle.