Olefin block copolymer

Abstract

The present description relates to an olefin block copolymer with excellences in elasticity, heat resistance, and processability. The olefin block copolymer comprises a plurality of blocks or segments, each comprising an ethylene or propylene repeating unit and an α-olefin repeating unit at different mole fractions. The olefin block copolymer comprises polymer chains containing 20 to 100 short-chain branches (SCBs) per 1,000 carbon atoms. A point where a first derivative of the number Y of the SCBs per 1,000 carbon atoms of each polymer chain with respect to the molecular weight X of the polymer chain is 0 exists between the minimum and maximum values of the molecular weight X.

What is claimed is: 
     
         1 . An olefin block copolymer comprising a plurality of blocks or segments, each comprising an ethylene or propylene repeating unit and an α-olefin repeating unit at different mole fractions,
 wherein the olefin block copolymer comprises polymer chains comprising 20 to 100 short-chain branches (SCBs) per 1,000 carbon atoms, 
 wherein a point where a first derivative of the number Y of the SCBs per 1,000 carbon atoms of each polymer chain with respect to the molecular weight X of the polymer chain is 0 exists between the minimum and maximum values of the molecular weight X. 
 
     
     
         2 . The olefin block copolymer as claimed in  claim 1 , wherein the point where the first derivative is 0 exists in a region below the maximum peak molecular weight Mp of the block copolymer. 
     
     
         3 . The olefin block copolymer as claimed in  claim 1 , wherein the first derivative is a positive number in a region where the molecular weight X is less than at the point where the first derivative is 0. 
     
     
         4 . The olefin block copolymer as claimed in  claim 1 , wherein the first derivative is a negative number in a region where the molecular weight X is greater than at the point where the first derivative is 0. 
     
     
         5 . The olefin block copolymer as claimed in  claim 1 , wherein the olefin block copolymer has a crystallization temperature Tc of 95 to 120° C. 
     
     
         6 . The olefin block copolymer as claimed in  claim 1 , wherein the olefin block copolymer has a melting temperature Tm of 110 to 135° C. 
     
     
         7 . The olefin block copolymer as claimed in  claim 1 , wherein the olefin block copolymer comprises a hard segment comprising a first mole fraction of the α-olefin repeating unit, and a soft segment comprising a second mole fraction of the α-olefin repeating unit,
 wherein the second mole fraction is greater than the first mole fraction. 
 
     
     
         8 . The olefin block copolymer as claimed in  claim 7 , wherein the mole fraction of the α-olefin repeating unit contained in the entire block copolymer has a value between the first and second mole fractions. 
     
     
         9 . The olefin block copolymer as claimed in  claim 7 , wherein the olefin block copolymer comprises 20 to 95 mol. % of the hard segment and 5 to 80 mol. % of the soft segment. 
     
     
         10 . The olefin block copolymer as claimed in  claim 7 , wherein the hard segment has a higher value than the soft segment in at least one property of the degree of crystallization, density, and melting temperature. 
     
     
         11 . The olefin block copolymer as claimed in  claim 1 , wherein the olefin block copolymer comprises 80 to 98 mol. % of the ethylene or propylene repeating unit and a remaining content of the α-olefin repeating unit. 
     
     
         12 . The olefin block copolymer as claimed in  claim 1 , wherein the olefin block copolymer has a density of 0.85 to 0.92 g/cm 3 . 
     
     
         13 . The olefin block copolymer as claimed in  claim 1 , wherein the olefin block copolymer has a weight average molecular weight of 5,000 to 3,000,000 and a molecular weight distribution of 2.5 to 6. 
     
     
         14 . The olefin block copolymer as claimed in  claim 1 , wherein the α-olefin repeating unit is a repeating unit derived from at least one α-olefin selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-itocene.