Soft propylene-based resin composition

Abstract

Soft propylene-based resin compositions, which comprise substantially the following block (I) and block (II): Block (I): propylene-based polymer having propylene unit chain segments that bond in a mode of head-to-tail bonding, in which the chain segment has an isotactic block-containing stereoblock structure; Block (II): copolymer containing at least propylene and ethylene, exhibit good flexibility, transparency, and heat resistance.

1 - 19 . (canceled)  
     
     
         20 . A soft propylene-based resin composition having a stereoblock-structure, which substantially comprises soft propylene-based resin particles having bulk density, measured according to JIS K 7365, of at least 0.3 g/cm 3 .  
     
     
         21 . The soft propylene-based resin composition of  claim 20 , which is prepared by polymerization with a single-site catalyst.  
     
     
         22 - 30 . (canceled)  
     
     
         31 . The soft propylene-based resin composition of  claim 21 , wherein a partial structure assigned to a pentad represented by rmrm exists in the head-to-tail-bonding propylene unit chain segments in the polymer, and its proportion is at most 7% relative to all pentads of the head-to-tail-bonding propylene unit chain segments of the polymer.  
     
     
         32 . The soft propylene-based resin composition of  claim 21 , which is prepared by gas-phase polymerization.  
     
     
         33 . The soft propylene-based resin composition of  claim 21 , which comprises a polymer main chain which has regio-irregular units based on 2,1-inserted propylene monomer and/or 1,3-inserted propylene monomer.  
     
     
         34 . The soft propylene-based resin composition of  claim 21 , which satisfies condition (D): (D) in the methyl carbon-derived  13 C-NMR peak pattern of the head-to-tail-bonding propylene unit chain segments in the polymer, when the chemical shift of the peak top of the peak assigned to the pentad of mmmm is defined as 21.8 ppm, then the ratio of the peak area S 1  for the peak top at 21.8 mm to the total area S of the peaks appearing within the range of from 19.8 ppm to 22.2 ppm is from 40% to 95%, and when the peak area for the peak top within the range of from 21.5 to 21.7 ppm is indicated by S 2 , then 4+(2S 1 /S 2 )>5.  
     
     
         35 . The soft propylene-based resin composition of  claim 34 , wherein said ratio of the peak area S 1  to the total area S is from 40% to 76.4%.  
     
     
         36 . The soft propylene-based resin composition of  claim 21 , which comprises 
 a propylene-based polymer having propylene unit chain segments that bond in a mode of head-to-tail bonding, in which the chain segment has an isotactic block-containing stereoblock structure; wherein said isotactic block is a partial structure in which at least four propylenes bond to each other in a mode of head-to-tail bonding and in which the absolute configuration of the methyl groups is the same.    
     
     
         37 . A soft propylene-based resin composition, which has: 
 (a) a tensile modulus, measured according to JIS K 7113, of from 10 MPa to 300 MPa;    (b) an internal parallel light transmittance, measured according to JIS K 7105, of from 70% to 100%; and    (c) a melting point profile, measured by DSC, with a peak top temperature in the range of from 100° C. to 165° C.; and    wherein said resin composition substantially comprises soft propylene-based resin particles having bulk density, measured according to JIS K 7365, of at least 0.3 g/cm 3 .    
     
     
         38 . The soft propylene-based resin composition of  claim 37 , which is prepared by polymerization with a single-site catalyst.  
     
     
         39 . The soft propylene-based resin composition of  claim 38 , which satisfies the following condition (C): 
 (C) a partial structure assigned to a pentad represented by rmrm exists in the head-to-tail-bonding propylene unit chain segments in the polymer, and its proportion is at most 7% relative to all pentads of the head-to-tail-bonding propylene unit chain segments of the polymer.    
     
     
         40 . The soft propylene-based resin composition of  claim 38 , which is prepared by gas-phase polymerization.  
     
     
         41 . The soft propylene-based resin composition of  claim 38 , which comprises a polymer main chain which has regio-irregular units based on 2,1-inserted propylene monomer and/or 1,3-inserted propylene monomer.  
     
     
         42 . The soft propylene-based resin composition of  claim 38 , which satisfies condition (D): (D) in the methyl carbon-derived  13 C-NMR peak pattern of the head-to-tail-bonding propylene unit chain segments in the polymer, when the chemical shift of the peak top of the peak assigned to the pentad of mmmm is defined as 21.8 ppm, then the ratio of the peak area S 1  for the peak top at 21.8 mm to the total area S of the peaks appearing within the range of from 19.8 ppm to 22.2 ppm is from 40% to 95%, and when the peak area for the peak top within the range of from 21.5 to 21.7 ppm is indicated by S 2 , then 4+(2S 1 /S 2 )>5.  
     
     
         43 . The soft propylene-based resin composition of  claim 42 , wherein said ratio of the peak area S 1  to the total area S is from 40% to 76.4%.  
     
     
         44 . The soft propylene-based resin composition of  claim 38 , which comprises 
 a propylene-based polymer having propylene unit chain segments that bond in a mode of head-to-tail bonding, in which the chain segment has an isotactic block-containing stereoblock structure; wherein said isotactic block is a partial structure in which at least four propylenes bond to each other in a mode of head-to-tail bonding and in which the absolute configuration of the methyl groups is the same.