Provided is a propylene-based elastomer having high tacticity and excellent mechanical properties. The propylene-based elastomer includes 50% by weight or more of a propylene-based repeating unit, and satisfies a particular relationship between an ethylene content and tacticity.

Provided is a propylene-based elastomer having high tacticity and excellent mechanical properties. The propylene-based elastomer includes 50% by weight or more of a propylene-based repeating unit, and satisfies a particular relationship between an ethylene content and tacticity.

Provided is A polypropylene-based resin composition comprising 2 mass % to 30 mass % of a polypropylene resin (X1) having specific properties, 5 mass % to 98 mass % of a polypropylene resin (X2) having specific properties, and 0 mass % to 80 mass % of a polypropylene-based resin (Y) having specific properties, wherein the total amount of the polypropylene resin (X1), the polypropylene resin (X2) and the polypropylene-based resin (Y) is 100 mass %.

Provided is A polypropylene-based resin composition comprising 2 mass % to 30 mass % of a polypropylene resin (X1) having specific properties, 5 mass % to 98 mass % of a polypropylene resin (X2) having specific properties, and 0 mass % to 80 mass % of a polypropylene-based resin (Y) having specific properties, wherein the total amount of the polypropylene resin (X1), the polypropylene resin (X2) and the polypropylene-based resin (Y) is 100 mass %.

[Problem to be Solved]

There is provided a process for producing an olefin polymer that is capable of producing an olefin polymer having high heat resistance and high molecular weight with excellent catalytic activity.

[Solution to Problem]

The process for producing an olefin polymer includes a step of polymerizing at least one olefin selected from ethylene and α-olefins having 4 to 30 carbon atoms in the presence of an olefin polymerization catalyst containing a transition metal compound represented by the general formula [I], the olefin polymer including constituent units derived from ethylene and α-olefins having 4 to 30 carbon atoms in a total amount between more than 50 mol % and not more than 100 mol %,

##STR00001##

[in the formula [I], R.sup.1, R.sup.3 and R.sup.5 to R.sup.16 are each independently a hydrogen atom, a hydrocarbon group or the like; R.sup.2 is a hydrocarbon group or the like; R.sup.4 is a hydrogen atom; M is a transition metal of Group IV; Q is a halogen atom or the like; and j is an integer of 1 to 4].

[Problem to be Solved]

There is provided a process for producing an olefin polymer that is capable of producing an olefin polymer having high heat resistance and high molecular weight with excellent catalytic activity.

[Solution to Problem]

The process for producing an olefin polymer includes a step of polymerizing at least one olefin selected from ethylene and α-olefins having 4 to 30 carbon atoms in the presence of an olefin polymerization catalyst containing a transition metal compound represented by the general formula [I], the olefin polymer including constituent units derived from ethylene and α-olefins having 4 to 30 carbon atoms in a total amount between more than 50 mol % and not more than 100 mol %,

##STR00001##

[in the formula [I], R.sup.1, R.sup.3 and R.sup.5 to R.sup.16 are each independently a hydrogen atom, a hydrocarbon group or the like; R.sup.2 is a hydrocarbon group or the like; R.sup.4 is a hydrogen atom; M is a transition metal of Group IV; Q is a halogen atom or the like; and j is an integer of 1 to 4].

This invention relates to high porosity (≧15%) and/or low pore diameter (PD<165 μm) propylene polymers and propylene polymerization processes using single site catalyst systems with supports having high surface area (SA≧400 m.sup.2/g), low pore volume (PV≦2 mL/g), a specific mean pore diameter range (PD=1-20 nm), and high average particle size (PS≧30 μm).

This invention relates to high porosity (≧15%) and/or low pore diameter (PD<165 μm) propylene polymers and propylene polymerization processes using single site catalyst systems with supports having high surface area (SA≧400 m.sup.2/g), low pore volume (PV≦2 mL/g), a specific mean pore diameter range (PD=1-20 nm), and high average particle size (PS≧30 μm).

Heterophasic polypropylene composition with an advantageous, respectively stiffness/impact balance and its use.

Heterophasic polypropylene composition with an advantageous, respectively stiffness/impact balance and its use.