A method for evaluating long-term durability of a resin for piping is provided. Unlike the conventional FNCT evaluation method requiring a long period of time, the method disclosed herein is capable of predicting long-term durability of a resin for piping in a short time, by a simple calculation using a content of tie molecules, an entanglement molecular weight (M.sub.e) and a content of ultrahigh molecular weight components. In addition, the olefinic polymer is configured to have a predetermined relationship in relation to the content of tie molecules, the entanglement molecular weight (M.sub.e) and the content of ultrahigh molecular weight components, whereby the polymer of the present application can be used in the manufacture of a heating pipe requiring excellent long-term durability.

[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].

A blended multimodal polymer product is disclosed that comprises a first polymer, wherein the first polymer is a homopolymer of propylene or a propylene copolymer having an ethylene or a C.sub.4 to C.sub.10 olefin comonomer; and a second polymer, wherein the second polymer is a propylene homopolymer and a propylene copolymer having an ethylene or a C.sub.4 to C.sub.10 olefin comonomer, and wherein the first polymer and second polymer have a difference in heat of fusion of about 25 J/g or more. Methods for making such a polymer product using at least two reactors in parallel and for separating a propylene-based polymer from a solvent using a liquid-phase separator are also disclosed.

A blended multimodal polymer product is disclosed that comprises a first polymer, wherein the first polymer is a homopolymer of propylene or a propylene copolymer having an ethylene or a C.sub.4 to C.sub.10 olefin comonomer; and a second polymer, wherein the second polymer is a propylene homopolymer and a propylene copolymer having an ethylene or a C.sub.4 to C.sub.10 olefin comonomer, and wherein the first polymer and second polymer have a difference in heat of fusion of about 25 J/g or more. Methods for making such a polymer product using at least two reactors in parallel and for separating a propylene-based polymer from a solvent using a liquid-phase separator are also disclosed.

A blended multimodal polymer product is disclosed that comprises a first polymer, wherein the first polymer is a homopolymer of propylene or a propylene copolymer having an ethylene or a C.sub.4 to C.sub.10 olefin comonomer; and a second polymer, wherein the second polymer is a propylene homopolymer and a propylene copolymer having an ethylene or a C.sub.4 to C.sub.10 olefin comonomer, and wherein the first polymer and second polymer have a difference in heat of fusion of about 25 J/g or more. Methods for making such a polymer product using at least two reactors in parallel and for separating a propylene-based polymer from a solvent using a liquid-phase separator are also disclosed.

Disclosed are a method and system for propylene polymerization utilizing a loop slurry reactor. The method can include polymerizing propylene in a loop slurry reactor under bulk polymerization conditions to produce polypropylene. The propylene polymerization system can include i) a loop slurry reactor and a heat exchange system that is configured to cool the legs of the loop slurry reactor and/or ii) an inlet manifold that is configured to connect flashline heaters to a separator.

A method for evaluating long-term durability of a resin for piping is provided. Unlike the conventional FNCT evaluation method requiring a long period of time, the method disclosed herein is capable of predicting long-term durability of a resin for piping in a short time, by a simple calculation using a content of tie molecules, an entanglement molecular weight (M.sub.e) and a content of ultrahigh molecular weight components. In addition, the olefinic polymer is configured to have a predetermined relationship in relation to the content of tie molecules, the entanglement molecular weight (M.sub.e) and the content of ultrahigh molecular weight components, whereby the polymer of the present application can be used in the manufacture of a heating pipe requiring excellent long-term durability.

[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 -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 -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 -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 -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].