A method of continuously producing an ethylene-vinyl acetate copolymer in a polymerization vessel containing a reaction liquid containing ethylene, vinyl acetate, a polymerization initiator and methanol, the polymerization vessel being connected via piping to a heat exchanger circulating a coolant, the method includes the steps of: supplying ethylene, the polymerization initiator and methanol to the polymerization vessel; introducing pressurized gas containing ethylene present in a gas phase portion of the polymerization vessel into the heat exchanger; supplying vinyl acetate cooled to between −50° C. and 23° C. to an upper portion of the heat exchanger; flowing vinyl acetate down in the heat exchanger while absorbing ethylene; letting vinyl acetate dissolving ethylene out of a bottom portion of the heat exchanger and adding to the reaction liquid in the polymerization vessel; and taking the reaction liquid out of the polymerization vessel. This provides a method of efficiently removing heat during polymerization of an ethylene-vinyl acetate copolymer.

The present invention relates to an olefin-based polymer satisfying requirements: (1) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 1.0 to 10.0 g/10 min; (2) a density (d) ranging from 0.875 to 0.895 g/cc; (3) 0.5 J/g≤dH(100)≤3.0 J/g and 1.0 J/g≤dH(90)≤6.0 J/g as measured by successive self-nucleation/annealing (SSA) using a differential scanning calorimeter (DSC); (4) 15≤T(90)−T(50)≤30 and 50° C.≤T(50)≤75° C. as measured by SSA using a DSC; and (5) a melting point (Tm) of 55° C.≤Tm≤80° C. as measured using a DSC. The olefin-based polymer according to the present invention is a low-density olefin-based polymer and has a highly crystalline region introduced therein, thereby exhibiting high mechanical stiffness.

The present invention relates to an olefin-based polymer satisfying requirements: (1) a melt index (MI, 190° C., 2.16 kg load conditions) ranging from 1.0 to 10.0 g/10 min; (2) a density (d) ranging from 0.875 to 0.895 g/cc; (3) 0.5 J/g≤dH(100)≤3.0 J/g and 1.0 J/g≤dH(90)≤6.0 J/g as measured by successive self-nucleation/annealing (SSA) using a differential scanning calorimeter (DSC); (4) 15≤T(90)−T(50)≤30 and 50° C.≤T(50)≤75° C. as measured by SSA using a DSC; and (5) a melting point (Tm) of 55° C.≤Tm≤80° C. as measured using a DSC. The olefin-based polymer according to the present invention is a low-density olefin-based polymer and has a highly crystalline region introduced therein, thereby exhibiting high mechanical stiffness.

A process for the continuous solution polymerization including the step of polymerizing a first olefin monomer of formula CH.sub.2═CHR.sup.1, wherein R.sup.1 is hydrogen or a hydrocarbon radical having from 1 to 8 carbon atoms with a second olefin monomer of formula CH.sub.2═CHR.sup.2, wherein R.sup.2 is a hydrocarbon radical having from 3 to 8 carbon atoms, in the presence of a polymerization catalyst and in the absence of an inert solvent, at a polymerization temperature (Tp) satisfying the following relationship:

Tp≥Tm+20° C.

wherein Tm is the melting temperature of the obtained polymer.

A process for the continuous solution polymerization including the step of polymerizing a first olefin monomer of formula CH.sub.2═CHR.sup.1, wherein R.sup.1 is hydrogen or a hydrocarbon radical having from 1 to 8 carbon atoms with a second olefin monomer of formula CH.sub.2═CHR.sup.2, wherein R.sup.2 is a hydrocarbon radical having from 3 to 8 carbon atoms, in the presence of a polymerization catalyst and in the absence of an inert solvent, at a polymerization temperature (Tp) satisfying the following relationship:

Tp≥Tm+20° C.

wherein Tm is the melting temperature of the obtained polymer.

A reactor for the polymerization of olefins comprising a first inlet for introducing a first stream comprising monomer(s), catalyst(s) and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof, at least one outlet for withdrawing a product stream, characterized in that the reactor further comprises at least one second inlet for introducing a second stream comprising monomer(s), catalyst(s) and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof; and a process for polymerizing olefins in a reactor according to the present invention, comprising the steps of introducing monomer(s), catalyst(s), and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof as the first stream via the first inlet into the reactor forming a reaction mixture; polymerizing a polymer from the reaction mixture; withdrawing the product stream via the at least one outlet from the reactor; characterized in that the process comprises a further step of introducing a second stream comprising monomer(s), catalyst(s), and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof into the reactor via the at least one second inlet into the reactor.

A reactor for the polymerization of olefins comprising a first inlet for introducing a first stream comprising monomer(s), catalyst(s) and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof, at least one outlet for withdrawing a product stream, characterized in that the reactor further comprises at least one second inlet for introducing a second stream comprising monomer(s), catalyst(s) and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof; and a process for polymerizing olefins in a reactor according to the present invention, comprising the steps of introducing monomer(s), catalyst(s), and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof as the first stream via the first inlet into the reactor forming a reaction mixture; polymerizing a polymer from the reaction mixture; withdrawing the product stream via the at least one outlet from the reactor; characterized in that the process comprises a further step of introducing a second stream comprising monomer(s), catalyst(s), and optionally hydrogen, solvent or comonomer(s) and/or mixtures thereof into the reactor via the at least one second inlet into the reactor.

The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.

The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.

The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.