The invention relates to a process for producing a polypropylene composition by sequential polymerization said polypropylene composition having low sealing initiation temperature (SIT) and high melting point (Tm), presenting thus a broad sealing window.

Disclosed are polyethylene polymers with good melt strength that can provide enhanced properties for compositions including such polyethylene polymers and films made therefrom.

Disclosed are polyethylene polymers with good melt strength that can provide enhanced properties for compositions including such polyethylene polymers and films made therefrom.

Embodiments of the invention described herein relate to a polyethylene polymer composition suitable for use in the manufacture of packaging articles, flexible films and/or sheets. In one embodiment, the copolymer comprises a polyethylene resin with density 0.918 g/cm.sup.3 to about 0.935 g/cm.sup.3, G′ at G″.sub.(500 Pa) value, as determined from Dynamic Mechanical Analysis at 190° C., of less than 40 Pa, M.sub.z/M.sub.w of greater than 2, CDBI.sub.50 of greater than 60. Other embodiments relate to polymer compositions with defined molecular characteristics and formulations suitable for use in the manufacture of articles including films, sheets, bags and pouches with improved creep resistance and high toughness and a good balance of film stiffness and processability in monolayer and/or multi-layer film structures.

Embodiments of the invention described herein relate to a polyethylene polymer composition suitable for use in the manufacture of packaging articles, flexible films and/or sheets. In one embodiment, the copolymer comprises a polyethylene resin with density 0.918 g/cm.sup.3 to about 0.935 g/cm.sup.3, G′ at G″.sub.(500 Pa) value, as determined from Dynamic Mechanical Analysis at 190° C., of less than 40 Pa, M.sub.z/M.sub.w of greater than 2, CDBI.sub.50 of greater than 60. Other embodiments relate to polymer compositions with defined molecular characteristics and formulations suitable for use in the manufacture of articles including films, sheets, bags and pouches with improved creep resistance and high toughness and a good balance of film stiffness and processability in monolayer and/or multi-layer film structures.

A terpolymer compositions made from or containing: A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and
the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.

A terpolymer compositions made from or containing: A) From 80 wt % to 97 wt %; of a first propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 7.2 wt % to 14.8 wt %; and B) From 20 wt % to 3 wt %; of a second propylene, ethylene, 1-butene terpolymer having: i) the content of ethylene derived units ranging from 0.5 wt % to 3.2 wt %; ii) the content of 1-butene derived units ranging from 14.4 wt % to 26.5 wt %; and
the terpolymer composition having the melt flow rate, MFR, measured according to ISO 1133 at 230° C. with a load of 2.16 kg, ranging from 3.0 g/10 min to 20.0 g/10 min; the sum of the amounts of A) and B) being 100 wt %.

Disclosed are ethylene polymer compositions containing a homogeneously-branched first ethylene polymer component and 15-35 wt. % of a homogeneously-branched second ethylene polymer component of higher density than the first ethylene polymer component. The ethylene polymer composition can be characterized by a density from 0.912 to 0.925 g/cm.sup.3, a ratio of Mw/Mn from 2 to 5, a melt index less than 2 g/10 min, and a CY-a parameter at 190° C. from 0.35 to 0.7. These polymer compositions have the excellent dart impact strength and optical properties of a metallocene-catalyzed LLDPE, but with improved machine direction tear resistance, and can be used in blown film and other end-use applications. Further, methods for improving film Elmendorf tear strength also are described.

Disclosed are ethylene polymer compositions containing a homogeneously-branched first ethylene polymer component and 15-35 wt. % of a homogeneously-branched second ethylene polymer component of higher density than the first ethylene polymer component. The ethylene polymer composition can be characterized by a density from 0.912 to 0.925 g/cm.sup.3, a ratio of Mw/Mn from 2 to 5, a melt index less than 2 g/10 min, and a CY-a parameter at 190° C. from 0.35 to 0.7. These polymer compositions have the excellent dart impact strength and optical properties of a metallocene-catalyzed LLDPE, but with improved machine direction tear resistance, and can be used in blown film and other end-use applications. Further, methods for improving film Elmendorf tear strength also are described.

Disclosed herein are ethylene-based polymers having low densities and narrow molecular weight distributions, but high melt strengths for blown film processing. Such polymers can be produced by peroxide-treating a metallocene-catalyzed resin.