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.

Provided herein are VLDPE polymer compositions suitable for use in the manufacture of flexible films or sheets. In one embodiment, the copolymer comprises a polyethylene VLDPE resin with M.sub.z/M.sub.w of greater than 2, CDBI.sub.50 of greater than 55 and a single melting peak in DSC measurement. The polymer compositions disclosed herein may be suitable for use in the manufacture of films with improved balance of film toughness, processability and sealability in monolayer and multi-layer film structures.

Provided herein are VLDPE polymer compositions suitable for use in the manufacture of flexible films or sheets. In one embodiment, the copolymer comprises a polyethylene VLDPE resin with M.sub.z/M.sub.w of greater than 2, CDBI.sub.50 of greater than 55 and a single melting peak in DSC measurement. The polymer compositions disclosed herein may be suitable for use in the manufacture of films with improved balance of film toughness, processability and sealability in monolayer and multi-layer film structures.

Novel catalyst compositions comprising three or more transition metals are effective in increasing catalyst efficiency, reducing polydispersity, and increasing uniformity in molecular weight distribution when used in olefin, and particularly, linear low density polyethylene (LLDPE), polymerizations. The resulting polymers may be used to form differentiated products including, for example, films that may exhibit improved optical and mechanical properties.

Novel catalyst compositions comprising three or more transition metals are effective in increasing catalyst efficiency, reducing polydispersity, and increasing uniformity in molecular weight distribution when used in olefin, and particularly, linear low density polyethylene (LLDPE), polymerizations. The resulting polymers may be used to form differentiated products including, for example, films that may exhibit improved optical and mechanical properties.

A polyethylene composition which when made into a film layer having a thickness of about 1 mil exhibits a machine direction (MD) 1% secant modulus of ≥190 MPa and an oxygen transmission rate (OTR) of ≥650 cm.sup.3 per 100 inch.sup.2 per day, and when made into a film layer having a thickness of about 2 mil exhibits a seal initiation temperature (SIT) of ≤100° C. and an area of hot tack window (AHTW) of ≥160 Newtons.Math.° C.

A polyethylene composition which when made into a film layer having a thickness of about 1 mil exhibits a machine direction (MD) 1% secant modulus of ≥190 MPa and an oxygen transmission rate (OTR) of ≥650 cm.sup.3 per 100 inch.sup.2 per day, and when made into a film layer having a thickness of about 2 mil exhibits a seal initiation temperature (SIT) of ≤100° C. and an area of hot tack window (AHTW) of ≥160 Newtons.Math.° C.

The present disclosure provides a low density polyethylene (LDPE) having (A) a density from 0.910 to 0.924 g/cm.sup.3, determined according to ISO 1183 at 23° C.; (B) an elongational hardening of at least 4.2, at 150° C. at an elongational rate of 1 s.sup.−1; (C) a ratio Mw/Mn of at least 18, where (i) Mw is the weight average molar mass, measured by a MALLS detector coupled to a GPC, and (ii) Mn is the number average molar mass, measured by GPC (Gel Permeation Chromatography); and (D) a Mw of at least 230,000 g/mol. The present disclosure also provides an article of manufacture made from or containing (A) a substrate and (B) a coating layer made from or containing the disclosed LDPE. The present disclosure further provides a polymerization process occurring (A) in the presence of oxygen as the only radical initiating agent and (B) in the absence of solvents.

The present disclosure provides a low density polyethylene (LDPE) having (A) a density from 0.910 to 0.924 g/cm.sup.3, determined according to ISO 1183 at 23° C.; (B) an elongational hardening of at least 4.2, at 150° C. at an elongational rate of 1 s.sup.−1; (C) a ratio Mw/Mn of at least 18, where (i) Mw is the weight average molar mass, measured by a MALLS detector coupled to a GPC, and (ii) Mn is the number average molar mass, measured by GPC (Gel Permeation Chromatography); and (D) a Mw of at least 230,000 g/mol. The present disclosure also provides an article of manufacture made from or containing (A) a substrate and (B) a coating layer made from or containing the disclosed LDPE. The present disclosure further provides a polymerization process occurring (A) in the presence of oxygen as the only radical initiating agent and (B) in the absence of solvents.

Disclosed herein are ethylene-based polymers generally characterized by a melt index of less than 15 g/10 min, a density from 0.91 to 0.945 g/cm.sup.3, a CY-a parameter at 190° C. from 0.2 to 0.6, an average number of long chain branches per 1,000,000 total carbon atoms of the polymer in a molecular weight range of 500,000 to 2,000,000 g/mol of less than 5, and a maximum ratio of η.sub.E/3η at an extensional rate of 0.03 sec.sup.−1 in a range from 3 to 15. The ethylene polymers have substantially no long chain branching in the high molecular weight fraction of the polymer, but instead have significant long chain branching in the lower molecular weight fraction, such that polymer melt strength and bubble stability are maintained for the fabrication of blown films and other articles of manufacture. These ethylene polymers can be produced using a dual catalyst system containing a single atom bridged metallocene compound with an indenyl group and a cyclopentadienyl group, and an unbridged hafnium metallocene compound with two cyclopentadienyl groups.