Abstract: A polyethylene composition comprising three specific types of polyethylenes; polyethylene (A), polyethylene (B) and polyethylene (C) respectively. The polyethylene composition has a melt index not less than 0.001 g/10 min. and not more than 10 g/cm and exhibits excellent processability under variant molding techniques. Molded objects exhibit excellent physical properties such as impact strength environmental stress cracking resistance and uniform thickness distribution. Polyethylene (A) has a molecular weight of from 5,000 to 90,000 and polyethylene (C) has a molecular weight of from 100,000 to 1,500,000 and the ratio of the molecular weight of polyethylene (C)/the molecular weight of polyethylene (A) is from 4 to 200.

Abstract: A modified linear medium- or low-density polyethylene composition obtained by uniformly melt kneading a mixture of a linear medium- or low-density polyethylene having a density of not less than 0.90 g/cm.sup.3 but less than 0.94 g/cm.sup.3 and a melt index (MI).sub.1 of not more than 3 g/10 minutes and a radical initiator in an amount of not less than 0.0005% by weight but less than 0.1% by weight based on the weight of the linear medium- or low-density polyethylene at a temperature of from the melting point of the linear medium- or low-density polyethylene to a temperature of less than the thermal decomposition temperature of the linear medium- or low-density polyethylene to such an extent that the ratio of the melt index of the modified linear medium- or low-density polyethylene composition (MI).sub.2 to that of the linear medium- or low-density polyethylene (MI).sub.1 [(MI).sub.2 /(MI).sub.1 ] is 0.05 to 0.9.

Abstract: A crosslinked polyethylene composition having excellent physical properties (e.g., a high stiffness, a high ESCR, and a high impact strength) and improved molding properties (e.g., an improved melt tension and an improved dye swell) is disclosed. This composition is obtained by lightly crosslinking and intimately melt blending a composition comprising high- and medium-density polyethylene (A) having a high molecular weight and high- and medium-density polyethylene B having a low molecular weight, wherein(i) the viscosity-average molecular weight of polyethylene (A) is 100,000 through 1,000,000, the viscosity-average molecular weight of polyethylene B is 1,000 through 100,000, and the ratio of the molecular weight of polyethylene (A) to that of polyethylene (B) is 2 through 100,(ii) the blending ratio of polyethylene (A) to polyethylene (B) is 5:95 through 80:20, and(iii) (MI).sub.1 is 0.01 through 3.5, the ratio of the expansion factor .alpha..sub.2 to .alpha..sub.1 (.alpha..sub.2 /.alpha..sub.1) is 1.

Abstract: An intimately melted and homogenized polyethylene composition having excellent physical properties and moldability and comprising a high-medium density polyethylene having a high molecular weight (A), a high-medium density polyethylene having a low molecular weight (B) and a low density polyethylene (C) characterized in that:(i) the average molecular weight of (A) is 100,000-1,000,000, the average molecular weight of (B) is 1,000-100,000, the molecular weight ratio of (A) to (B) is 5-200, and (C) has an intrinsic viscosity [.eta.] of 0.70 dl/g or more in decalin at 135.degree. C. and an expansion factor of 3.3 or more, and(ii) the mixing ratio (A)/(B) is 30/70 to 80/20 and the mixing ratio of (C) in the composition is within the range from 1% by weight to less than 15% by weight.

Abstract: An ethylene polymer film exhibiting improved impact strength and tear strength is provided. This film is made of an inorganic filler-incorporated ethylene polymer composition which is comprised of:(a) 35-90 wt.%, based on the ethylene polymer composition, of an ethylene polymer having a melt index of 0.005-0.2 and a specific gravity of 0.94- 0.98 as measured at a temperature of 23.degree. C.,(b) 10-65 wt.%, based on the ethylene polymer composition, of a finely divided inorganic filler particle having an average particle size of 0.01-10 microns,(c) 0.1-10 wt.parts, based on 100 wt.parts of the ingredient (b), of a higher fatty acid,(d) 0.5-15 wt.parts, based on 100 wt.parts of the ingredient (b), of a metal salt of a higher fatty acid, and(e) 0.05-5 wt.parts, based on 100 wt.parts of the ingredient (b), of a stabilizer composition predominantly comprised of a phenolic stabilizer.The ethylene polymer film is produced by extruding the ethylene polymer composition at 150.degree.-250.degree. C.