US 6,903,162 B2 · Preparation of polyethylene films

Abstract

A process for preparing polyethylene thin films is disclosed. The process comprises extruding a blend that comprises a linear low density polyethylene (LLDPE) and a high molecular weight, high density polyethylene (HMW-HDPE) or high molecular weight, medium density polyethylene (HMW-MDPE). The blend has an LLDPE/HMW-HDPE or HMW-MDPE weight ratio at least 50/50. The blend is extruded through an annular die to form a molten material tube. The molten material tube is then pulled around a flexible internal orientation device (FIOD) to form the film. The FIOD makes it possible to prepare polyethylene thin films from LLDPE-rich LLDPE/HMW-HDPE or HMW-MDPE blends on a high stalk film line. The films have increased machine-direction (MD) tears.

Claims10

Dependent claims

A process for preparing a thin film on a high stalk extrusion line, said process comprising:

(a) extruding a blend through an annular die to form a molten material tube, said blend comprising:
(i) a linear low density polyethylene (LLDPE) which has a density within the range of about 0.90 to about 0.93 g/cc and an MI2 within the range of about 0.5 to about 50 dg/min;
and
(ii) a high molecular weight high density polyethylene (HMW-HDPE) which has a density within the range of about 0.95 to about 0.97 g/cc and an MI2 within the range of about 0.01 to about 0.5 dg/min;
in a weight ratio of (i)/(ii) greater than or equal to 50/50;
and
(b) pulling the molten material tube around a flexible internal orientation device (FIOD) to form the film;
wherein the film has a thickness of 0.5 mil or less.

5 more elements

Dependencies are inferred from the claim text.

Preparation of polyethylene films

Life of this patent

Preparation of polyethylene films

Life of this patent

Abstract

Claims10