E.i. Dupont De Nemours and Company

Chi C Lee

Richard E Ludwig

Homan B Kinsley, Jr

James Ross Waggoner

Gurvinder P Kochar

Robert J Evans

Karl M Martin

Richard B Smith

Silas S Shelburne, Jr

A process for producing high grade polyethylene paper on conventional continuous wet-lay papermaking equipment. In particular, the process comprises preparing a furnish of 75-99 wt. % oriented polyethylene pulp, 0.5-15 wt. % fibrous stabilizing agent and 0.5-10 wt. % strengthening agent and depositing the furnish on the forming screen of a conventional wet-lay papermaking machine. The resulting waterleaf sheet is dried on heated drying cans and then thermally bonded to provide a high grade polyethylene paper having high dry strength and toughness, exceptional dimensional stability and superior uniformity (i.e., no holes). The high grade polyethylene paper made by the inventive process is particularly useful in microfiltration end-uses such as vacuum cleaner bags.

High grade polyethylene paper

Lightweight nonwoven sheets of polyethylene plexifilamentary film-fibril strands are made by a stretching-and-bonding operation in which the unit weight of the sheet is decreased in stages while at a temperature within 3.degree. to 8.degree. C. of the melting point of the polyethylene. The resultant sheet has a novel combination opacity, X-ray scattering and physical characteristics and is particularly suited for sterile packaging, lightweight envelopes and surgical drapes.

Stretched-and-bonded polyethylene plexifilamentary nonwoven sheet

A security paper is provided in which identifying material is contained as an intercalary layer within the thickness of a bonded, nonwoven, polyethylene-film-fibril sheet having an opacity of at least 70% and a delamination resistance of at least 60 grams per centimeter. A process for making such paper includes forming an assembly of two unbonded, lightly consolidated, nonwoven, polyethylene film-fibril sheets containing identifying material between them, compressing the assembly in an unheated nip at 17 to 85 kilograms per centimeter of assembly width and then self-bonding the compressed assembly while under restraint by contact with a heated drum. Such security paper is useful for bank notes, stock certificates, paper currency and the like.

Security paper from film-fibril sheets

A security paper is provided in which identifying material is contained in a plane within the thickness of a bonded, nonwoven polyethylene film-fibril sheet having an opacity of at least 70% and a determination resistance of at least 60 grams per centimeter. A process for making such paper includes forming an assembly of two unbonded, lightly consolidated, nonwoven, polyethylene film-fibril sheets containing identifying material between them, compressing the assembly in an unheated nip at 17 to 85 kilograms per centimeter of assembly width and then self-bonding the compressed assembly while under restraint by contact with a heated drum. Such security paper is useful for bank notes, stock certificates, paper currency and the like.

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Richmond, VA, United States of America

Chi C Lee