A formulation for producing a polymeric material including high-density polyethylene, a chemical blowing agent, and other optional components is described.

A polymeric film has an orthogonal length and width. The polymeric film includes a substrate and a plurality of fins extending away from the substrate and substantially coextensive with the substrate along the length. The fins are arranged across the width. Each fin in at least a majority of the fins includes a first portion extending from the substrate to a tip of the fin opposite the substrate; and a second portion extending from the tip of the fin toward or to the substrate. The second portion is attached to the first portion proximate the tip and separated from the first portion proximate the substrate along at least a portion of the length. The first and second portions have different respective first and second compositions.

A polymeric film has an orthogonal length and width. The polymeric film includes a substrate and a plurality of fins extending away from the substrate and substantially coextensive with the substrate along the length. The fins are arranged across the width. Each fin in at least a majority of the fins includes a first portion extending from the substrate to a tip of the fin opposite the substrate; and a second portion extending from the tip of the fin toward or to the substrate. The second portion is attached to the first portion proximate the tip and separated from the first portion proximate the substrate along at least a portion of the length. The first and second portions have different respective first and second compositions.

The disclosure relates to forming shaped thermoplastic articles having smooth peripheries. Many thermoplastic articles have sharp edges formed upon molding or cutting the article from a feedstock sheet. Such sharp edges can damage thin plastic films or flesh which they contact, and smoothing the edges is desirable. Described herein are methods of forming a smooth periphery for such sharp-edged articles by rolling over the sharp edge. The smoothing operation is performed by forming a deflectable flange including a bend region separated from the potentially sharp peripheral edge by a spacer, deflecting a portion of the deflectable flange, and softening at least one bent portion of the deflectable flange to yield a smooth periphery upon cooling.

The disclosure relates to forming shaped thermoplastic articles having smooth peripheries. Many thermoplastic articles have sharp edges formed upon molding or cutting the article from a feedstock sheet. Such sharp edges can damage thin plastic films or flesh which they contact, and smoothing the edges is desirable. Described herein are methods of forming a smooth periphery for such sharp-edged articles by rolling over the sharp edge. The smoothing operation is performed by forming a deflectable flange including a bend region separated from the potentially sharp peripheral edge by a spacer, deflecting a portion of the deflectable flange, and softening at least one bent portion of the deflectable flange to yield a smooth periphery upon cooling. A liner sheet may be attached to the feedstock sheet prior to, during, or after forming and can be peelable therefrom.

A device comprises a first portion including a first polymer, and a second portion that is relatively flexible in comparison to the first portion and includes a second polymer that is substantially not bondable to the first polymer. A chamber of the device is hermetically sealable with respect to ambient atmosphere and is defined by (i) an interior of the second portion, and/or (ii) a space formed between the first and second portions. A third portion of the device includes a third polymer that is bondable to the first and second polymers and fixedly secures the first and second portions to each other.

The invention comprises a peelable membrane for resealably closing a metal end comprising an outer layer, a tacky layer, and a heat seal layer. The heat seal layer is permanently sealed to the metal end to cover at least one opening in the metal end. The tacky layer causes the peelable membrane to be resealable onto the metal end.

The invention comprises a peelable membrane for resealably closing a metal end comprising an outer layer, a tacky layer, and a heat seal layer. The heat seal layer is permanently sealed to the metal end to cover at least one opening in the metal end. The tacky layer causes the peelable membrane to be resealable onto the metal end.

A method of fabricating a high-altitude balloon. The method includes coextruding at least two adjacent continuous layers of extrudate, extrusion-bonding the layers of extrudate to one another along an edge of the sheets of extrudate to form a seam, and cooling the extrudate.

A wall, for example the wall of a vascular graft, has multiple channels within it. The channels may be used to hold drugs or reinforcing fibers. The channels may have a predetermined roughness. The channels may be formed by coextrusion using a soluble material, for example, to define the channels and then dissolving them to open the channels in the extrudate.