A method of forming a blown polymeric foam film is described herein. As described further below, equipment design (e.g., die design) and processing conditions may be controlled to form blown films having desired characteristics.

The present invention relates to a method and apparatus for cooling. An exemplary apparatus includes an annular cooling ring operable for receiving a flow of a molten film bubble and expelling a flow of cooling gas, the annular cooling ring comprising a middle lip and an adjacent radially spaced apart outer lip, the middle lip having an extended length longer than the outer lip, a radially inner surface of the outer lip and a radially outer surface of the middle lip define a channel operable to allow the flow of cooling gas along the radially outer surface of the middle lip, wherein the middle lip is located radially intermediate the channel and the molten film bubble, and wherein the middle lip isolates the molten film bubble from the flow of cooling gas until the flow of cooling gas passes beyond the extended length of the middle lip.

The present invention relates to a method and apparatus for cooling. An exemplary apparatus includes an annular cooling ring operable for receiving a flow of a molten film bubble and expelling a flow of cooling gas, the annular cooling ring comprising a middle lip and an adjacent radially spaced apart outer lip, the middle lip having an extended length longer than the outer lip, a radially inner surface of the outer lip and a radially outer surface of the middle lip define a channel operable to allow the flow of cooling gas along the radially outer surface of the middle lip, wherein the middle lip is located radially intermediate the channel and the molten film bubble, and wherein the middle lip isolates the molten film bubble from the flow of cooling gas until the flow of cooling gas passes beyond the extended length of the middle lip.

Disclosed is a composition that comprises or is produced from a first ethylene -olefin copolymer, a modified first ethylene -olefin copolymer, and a second ethylene -olefin copolymer or propylene -olefin copolymer. Also disclosed is a multilayer film or sheet structure containing at least one barrier layer; at least one predominantly propylene-based layer, at least one predominantly ethylene-based layer, or both; and at least one adhesive layer produced from the composition. Further disclosed is a produced for producing a multilayer structure using the composition as adhesive layer.

Disclosed is a composition that comprises or is produced from a first ethylene -olefin copolymer, a modified first ethylene -olefin copolymer, and a second ethylene -olefin copolymer or propylene -olefin copolymer. Also disclosed is a multilayer film or sheet structure containing at least one barrier layer; at least one predominantly propylene-based layer, at least one predominantly ethylene-based layer, or both; and at least one adhesive layer produced from the composition. Further disclosed is a produced for producing a multilayer structure using the composition as adhesive layer.

A heat-shrinkable multilayer film for being filled with contents, comprising an outer surface layer (A) comprising a heat-resistant thermoplastic resin, an intermediate layer (B) comprising a polyamide-based resin, an inner surface layer (D) comprising an ethylene-based copolymer, and adhesion strength between inner surface layers after treatment with 80 C. hot water being not less than 10 N/15 mm. The polyamide-based heat-shrinkable multilayer film obtained in this manner has optimal characteristics for applications that primarily require strength, and has greatly improved self-weldability demanded in packaging films for meat products such as fresh and processed meats.

A heat-shrinkable multilayer film for being filled with contents, comprising an outer surface layer (A) comprising a heat-resistant thermoplastic resin, an intermediate layer (B) comprising a polyamide-based resin, an inner surface layer (D) comprising an ethylene-based copolymer, and adhesion strength between inner surface layers after treatment with 80 C. hot water being not less than 10 N/15 mm. The polyamide-based heat-shrinkable multilayer film obtained in this manner has optimal characteristics for applications that primarily require strength, and has greatly improved self-weldability demanded in packaging films for meat products such as fresh and processed meats.

The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process, comprised of one or more enclosures with one or more respective cavities that directly receive a portion of cooling gas emanating from one or more associated cooling elements. Each enclosure includes a port containing a variable exhaust device and optional flow buffer, acting to maintain a pressure differential between the cavity and an adjacent inside volume of the molten film tube, adjustable to optimize molten film tube stability cooling element efficiency and spaced apart dimension between cooling elements. Significant increases in production speeds are achieved with improved film quality over an increased range of tubular film sizes, down to a minimum size which occurs when operating at zero internal to molten film tube pressure.

The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process, comprised of one or more enclosures with one or more respective cavities that directly receive a portion of cooling gas emanating from one or more associated cooling elements. Each enclosure includes a port containing a variable exhaust device and optional flow buffer, acting to maintain a pressure differential between the cavity and an adjacent inside volume of the molten film tube, adjustable to optimize molten film tube stability cooling element efficiency and spaced apart dimension between cooling elements. Significant increases in production speeds are achieved with improved film quality over an increased range of tubular film sizes, down to a minimum size which occurs when operating at zero internal to molten film tube pressure.

The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process, comprised of a divergent cooling element with a divergent cooling interface containing a cooling gas deflector spaced adjacent to the molten film tube and providing an expelled cooling gas (i) in a path opposing the flow of the molten film tube toward a first exit gap and (ii) in a path with the flow of the molten film tube toward a second exit gap. A minimum gap between the divergent cooling interface and the molten film tube occurs at the first exit gap and/or the second exit gap. Advantageously, the divergent cooling interface is provided with one or more compound angles to maximize stability and cooling efficiency. Additionally, multiple cooling elements can preferably be arranged in a stackable configuration to achieve higher throughput rates. Operation is characterized by improved film holding forces without the presence of high noise levels or detrimental vibration, flutter, and drag. Additionally, employing simplified single air delivery channels, and a stackable design, significantly reduces complexity and manufacturing costs.