Abstract: The invention provides systems, methods, and articles useful in the production of foams, and, in particular microcellular foams. The systems include a restriction element that reduces the backflow of polymer melt in an extruder while polymeric material is injected into a mold or ejected from a die. The restriction element is positioned upstream of a blowing agent injection port to maintain the solution of polymer and blowing agent in the extruder above a minimum pressure throughout an injection or ejection cycle, and preferably above the critical pressure required for the maintenance of a single-phase solution of polymer and blowing agent. The systems can be used in injection molding, blow molding, or in any other processing techniques that include injection or ejection cycles. In some embodiments, the systems utilize reciprocating screws for injection or ejection.

Abstract: A microcellular injection blow molding system and method, and microcellular blow molded articles produced thereby, are described. The system is equipped to extrude microcellular material that changes in thickness, material density, or both in the machine direction while maintaining a constant pressure drop rate during nucleation just prior to extrusion, providing the ability to produce consistent uniform microcellular material independent of material thickness. The systems and methods are particularly useful in production of strong, thin-walled, non-liquid-permeable, opaque containers that do not contain reinforcing agent, chromophore, or residue of chemical blowing agent or chemical blowing agent by-product.

Abstract: Foams with low water absorption are provided, along with thermoplastic elastomeric foam materials and methods of forming the same. In some embodiments, the TPE foams have a low water absorption. Microcellular foams are included. Processing conditions (e.g., blowing agent type and content, die geometry, exit melt temperature, among others) may be controlled to produce foams having desirable characteristics, such as low water absorption.

Abstract: A microcellular injection blow molding system and method, and microcellular blow molded articles produced thereby, are described. The system is equipped to extrude microcellular material that changes in thickness, material density, or both in the machine direction while maintaining a constant pressure drop rate during nucleation just prior to extrusion, providing the ability to produce consistent uniform microcellular material independent of material thickness. The systems and methods are particularly useful in production of strong, thin-walled, non-liquid-permeable, opaque containers that do not contain reinforcing agent, chromophore, or residue of chemical blowing agent or chemical blowing agent by-product.

Abstract: Foams with low water absorption are provided, along with thermoplastic elastomeric foam materials and methods of forming the same. In some embodiments, the TPE foams have a low water absorption. Microcellular foams are included. Processing conditions (e.g., blowing agent type and content, die geometry, exit melt temperature, among others) may be controlled to produce foams having desirable characteristics, such as low water absorption.

Abstract: A valve for controlling the flow of a high pressure fluid is provided. The valve provides a reliable way of controlling the flow of high pressure fluids in applications requiring multiple cycles where equipment may be exposed to environmentally harsh conditions, such as high temperatures and pressures.

Abstract: The invention provides a blowing agent metering system and method for use in polymeric foam processing. The system may be used to control the rate of introduction of blowing agent into polymeric material in a processing apparatus to form a mixture having the desired blowing agent weight percentage. The metering system includes a restriction orifice which is positioned in a pathway between a blowing agent source and a blowing agent port within a foam processing apparatus. The metering system measures the pressure differential as blowing agent flows across the restriction orifice from the source to the port and may also measure the temperature of the blowing agent at one or more locations. Using a pre-determined relationship between the flow rate, the orifice dimensions (e.g., length, diameter) and the measured variables (e.g.

Abstract: A valve for controlling the flow of a high pressure fluid is provided. The valve provides a reliable way of controlling the flow of high pressure fluids in applications requiring multiple cycles where equipment may be exposed to environmentally harsh conditions, such as high temperatures and pressures.

Abstract: Microcellular thermoplastic elastomeric polymeric structures are provided. The articles have an average cell size of less than 100 &mgr;m and a compression set ranging from less than about 30% to less than about 5%, and a rebound value of at least 50%. The articles may be formed from a thermoplastic elastomeric olefin, preferably metallocene-catalyzed polyethylene. The density of the articles ranges from less than 0.5 gm/cm3 to less than 0.3 gm/cm3.

Abstract: The invention provides a blowing agent delivery system and method for introducing a blowing agent into a polymeric foam processing system. The delivery system is designed to introduce blowing agent into polymeric material within an extruder when polymeric material is being plasticated, for example, during the plastication period of an injection molding cycle. The rate of introduction of blowing agent into polymeric material may be coupled to the flow rate of polymeric material in the extruder to ensure precise control over blowing agent percentage in the resulting mixture of polymeric material and blowing agent. The delivery system is also designed to prevent the introduction of blowing agent into the polymeric material when polymeric material is not being plasticated, for example, during the injection period of an injection molding cycle. The delivery system may be used in conjunction with discontinuous systems including injection molding or blow molding systems.

Abstract: The invention provides a counter-rotating extrusion system for processing foam material. The system is designed to introduce a physical blowing agent into the extruder, thoroughly disperse the blowing agent within the polymer melt and, preferably, to maintain relatively high pressures downstream from the point of blowing agent introduction. High quality polymeric foams, including microcellular foams, can be produced using the extrusion system. The system is particularly suitable for the production of foams using shear sensitive and degradable materials, such as PVC.

Abstract: Systems and techniques for forming microcellular polymeric material, via injection molding, blow molding, continuous extrusion, or the like, at very low blowing agent levels, are described. The invention involves, in one aspect, the discovery of a region of very low blowing agent level where, surprisingly, microcellular material can be formed. Articles with particularly good surface properties are provided.

Abstract: The invention provides systems, methods, and articles useful in the production of foams, and, in particular microcellular foams. The systems include a restriction element that reduces the backflow of polymer melt in an extruder while polymeric material is injected into a mold or ejected from a die. The restriction element is positioned upstream of a blowing agent injection port to maintain the solution of polymer and blowing agent in the extruder above a minimum pressure throughout an injection or ejection cycle, and preferably above the critical pressure required for the maintenance of a single-phase solution of polymer and blowing agent. The systems can be used in injection molding, blow molding, or in any other processing techniques that include injection or ejection cycles. In some embodiments, the systems utilize reciprocating screws for injection or ejection.

Abstract: High-density polyethylene (HDPE) foams that are essentially free of residual chemical blowing agents and reaction-by-products of chemical blowing agent are provided. The HDPE foams can be either microcellular foams or conventional foams. She foams can be produced in extrusion, injection molding, and blow molding processes that utilize a physical blowing agent. Specific die designs useful for making high quality foams are described.

Abstract: The invention provides systems, methods, and articles useful in the production of foams, and, in particular microcellular foams. The systems include a restriction element that reduces the backflow of polymer melt in an extruder while polymeric material is injected into a mold or ejected from a die. The restriction element is positioned upstream of a blowing agent injection port to maintain the solution of polymer and blowing agent in the extruder above a minimum pressure throughout an injection or ejection cycle, and preferably above the critical pressure required for the maintenance of a single-phase solution of polymer and blowing agent. The systems can be used in injection molding, blow molding, or in any other processing techniques that include injection or ejection cycles. In some embodiments, the systems utilize reciprocating screws for injection or ejection.

Abstract: Semi-crystalline microcellular foams that include a midlevel amount of nucleating agent, and methods of their production, are provided. The microcellular foams can be produced in typical polymer processing techniques such as extrusion, injection molding and blow molding. The foams exhibit excellent mechanical properties and can be formed over a broad range of density into a number of different foam articles.

Abstract: Continuous polymeric extrusion nucleation systems and methods useful for making polymeric microcellular foamed materials, including crystalline and semi-crystalline polymeric microcellular materials, are provided. Pressure drop rate is an important feature in some embodiments, and the invention provides systems for controlling these and other parameters. One aspect involves a multiple-pathway nucleator that is separated from a shaping die by a residence chamber. Another aspect involves a die for making advantageously thick articles, including a multiple-pathway nucleation section. Microcellular material can be continuously extruded onto wire, resulting in a very thin, essentially closed-cell microcellular insulating coating secured to a wire. Other very thin microcellular products can be fabricated as well.

Abstract: Articles including material laminated to a surface of a microcellular substrate are disclosed, as well as methods of making these articles. Microcellular polymeric material in sheet form can be extruded and continuously fed from the extruded to a lamination system, or microcellular sheet can be produced and stored, and then fed into a lamination system.

Abstract: A polymeric foam article is comprised mainly of homopolymeric polypropylene, or unimodal polypropylene. The polymeric article can be microcellular, and can be formed into a drinking straw.

Abstract: Semi-crystalline microcellular foams that include a midlevel amount of nucleating agent, and methods of their production, are provided. The microcellular foams can be produced in typical polymer processing techniques such as extrusion, injection molding and blow molding. The foams exhibit excellent mechanical properties and can be formed over a broad range of density into a number of different foam articles.