University of Tennessee Research Foundation

Cryovac, Inc.

Paul D Spence

Drew V Speer

Gregory E McDonald

Larry C Wadsworth

Csaba Frank Kiss

Peter P Tsai

John R Roth

Charles C Zende

Gregory H Grossman

Jason G Verrett

Timothy S Dennison

Mounir Laroussi

Chaoyu Liu

W Edward Deeds

Qin Sun

Chaoya Liu

Dong Zhang

John Lynch

The invention is a method, triggering unit, and system for activating an oxygen scavenging composition at high speeds. The triggering unit includes a plurality of UV lamps that can operate at increased temperatures and have high output intensites from about 10 to 35 mW/cm. The triggering unit can activate films at speeds from about 20 to 100 fps. Mercury amalgam lamps are useful in the practice of the invention. The invention also includes a UV dose management system and film tensioning system that facilitates triggering at high film speeds. The UV dose management system controls the amount of UV exposure that the film receives so that the oxygen scavenging rate of the activated composition can be controlled.

Method and apparatus for high speed activation of oxygen scavenging compositions

Hydrophobic polymer materials having improved dyeability with water-based dyes are prepared by treating a hydrophobic polymer with aglow discharge plasma generated from working gases selected from SO , O , N , He, H , CO , CF , NO, N O, 2-Hydroxypropyl Methacrylate (HPMA), air or combinations thereof, in which a treated material comprises a hydrophobic inner core and a hydrophilic outer sheath having polar functional groups. A method of treating hydrophobic polymer materials using a glow discharge plasma, preferably at high pressure (e.g., about 50 Torr or greater), thereby modifying the active surface characteristics of the polymer to contain polar functional groups is also presented.

Plasma treatment of polymer materials for increased dyeability

Two methods and corresponding electrode designs are provided for the generation of a plasma, for example, at or about one atmosphere. Using these methods, various webs, films and three-dimensional objects are beneficially treated in a reduced amount of time. A first method utilizes a repetitive, asymmetric voltage pulse to generate a plasma discharge between two electrodes. An asymmetric voltage pulse is used to generate a discharge in which a substrate can be exposed predominately to either positive or negative plasma species depending on the voltage polarity used. A second method uses the gap capacitance of an electrode pair and an external inductor in shunt to form a resonant LC circuit. The circuit is driven by a high power radio frequency source operating at 1 to 30 MHz to generate a uniform discharge between the electrode pair. Both methods have temperature controlled discharge surfaces with supply gas temperature, humidity and flow rate control. The gas flow is typically sufficient to cause a turbulent flow field in the discharge region where materials are treated. Electrode pairs implement these methods and include a metal faced electrode and a dielectric covered electrode, one or both of which have a series of holes extending through the electrode face for supply gas flow. The second of the above-described methods will also operate with paired, metal faced electrodes, but under more restricted operating conditions.

Resonant excitation method and apparatus for generating plasmas

A waveguide structure has at least one shaped slot machined in the wall of the waveguide. The slot is configured such that a high voltage is generated across the slot when the waveguide is suitably excited with high-power microwaves. The strong electric fields generated in the region of the slot can be used to produce a non-equilibrium plasma discharge in a working gas introduced in the vicinity of the slot. Various substrates can be translated past the slot and exposed to the plasma species generated by the microwave discharge. The slotted waveguide structure is designed to operate as a traveling wave structure with microwave energy uniformly dissipated along the length of the slot. Several methods are disclosed for providing uniform power dissipation. These methods include changing the dimensions of the waveguide, altering the position and shape of the wall slot, coupling power into the waveguide by means of auxiliary sources, and using an auxiliary ground plane. The auxiliary ground plane can also serve as a secondary electrode for the application of a low-frequency voltage for the enhancement of high-pressure operation. Altering the background gas pressure, gas composition, gas flow rate, and gas flow pattern provide additional ways to affect the plasma discharge. The structure can be designed to operate over the pressure range of about 10 Torr to atmospheric pressure (i.e., about 760 Torr) using a wide variety of gases and gas mixtures.

Slotted waveguide structure for generating plasma discharges

Continuous-feed plasma treater systems are designed to treat continuous substrates, such as webs or films, by continuously feeding the substrates through an enclosure having a plasma discharge that alters the substrate's surface properties in some desirable fashion. According to the present invention, the enclosure has one or more electrode assemblies that generate plasma discharges at working-gas pressures ranging from moderate pressures (e.g., rough vacuums as low as about 10 Torr) to high pressures (e.g., about one Atmosphere). The electrode assemblies are driven by power supplies that excite the electrode assemblies in either an RF resonant excitation mode or a pulsed voltage excitation mode. By operating in the moderate, rough-vacuum pressure range, plasma treater systems of the present invention can be used (a) to treat substrates in an efficient cost-effective manner and (b) to produce treated substrates having superior surface properties as compared to those generated using prior-art systems, such as corona-type discharge systems operating at either low pressures (i.e., &lt;1 Torr) or high pressures.

Treater systems and methods for generating moderate-to-high-pressure

Continuous-feed plasma treater systems are designed to treat continuous substrates, such as webs or films, by continuously feeding the substrates through an enclosure having a plasma discharge that alters the substrate's surface properties in some desirable fashion. The plasma discharges are generated by one or more electrode assemblies housed within the enclosure. In general, the plasma treater systems of the present invention have one or more cylinder-sleeve electrode assemblies and/or one or more cylindrical cavity electrode assemblies. A cylinder-sleeve electrode assembly comprises a cylinder electrode and a sleeve electrode positioned with its concave face facing and substantially parallel to the cylinder electrode to form an annular gap between the outer surface of the cylinder electrode and the inner surface of the sleeve electrode. The electrode assembly is adapted to be excited to generate a plasma within the annular gap to form a primary plasma discharge zone for exposure of the plasma to a substrate. A cylindrical cavity electrode assembly comprises (1) a cavity electrode, having a cylindrical bore and a wall slot running parallel to the cylindrical bore and exposing the cylindrical bore; (2) a cylinder electrode coaxially positioned within the cylindrical bore of the cavity electrode to form an annular gap between the outer surface of the cylinder electrode and the surface of the cylindrical bore, the annular gap forming a primary plasma discharge zone; and (3) a treater drum positioned adjacent to the wall slot of the cavity electrode. During operations, the substrate is translated past the wall slot by the treater drum and exposed to plasma species that are convected from the primary plasma discharge zone to the wall slot. Plasma treater systems of the present invention can be used (a) to treat substrates in an efficient cost-effective manner and (b) to produce treated substrates having superior surface properties as compared to those generated using prior-art systems, such as corona-type discharge systems.

Electrodes for plasma treater systems

Discharge method and apparatus for generating plasmas

Two methods and corresponding electrode designs are provided for the generation of a plasma at or about one atmosphere. Using these methods, various webs, films and three-dimensional objects are beneficially treated in a reduced amount of time. A first method utilizes a repetitive, asymmetric voltage pulse to generate a plasma discharge between two electrodes. An asymmetric voltage pulse is used to generate a discharge in which a substrate can be exposed predominately to either positive or negative plasma species depending on the voltage polarity used. A second method uses the gap capacitance of an electrode pair and an external inductor in shunt to form a resonant LC circuit. The circuit is driven by a high power radio frequency source operating at 1 to 30 MHz to generate a uniform discharge between the electrode pair. Both methods have temperature controlled discharge surfaces with supply gas temperature, humidity and flow rate control. The gas flow is typically sufficient to cause a turbulent flow field in the discharge region where materials are treated. Electrode pairs implement these methods and include a metal faced electrode and a dielectric covered electrode, one or both of which have a series of holes extending through the electrode face for supply gas flow. The second of the above-described methods will also operate with paired, metal faced electrodes, but under more restricted operating conditions.

Discharge methods and electrodes for generating plasmas at one

A steady-state, glow discharge plasma is generated at one atmosphere of pressure within the volume between a pair of insulated metal plate electrodes spaced up to 5 cm apart and R.F. energized with an rms potential of 1 to 5 KV at 1 to 100 KHz. Space between the electrodes is occupied by air, nitrous oxide, a noble gas such as helium, neon, argon, etc. or mixtures thereof. The electrodes are charged by an impedance matching network adjusted to produce the most stable, uniform glow discharge.

One atmosphere, uniform glow discharge plasma

Polymer materials such as film and fabrics, woven, non-woven and meltblown, may be non-destructively surface treated to improve water wettability, wickability, and other characteristics by exposure to a glow discharge plasma sustained at substantially atmospheric pressure in air or modified gas atmospheres comprising helium or argon.

Growing community of inventors

Greenville, SC, United States of America

Paul D Spence