The use of gas and/or liquid-phase carbon dioxide (CO2) with atmospheric plasma discharge surface pretreatment technology can remove micron and submicron particulates and hydrocarbon-based contaminations on plastics and metals. The cleaning process is based upon the expansion of either liquid or gaseous carbon dioxide through an orifice. The paper provides an understanding of the basic removal mechanism and provides experimental evidence of remarkable adhesion improvements relative to a broad range of applications in electrical, medical, and automotive manufacturing communities.

RFID research and development requires technical expertise of ink and adhesive manufacturers, surface treatment and printing equipment manufacturers, package printers, and electronics firms. In this framework, a strong enhancement in production and quality can be obtained with surface substrate treatments. Here we will discuss the state-of-art in RFID production and the advantages that a plasma treatment of the substrate can give to RFID label printing.

A recent study has illustrated a sizeable increase in the printing characteristics of nonwovens following atmospheric plasma treatments. The improvement of properties such as wettability, printability and adhesion opens up new application prospects for treated fabrics.

Extrusion coating, lamination and film lamination give rise to complex manufacturing techniques which allow a converter to make high-performance packaging films. The physical properties and the related performance characteristics of composites obtained by extrusion coating and lamination can be comparable to that produced by film lamination. This is not surprising since many of the major components involved by these techniques in the production of the final composites are also the same. The paper examines how the use of ozone combined with corona discharge compares to ozone combined with atmospheric plasma relative to seal strength for these composite film constructions, and suggests a direction for future improvements in seal strength.

There are many current and emerging wetting and adhesion issues which require an additional surface processing to enhance interfacial surface properties. Materials which are non-polar, such as polymers, have low surface energy and therefore typically require surface treatment to promote wetting of inks and coating. One way of increasing surface energy and reactivity is to bombard a polymer surface with atmospheric plasma. When the ionized gas is discharged on the polymer, effects of ablation, crosslinking and activation are produced on its surface. In this paper we will analyse the role of plasma and its use in increasing the surface energy to achieve wettability and improve adhesion of polymeric surfaces.

The surface characteristics of shaped structures of fluorocarbon polymers containing at least five mole per cent. of recurring units of formula: wherein -X1 is -H, -F, -Cl or -CF3; -X2 is -H, -F, -R1 or R2; -R1 is an aryl or alkyl radical containing 1 to 8 carbon atoms and -R2 is -OR1, -CH2OR1, -CO.R1, -CH2CO.R1, -CO.OR1, -OCO.R1 or -CH2OCO.R1, are modified by subjecting the surface of such structures to the action of an electrical discharge having an energy level less than 15 electron volts in a gaseous atmosphere having a moisture content of not more than 3.5 gms. per cubic metre at 25 DEG C. Specified articles are sheets, rods, tubes, fabrics and filamentary articles. Specified polymers are the homopolymers and copolymers of vinyl fluoride, vinylidene fluoride, 1, 2-difluoroethylene, trifluoroethylene, 1-fluoropropylene and 1, 1-difluoropropylene; interpolymers of the above monomers with tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene; and interpolymers of the above monomers with olefins, halogen substituted olefins, vinyl and allyl esters, ketones and ethers, unsaturated acids and the esters, nitriles, amides, anhydrides and halides thereof, and vinyl heterocyclic compounds. The preferred articles are films, and the preferred polymers polyvinyl fluoride, polyvinylidene fluoride, copolymers of vinyl fluoride with vinyl acetate, tetrafluoroethylene or hexafluoropropylene, and copolymers of tetrafluoroethylene with ethylene. Preferred gaseous atmospheres are of oxygen, nitrogen and air. Examples describe the treatment of films of the following polymers in the specified atmospheres:-(1, 2 and 5) oriented polyvinyl fluoride in oxygen; (3) oriented polyvinyl fluoride in nitrogen; (4) oriented polyvinyl fluoride in air; (6) polyvinyl fluoride pigmented with titanium dioxide in air; (7) polyvinyl fluoride pigmented with titanium dioxide, chrome yellow, lamp black and phthalocyanine pigment in oxygen; (8) vinyl fluoride/vinylidene fluoride copolymer in nitrogen; (9) vinyl fluoride/vinyl acetate copolymer in oxygen; (10) vinyl fluoride/tetrafluoroethylene copolymer in air; (11) vinyl fluoride/hexafluoropropylene copolymer in oxygen; (12) vinyl fluoride/ethylene copolymer in nitrogen; (13) polyvinylidene fluoride in oxygen; and (14) tetrafluoroethylene/ethylene copolymer in air. The films may be laminated using conventional adhesives. Specifications 605,445, 920,860 and 923,846 are referred to.

In this study, the adhesion properties of adhesives and paints on wood–plastic composites (WPCs) after plasma treatment at atmospheric pressure and ambient air were investigated. Surface energy determination by means of contact angle measurements according to the Owens–Wendt approach and atomic force microscopy to detect changes in surface topography were carried out. An increase in the polar component of surface energy and an increase in surface roughness after plasma treatment were detected, indicating enhanced bond strength. To confirm these results, bond strength tests were conducted. By tensile bond strength tests, increased adhesion of waterborne, solventborne and oil-based paints on plasma treated surfaces was found. Furthermore, by shear bond strength tests, an increase in bond strength of plasma treated WPCs bonded with poly(vinyl acetate) and polyurethane adhesives was ascertained.

A web of polythene &c. or a plastics article such as a bottle is treated to render its surface more receptive to printing ink by subjecting it to an elongated electrical discharge between two electrically conducting electrodes such as 2, 3, the discharge traversing a gaseous medium only and the surface to be treated entering and leaving the discharge on the same side thereof. The plastics material to be treated may alternatively be polyethylene terephthalate or a polyolefine. The discharge is preferably of the corona type and may be accompanied by sparking, the discharge being caused by either direct or alternating current. A potential between 20-60 thousand volts and a frequency between 60-3,000 c.p.s. may be employed. The web 1, Fig. 4, may be treated by four pairs of electrodes as shown, one electrode of each pair being connected to a high tension source 13 via a resistor such as 6, and the web being arranged over insulating guide rollers 10, 101 and 4, 41. The electrodes are preferably in the form of knife edges, brushes or combs, and one electrode may be a heated wire. A web moving in a linear path, Fig. 1 (not shown), may be similarly treated.

Polyolefin plastomer films formulated with slip and antiblock were blown on a wide die gap with and without two Dynamar^™ polymer processing additives (PPAs). A wide die gap was used so that melt fracture-free film could be obtained with no PPA present for comparison purposes. The films were analyzed for the following properties: surface tension (on treated films), gloss, haze, clarity, transmittance, hot tack, heat seal, COF and block. In addition, the surface of films was examined using ESCA (Electron Spectroscopy for Chemical Analysis) and SSIMS (Static Secondary Ion Mass Spectrometry) to determine the surface chemical composition. PPAs when used at typical dose levels were shown to have essentially no effect on the surface and optical properties of plastomer films.

A superhydrophobic polyurethane-based film is described, on which the water advancing and receding contact angles are 150° and 82°, respectively. The film was prepared from surface-fluorinated polyurethane (PU), obtained from a well-defined fluorinated isocyanate, with silica particles incorporated within the film. In the absence of the silica particles, smooth fluorinated PU films with about 2 wt% fluorine demonstrate water advancing and receding contact angles of 110° and 63°, respectively. A major cause for the large contact angle hysteresis, similar to the so-called 'sticky' superhydrophobic behavior, on the roughened PU films is believed to originate from the surface reorganization of the fluorinated PU upon contact with water, which is characteristic for the partially fluorinated PU film. When a similar poly(dimethylsiloxane) (PDMS)-based roughened film was made, the water contact angle hysteresis could be reduced significantly, since the long PDMS chain can effectively suppress the surface reorganization upon contact with water.