The polypropylene films are pretreated in a nitrogen or ammonia low-pressure plasma in order to improve their adhesive properties towards an in-situ deposited aluminium coating. The treatment conditions are similar to industrial ones and treatment times as short as 23 ms allow a considerable improvement of the adhesion between the polypropylene and the aluminium. The aim of this work is to understand better the mechanisms involved in the adhesive phenomena. Indeed, the modifications created by the plasma (for very short treatment times) are not easily detected. SSIMS has revealed the presence of a thin non-homogeneous film of light-weight hydrocarbons on the non-pretreated polymer. This film is responsible for the non-adhesion of the aluminium coating onto the polymer. Actually when this film is removed by a cleaning process induced by the plasma, the interactions between the aluminium and the polypropylene are strong enough to allow a good adhesion. This explains one of the effects of the plasma and more experiments will be carried out in order to determine the key factor of the phenomenon: the role of the oxygen at the interface on the treated polymer will be investigated as well as the diffusion depth of the treating gas.

Transmission electron microscopy and X-ray photoelectron spectroscopy (XPS) were used to characterise thin metal films (Mg, Al, Cu, Ag) thermally evaporated onto polyethylene terephthalate (PET) and to study the formation of the Al/PET interface. The adhesion was measured with a 180° peel test technique. XPS spectra show that the Al atoms react preferentially with the carboxylic group of the PET and that the Al/PET interface exhibits a pseudo layer-by-layer growth mechanism. Two factors strongly favour the increase of metal/PET adhesion: (1) a PET temperature higher than 100°C during metal deposition (Al, Cu and Ag) and (2) a partial pressure of oxygen higher than 10⁻⁵ mbar for the Al evaporation. Furthermore, atomic metal diffusion tends to increase the adhesion while cluster segregation within the PET skin decreases the metal/PET adhesion.

Wettable surface of polymers (advanced wetting angle ∼10° and surface energy ∼ 60 ∼ 70 erg/cm²) have been accomplished by the ion assisted reaction, in which energetic ions are irradiated on polymer with blowing oxygen gas. The energies of ions are varied from 0.5 to 1.5 keV, doses 10¹⁴ to 10¹⁷ ions/cm², and blowing rate of oxygen 0 ∼ 8 ml/min. The wetting angles are increased when the wettable polymers were exposed in air, but are remained in pure water. Improvement of surface energy is mainly due to the polar force. Surface analysis shows hydrophilic functional groups such as CO, (CO)O, CO, etc., are formed without surface damage after the ion assisted reaction treatment. Comparisons between the conventional surface treatments and the ion assisted reaction are described in term of physical bombardment, surface damage, functional group, and chain mobility in polymer.

Atmospheric pressure gas discharge plasmas, especially those operated at energy non-equilibrium and low gas temperatures, have recently become a subject of great interest for a wide variety of technologies including surface treatment and thin-film deposition. A driving force for these developments is the avoidance of expensive equipment required for competing vacuum-based plasma technologies. Although there are many applications where non-equilibrium (cold) plasma at atmospheric and higher pressures represents a substantial advantage, there are also a number of applications where low-pressure plasmas simply cannot be replaced due to specific properties and limitations of the atmospheric plasma and related equipment. In this critical review, the primary principles and characteristics of the cold atmospheric plasma and differences from vacuum-based plasma processes are described and discussed to provide a better understanding of the capabilities and limits of emerging atmospheric plasma technologies.

Commercial polymers in thin film form were used for modification by atmospheric RF plasma. The influence of the plasma treatments using Ar and Ar+O₂ on surface energy, morphology and chemical structure of the films was investigated. It was revealed that both modifications caused surface activation of the polymer film, but they obeyed different mechanisms enhancing polymer wettability. First, surface graphitization due to argon sputtering caused hydrogen to free the surface and then reacts with oxygen in the air. Second, surface oxidation is connected with the functional group formation. The reactions of Ti with the polymer led to the simultaneous formation of TiCl₂, TiC, Ti-oxide and they contributed to film adhesion. In comparison with Ar, the mixed Ar+O₂ RF plasma treatment was a more timesaving process and had more influences on surface activation and film adhesion.

An analogy between the phenomena of miscibility and wetting is pointed out, and developed to predict critical wetting temperatures: and a relation between the contact angle and the respective latent heats of evaporation between two phases. The theory is compared with experimental results on oleophobic monolayers.

The carbon fibers (CFs) reinforced polytetrafluoroethylene (PTFE) composites have been modified using proton irradiation, and the surface energy, hardness and tribological properties have been investigated before and after irradiation. The CFs increased the hardness and the wear resistance. Proton irradiation led to defluorination and carbonization of the CF/PTFE composite surface, and decreased the surface wettability and the surface energy. The irradiation depth was 820 nm from the material surface calculated with SRIM software package. In addition, the wear resistance was improved after proton irradiation. Proton irradiation improved the wear resistance of the composite and induced the material transfer from Cu alloy surface to CF/PTFE. These significant improvements could enable potential applications in aeronautics and smart medical materials.

A method and device of treating an irregularly shaped article to prepare the article for painting is provided. The device includes a burner which can produce an adjustable flame tongue which can fit into crevices, openings and other irregular topographical features of an item to be painted or otherwise coated. The burner device further provides means to apply a grafting chemical on a freshly oxidized surface. Further, the invention provides means to colorize treated objects so that they may be recognized as having been treated. In another embodiment, the grafting chemicals may be enhanced with electrolytic solutions such that electrostatic methods of painting may be subsequently employed on the item. In an alternate embodiment, the burner is adapted to spray a powder inside of a generally enclosed flame, and is used in conjunction with chop guns to manufacture glass or carbon fiber preforms. In a preferred embodiment all of the main systems of the present invention are provided with redundancies that allow the continuous operation of the device. Further, the device provides means to run and modify the process either locally or by remote communication means.

Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin

A method of treating plastic film to improve the adhesion of ink impressions imprinted thereon comprises subjecting the opposite surfaces of the plastic film simultaneously to the action of high voltage stress accompanied by corona discharge. As shown, a web 10 is unwound from a supply reel 12 and after passing over rollers 16, 18 passes between electrodes 24, 26 one of which is earthed and the other of which has a high voltage applied thereto by means of a high-voltage transformer 60. The web then passes over rollers 20, 22 on to a take-up roll 14. Alternatively the web may be fed directly to a printing machine. The ground electrode 24 is carried on posts 30 and is provided with notches, Fig. 3 (not shown), on each longitudinal edge so that a glass cord may be threaded therethrough and held in position, thus acting as a spacing member for the web. The high voltage electrode 26 is secured in a recess formed in the inner periphery of a frame 40 formed of insulating material and a solid dielectric 42 is disposed on the upper surface of the electrode. The electrode 26 is supported on posts 50, and a glass cord 46, for spacing purposes, is wound on pins .44 extending from the frame 40. In alternative arrangements the glass cords may be wound spirally around the electrodes, Fig. 4 (not shown), or a fabric may be disposed over each electrode, Fig. 5 (not shown), or both methods employed. The voltage on the high voltage electrode 26 is preferably between 10,000 and 20,000 v., and the electrode may be made of stainless steel.

This invention relates to a method of treating plastic materials in various structural forms to improve the anchorage characteristics of the surfaces thereof, more especially relating to the treatment of polyethylene, principally in sheet or film form, to improve the anchorage characteristics of its exposed surface whereby various coating materials such as printing ink may be more firmly secured thereto. In particular the invention is concerned with an improvement in the treating method fully disclosed and claimed in copending application Ser. No. 359,352 filed on June 3, 1953 and assigned to the same assignee as is this invention.

This invention relates to the treatment of plastic material, and more particularly polyethylene, to improve the anchorage or adherence characteristics of the surface thereof. More particularly the invention is concerned with such a treatment or the control of such a treatment which does not destroy the heat scalability characteristic of the material or result in an unsatisfactory one.

A method of treating the surface of an organic plastic material, to improve the receptivity and adhering of said surface to substances such as ink, coating materials, decorations, or laminations, comprises contacting said surface with a dielectric material different from said organic plastic material in the presence of a varying electric field. As shown, a plastic web P is passed between a drum 16, having a conducting surface or covered with a dielectric material the same as that of the web, and a series of drums 34 covered with a dielectric material other than that of the web, and in contact with at least the latter dielectric. The drums 34 are of steel with a copper-plated layer and an outer chromium layer, and may be slightly shorter than the web width to leave the edges of the web untreated. The upper drums are the treating drums, and increased receptivity to ink &c. is imparted to the upper surface of the web. Alternatively, the lower drum may be used as the treating drum by reversing the dielectrics. The dielectric on the treating drums may be of kraft paper, nylon, varnished or shellaced silk, linen or cabric, with underlayers of wax paper, and less than 20 mm. thick, and should exhibit higher dielectric losses than the web material. The web may be of polyethylene and may contain slip-agents, or may be of polytetrafluorethylene, polymonochlorotrifluoroethylene, or copolymerized vinyl chloride-vinyl acetate. The drums 34 are electrically connected through inductors, the drum 16 is grounded, and the drums 34 are connected to the + terminal of a D.C. supply 65, the negative terminal of which is grounded. A coil 63 is provided in the circuit. A triode 50 is provided, of which the cathode is grounded, the grid is grounded through a resistor 52, and the anode is connected through an R.F. choke 60 to the positive terminal of a D.C. supply, the negative terminal of which is grounded. Connected between the anode and grid through coupling and isolating condensers 54 is a coil 56, across which are connected the stators of a tuning condenser 58, the rotor of which is grounded. By means of the condenser 58, the frequency of the oscillator constituted by the triode and its associated circuits is adjusted to the resonant frequency of the electrode circuit, which is a function of the coil 63 and the inter-electrode capacitance. By means of the coils 56, 63 a high-frequency A.C. voltage is superimposed on the D.C. voltage. The A.C. voltage, owing to the inductors connecting the drums 34, will appear on successive drums 34 in phase-delayed relationship. The D.C. voltage may be 1000-3000 and the A.C. voltage 900-2000 at from 1 Kc. to 1 mc. In general, a higher voltage rate is required for a higher treatment rate, higher speed of web feed, and greater slip-agent content. The voltage required is reduced if the web is given a prior electrostatic charge by passing it over a burlap apron. Alternatively, an A.C. voltage of 800-1500 at 1-1000 kc/s. may be superimposed on the low-frequency A.C. voltage of 900-2000 at 25-500 cycles. For treating separate flat articles of organic plastic material, one of the electrodes may be an endless belt having a conducting core or surface. The non-treating surface may be spaced 1/8 -\ba1/4 inch from the web, in which case it is a conducting surface, the D.C. voltage applied is in the neighbourhood of gaseous discharge point in the electrode zone, and the A.C. voltage alternately establishes and extinguishes an electrical gaseous discharge between the electrodes. The drum 16 may be replaced by a number of small rollers, which may each be earthed, or alternatively may be connected by phase delay element, only one then being earthed.

This invention relates principally to apparatus for treating plastic sheet materials, especially polyethylene sheets or film to improve the anchorage or adherence More particularly the invention is concerned with an apparatus which constitutes an improvement over that disclosed and claimed in copending application Serial No. 359,35l, filed June 3, 1953 and assigned to the same assignee as is this invention.

This invention relates to the treatment of polyethylene resins and relates more particularly to the treatment of polyethylene resin sheet material in order to make the surface of said material receptive to printing inks.

Articles, such as films, of polyethylene resins have been employed extensively in the arts because of the numerous advantages of these lightweight, relatively inert, tough materials. However, it has been found very difficult to provide decorative or informative matter on the surfaces of such articles, since these surfaces are not receptive to printing inks. Thus, while the inks may be applied readily to the surface of the polyethylene resin material, they do not adhere well thereto and are easily rubbed off.

It is therefore an object of this invention to provide an article of polyethylene resin having a surface which is receptive to printing inks.

This invention relates to a method of treating sheets and other articles of plastic material to improve the anchorage or adherence characteristics of the surfaces thereof. More particularly, the invention is concerned with a method of treating polyethylene sheets or articles to improve the anchorage or adherence characteristics of the surfaces thereof whereby various coating materials including printing inks applied thereto are tightly adhered thereto.

Surface shaping of articles, e.g. embossing; Apparatus therefor by electric discharge treatment

The present invention relates to the surface treatment of thermoplastic tubing for the reception of protective and decorative coatings, printing inks, adhesives and the like in a manner which causes them to readily and firmly adhere thereto, and has particular reference to a method of and apparatus for improving the adherence characteristics of exterior and interior surfaces of polyethylene or the like thermoplastic tubing by the application of a high voltage electrical stress accompanied by corona discharge as the tubing is extruded in substantially continuous lengths.

This invention relates to a method of electrically treating polyethylene film to improve the anchorage characteristics of its exposed surface whereby various materials such as printing ink or adhesive may be firmly secured thereto. More particularly, it relates to the use of an electrically conductive treating roll coated with a phenol-formaldehyde resin, in the process of passing a polyethylene film through an electrical discharge between an electrode and a dielectrically coated conductor roll.

This invention relates to a novel apparatus for treating the surface of plastic articles with a corona discharge, and more particularly to an apparatus for the treatment of the surface of an article made from a hydrocarbon resin with a corona discharge in order to render the surface more readily printable, which apparatus is located on one side only of the plastic article.

This invention relates to surface and interior modification of thermoplastic resinous bodies, and is particularly useful in the treatment of resin plastics which are normally non-adherent or only slightly adherent to inks, adhesives, and other coatings. The invention is particularly useful in the treatment of such substantially non-adherent plastics as polyethylene and polypropylene, but is also useful in the treatment of polyvinyl chloride, polyvinylidene chloride, and copolymers, homologues, and mixtures thereof.

This invention pertains to the surface treatment of film, and more particularly to the flame treatment of the surface of polyvinyl fluoride film whereby to enhance the ad herability characteristics of said surface.

Polyvinyl fluoride is noted for its attractive properties, and in film form possesses an unusual combination of excellent resistance to outdoor weathering exposures, a high degree of physical toughness, chemical inertness, abrasion resistance, resistance to soiling and the action of solvents as well as an amazing retention of these properties at both low and elevated temperatures. The above combination of properties not only suggests many areas of use for polyvinyl fluoride in the form of self-supporting films, but also the use of such films as the outer layers of a wide variety of laminar structures destined chiefly for outdoor use wherein the polyvinyl fluoride films serve to upgrade less functional substrates, imparting to the final structure a degree of utility not to be found solely in either film or substrate.

This invention relates to the surface treatment of hollow plastic articles to provide thereon a surface receptive to inks, coatings, adhesives and the like and especially to the interior treatment of hollow containers to insure that interior coatings will adhere reliably and uniformly thereto.

This invention relates to corona treating of shaped articles and particularly articles of irregular shaped surface areas and made of synthetic resinous material such as polyethylene.

In a method for treating a surface of organic plastics material to improve the bonding or adhesion properties thereof (e.g. ink receptivity), the plastics material is passed between a current-conductive material and at least two electrodes spaced and electrically insulated therefrom and maintained at high voltage direct current of opposite polarity, the surface of the material to be treated being exposed to and spaced from the electrodes with the reverse side of the material in intimate contact with the current-conductive material, whereby a direct current corona aura is developed and maintained from the electrodes to the moving surface of the plastics material being treated. The electrodes are on the same side of the current-conductive surface, so that the corona, which increases in intensity with the speed of surface being treated, does not pass through the plastics material but operates on only one surface thereof. In one embodiment (Fig. 1, not shown), a D.C. voltage, e.g. 17,000 volts, is applied to each of alternate electrodes 20, intermediate electrodes 21 being of opposite polarity. The electrodes are sharp-pointed sections of a hacksaw blade. A film 23 made of e.g. polyethylene polypropylene, polystyrene is passed via rolls 24, 26 over a conductive plate 22 which is in contact with the film, and insulated from the D.C. supply. In Fig. 2 (not shown), a corona is developed in the air gap between film 23, passing round insulated metal roll 221, and electrodes 201, 211 of opposite polarity.

The present invention relates to the treating of plastic film materials and more particularly to a method and apparatus for improving the exposed surface adhesion qualities of films of plast'c such as polyethylene which have been applied to electrically conductive substrates such as metal foils.

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.

The present invention relates to the treatment of plastic coated paper, and more particularly to the treatment of plastic coated paper to improve the adherence of ink and adhesives thereto. The principal utility of the invention at the present time resides in the treatment of polyethylene coated paper, and, for convenience, the invention will be described primarily in connection with tre-atment of such polyethylene coated paper. But it should be understood that the principles of the invention are applicable to the treatment of other plastics which may be coated on paper and which plastics exhibit generally similar response to the treatment of the invention, particularly polymers and copolymers of the lower olens. Similarly, the principles of the invention are also applicable to the treatment of certain plastic coated substrates other than paper.

This invention relates to treatment of organic thermoplastic polyme-ric surfaces to render the surfaces more wetta'ble by water and/or other liquids, more printable and dyeable and, in general, more adherable.

This invention relates to an improved method for treating the surface of plastic materials to render them capable of adhering to subsequently applied coatings such as printing inks, paints, pigments, adhesives, and various other materials which it may be desired to coat, print or otherwise attach to the treated surfaces.

The present invention relates generally to an improved method of treating surfaces of materials, such as synthetic resinous materials, to render these surfaces more adherent to substances such as printing inks, paints, lacquers and glues. More particularly, it relates to a process which comprises treating these materials with monatomic gases.

A process for flame treating and heat sealing an uncoated biaxially oriented heat shrinkable film formed from a homogeneous blend of low density and high density ethylene polymers and copolymers comprising passing the film through a flame fed by a fuel of paraflinic and olefinic hydrocarbons, said fuel having a fuel equivalency when mixed with oxygen-enriched air of between 0.95 and 1.05, with said film being supported as it traverses the flame on a surface maintained at a temperature from about room temperature to 40 C., said film being exposed to the flame for a time between .0005 and .1 second; and heat sealing the flame treated film to itself or to another such film similarly treated.

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.

This invention relates to a method by which substantial improvement can be obtained in the electric glow discharge treatment of polyolefin, such as polyethylene or polypropylene, structures to improve the anchorage characteristic of a surface thereof. More particularly, the invention is concerned with improving processes and apparatus for treating polyethylene or other thermoplastic film or article to render its surface adherent to printing inks or other coating materials, wherein the surface treatment is accomplished by means of an electric glow discharge, as for example, in accordance with the disclosure of the copending applications of Kaghan and Stoneback, Ser. No. 540,137, filed Oct. 12, 1955, and issued Nov. 11, 1958, as U.S. 2,859,481 and of Berthold and Pace, Ser. No. 359,352 filed June 3, 1953, and issued May 3, 1960, as U.S. 2,935,418. This application is a continuationin-part of our copending application Ser. No. 602,506 filed Aug. 7, 1956, now abandoned.