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.

Described is a method of treating or coating homogeneously at least a portion of the surface of a material selected from metallic materials having a thickness of less than 100 mum and/or polymeric materials. The method of the present invention comprises exposing at least a portion of the surface of the material to an atmospheric plasma generated by an indirect plasmatron. In the method of the present invention, the surface of the material may undergo at least one of an increase in surface tension, a surface grafting, a surface cleaning and a surface sterilization.

The present invention provides a method of modifying the surface of a polymeric substrate, e.g., to improve the wettability of the polymer film surface and/or alter the metal adhesion properties of the surface of the substrate by exposing the substrate to a flame. The flame is supported by an oxidizer and fuel mixture that includes an effective amount, for modifying the polymeric substrate, of at least one sulfur-containing compound that functions as a fuel substitute. In addition, substrates are provided that have increased wettability or increased metal adhesion performance.

A treatment method for the internal surface of a molded polyethylene plastics material container such as a drum, including the steps of: introducing an ionizable gas, such as argon, into the container; generating a plasma of the introduced gas by applying electric field of sufficient strength to the container and introduced gas, so as to cause an interaction with the internal surface of the container; coating the internal surface of the container with a curable epoxy-based first polymeric composition; and then curing the polymeric composition to form a coating on the internal surfaces of the container. A second coating, preferably with electrical conductive properties, may be applied and cured over the first coating. Conductive properties may be provided by including conductive particles such as antimony doped tin dioxide, graphite or metal powders, in the second composition.

A liquid to solid material surface contact angle measurement system operating by way of detecting a transition in the behavior of a liquid sample with the solid material in a changing angular confinement environment along with use of a mathematical algorithm to then determine contact angle. Measurement of the angle at which the tested liquid transitions between apparent wetting and apparent non-wetting behavior, regardless of whether the liquid and solid material are truly classified as wetting or non-wetting, provides a measurement from which disclosed mathematical algorithms can predict the surface wetting characteristics of the liquid on the solid material. Automated performance of the confinement environment measurement and examples are included.

A corona discharge device is adapted to be used in conjunction with a printing press. The device includes a cabinet housing an on-board power supply associated with a high voltage transformer. A rear end plate and a front end plate spaced apart in parallel relationship from the rear end plate both depend from the cabinet. An electrode support tube is fixedly mounted to the cabinet and has an electrode magazine slidably mounted on the support tube between an operative position and an inoperative position, the magazine including a series of parallel electrodes. A grounded treater roll is rotatably mounted on a first shaft between the rear end plate and the front end plate and below the support tube. A pair of spaced idler rolls is rotatably mounted on respective second and third shafts between the rear end plate and the front end plate below the treater roll such that a flexible web is guided upwardly by the idler rolls and wound about the treater roll beneath the electrodes.

Methods for treating polymeric substrates by placing the substrate in a gaseous mixture and subjecting it to a dielectric barrier electrical discharge. The gaseous mixture, which has a pressure around atmospheric, contains a carrier gas, a reducing gas and an oxidizing gas. The amount of the oxidizing gas in the gas mixture is between about 50 ppm and about 2000 ppm by volume, while the amount of the reducing gas in the gas mixture is between about 50 ppm and 30000 ppm by volume.

The invention relates to equipment for area-based surface treatment of an article by electric dielectric barrier discharge in the presence of a non-atmospheric controlled gaseous mixture, comprising a hollow metal electrode enabling the gaseous mixture to circulate therewithin and the mixture to be transported to a discharge area, whereby said electrode is divided into individual elements which can each be pivoted about a central axis to ensure sufficient distance between the element which is considered as being pivoted and the area of the article opposite the element in question so that the discharge cannot develop; the central pivoting axis is used as a channel for the circulation of the gaseous mixture inside the electrode and is provided with openings enabling the gaseous mixture to be evacuated to the discharge area; pivoting one of the elements of the electrodes blocks up the evacuating opening associated therewith and the gaseous mixture can only be evacuated via the evacuating openings of non-pivoted elements.

The present invention relates to a biodegradable substrate having a durable hydrophilic surface prepared from a biodegradable polymeric substrate having a surface, wherein the biodegradable polymeric substrate has been rendered hydrophilic by subjecting the substrate to a corona glow discharge and/or coating the substrate with a hydrophilic polymeric material in an amount of from about 0.01 to about 2.0 percent by weight, based on the dry weight of the substrate. The biodegradable substrate can be used in absorbent personal care product, biomedical devices and food packaging.

The invention relates to a method for raising the surface tension of biaxially-stretched films made of thermoplastic polymers. According to the method, a film is first treated on a surface by means of an atmospheric pressure plasma before being stretched transversally or simultaneously across the width thereof, and the film is additional a subjected to a second treatment by means of a corona or flame after being stretched transversally or simultaneously, the second treatment being done on the same surface which has already been plasma-treated.

Systems and methods for improving adhesion of an insulating foam to a molded polymeric insulating structure through use of ozone gas for functionalization of molded polymeric surfaces of an internal cavity of the insulating structure.

Devices are presented which allow determination of unknown surface properties through the creation of a channel capillary, comprised in part of the subject surface or surfaces, and measurement of the capillary pressure created by a test fluid within the resultant channel. In various embodiments of the invention, a channel is created in a reference material which is bonded, through some mechanism, to the test surface in order to create a narrow capillary channel. In other embodiments of the invention, the capillary channel is created with test surfaces on either side of standoff strips which space the surfaces a precise distance from one another. Methods are presented for using these capillaries through immersion, along their length, in a bath of test fluid, such that the resultant fluid level provides a measure of capillary pressure. Being, in part, a consequence of the contact angle between the test fluid and the surface or surfaces under consideration, the capillary pressure is a convenient measure of surface properties inherently related to printability, affinity for adhesives, surface contamination by foreign substances, surface roughness, and the like. Devices are presented which allow measurement of test fluid height within the capillary, both in situations where a static equilibrium is achieved, and in situations where a dynamic contact angle is operative as the fluid rises or falls within the capillary.

This paper reviews the theoretical principles of macromolecular design of polymer interface/interphase systems for obtaining maximum adhesion. Subsequently, a relatively simple and industry-feasible technology for surface grafting connector molecules is discussed in detail and supported by a range of experimental examples. It is shown, in agreement with contemporary theory, that the use of chemically attached graft chemicals of controlled spatial geometry and chemical functionality enables a significant increase in the strength and fracture energy of the interphase, to the point of cohesive fracture of the substrate, or that of an adjacent medium such as adhesives, paints or elastomers. This occurs even after prolonged exposure of bonded or painted materials to adverse environments such as hot water, thermal shock, UV radiation and other hostile ambients.

Contact angle hysteresis on rough surfaces is caused by the contortion of the liquid surface that must occur as the liquid front passes from one metastable configuration to another. We have combined the Wenzel equation for the effect of roughness on the contact angle, 0, with the well-known equation relating contact angles to the surface free energy of the solid and of the liquid, and with Good’s hypothesis of a free energy barrier to liquid front motion. The method that is developed calls for measuring 0 for a series of liquids and plotting cos0a vs./yi and extrapolating to the limit of (\/yi) 0. On a perfectly smooth, homogeneous surface, the intercept is—1 and the Wenzel ratio for a rough surface is given, approximately, by the negative of the value of the intercept. A shift of the yc value for the solid, due to roughness, is also predicted. Experimental data are presented for measurements with Teflon FEP.

Many wetting processes involve interpretation using Young’s equation to describe contact angle equilibrium on a solid surface. By assuming the solid to be rigid, no account is made of the component of the liquid surface tension perpendicular to the solid surface. It is shown that a wetting ridge must be formed and, although negligible for hard solids, this mesoscopic disturbance of the solid near the wetting front can have significant consequences on a soft solid. The theory of triple line displacement, taking into account viscoelastic dissipation in the wetting ridge, is developed both for wetting and dewetting processes. Experimental studies using tricresyl phosphate and two types of model solid—a rigid polymer and silicone elastomers—have been carried out. Both for wetting and dewetting, triple line motion is markedly slowed down on the soft solids as a result of viscoelastic dissipation near the triple line. Theoretical predictions and experimental findings are found to be in good agreement.

The Harkins relationship, that the spreading coefficient of an adhesive on a release coating is the difference between the work of adhesion of the materials and the work of cohesion of the adhesive, has been found to apply to a variety of silicone release coatings. The works of adhesion and cohesion were estimated from contact angle data using the Owens and Wendt approach. The prediction of the Harkins relationship is obeyed by almost all the combinations of pressure-sensitive adhesive and release coatings we have examined. Release occurs when the spreading coefficient is negative and does not when it is positive. The main exception to this general spreading coefficient rule is the failure of polytetrafluoroethylene to release polydimethylsiloxane-based pressure-sensitive adhesives. The cause is believed to be roughness of the polytetrafluoroethylene surface.

The most effective commercial methods for pretreating fully fluorinated polymers at present are sodium in liquid ammonia and sodium naphthalenide in a solvent such as tetrahydrofuran. A number of other methods can produce large increases in bondability but are relatively inefficient. Plasma treatments of fully fluorinated polymers such as PTFE often introduce functional groups and/or increase wettability but result in moderate improvements at best in bondability. However, recent work with ammonia plasmas has resulted in big improvements in bondability. Some batches of partially fluorinated polymers may be effectively bonded without a pretreatment. However, other batches possess surface regions of low cohesive strength. Partially fluorinated polymers such as poly (vinyl fluoride) may be rapidly and effectively treated with a conventional flame treatment. Where a flame treatment is unsuitable, as with complex shapes, potassium hydroxide solutions provide effective treatments for partially fluorinated polymers such as poly (vinyl fluoride) and poly (vinylidene fluoride).

Injection-moulded plates of four commercial thermoplastic polyolefins (TPOs) were subjected to oxygen plasma treatment. The modified surfaces were analyzed by water contact angle measurements and X-ray photoelectron spectroscopy (XPS), and the adhesion properties of the plates were evaluated by a 90 peel test after being lacquered with a two-component polyurethane lacquer. The study included treatments in two different plasma reactors operating at different frequencies. The influence of certain processing parameters, such as discharge power, flow rate and gas pressure, was investigated, as was that of frequency (using the same reactor). While the results revealed that oxygen plasma treatment indeed led to improved wettability, the degree of surface modification was not highly affected by changes in the processing conditions. In contrast, there was a great effect on the lacquer adhesion, in particular by changes in discharge power and gas pressure. The results also showed that the TPOs were sensitive in different ways towards changes in the processing conditions. It was also found that, regardless of the absolute peel force, the failures occurred in the substrate at some distance below the oxidized layer. These observations were attributed to a VUV-induced formation of radicals which, in the case of polypropylenebased materials, predominantly lead to^-scissions. As secondary radicals have a higher tendency to form crosslinks that can compensate for chain scission reactions, the difference in the sensitivity of the TPOs was proposed to be related to the amount and distribution of ethylene in the materials.