SQUEAK RESISTANT ARTICLE

Abstract: A squeak resistant article comprising a polymer-fluorocarbon composition, method for preparation of the composition and fabrication of a squeak resistant article therefrom.

Description: TITLE SQUEAK RESISTANT ARTICLE BACKGROUND OF THE INVENTION Technical Field This invention relates to a squeak resistant article comprising a polymer- fluorocarbon composition and to a method for making said article. DESCRIPTION OF RELATED ART There is abundant literature concerning the use of additives or surface coatings to polymers to improve performance in a variety of applications of articles manufactured from polymers. Although lubrication and surface treatments have long been used to minimize or prevent squeaks in moving parts the incorporation of fluoro carbons into polymers and elastomers to produce a composition from which non-squeaking articles can be made is not known to the art. U.S. Pat. No. 5,264,270 describes a relatively thin coating of an elastomeric composition on a more rigid polymeric gasket material, which is used in vehicle panel assemblies such as automobile weather-stripping or sealing panels. This enables squeaks and other undesirable noises originating from the gasket material to be eliminated or minimized. The elastomeric composition is applied to the polymeric gasket as an in-mold release agent, or applied after gasket manufacture. The elastomeric composition can be a thermoplastic or thermosetting material having a tensile modulus at 100% elongation of less than 10,000 psi. This process incorporates an additional, expensive, labor intensive step and the effective lifetime of a thin coating is limited. U.S. Pat. No. 5,061,759 describes rubber compositions vulcanizable by means of peroxides and containing processing-coadjuvating additives which are perfluoropolyethers in amounts ranging from 0.5 to 1 part by weight of the rubber composition. The additives improve processability in extrusion and provide better detachability of a vulcanized article from a molding die without adversely affecting the vulcanizing system or the properties of the vulcanized article. The only described articles are test pieces for evaluation of physical properties. There is no reference to squeak resistance. Japanese Pat. App. Pub. No. 60-104161 describes an abrasion resistant molding material comprising a thermosetting resin or a thermoplastic resin with l%to 10% of a fluorinated oil uniformly adhered to, impregnated or dispersed in the molding material. Suitable fluorinated oils include perfluoropolyethers (such as, hexafluoropropylene oxide oligomers), and fluorocarbon oils (such as, tetrafluoroethylene oligomers). The molding material is used to make improved wear resistant sliding components for electrical contact switches, electromagnetic switches and the like. These components are not described as squeak resistant. U.S. Pat. No. 5,143,963 and U.S. Pat. No. 5,286,773 relate to a composition of matter formed by melt blending a thermoplastic polymer and from 0.01% to less than 1% of a fluorocarbon additive and to a method of forming the composition. The fluorinated additive is a fluorocarbon oil, gum or grease including fluorinated hydrocarbons and fluorinated hydrocarbon polyether oils. The compositions are said to enhance and accelerate molding and extrusion operations for films and fibers. The basic bulk mechanical, physical and chemical properties of the thermoplastic polymers are retained or even enhanced. Due to the concentration of the fluorocarbon additive at the surface of articles made from the composition the articles acquire fluorocarbon-like surface properties. There is no disclosure that the articles are squeak resistant. The composition is useful for medical products e.g. vascular grafts, mammary or ocular implants, electronic equipment, electro-optical or electro-mechanical components and as molds for precision parts for such devices. U.S. Pat. No. 4,481,333 describes a thermoplastic composition which comprises mixtures of vinyl chloride polymers and chlorinated polyethylene and which contains up to 0.4% of finely divided fluoropolymers, such as polytetrafluoroethylene, polytrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride and fluorinated polyethers e.g. perfluorovinylpolyether. The composition has a markedly improved processability, particularly when shaped into articles by extrusion. The use of such compositions for making shaped articles such as slabs, tubes, and sheeting is described. There is no mention of such articles being squeak resistant. U.S. Pat. No. 4,505,982 relates to a shaped article exhibiting good long term thermal stability, comprising a thermoplastic heat resistant polymer mixed with 20 to 80%) of at least one fluorocarbon polymer. The fluorocarbon polymer may be polyvinylidene fluoride, polyvinyl fluoride or copolymers with tetrafluoroethylene, perfluorovinyl ethers and the like. Uses in films, fibers and threads are described. There is no reference to squeak resistance of a shaped article of the invention. There is a continuing need to improve performance in use, simplify production method and improve cost effectiveness for articles made from polymers. An object of the present invention is to make available articles which are useful in applications where squeaks and other undesirable noises need to be eliminated or reduced to a minimum. Articles made from polymer-fluorocarbon compositions by the procedures of this invention are found not to squeak or to squeak far less in a wide range of applications. Incorporation of the fluorocarbon into the bulk polymer greatly increases the longevity or permanence of the beneficial effect compared to surface treatments used heretofore. SUMMARY OF THE INVENTION It has now been found that a squeak resistant article can be made from a polymer or mixed polymers with which is incorporated from about 0.01% to 5%, typically from about 0.1% to less than 1% of an additive consisting of a fluorocarbon or mixture of fluorocarbons said additive having a lower surface energy than that of said polymer and the concentration of said fluorocarbon being substantially higher at the surface of said article than the nominal bulk concentration. The squeak resistant article may also contain conventional compounding additives such as fillers, reinforcing agents, colorants and the like. A valuable property of an article of this invention is that its squeak resistant character extends throughout its useful life. In a further aspect the invention relates to a method for making a squeak resistant article of this invention which consists of mixing a polymer, a fluorocarbon and other compounding additives and producing the desired shape by an appropriate procedure such as molding or extrusion. DETAH.ED DESCRIPTION OF THE INVENTION The squeak resistant article of this invention comprises a polymer or mixed polymers and an additive consisting of a fluorocarbon or mixture of fluorocarbons the proportion of the latter ranging from about 0.01% to about 5%, typically from about 0.1% to less than 1% of the amount of polymer, said fluorocarbon additive having a lower surface energy than that of said polymer and the concentration of said fluorocarbon being substantially higher at the surface of said article than the nominal bulk concentration. The squeak resistant article may also contain conventional compounding additives such as fillers, reinforcing agents, colorants and the like. A valuable property of an article of this invention is that its squeak resistant character remains throughout its useful life. By "squeak resistant" it is meant that the article's tendency to sound (i.e., to squeak), when moved relative to a contacting surface in its intended use, is reduced or preferably eliminated. This invention also relates to a method for incorporating a polymer resin with a fluorocarbon and other compounding additives and for forming a squeak resistant article of the invention from such a composition. Squeak Resistant Article As used herein the term "gasket" includes (1) articles inserted between two relatively hard surfaces to cushion their contact, and (2) articles that contact against a hard surface to form a seal, such as weatherstripping or lubricant seals; and the term "blade" includes articles that move across a hard surface to remove a substance, such as windshield wipers and squeegees. Panel assembly gaskets are preferred squeak resistant articles of this invention. The panels, which may be transparent, semi-transparent or opaque, are framed by a gasket which provides a seal when the panel is installed for example in vehicle bodies or building structures. Panel assemblies which incorporate such gaskets typically comprise windows, doors, decorative panels, vehicle, tail-light assemblies and the like. Gaskets for window assemblies for vehicles, especially for automobiles are a preferred aspect of this invention. In modular or encapsulated window assemblies, the window has a gasket, "weather-stripping", molded around the periphery. In another type, described as "window-lacing" the gasket is produced separately and is then either attached to the panel or placed within the vehicle window mounting channel prior to installing the window. In both types the gasket provides a seal for the window. Other examples of squeak resistant articles of this invention are in sealing joints between flanges, such as gaskets for engines, for lines which carry gases or liquids, pumps, reaction vessels and the like, engine drive belts, seal caps or boots for lubricated joints, wear pads, wire harness connectors and spark plug caps, windshield wiper blades, bumper suspensions, oriented bumpers, gears, window hardware components, luggage straps and buckles, conveyer line sections, constructional engineering and architectural applications, gears and bearings, footwear (particularly footwear for athletic purposes), parts for domestic and commercial appliances, and the like. The squeak resistant articles of this invention are suitable in applications where some flexibility, and the maintenance of a high level of performance when exposed to adverse conditions over extended periods, are desirable. They meet these requirements when they are used as sealing elements or as items for aesthetic or functional purposes. The recent trend towards using harder polymers was prompted by deficiencies inherent in softer polymers known to the prior art. The softer polymers do not provide as good or as durable a seal when used as gaskets because they tend to develop shape deformities on prolonged exposure to adverse conditions. Such deformities may also evidence themselves as unsightly bulges and irregularities which is undesirable in accessories intended to have aesthetic appeal, such as window hardware and articles used in architectural applications. The harder materials currently used largely overcome these problems. However there is a need for improvement in applications where components are subjected to shifts, torques or vibrations, such as in a vehicle, travelling on bumpy road surfaces or when changing speed. Both hard and soft polymer materials can give rise to undesirable noises, such as squeaks. To some extent this can be overcome by using elastomeric surface coatings. By way of illustration, weatherstrip made from reaction injection molded (RIM) polyurethane was tested on squeak generating and measuring equipment. At the highest level of displacement the sound pressure level was found to be about 74 decibels. Samples of the weather-strip were surface coated with a perfluoroalkylpolyether (Krytox®) and subjected to the same testing. The sound pressure level decreased to less than 50 decibels corresponding to a significant reduction in squeak. It is desirable to decrease squeak still further and preferably to eliminate such noise completely. Surface coatings are lacking in durability so that squeaking tends to increase over the life of the treated article. A great advantage of the squeak resistant articles of the invention derives from compounding the fluorocarbon material and polymer components prior to fabrication of the desired shape. Migration of the fluorocarbon towards the surface of the article occurs during the fabrication step so that the concentration of fluorocarbon is much greater at the surface than the nominal bulk concentration. The high concentration of fluorocarbon additive near the surface gives rise to fluorocarbon-like surface properties such as, lower friction, hydrophobicity, chemical inertness and non-adherent surfaces. These properties are often beneficial and in particular the degree to which squeaking occurs can be considerably less than is achieved by surface coating and it can be virtually eliminated in many situations. An important additional benefit which derives from mixing the fluorocarbon component with the polymer and other additives prior to or during fabrication is the greater longevity of performance compared with that obtained with post applied surface coatings. Polymer Resin Thermoplastic or thermosetting polymer resins or mixtures of the two types of polymer resin can be used in the compositions from which the squeak resistant articles of the invention are made. Thermoplastic polymer resins are those resins that are softened by heat, even in the finished product. Thermosetting polymer resins are converted to infusible material during the fabrication process and thus the finished product is no longer susceptible to molten reprocessing without severe loss of desired properties. Both hard and soft categories of these polymer resins are useful to make compositions suitable for fabricating the squeak resistant articles of this invention. In general hard polymer resins can be classified as having a Rockwell R scale hardness in the range of from about 50 to about 115, as measured by ASTM method D-785-89. Soft polymer resins are those having a Durometer Shore A scale hardness in the range of from about 10 to about 90, as measured by ASTM method D-2240-91. There is some degree of overlap between the top of the range on the Shore D scale and the bottom of the range on the Rockwell R scale. Although measured Shore D scale hardness values above 90 and Rockwell R scale hardness values above 115 are not thought to be reliable, polymers having such hardness values are within the purview of this invention. A polymer resin having a hardness which lies within both the designated ranges can also be used in compositions from which the squeak resistant articles of the invention are made. The polymer resins are used in the form of molding granules or powders and are mixed with fluorocarbons and other compounding additives prior to or during the fabrication step. Thermoplastic hard and soft polymer resins suitable for making the squeak resistant articles of the present invention include, but are not necessarily limited to: acrylonitrile-butadiene-styrene(AB S), acrylonitrile-chlorinated polyethylene- styrene (ACS), acrylic-styrene-acrylonitrile (ASA), polyacetal homopolymers and copolymers, acrylics, cellulosics, fluoropolymers, polyamides, polyacrylates, polybutylene, polycarbonates, polyesters, polyethylenes, ethylene acid copolymers, ethylene-ethyl acrylates, ethylene-methyl acrylates, polymethyl acrylate, polymethyl methacrylate, polybutyl methacrylate, ethylene-vinyl acetates, ethylene vinyl alcohol copolymers, ionomers, polymethylpentene, polyphenylene oxides, polypropylene, ethylene-propylene copolymers, polypropylene impact copolymers, polypropylene random copolymers, polystyrenes, styrene-acrylonitrile (SAN), styrene-butadiene copolymers, styrene-ethylene/butylene-styrene, styrene-maleic anhydride copolymers, polyvinyl chloride, chlorinated polyvinyl chloride (PVC), vinylidene chloride homopolymers and copolymers, thermoplastic elastomers such as styrenic block copolymers, polyolefin blends, elastomeric alloys, thermoplastic urethanes, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), thermoplastic copolyesters, polyethers, thermoplastic polyamides and polyether- polyamide block copolymers. Thermoplastic random, block or graft copolymers are suitable for making squeak resistant articles of this invention. Blends and alloys of two or more thermoplastic polymers are suitable for making squeak resistant articles of this invention. Thermosetting hard and soft polymer resins which are also suitable for making the squeak resistant articles of the present invention, include, but are not necessarily limited to: allyl molding compounds, bis-maleimides, epoxy resins, phenolic resins, polyesters, ethylene-propylene diene terpolymers (e.g., EPDM rubber), polyimides, ionomers (e.g., Surlyn®), polyurethanes, segmented polyurea/urethanes, reaction injection molded (RIM) polyurethanes, silicones, and urea-melamine formaldehyde resins. Thermosetting resins are also meant to include thermoplastic resins which have been cross-linked to a high enough degree such that molten reprocessing is no longer possible without severe loss of desirable properties. Mixtures of thermoplastic and thermosetting polymers, such as EPDM rubber "alloys" with polypropylene (Santoprene®) and with PVC (Alcryn®) are also suitable for making the squeak resistant articles of this invention. Articles comprising foamed polymer-fluorocarbon compositions are also within the purview of this invention. Based on the best balance of desirable properties, availability ease of processing and cost the preferred soft thermoplastic polymers are PVC, RIM polyurethanes, EPDM rubbers and their "alloys" with polypropylene (Santoprene®) and with PVC, (Alcryn®). In the hard thermosetting polymers category the most preferred are polyacetals, polyesters, polyamides, ionomers, (e.g. Surlyn®). Articles comprising foamed polymer-fluorocarbon compositions are also within the purview of this invention. Articles fabricated from the foregoing polymer resins prove to be essentially free from squeaks and other undesirable noises when used in a wide variety of applications. Additives for Polymer Resin The polymer resins used for the squeak resistant articles of this invention usually also contain one or more conventional resin compounding ingredients, such as but not necessarily limited to: organic or inorganic fillers, reinforcing agents, colorants, thermal stabilizers, antioxidants, antiozonants, antistatic agents, antimicrobial agents, plasticizers, lubricants, antifogging agents, coupling agents, flame retardants, foaming agents, fragrances, heat stabilizers, impact modifiers, mold release agents, titanates, ultraviolet stabilizers, thermally conductive fillers, electrically conductive fillers, curing agents, cross-linking agents, catalysts, and the like. Fluorocarbon Additive Suitable fluorocarbon additives are oils, gums, or greases comprising fluorinated hydrocarbons or fluorinated hydrocarbonpolyethers having six or more carbon atoms, including linear, branched and cyclic compounds. Examples of suitable compositions are perfluoroalkylpolyethers, (Krytox®, Fomblin®, Demnum® and Aflunox®), perfluoropolyethylene oxide, perfluoropolypropylene oxide, polytetrafluoroethylene (Teflon®) perfluoropolyethylene-polypropylene, perfluoropolybutadiene, polyvinylidene fluoride, perfluorocarbons and fluorohydrocarbons including ethers containing functional group(s) such as but not limited to alcohols, amines, amides, esters, nitriles, thiols, acids, acid halides, chlorine, bromine and iodine. Higher molecular weight homologous linear and branched fluorohydrocarbons and fluorinated cyclic hydrocarbons also may be used, as well as partially fluorinated additives, such as those more than 50% fluorinated, preferably more than 75% fluorinated. For example, polychlorotrifluoroethylenes, polytetrafluoroexetanes, or other highly fluorinated compounds may be selected. Fluorocarbon or mixed fluorocarbon additives which are compounded with a polymer resin preferably have a surface energy substantially lower than that of the polymers. This leads to migration of the fluorocarbon to the surface of the wear resistant article during the fabrication process. Generally it is preferred that a fluorocarbon have a surface energy at least 5 dynes/cm lower than the surface energy of the polymer with which it is compounded. The amount of fluorocarbon which can be compounded with a polymeric material is in the range of about 0.01% to 5%>, typically from about 0.1% to 1% on a weight basis. The beneficial effects of the fluorocarbon additive are evident at the lowest end of the range, due to the concentration at the surface being much higher than the nominal bulk concentration. At bulk loading levels of 1% and 10% the concentration of fluorocarbon in a surface layer lOnm thick is respectively between about 88% to about 99%>. It is preferred that at least 0.1% of fluorocarbon be used in many of the shaped articles of the invention in order to obtain a desirable level of performance in most applications. The optimum amount of fluorocarbon additive will vary with the selected polymer, processing conditions, and intended use, and is readily determined by routine experimentation. Surface Concentration of Fluorocarbon Additive The relationship between the surface concentration and the nominal bulk loading of fluorocarbon additive in a polymer has been ascertained by determining the former by conducting the ESCA analytical procedure on test specimens, "poker chips", molded from polyvinyl chloride compounded with different levels of perfluoroalkylpolyether oil, (Krytox®). This procedure, which quantitatively analyses the atomic concentration of elements in a surface layer about 5 to 10 nanometers (nm) thick, was calibrated by applying a film of Krytox® oil to a glass slide and determining the level of fluorine in the film. This amount of fluorine, about 65wt% corresponds to 100%) coverage, with Krytox® oil. By determining the fluorine level in the surface layer of a PVC "poker chip" the level of Krytox® oil in the surface layer is ascertained. The data given in Table 1 are from a series of samples in which the Krytox® additive ranged from 0.1 to 1.0wt%. The level of Krytox® is clearly much higher in the surface layer than in the bulk of the sample. The degree to which fluorocarbon surface enrichment occurs depends upon the particular polymer and fluorocarbon components of a composition and the procedure used to mix them and fabricate an article of this invention. Table 1 84A Durometer Grade PVC Compounding the Polymer Resin Fluorocarbon Composition At some point during fabrication, the polymer-fluorocarbon composition must be processed as a liquid. The fluorocarbon is completely or to a large degree immiscible with the polymer and other components. Sufficient mixing must be provided to disperse the fluorocarbon throughout the polymer-fluorocarbon composition. The fluorocarbon wets the processing equipment surfaces because of its low surface tension. Processing a polymer-fluorocarbon composition from the liquid state to a solid article includes an essentially non-turbulent (i.e., not well mixed) flow field and adequate quench time to allow the fluorocarbon enriched surface layer to develop. Antithetically, if the liquid state were in a highly turbulent (i.e., well mixed) flow field and instantaneously quenched to the solid state considerably less fluorocarbon surface enrichment would occur. In order to maximize the fluorocarbon surface enrichment when the polymer-fluorocarbon composition contains other additives which remain as solids when the polymer-fluorocarbon composition is being processed as a liquid, these solid ingredients should be wetted with molten polymer or molten composition ingredients other than the fluorocarbon prior to addition of the fluorocarbon. Otherwise, the fluorocarbon having a very low surface tension would wet the solid additive surfaces resulting in decreased fluorocarbon surface enrichment for the polymer-fluorocarbon phase. Polymer-fluorocarbon compositions wherein the polymer is a thermoplastic involve melting the thermoplastic polymer in order to mix with the fluorocarbon as a liquid. The molten thermoplastic polymer-fluorocarbon composition is mixed to disperse the fluorocarbon throughout the thermoplastic polymer-fluorocarbon composition. The molten thermoplastic polymer-fluorocarbon is then solidified by freezing, and when this constitutes the final article a low shear flow regime and adequate quench time is needed to allow fluorocarbon surface enrichment to occur. Some of the possible, yet not meant to be all inclusive, processing methods for incorporating fluorocarbon into a thermoplastic polymer-fluorocarbon composition are: 1) dry mixing a polymer powder, a plasticizer, and other additives so as to wet the ingredients which remain solid during molten processing, adding the fluorocarbon last to the dry blend, and feeding to the molten mixing device; 2) dry blending all ingredients except the fluorocarbon, using this dry blend to feed the molten mixing device, and liquid injecting the fluorocarbon into the molten mixing device; 3) compounding the polymer and additives without the fluorocarbon and feeding the compounded polymer to a molten mixing device with liquid injection of the fluorocarbon into the molten mixing device. Liquid injection of the fluorocarbon into the molten mixing device is the preferred manner of adding the fluorocarbon to the polymer-fluorocarbon composition. Some examples of molten mixing devices which could be used to mix the thermoplastic polymer-fluorocarbon compositions are continuous mixers, extruders, kneaders and injection molding machines. Thermosetting polymer-fluorocarbon compositions can be made via two different routes. 1) Involves molten processing of additives and fluorocarbon with an already formed polymer with simultaneous or subsequent curing (i.e., cross-linking) to affect its thermoset character. 2) Involves contacting monomer, additives and fluorocarbon to form the thermo-setting polymer directly. In either case, it is unlikely that the fluorocarbon will interfere with polymerization or curing reactions. In the case where molten processing of the thermosetting polymer-fluorocarbon occurs, some of the possible (but not inclusive) processing methods are: 1) dry mixing a polymer powder, a plasticizer, and other additives so as to wet the ingredients which remain solid during the molten processing, adding the fluorocarbon last to the dry blend, and feeding to a molten mixing device; 2) dry blending all the ingredients except the fluorocarbon, using the dry blend to feed the molten mixing device, and liquid injecting the fluorocarbon into a molten mixing device; 3) compounding the polymer and additives without the fluorocarbon and feeding the compounded polymer to a molten mixing device with liquid injection of the fluorocarbon into a molten mixing device. Liquid injection of the fluorocarbon into a molten mixing device is the preferred manner of adding fluorocarbon to the polymer composition. Some examples of molten mixing devices which can be used to mix the polymer- fluorocarbon composition are continuos mixers, extruders, kneaders and injection molding. In the case of a thermosetting polymer-fluorocarbon composition when the polymer is directly formed from reactants, the fluorocarbon will need to be well mixed in the reactants as they contact each other, and will form the enriched surface layer as the thermoset polymerization occurs. Fabrication of a Squeak Resistant Article Polymer-fluorocarbon articles, the concentration of said fluorocarbon being 0.01-5.0 percent by weight can be formed by a number of conventional fabrication processes. The fabrication process will usually be determined by cost effectiveness, for example the elimination of topical application labor costs, and/or the need to fit existing process equipment. In turn, the fabrication process used to make the polymer-fluorocarbon article will determine the nature of the polymer and fluorocarbon feedstocks to the process. If the fabrication process involves little or no mixing, e.g., compression molding, then a pre-compounded polymer-fluorocarbon composition would best serve as the feedstock. However, if the fabrication process employs a molten mixing device with sufficient mixing, the process feeds could be a post- compounded polymer-fluorocarbon composition, polymer with fluorocarbon liquid injection, or blends of polymer and a pre-compounded polymer-fluorocarbon composition. If the polymer-fluorocarbon article is comprised of a polymer foam, then the maximum outer surface enrichment by the fluorocarbon will be obtained if the fluorocarbon surface enrichment largely occurs prior to the foam expansion and freezing step. Conversely, if the foamed polymer-fluorocarbon composition is processed molten as an expanded foam the fluorocarbon, due to its low surface tension, would enrich the surfaces of the interior foam cells decreasing enrichment of the outer surface of the article. Some examples of polymer-fluorocarbon article fabrication processes include, but are not limited to: extrusion, injection molding, injection blow molding, extrusion blow molding, calendaring, pultrusion, reactive injection molding, and reactive extrusion. Migration of the fluorocarbon towards the surface of the article also occurs during the fabrication step so that the concentration of fluorocarbon is much greater at the surface than the nominal bulk concentration. The high concentration of fluorocarbon additive near the surface gives rise to fluorocarbon-like surface properties such as, lower friction, hydrophobicity, chemical inertness and non- adherent surfaces. These properties result in performance improvements such as decreased wear and noise reduction. An important additional benefit which derives from mixing the fluorocarbon component with polymer and other additives prior to or during fabrication is the greater longevity of performance compared with that obtained with post applied surface coatings. Some examples of shaped articles that can be fabricated include, but are not limited to; fibers, rods, films, sheets, profiles and intricately shaped parts. These shaped articles may have utility as, for example, watercraft hulls, polymer ropes and cables, resin-coated fabric, drawer glides, screw cap jar gaskets, o-rings, book covers and dust jackets, reinforced resin wall coverings, resin cable sheaths and conduits, etc.

Claims: WHAT IS CLAIMED IS: 1. A squeak resistant article comprising a polymer and a fluorocarbon additive having a nominal bulk concentration in the range of from 0.01% to 5% > by weight based on the polymer, said fluorocarbon additive having a lower surface energy than that of said polymer. 2. The article of claim 1 wherein the concentration of said fluorocarbon additive is higher at the surface of said article than the nominal bulk concentration. 3. The article of claim 2 wherein said fluorocarbon additive has a surface energy at least 5 dynes/cm lower than the surface energy of said polymer. 4. The article of claim 3 wherein said fluorocarbon additive has a nominal bulk concentration in the range of 0.1% to 1.0% by weight based on the polymer, the concentration of said fluorocarbon in an outer layer of said article having a thickness of 10 nanometers being between about 35% and about 88%. 5. The article of claim 2 wherein said fluorocarbon additive has a nominal bulk concentration in the range of 0.1% to 1.0% by weight based on the polymer, the concentration of said fluorocarbon in an outer layer of said article having a thickness of 10 nanometers being between about 35% and about 88%. 6. An article of claim 4 or 5 wherein the polymer is a thermoplastic resin. 7. An article of claim 4 or 5 wherein the polymer is a thermosetting resin. 8. An article of claim 4 or 5 wherein the polymer is a polyvinyl resin. 9. An article of claim 4 or 5 wherein the polymer is a polyurethane resin. 10. The article of claim 1, 2, 3, 4 or 5 in the form of a gasket. 11. The article of claim 1, 2, 3, 4 or 5 in the form of a blade. 12. The article of claim 1, 2, 3, 4 or 5 in the form of a footwear sole.

Inventors: DU PONT BENJAMIN F, DUCH MICHAEL WILLIAM, KOSINSKI LEONARD EDWARD RAYMON, DU PONT, BENJAMIN, F., DUCH, MICHAEL, WILLIAM, KOSINSKI, LEONARD, EDWARD, RAYMOND
Applicants: DU PONT, E.I. DU PONT DE NEMOURS AND COMPANY
Application year: 1998
Main classification: C08K5
IPC codes: C08K5, C08L101