Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/62—Record carriers characterised by the selection of the material
  • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
  • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
  • G11B5/71—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the lubricant
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C11/00—Auxiliary processes in photography
  • G03C11/06—Smoothing; Renovating; Roughening; Matting; Cleaning; Lubricating; Flame-retardant treatments
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
  • G11B23/50—Reconditioning of record carriers; Cleaning of record carriers ; Carrying-off electrostatic charges
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B3/00—Recording by mechanical cutting, deforming or pressing, e.g. of grooves or pits; Reproducing by mechanical sensing; Record carriers therefor
  • G11B3/58—Cleaning record carriers or styli, e.g. removing shavings or dust or electrostatic charges
  • G11B3/589—Cleaning record carriers or styli, e.g. removing shavings or dust or electrostatic charges before or after transducing operation
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
  • C10M2211/02—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen and halogen only
  • C10M2211/022—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen and halogen only aliphatic
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
  • C10M2211/04—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen, halogen, and oxygen
  • C10M2211/044—Acids; Salts or esters thereof
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
  • C10M2211/06—Perfluorinated compounds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/30—Refrigerators lubricants or compressors lubricants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/32—Wires, ropes or cables lubricants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/34—Lubricating-sealants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/36—Release agents or mold release agents
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/38—Conveyors or chain belts
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/40—Generators or electric motors in oil or gas winning field
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/42—Flashing oils or marking oils
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/44—Super vacuum or supercritical use
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/50—Medical uses
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/90—Magnetic feature
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
  • Y10T428/31544—Addition polymer is perhalogenated

Definitions

• the present invention relates to compositions of lubricants for use on moving solid surfaces. More specifically, it relates to halogen containing lubricant compositions. It also relates to solutions containing such compositions, applicators for applying such compositions, methods of utilizing, said compositions and to the articles produced by the use of said compositions.
• each of these media is difficult to protect from destructive wear.
• These media are generally relatively soft by comparison with the drive and transducer systems with which they are utilized. Therefore, in order to be utilized effectively, while avoiding destruction, they must be provided with a lotf coefficient of friction with respect to the environment through which they pass.
• they are also provided with a protective wear coating, which coating has a lowcoefficient of friction. In this manner, the coating provides both a low coefficient of friction and a sacrificial surface which can be worn while leaving the actual media intact.
• the present invention consists of compositions including fluorinated alkyl esters, which provide a low coefficient of friction coating for the surface of an article. These compositions are useful for cleaning and lowering the coefficient of friction of the surface of various articles. In certain preferred embodiments tetrafluoroethylene telomers and/or antistatic materials are included in the compositions. Fluorinated alkyl esters are normally provided for use only as surfactants.
• an object of the present invention is to provide a composition which, when applied to a surface, cleans the surface and lowers its coefficient of friction.
• a further object of the present invention is to provide an improved, thin coating for substrates having data stored.thereon and which are subjected to relative mechanical motion when used.
• fluorinated alkyl ester containing compositions are provided which are capable of being coated on the surface of an article to provide abrasion resistance, a low friction surface, and which coating is capable of carrying high loads that would normally damage a surface.
• the compositions are also characterized by low surface tension so that they easily wet and adhere to surfaces of almost any material, without regard to the degree .of cleanliness of those surfaces.
• the compositions consist of a mixture including relatively high molecular weight, normally solid, fluorinated alkyl esters which provide a hard, wear resistant matrix coating.
• fluorinated alkyl esters can serve as a useful coating matrix in these compositions, as these materials are normally provided for use as surfactants.
• the particular fluorinated alkyl esters preferred in this application are known as Fluorad fluorochemical surfactants, a tradernarked product of 3M Company. More specifically, the fluorinated alkyl ester Fluorad surfactants designated as FC-430, FC-431, and FC-432 have been found to be useful as matrix binders in thepractice of the present invention.
• These compositions include a chemical structure including a fluorinated alkyl hydrophobic tail terminating in a hydrophilic ester group. These materials are reported to have a structure:
• R(CF 2 ) n COOR 1 wherein R is H, CF 3 or an alkyl compound, R 1 is a short chain alkyl compound, and n is equal to a positive integer such that the molecular weight of the compound is equal to or greater than 300.
• FC-432 has a higher molecular weight than FC-431, which in turn has a higher molecular weight than FC-430. Mixtures of these fluorinated alkyl esters can also be utilized in the compositions of the present invention.
• the fluorinated alkyl esters When utilized as coating compositions, the fluorinated alkyl esters provide a thermoplastic coating. As used herein, the term thermoplastic is intended in its normally understood sense. Fluorinated alkyl esters are provided by any number of techniques. In one method of production, a fluorinated alkyl acid is reacted with an organic alcohol to produce the desired ester. In another technique, a fluorinated alkyl of the desired chain length, is reacted so that its termination includes either an alcohol or an acid group. It is then subsequently reacted with an organic alcohol or acid, as the case may be, to produce the desired ester.
• Tetrafluorethylene telomers useful .in the practice of certain preferred embodiments of the present invention are available from a number of sources, for example, under the tradename VYDAX AR, a trademarksd product of E. I. du Pont de Nemours & Company.
• the material has an average molecular weight of about 3,700 and melts at about 300°C. Additional data on suitable tetrofluoroethylene telomers may be found in U.S. Patent 3,067,362.
• the present invention is not limited to the specific commercial compositions exemplified herein. In some instances, it may be desirable to purify the commercial chemicals used in the practice of the present invention.
• solvents useful in this purifying step include trichlorotrifluoroethane although any number of other solvents are useful for this purpose, including halogenated aliphatic hydrocarbons.
• the molecular weights of the tetrafluoroethylene telomers utilized in the present invention do not appear to be critical.
• the fluorinated alkyl esters should be chosen to provide character sites, such as molecular weight greater than about 300, such that they will normally be solid under ambient conditions.
• antistatic agents can be included in the coating. This is an especially useful additive where information carrying media is to be coated and static build-up on the media could encourage accumulations of dirt and dust which would be detrimental to their operation and wear. Any compatible coimiercial antistatic agent can be utilized for this purpose.
• Orewplast 017, a.tradenamed product of PVO International, Inc., an ester having the following structural formula is useful for this purpose:
• R is H, or an organic radical containing 6 or less carbon atoms.
• Another useful, but chemically unrelated antistatic agent, which may be incorporated in the composition is Sandin PU, a product of Sandoz Color and Chemical Company.
• Sandin PU is an amine.
• compositions of the present invention are applied to substrates such as phonograph records, magnetic recording media, and photographic film in any number of ways.
• substrates such as phonograph records, magnetic recording media, and photographic film
• the composition is applied to an applicator substrate and allowed to dry.
• the composition is then applied to the to-be-coated substrate by wiping the surface with the composition containing applicator.
• the composition is applied to the substrate as a solution in a solution in a suitable solvent and the solvent is allowed to evaporate.
• This solution application is preferably accomplished by means of a spray, either from a pump mechanism, or a self-contained aerosol container.
• other means of solution coating may be utilized as desired. These include brushing, flowcoating, dipping, doctoring and other well known techniques.
• the media substrates to-be-coated will normally be of plastic or polymeric solid materials, other solid materials such as wood, metal, glass, paper, and leather may be treated with the compositions of the present invention to lower their coefficients of friction .and improve their wear characteristics.
• dry buffing the coating, after it is applied, may improve the uniformity and distribution of the coating.
• dry buffing is optional and is normally a matter of choice.
• the thickness of the coating provided by the compositions of the present invention are not critical, there are preferred thicknesses, some of which may be important based upon the use to which the coating composition is placed. For example, a coating thickness of a minimum of about 0.025 micron (1 microinch) will provide a minimum thickness coating which can be relied upon to provide useful results. Coating thicknesses in the range of about 0.07 to about 0.90 micron (about 3 to 36 microinches) are effective to lubricate and protect media such as phonograph records, magnetic media and photographic film. Coating thicknesses of about 0.12 to about 0.50 micron (about 5 to 20 microinches) have beenfound to be especially effective for photograph records to supply good wear protection without causing distortion or signal loss.
• compositions of the present invention may vary somawhat, but should be such that it either lowers the coefficient of friction or improves the wear of the article upon which it is coated.
• the esters may effectively constitute from about 2% to about 95% of the composition while the telomers may constitute from about 5% to about 98% of the composition.
• One preferred composition includes about 5% fluorinated alkyl esters and about 95% tetrafluoroethyene telomers. Where compositions of fluorinated alkyl esters and antistatic agents are utilized in combination, the esters may effectively constitute from about 15% to about 85% of the composition while the antistatic agent may also constitute from about 15% to about 85% of the composition.
• One preferred composition includes about 25% fluorinated alkyl esters and about 75% antistatic agents. Where the compositions include fluorinated alkyl esters, tetrafluoroethylene telomers and antistatic agents, then the composition may constitute from about 1% to about 98% esters, from about 1% to about 85% telomers and from about 1% to about 60% antistatic agent.
• compositions of this invention include about 5% fluorinated alkyl esters and about 48% tetrafluoroethylene telomers and about 7% amine antistatic agents.
• percent (%) or “parts” means “by weight”.
• the compositions of this invention may also contain other ingredients such as conventional fillers, coloring agents, fragrances, and the like so long as the quantity thereof does not prevent the composition from adhering to the surface of the substrate and does not destroy the lubricating character of the coating.
• compositions of the present invention are dissolved in suitable solvents and applied as a solution.
• suitable sol- vents for this purpose are, for example: fluorinated hydrocarbons; chlorinated hydrocarbons such as ethylene chloride, trichloroethane, methylene chloride, chloroform, carbon tetrachloride and perchloroethane; aromatic hydrocarbons such as benzene, toluene and heptane; and chlorofluorocarbons such as trichlorotrifluoroethane.
• the compositions are slightly soluble in water, alcohols, acetates and ketones. The choice of solvents and the relative concentration of the composition depends on the use to which the solution is to be placed.
• dilute solutions in the range of about at least 0.01 to about 0.10% solids, by weight, are useful. Specifically, for spray coating phonograph records, solutions of about 0.08% solids, by weight, are preferred. Seldom would any use require a solution containing more than about 5% solids, by weight.
• the compositions of the present invention are transparent and colorless and can be utilized to coat photographic film without any deleterious effects.
• a lubricating composition according to the present invention was prepared containing 25% fluorinated alkyl esters and about 75% purified tetrafluoroethylene telomer. This composition was dissolved in trichlorotrifluoroethane solvent to provide a 2% solution. The solution was sprayed on a magnetic disk and tested for durability of the coating. Testing was by means of the well known pin and disk technique wherein a one-quarter inch diameter ceramic ball, loaded with 80 grams, is placed on a disk rotated at 60 revolutions per minute. The composition so appl ied supported the load for 840 cycles of the disk.
• the wear resistance of the composition is seen to be approximately 40% greater than that of tetrafluoroethylene telomers by themselves.
• EXAMPLE II It has been determined that utilizing a composition of fluorinated alkyl esters with the addition of materials such as antistatic agents, can greatly lower the coefficient friction of both the ester and the antistatic agent and provide a useful lubricant and wear resistant coating composition.
• a composition containing 5.6 grams of purified fluorinated alkyl ester and 6.0 grams of a conventional amine antistatic agent such as Sandin PU was dissolved in trichlorofluoroethane to provide a 0.12% solution, then applied, by spraying, to the sub- strates listed below and the coefficient of friction measured by the incline plane method as described in SMPTE Journal, Vol. 80, Sept. 1971, pp. 734-739.
• solutions containing only the fluorinated alkyl ester and only the antistatic agent were also prepared, applied in the same manner, and tested for friction.
• a coating containing 50% fluorinated alkyl ester and 50% antistatic agent was applied to a phonograph record, and the phonograph record was rubbed with wool four times. No static charge could be induced on the surface of the phonograph record. When the untreated opposite side of the same phonograph record was rubbed with wool four times a static charge was induced, which charge was still present when tested for, after 30 minutes.
• a composition containing approximately 5% fl uorinated al kyl esters , 53% purified tetrafl uoroethylene tel omers and 42% amine anti static agent was dissolved in trichl orotrifi uoroethane to form an 0.08% sol ution.
• the resulting solution was util ized to cl ean and coat phonograph records . It was found to efficiently and effectively cl ean the reocrd and provide it with an antistatic coating. It al so el imi nated or reduced record wear. It was found to not fil l the grooves of the record surface .
• composition of the foregoing example was applied to a substrate to form an applicator and allowed to dry.
• applicator was rubbed on a phonograph record, it was found to duplicate the results achieved by the solution of Example IV.
• the use of dry applicators may be environmentally important as there is growing concern as to the effect which chloro-fluorocarbon solutions have upon the atmosphere and the earth's ozone layer.
• the present invention provides compositions which are useful in improving wear and lowering the coefficient of friction.
• the combination of fluorinated alkyl esters with other ingredients, including tetrafluoroethylene telomers and antistatic ingredients provides coatings which have coefficients of friction lower than the coefficients of friction of the original article or of the individual components. Further, methods of coating materials to improve their wear characteristics and to lower their coefficients of friction have been shown. Applicators containing the compositions have been taught. Articles coated with the compositions of the present invention have improved wear characteristics and lower coefficients of friction.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Lubricants (AREA)
• Paints Or Removers (AREA)

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Publications (1)

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Family Applications (1)

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Cited By (2)

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Citations (7)

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• 1977
  • 1977-07-29 US US05/820,351 patent/US4213870A/en not_active Expired - Lifetime
• 1978
  • 1978-07-27 JP JP9096178A patent/JPS5445456A/ja active Granted
  • 1978-07-28 CA CA308,316A patent/CA1105441A/en not_active Expired
  • 1978-07-28 GB GB8026742A patent/GB2058831B/en not_active Expired
  • 1978-07-28 WO PCT/US1978/000052 patent/WO1979000075A1/en not_active Ceased
  • 1978-07-28 DE DE19782857719 patent/DE2857719A1/de not_active Withdrawn
• 1979
  • 1979-02-27 EP EP78900067A patent/EP0008598A1/en not_active Withdrawn

Patent Citations (7)

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