Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing silicon
Reexamination Certificate
2000-12-20
2003-01-21
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic compound containing silicon
C508S485000, C508S579000, C508S583000, C198S500000
Reexamination Certificate
active
06509302
ABSTRACT:
BACKGROUND OF THE INVENTION
In commercial container filling or packaging operations, containers are moved by a conveyor or a conveying system at high rates of speed, up to 1000 containers per minute or more. In current bottling operations, copious amounts of lubricant solutions in dilute aqueous form (usually based on ethoxylated amines or fatty acid amines) are typically applied to the conveyor or containers using spray, fountain or other pumping equipment. Some aqueous conveyor lubricants are not compatible with thermoplastic beverage containers made of polyethylene terephthalate (PET) and other plastics. Conventional lubricants typically require use of large amounts of diluent water on the conveying line, which must then be disposed of or recycled, causing a wet environment.
The containers are filled with foods, water, carbonated or non-carbonated beverage in a filling apparatus that involves a moving conveyor surface that transports the container during filling. The conveyor structure comprises a filling or packing station, a capping station and often ends at a station for labeling or final storage. Initially such conveyor systems were lubricated using large amounts of lubricant diluted with large amounts of water. Representative examples of such aqueous conveyor lubricant compositions applied to conveyors are found in Stanton et al., U.S. Pat. No. 4,274,973 and Stanton, U.S. Pat. No. 4,604,220. A series of allegedly stress crack inhibiting substantially soluble aqueous lubricants were introduced including Rossio et al., U.S. Pat. Nos. 4,929,375 and 5,073,280; and Wieder et al., U.S. Pat. No. 5,009,801. These patents assert that certain substituted aromatic compounds, certain couplers and saponifying agents and certain amine compounds can inhibit stress cracking in appropriately formulated materials.
In large part the compositions used in these conventional systems are either clear solutions or suspensions (macroemulsions) of sparingly soluble materials in water. Many conventional systems are clear solutions of neutralized fatty acids in an aqueous base or solutions of soluble ethoxylated amines in an aqueous medium. However, conventional silicone emulsions are either opaque or translucent depending on concentration. Conventional silicone emulsions are macroemulsions of sparingly soluble or insoluble materials dispersed in an aqueous medium.
A substantial need exists for improved methods lubricating common container materials in any environment. Lubricant composition should provide an acceptable level of lubricity for the system. The lubricant preferably has a viscosity which allows it to be applied by conventional pumping and/or application apparatus, such as by spraying, roll coating, wet bed coating, and the like, commonly used in the industry.
We have found that current methods of lubricating such containers are wasteful of the lubricant material since a substantial proportion of the materials is lost as it leaves the container surface. Further, substantial proportions of the lubricant remain on the container as a foam and are carried from the conveyor as the food packaging or beverage-bottling operations are continued. Many available lubricant materials that have sparingly soluble or insoluble lubricant materials in an aqueous medium can separate and form a separate phase which, under certain circumstances, can be incompatible with operating systems. Such materials can plug lines, pumps and nozzles. Further, such lubricant materials often are not preferred by operating personnel for use in lubricating lines because of their hazy, translucent appearance or lack of clarity.
BRIEF DESCRIPTION OF THE INVENTION
We have found that the properties of lubricants can be substantially improved if a substantially clear or transparent lubricant is formulated such that two separate, mutually insoluble hydrophilic and oleophilic phases are used in a formulation such that one phase is dispersed in another phase. The dispersion form is a thermodynamically stable composition. Preferred compositions are considered to be in the form of a microemulsion. The composition can be a oleophilic phase dispersed in a hydrophilic phase or a hydrophilic phase dispersed in an oleophilic phase. A preferred product format involves dispersing oleophilic materials into a hydrophilic phase. The oleophilic material can be common oils including natural oils, petroleum derived oils, silicone oils, or other oily or oleophilic material that can be dispersed in aqueous phase. The hydrophilic phase can comprise water, an aqueous solution or a water soluble, water miscible or aqueous compatible composition.
A microemulsion is a thermodynamically stable dispersion of one liquid phase in another phase, each phases being substantially insoluble in the other. An interfacial film of surfactant typically stabilizes a microemulsion. The microemulsion may be in the form of either an oil-in-water or water-in-oil composition. In oil-in-water forms, the oil is dispersed as very small droplets in continuous water or aqueous phase. In a water-in-oil microemulsion, water droplets are dispersed into an oil continuous phase. Microemulsions, different than a typical, opaque or translucent suspension, emulsion or macroemulsion, are typically clear compositions. The clarity of the solution results from the droplet size which is typically smaller than the smallest wavelength of a visible light radiation (about 350 nm). Since the particle size is smaller than light wavelengths, it is believed that the light is not scattered by the small droplets resulting in transparent solutions. The interfacial tension between the two phases are relatively low, adding to the thermodynamic stability of the microemulsion particles in the continuous phase. In substantial contrast to a microemulsion, a dispersion, emulsion (or macroemulsion) is an unstable suspension of droplets in a continuous phase. Such droplets will typically agglomerate, coalesce and, at some point, can separate from the continuous phase. In macroemulsions, the droplet sizes are much larger, typically 1 micron or more resulting in a cloudy or milky dispersion. The clear lubricants of the invention which we believe is a microemulsion may be applied to the conveyor without dilution or with a relatively modest dilution, e.g. at a water:lubricant ratio of less than 10:1 in a thin coating of lubricant formed by applying relatively small amounts of lubricant onto the moving container bearing surface of the conveyor. Alternatively, the microemulsion compositions of the invention can be diluted with water to form a dilution of the lubricant in water at a ratio of about 1:100 to about 1:500 parts of lubricant per parts of aqueous diluent and applied to conveyor surface. The continuous phase medium can comprise either an aqueous, hydrophilic or aqueous solution or composition or aqueous medium or a oleophilic, non-aqueous composition or oleophilic medium. Such materials can be applied in limited amounts directly onto a conveyor surface and can provide adequate lubricating properties at the container conveyor interface. Lubricants of the invention can comprise a transparent dispersion of an oleophilic, typically a silicone fluid, natural oil, a petroleum oil or other oleophilic materials in a hydrophilic phase such that the oil or oleophilic material has a reduced particle size of less than 300 nm, preferably less than 100 nm in the continuous hydrophilic phase. Alternatively, the dispersion can comprise small particles of a hydrophilic material dispersed in an oil phase. In such an embodiment, the hydrophilic phase can have a particle size of less than 300 nm., preferably less than 100 nm. as described above, most preferably about 1 to 80 nm. The clarity or cloudiness (turbidity) of the lubricant compositions can be measured by common spectrophotometers such as a Spectronic Genesys 5 spectrophotometer at a wavelength of about 400 nm. Other wavelengths can be used if the selected wavelength can measure the scattering of light representative of clear solutions. Other conventional particle s
Haupert Amy
Hei Kimberly Person
Li Minyu
Ecolab Inc.
McAvoy Ellen M.
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