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Prior Publication Data
US 2008/0210522 Al Sep. 4, 2008
Related U.S. Application Data
Continuation of application No. 10/639,613, filed on Aug. 11, 2003, now Pat. No. 7,364,033, which is a continuation of application No. 10/190,235, filed on Jul. 3, 2002, now Pat. No. 6,780,823, which is a continuation of application No. 09/595,835, filed on Jun. 16, 2000, now Pat. No. 6,427,826, which is a continuation-in-part of application No. 09/441,881, filed on Nov. 17, 1999, now Pat. No. 6,288,012.
B6SG 45/02 (2006.01)
U.S. CI 198/500; 508/208
Field of Classification Search 198/500;
See application file for complete search history.
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CA 2381345 3/2001
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Primary Examiner—Gene Crawford
Assistant Examiner—William R Harp
(74) Attorney, Agent, or Firm—Andrew D. Sorensen; Amy J.
7 9 11
Example 25 - Lube wt applied
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* cited by examiner
CONTAINER, SUCH AS A FOOD OR
BEVERAGE CONTAINER, LUBRICATION
CROSS-REFERENCE TO RELATED 5
This application is a continuation of U.S. patent application Ser. No. 10/639,613, filed Aug. 11, 2003, now U.S. Pat. No. 7,364,033 which is a continuation of U.S. patent appli- 10 cation Ser. No. 10/190,235 filed on Jul. 3,2002, now U.S. Pat. No. 6,780,823. U.S. patent application Ser. No. 10/190,235 is a continuation of U.S. patent application Ser. No. 09/595,835, filed on Jun. 16, 2002, now U.S. Pat. No. 6,427,826. U.S. patent application Ser. No. 09/595,835 is a continuation-in- 15 part of U.S. patent application Ser. No. 09/441,88 1, filed Nov. 17, 1999, now U.S. Pat. No. 6,288,012.
The entire contents of each of these patent applications are hereby expressly incorporated herein by reference including, without limitation, the specification, claims and abstract, as 20 well as any figures, tables, or drawings thereof.
FIELD OF THE INVENTION
The invention relates to conveyor lubricants and lubricant 25 compositions, and to methods of use, for example, to treat or lubricate a container(s) and conveyor surfaces or system for containers. The invention also relates to containers and conveyor surface or system treated with a lubricant or lubricant composition. The container is, for example, a food or bever- 30 age container.
DESCRIPTION OF RELATED ART
Containers are receptacles in which materials are or will be 35 held or carried. Containers are commonly used in the food or beverage industry to hold food or beverages. Often lubricants are used in conveying systems for containers, to ensure the appropriate movement of containers on the conveyor.
In the commercial distribution of many products, including 40 most beverages, the products are packaged in containers of varying sizes. The containers can be made of paper, metal or plastic, in the form of cartons, cans, bottles, Tetra PakTM packages, waxed carton packs, and other forms of containers. Inmost packaging operations, the containers are moved along 45 conveying systems, usually in an upright position, with the opening of the container facing vertically up or down. The containers are moved from station to station, where various operations, such as filling, capping, labeling, sealing, and the like, are performed. 50
Containers, in addition to their many possible formats and constructions, may comprise many different types of materials, such as metals, glasses, ceramics, papers, treated papers, waxed papers, composites, layered structures, and polymeric materials. Any desired polymeric material can be used, such 55 as polyolefins, including polyethylene, polypropylene, polystyrene, and mixtures thereof, polyesters such as polyethylene terephthalate (PET or PETE) and polyethylene naphthalate (PEN) and mixtures thereof, polyamides, polycarbonates, and the like. 60
Lubricating solutions are often used on conveying systems during the filling of containers with, for example, beverages. There are a number of different requirements that are desirable for such lubricants. For example, the lubricant should provide an acceptable level of lubricity for the system. It is 65 also desirable that the lubricant have 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.
In the beverage industry, it is also important that the lubricant be compatible with the beverage so that it does not form solid deposits when it accidentally contacts spilled beverages on the conveyor system. This is important since the formation of deposits on the conveyor system may change the lubricity of the system and could require shutdown of the equipment to facilitate cleaning.
It is also important that the lubricant can be cleaned easily. The container and/or the conveyor system may need to be cleaned. Since water is often in the cleaning solution, ideally the lubricant has some water-soluble properties.
Currently, containers, including polyethylene terephthalate (PET) bottles, and conveying systems for containers are often contacted with a volume of a dilute aqueous lubricant to provide lubricity to the container so that it can more easily travel down the conveyor system. Many currently used aqueous-based lubricants are disadvantageous because they are incompatible with many beverage containers, such as PET and other polyalkylene terephthalate containers, and may promote stress cracking of the PET bottles.
Furthermore, aqueous based lubricants are in general often disadvantageous because of the large amounts of water used, the need to use a wet work environment, the increased microbial growth associated with such water-based systems, and their high coefficient of friction. Moreover, most aqueousbased lubricants are incompatible with beverages.
Flooding a conveyor surface with a substantial proportion of aqueous lubricant typically occurs on food container filling or beverage bottling lines. Sufficient lubricant is used such that the lubricant is not retained entirely by the surface of the conveyor but tends to flow from the surface of the container, drip onto a conveyor support members and the surrounding environmental area around the conveyors. Further, sufficient amounts of lubricant are applied to the conveyor and other mechanisms of the plant under such conditions that a substantial foam layer of lubricant can form on the surface of the conveyor. As much as one inch (about 2.5 cm or more) thick of lubricant foam can contact a substantial portion of the base of a food container such as polyethylene terephthalate beverage bottle. 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 and are carried from the conveyor as the food packaging or beverage-bottling operations are continued. A substantial need exists for approved methods that waste little or no lubricant during packaging or bottling operations.
The tendency of polyester beverage containers to crack or craze is promoted by the presence of a number of common lubricating materials in contact with a substantial proportion of the surface of a polyester beverage container under pressure. The stress arises during manufacture of the polyester bottle from a preform. The stress is locked into the beverage container during manufacture and is often relieved as the lubricant materials contact the bottle. Lubricant materials appear to promote movement of the polyester molecules with respect to each other, relieving stress and leading to the creation of stress cracking. We have found that the degree of stress cracking is attributable, at least in part, to the amount of surface area of the bottle contacted by the lubricant. We have found in our experimentation that limiting the amount of surface area of the bottle that comes in contact with the lubricant can substantially improve the degree of stress cracking that occurs in the bottle material. Clearly, a substantial