US 20040235680 A1
A lubricant composition which protects polymeric articles, and which also inhibits corrosion of metal, the composition including at least one oxyalkylated alcohol carboxylatic acid or salt thereof, and methods of using the same. The composition is advantageous where hydrogen peroxide is also present.
1. A composition comprising at least one oxalkylated alcohol carboxylic acid or salt thereof, wherein said composition inhibits the corrosion of metal in the presence of hydrogen peroxide.
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23. A lubricant composition for containers and/or conveyors comprising an effective amount of at least one lubricant and at least one oxyalkylated alcohol carboxylic acid or salt thereof.
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39. A method of lubricating the interface between a container and a moving conveyor surface, the method comprising:
(a) applying an aqueous lubricant composition to the container, the conveyor or both, the lubricant comprising an effective amount of at least one lubricant and at least one oxalkylated alcohol carboxylic acid or salt thereof; and
(b) moving the container on the conveyor surface in order to transport the container from a first location to a second location.
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52. A method of protecting a polymeric article of manufacture by coating at least a portion of the surface of said polymeric article with a lubricating composition, said composition comprising an effective amount of at least one lubricant and at least one oxalkylated alcohol carboxylic acid or salt thereof.
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 This is a continuation-in-part of U.S. patent application Ser. No. 10/664265 filed Sep. 17, 2003 which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/411937 filed Sep. 18, 2002.
 The present invention relates to conveyor lubricant compositions and to methods of using the same.
 In commercial container filling or packaging operations, the containers typically are moved by a conveying system at very high rates of speed. In most packaging operations, the containers are moved along 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 are performed including, for example, filling, capping, labeling, sealing, and so forth. In a beverage operation in particular, it is important that the containers move without hindrance along the conveyor such that no liquid is spilled onto the conveyor during the times when the containers are open. This is especially important for dairy based beverages such as milk because milk can coagulate on the equipment surfaces. Lubricants are thus commonly used to ensure the appropriate movement of the containers on the conveyor.
 Lubricant compositions are used on conveying systems in the beverage industry during the filling of containers with dairy products or other beverages. The conveyor systems are typically lubricated to reduce friction between the package and the load bearing surface of the conveyor. These lubricants are typically applied to the conveyor belts and/or the containers to reduce friction between the container and the conveyor. This facilitates unhindered conveyance of bottles on the conveyor belt. These lubricants may also be referred to as chain conveyor or belt lubricants.
 Good lubricating properties are not the only important considerations when selecting a lubricant for use in the beverage bottling industry. Another consideration is that the lubricant be compatible with the beverage such that it does not form coagulates or other solid deposits when it accidentally contacts spilled beverages on the conveyor system. Formation of such deposits on a conveyor can change the lubricity of the conveyor and require shutdown to permit cleanup. The lubricant must also be readily cleaned from the equipment.
 In the commercial distribution of most beverages, the beverages are packaged in containers of varying sizes, such containers being in the form of cartons, cans, bottles, tetrapack packages, waxed carton packs, and other forms of containers. The 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.
 Polymeric materials are commonly used in the beverage industry. Examples of commonly used polymeric materials include, polyolefins such as polyethylene, polypropylene, polystyrene, copolymers thereof; polyesters and copolymers thereof such as polyethyleneterephthalate and polyethylenenaphthalate; polyamides and copolymers thereof; polycarbonates and copolymers thereof; and so forth and mixtures thereof. Some aqueous conveyor lubricants are incompatible with thermoplastic beverage containers made of polyethylene terephthalate (PET) and other plastics, for example, and can cause stress cracking (crazing and cracking that occurs when the plastic polymer is under tension) in carbonated beverage filled plastic containers.
 There remains a need in the industry for an alternative to currently available lubricants for containers and conveyors that overcomes one or more of the disadvantages of currently used lubricants.
 The present invention relates to a lubricant composition that reduces the coefficient of friction of coated conveyor parts and containers and thereby facilitates movement of containers along a conveyor line, and to methods of making and using the same.
 The present invention relates to lubricants with additives that provide improved corrosion resistance to metals as well as protection to polymeric containers against stress cracking and hazing.
 The compositions according to the invention include at least one corrosion inhibitor which is an oxyalkylated alcohol carboxylic acid or salt thereof, suitably an oxalkylated alcohol dicarboxylic acid or salt thereof. In one embodiment, the oxalkylated alcohol carboxylate is an ethoxylated linear alcohol carboxylic acid or salt thereof. These compounds may also be referred to in the art as polycarboxylated alkylene oxide condensates of fatty alcohols.
 A specific example is POLYTERGENT® CS1 available from BASF which is an ethoxylated linear alcohol carboxylic acid.
 The oxalkylated linear alcohol carboxylic acid or salt thereof, such as POLYTERGENT® CS1, may be represented by the following general formula:
 R is a typical surfactant hydrophobe, X and Y are independently H, CH3 or a succinic acid radical. For example, R may be a hydrocarbon group having from about 8 to about 20 carbon atoms, more typically about 9 to about 16 carbon atoms.
 Other useful dicarboxylic acids, triacarboxylic acids, and so forth useful herein are described in commonly assigned U.S. patent application Ser. No. 5,723,418, which is hereby incorporated by reference in its entirety. One example is SOKALAN® DCS, a mixture of adipic, glutaric and succinic acids, available from BASF.
 The oxalkylated alcohol carboxylatic acid or salt thereof is useful in amounts of less than 20 wt-%, more suitably about 1 wt-% to about 15 wt-% and most suitably about 1 wt-% to about 10 wt-% of the composition.
 The compositions further include an effective amount of at least one lubricant. The present invention is not limited by the type of lubricant employed herein, and any lubricant known in the art may be used. Examples of suitable lubricants include, but are not limited to, amines including amine acetates, primary, secondary and tertiary amines, diamines, and fatty amines; phosphate esters; anionic surfactants, cationic surfactants; nonionic surfactants including ethylene oxide/propylene oxide block copolymers; silicones including polymers, oils, and emulsions thereof; and so forth.
 As used herein, the term block copolymer, shall be used to refer to diblocks, triblocks and so forth.
 The lubricant compositions used in the invention may contain water or a hydrophilic diluent, as a component or components in the lubricant composition as sold or added just prior to use.
 The compositions may be diluted with water at the time of use at a ratio of about 1:200 to about 1:1000, suitably about 1:600 to about 1:800 of the composition to water.
 The compositions exhibit excellent corrosion inhibition for metals in the presence of hydrogen peroxide. Hydrogen peroxide may be employed in a variety of different types of compositions for a variety of different reasons, including, but not limited to, cleaning booster in hot caustic cleaning solutions, in dilute lubricant compositions as a biocide, as a bleaching agent, for the destruction of bleach, and so forth. When used in alkaline cleaning solutions, peroxide is added as an adjunct chemical additive. Peroxide is not stable in solutions with a higher pH. It is effective as a booster for the removal of baked-on and carbonized soil. It may also be used to produce alkylamine oxide surfactants from alkylamines. It is, however, corrosive to metal such as steel. The additives according to the invention may be added to compositions, wherein hydrogen peroxide is employed, to inhibit the corrosion of metal.
 Other aspects and advantages will become clear from the following Detailed Description.
 While this invention may be embodied in many different forms, there are described in detail herein specific embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated.
 The additive for inhibiting corrosion of metals includes at least one oxalkylated alcohol carboxylic acid or salt thereof. These compounds are also referred to in the art as polycarboxylated alkylene oxide condensates of fatty alcohols.
 Oxalkylated alcohol carboxylic acids or salts thereof may be represented by the following general formula:
 R is a typical surfactant hydrophobe, X and Y are independently H, CH3 or a succinic acid radical. For example, R may be a hydrocarbon group having from about 8 to about 20 carbon atoms, more typically about 9 to about 16 carbon atoms.
 A specific example is POLYTERGENT® CS1 which is an ethoxylated linear alcohol dicarboxylic acid available from BASF Corp.
 The oxalkylated alcohol carboxylic acid or salt thereof may be used in amounts of less than about 20 wt-%, more suitably about 1 wt-% to about 15 wt-% and most suitably about 1 wt-% to about 10 wt-% of the composition.
 Any lubricants known in the art may find utility in the compositions of the present invention and including synthetic lubricants such as silicones, glycerin, petroleum based lubricants such as mineral oil, and natural lubricants including fatty oils and animal and vegetable oils including those which are edible.
 Lubricants may be natural or synthetic, and come in a variety of classes including, for example, amines, cationic, anionic and nonionic surfactants, phosphate esters, silicones, and so forth. Acids may come in a form which has been neutralized with a base such as potassium or sodium hydroxide.
 More specific examples include, but are not limited to, synthetic hydrocarbons; organic esters; high molecular weight alcohols; perfluoroalkylpolyethers (PFPE); silicates; silicones including polymers, oils and emulsions thereof; fluoropolymers such as chlorotrifluoroethylene; polyphenyl ethers; poly(alkylene) glycol(s) including polyethylene and polypropylene glycols; oxypolyalkylene glycols; copolymers of ethylene and propylene oxide, polyhydroxy compounds; ethoxylated amines; primary, secondary and tertiary amines; alkanolamines; fatty acid amines including N-coco B-Amino propionic acid amphoteric surfactant; perfluoroalkylpolyethers (PFPE); polyhydroxy compounds; and so forth and mixtures thereof. This list is intended for illustrative purposes only, and is not intended to limit the scope of the present invention.
 The ethylene oxide/propylene oxide block copolymers including triblock copolymers having the following general formulas find utility herein:
 wherein EO represents ethylene oxide residue, PO represents propylene oxide residue, and x, y, and z equal independently selected integers from about 2 to 100. These lubricants are available from BASF under the tradename of PLURONIC® and include PLURONIC® 10R5 and PLURONIC® G F108 which is an EO-PO-EO triblock polymer.
 Another example of suitable lubricants are the ethoxylated alcohols. A specific example is TOMADOL® 45-13, an alcohol ethoxylate that includes a 14-15 carbon alcohol with 13 moles ethylene oxide. This is available from Tomah Products, Inc. in Milton, Wis.
 Another specific example are the alkyl polyglucosides available from Cognis North America in Cincinnati, Ohio under the tradename of GLUCOPON® including GLUCOPON® 220, 225, 425, 600 and 625.
 Other specific examples of useful lubricants include fatty acids or salts thereof such as oleic acid, corn oil, mineral oil available from Vulcan Oil and Chemical Products under the Bacchus® trademark; fluorinated oils and fluorinated greases, available from DuPont in Wilmington, Del. under the trademark Krytox®; siloxane fluids available from General Electric silicones, such as SF96-5 and SF 1147 and other silicone emulsions; synthetic oils and their mixture with PTFE available from Synco Chemical under the trademark Super Lube®; polyalkylene glycols from Union Carbide such as UCON® LB625 and CARBOWAX® 300; block copolymer surfactants such as UCON® 50HB660 ethylene oxide(EO)/propylene oxide (PO) monobutyl ether; and so on and so forth.
 Lubricants are available in solid form as well. Examples include, but are not limited to, molybdenum disulfide, boron nitride, graphite, silica particles, silicone gums and particles, polytetrafluoroethylene (PTFE, Teflon), fluoroethylene-propylene copolymers (FEP), perfluoroalkoxy resins (PFA), ethylene-chloro-trifluoroethylene alternating copolymers (ECTFE), poly (vinylidene fluoride) (PVDF), and the like. The lubricant composition can also contain a solid lubricant as a suspension in a substantially aqueous or non-aqueous liquid.
 Lubricants are useful from about 1 wt-% to about 20 wt-% of the composition, suitably about 1 wt-% to about 10 wt-%.
 The above lists are not exhaustive, and are intended for illustrative purposes only, and not as a limitation on the scope of the present invention. One of ordinary skill in the art has knowledge of such lubricants. Suitable lubricants are described, for example, in commonly assigned U.S. Pat. Nos. 6,576,298, 5,925,610, 5,559,087 and 5,352,376, each of which is incorporated by reference herein in its entirety.
 The lubricant compositions used in the invention may be available as concentrates, or as diluted use solutions. As such, the lubricant compositions may contain water or a hydrophilic diluent, as a component or components in the lubricant composition as sold or added just prior to use. Suitably, the lubricant composition does not require in-line dilution with significant amounts of water, that is, it can be applied with little or no dilution.
 Suitably, the lubricant compositions include about 1 wt-% to about 90 wt-% water, and more suitably about 25 wt-% to about 85 wt-% and most suitably about 50 wt-% to about 85 wt-%. Of course, such compositions can be further diluted during use.
 The lubricant compositions may be diluted with water at a ratio of about 1:200 to about 1:1000, suitably about 1:600 to about 1:800 of the composition to water.
 A variety of other optional ingredients may be incorporated into the compositions including, but not limited to, pH adjusters such as potassium or sodium hydroxide or other neutralizing agents, surfactants, emulsifiers, sequestrants, solubilizers, other lubricants, buffers such as potassium carbonate, detergents, bleaching or decolorizing agents, antioxidants, preservatives such as methyl and/or propyl paraben, antistatic agents, binders, thickeners or other viscosity modifiers, processing aids, carriers, water-conditioning agents, antimicrobial agents, foam inhibitors or foam generators, film formers, hydrotopes, also called coupling agents, combinations thereof, and so forth. The amounts and types of such additional components are apparent to those skilled in the art.
 The compositions according to the invention have also been found to exhibit superior corrosion resistance, particularly hydrogen peroxide-containing compositions when employing the oxalkylated alcohol carboxylates as the protectant, and particularly when lower grades of steel, such as cold rolled steel, are exposed to such compositions. Hydrogen peroxide tends to aggravate corrosion of lower grade steel such as cold rolled steel. However, when exposed to the hydrogen peroxide-containing compositions with the oxalkylated alcohol carboxylates as the protectant, the cold rolled steel exhibited a weight loss of less than 0.2 wt % and even less than 0.1 wt %. Based on a starting weight of 23 g, the weight loss was about 5 mg, and even less than 2 mg, while prior compositions exhibited weight loss of as much as >120 mg.
 The lubricant compositions may be employed to lubricate the interface between a moving conveyor and any work piece that is moved along by the conveyor, and in particular for containers that are moved from one location to another. Such a method involves applying an aqueous liquid lubricant composition to the container, the conveyor, or both. The lubricant comprising an effective amount of at least one lubricant and at least one protectant and moving the container on the conveyor surface in order to transport the container from a first location to a second location.
 The present invention is particularly advantageous where the containers are filled with liquids prior to moving from one location to another, wherein it is desirable that the liquids are not spilled. For example, the lubricant composition can be used for conveying a wide variety of containers including beverage containers; food containers; household or commercial cleaning product containers; and containers for oils, antifreeze or other industrial fluids.
 The containers can be made of a wide variety of materials including glasses; polymeric materials such as polyolefins including polyethylene and polypropylene and copolymers thereof; polystyrenes and copolymers thereof; polyesters and copolymers thereof such as PET and polyethylene naphthalate (PEN); polyamides and copolymers thereof; polycarbonates and copolymers thereof; and so on and so forth; metals including, for example aluminum, tin or steel; papers including untreated, treated, waxed or other coated papers or laminates thereof; ceramics; and laminates or composites of two or more of these materials. The containers can have a variety of sizes and forms, including cartons such as waxed cartons. TETRAPACK® boxes, cans, bottles and the like.
 The lubricant composition may be applied to the container and/or conveyor using any suitable means known in the art. Although any desired portion of the container can be coated with the lubricant composition, the lubricant composition is suitably applied only to parts of the container that will come into contact with the conveyor or with other containers, and suitably, the lubricant composition is not applied to parts that later come into contact with a user who grips or holds the container, or, if so applied, is preferably removed from such portion prior to shipment and sale of the container. Application of the lubricant composition to the conveyor, rather than the container, can alleviate problems of slipperiness with the latter.
 The surface of the conveyor that supports the containers may comprise fabric, metal, plastic, elastomer, composites, or mixture of these materials. Any type of conveyor system used in the field can be treated according to the present invention. The lubricant composition can be applied to a conveyor system surface that comes into contact with containers, the container surface that needs lubricity, or both. The lubricant composition can be applied in any desired manner, for example, by spraying, wiping, rolling, brushing, or a combination of any of these, to the conveyor surface and/or the container surface. If the container surface is coated, it is only necessary to coat the surfaces that come into contact with the conveyor, and/or that come into contact with other containers. Similarly, only portions of the conveyor that contacts the containers need to be treated. Methods of application are discussed in commonly assigned U.S. Pat. Nos. 6,576,298 and 6,495,494, for example, each of which is incorporated by reference herein in its entirety.
 A variety of kinds of conveyors and conveyor parts can be coated with the lubricant composition. Parts of the conveyor that support, guide, or move the containers are preferably coated with the lubricant composition. These parts include belts, chains, gates, chutes, sensors, and ramps having surfaces made of fabrics, metals, plastics, composites, or combinations of these materials.
 The additives, according to the invention, find utility for the protection of polymeric articles to prevent hazing and stress cracking. This is especially a concern when the polymeric articles are exposed to alkaline conditions.
 The additives, according to the invention, also find utility in any composition having hydrogen peroxide or under any circumstances where metal such as steel comes into contact with hydrogen peroxide. The additives, according to the invention, find utility, not only in lubricant compositions, but in cleaning compositions, particularly hot caustic cleaning compositions, bleaches, and so forth. When used in alkaline cleaning solutions, peroxide is added as an adjunct chemical additive. Peroxide becomes less stable at a higher pH such as at those pH values of greater than 7.
 The following non-limiting examples further illustrate the present inventive concepts.
 Test Methods
 1. PET Stress Crack Test
 Standard 2-liter PET beverage bottles (commercially available from Constar International) were charged with 1850 g of chilled water, 31.0 g of sodium bicarbonate and 31.0 g of citric acid. The charged bottle was capped, rinsed with deionized water and set on clean plastic liners or paper towels overnight. The bottoms of 12 bottles were dipped in a 200 g sample of 0.5% lube solution that was prepared using DI water with 200 ppm added alkalinity. The bottles were then placed in a bin and 85.2 g of the lube solution is evenly distributed to the bottom of the bin. The bottles/bin were stored in an environmental chamber at 37.8° C., 90% relative humidity for 28 days. Burst bottles were tracked throughout the test. At the end of the test the bottles were removed from the chamber, observed for crazes, creases and crack patterns on the bottom.
 2. Corrosion Test
 The corrosion test is based on test method ASTM 3.02, G31-72 and 3.02 G1-90.
 Coupons of cold rolled steel and stainless steel were cleaned using Bon-Ami cleanser, rinsed with deionized water, rinsed with acetone, and dried with canned air. The coupons were set in wood drying racks overnight. Each coupon was then weighed on an analytical balance to 0.1 mg. Each coupon originally weighed approximately 23 g.
 Approximately 215 grams of each test solution was added to 8 ounce glass bottles labeled to identify the solution inside. The lubricant concentration was 0.5% for all solutions. The bottles were capped and placed in an oven at 50° C. overnight. One coupon was added to each jar and the jars were capped. The capped jars were returned to the oven at 50° C. Each coupon type was tested in triplicate for each solution type. The coupons were visually inspected each day for corrosion without removing them from the jars. The jars were left capped the entire testing period. One of each coupon type was soaked in each solution type for 7 days and two of each type of coupon were soaked in each solution type for 14 days.
 Post-cleaning of the cold rolled steel coupons included rinsing each coupon after removal from the jar and then soaking each coupon for 3 minutes at room temperature in a 100 mls of a solution of 20 g of Sb2O3, 50 g of SnCl2 and 1000 mL HCl in a 150 mL beaker. Each coupon was then removed from the cleaning solution, rinsed with deionized water, rinsed with acetone, and dried with canned air. The coupons were then set in the wood drying racks and were weighed when all coupons had been cleaned and dried.
 Post-cleaning of the 316 stainless steel coupons included rinsing each coupon after removal from the jar and then placing the coupons in a stainless steel rack. The rack was then lowered into a large beaker with a solution of 150 g diammonium citrate/liter water. The beaker was then placed in an oven at 70° C. for 20 minutes. After 20 minutes, the metal rack was removed from the solution and each coupon was rinsed with deionized water, rinsed with acetone, and dried with canned air. The coupons were then set in the wood drying racks and were weighed when all coupons had been cleaned. The weight loss was calculated for each coupon by subtracting the final weight from the initial weight, and adjusting the weight loss by adding back or by subtracting any weight loss/gain that occurred during exposure of the coupons to air in the oven. The air samples were used as blanks so that the only weight loss/gain is due solely to corrosion in the test solutions and is not due to weight loss/gain due to the post-cleaning procedure.
 The amount of POLYTERGENT® CS1 was doubled from the amount in example 1. This is comparative example A. Comparative example B was prepared with no protectant. Example 1 and comparative examples A and B were then tested using the PET Stress Crack test described above. Example 1 exhibited only 1 failure in 24 total tests, comparative example A, at higher levels of Polytergent® CS1, exhibited 5 failures and comparative example B exhibited 4 failures out of 24.
 A second example was prepared; the composition is found in Table 3.
 The amount of POLYTERGENT® CS1 was increased by 10% from the amount in example 2. This is comparative example C. Comparative example D was prepared with no protectant. These formulas were also tested according to the PET Stress Crack test described above. Example 2 exhibited 1 failure out of 24, comparative example C exhibited 6 failures out of 24 and comparative example D exhibited 4 failures out of 24.
 The results are found in the following table 3.
 A base formula was employed for preparing various compositions which were then tested for corrosion inhibition of metals. The base composition is also comparative example A and is considered to be an industry standard. To the base formula, several different compounds were added. The compositions as well as the results of the testing are found in Table 4, below. The corrosion resistance was tested using the test method described above.
 The base composition was the following.
 Base Composition (BC)=Comparative Example E
 5.0 wt-% Tomadol® 45-13; alcohol ethoxylate (Tomah Products, Inc.)
 3.0 wt-% Pluronic® 10R5; ethylene oxide/propylene oxide block copolymer (BASF)
 1.0 wt-% Glucopon® 625; alkyl polyglucoside (BASF)
 5.7 wt-% hydrogen peroxide, 35% active
 85.3 wt-% deionized water
 Example 1 was compared to a variety of compositions for corrosion to metal in the presence of hydrogen peroxide. The compositions and results are summarized in Table 5 as follows:
 Example 1 exhibited the lowest degree of weight loss of any of the compositions, including the industry standard, Lubrodrive® RX.
 The above compositions were tested according to test method no. 1 described above. The results are found in table 6.
 The dicarboxylated ethoxylated alcohol protectant was tested in combination with an alternative lubricant which was based on the sodium salt of a fatty acid. The following table shows the formulas employed.
 The compositions were tested according to test method no. 1 described above. The results are shown in table 8.
 While the fatty acid based lubricant composition exhibited improvement using a protectant in contrast to the fatty acid lubricant with no protectant, the results were not as good as with other types of lubricants.
 The above disclosure is intended to be illustrative and not exhaustive. The description will suggest many variations and alternatives to those of ordinary skill in the art. All of these alternatives and variations are intended to be included within the scope of the attached claims. Equivalents to these specific examples should also be encompassed by the attached claims.
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