MX2007011585A

MX2007011585A - Food grade lubricant compositions.

Info

Publication number: MX2007011585A
Application number: MX2007011585A
Authority: MX
Inventors: Helen T Ryan; Patricia M Corbett; Roger M Sheets
Original assignee: Afton Chemical Corp
Priority date: 2006-11-29
Filing date: 2007-09-20
Publication date: 2009-02-19
Also published as: JP2008138171A; CA2605903A1; SG143128A1; CN101191094A; EP1939272A1; US20080125338A1; AU2007221894A1

Abstract

A food grade lubricant composition and method of lubricating food processing machinery. The food grade lubricant composition includes a major amount of food grade base oil and a minor amount of at least one additive composition. The additive composition includes one or more non-sludge promoting wear reducing agents. An advantage of the lubricant composition is that it may exhibit lower sludge formation tendencies than a lubricant composition containing a conventional wear reducing agent.

Description

FOOD GRADE LUBRICATING COMPOSITIONS FIELD OF THE INVENTION The embodiments described herein relate to food grade lubricant compositions and in particular to lubricant compositions having improved mud control properties as compared to conventional food grade lubricants.

BACKGROUND OF THE INVENTION The equipment used in the food processing industry varies by segments with the three leading segments comprising meat and poultry, beverages and dairy products. Although the equipment varies from one segment to another, moving parts such as bearings, gears and sliding mechanisms are similar and often require lubrication. The lubricants very often used include hydraulic, cooling and gear oils as well as greases for all purposes.

However, oils from the food industry must meet stricter standards than other lubricants in the industry. Lubricant contamination has been a problem in the food and beverage processing industry, in Ref. 186043 where a major accident could require a company to do a massive product cancellation, which could be devastating to its reputation. Minor lubricant leaks in machinery are common, sometimes unavoidable and not always obvious. Only normal wear and seizure of seals can cause a gearbox or hydraulic system to leak, and release tiny levels of oil that may come in contact with food. The contamination can also come from chain run-off or a release of compressed air containing an oil mist. If a plant uses a non-food grade lubricant, the food and drug administration of E.U.A. (FDA) allows zero amounts of lubricant to come into contact with food. If the lubricant accidentally comes in contact with the food, the batch must be discarded. If the plant uses food grade lubricants that are non-toxic, odorless, colorless and tasteless, the FDA limits lubricant contamination to 10 parts per million. The Food Safety and Inspection Service (FSIS) is the custodian of the official list of compounds authorized for federal use at inspected plants. The official list states that lubricants and other substances that are susceptible to contact with incidental feed are considered indirect food additives under USDA regulations. Therefore, it is required that these lubricants, classified either as H-1 or H-2, be approved by the USDA before being used in food processing plants. The strictest classification, H-1, is for lubricants approved for contact with incidental food. Lubricants that meet the H-l classification are used where the food can be potentially exposed to the lubricated part of the machine. The H-2 classification is for uses where there is no possibility of contact with food and ensures that no poisons or carcinogens are used in the lubricant. For the purpose of this description, the terms "food grade" and "lubricant" will be used interchangeably herein. In addition to meeting the safety requirements established by federal regulatory agencies, the lubricant must be effective for the particular application and may also be required to meet the requirements of Kosher and Halal. Lubricating oils for food processing plants should lubricate parts of the machine, resist viscosity change, resist oxidation, protect against rust and corrosion, provide protection against wear, prevent foaming and resist sludge formation during service. The product must also perform effectively in various lubrication regimes that range from coarse hydrodynamic film regimes to thin film regimes of adjacency. Lubricants that can meet or exceed the specification in Part II of DIN 51524 can meet the above performance criteria. Conventional food-grade lubricants contain anti-gaseous agents. Of the anti-wear agents used in food grade applications, certain amine salts of acidic phosphates can result in increased sludge / varnish formation. Therefore, it is desirable to provide an improved food grade lubricating oil that overcomes the mud and varnish tendencies of conventional food grade lubricants.

SUMMARY OF THE INVENTION In one embodiment of the invention there is presented a food grade lubricant composition that includes a larger amount of food grade base oil and a smaller amount of at least one additive composition. The additive composition includes one or more wear reducing agents that promote the non-formation of sludge. An advantage of the lubricant composition is that it may have lower mud formation tendencies than a composition lubricant containing a conventional wear reducing agent. In another embodiment, a method of operating machinery for food processing is provided. The method includes providing the machinery with a food-grade lubricant containing a larger amount of food grade base oil and a smaller amount of an additive composition and the operation of the machinery. The additive composition includes one or more wear reducing agents that promote the non-formation of sludge. During the operation of the lubricant machinery, the lubricating composition may exhibit lower mud formation tendencies than a lubricant composition containing a conventional wear reducing agent. As briefly discussed above, embodiments of the disclosure may provide an improved food grade lubricant composition that exhibits reduced sludge and / or varnish formation and meets the wear criteria for food grade lubricants. Other features and advantages of the compositions and methods described herein may be apparent by reference to the following detailed description intended to exemplify aspects of the embodiments without intending to limit the embodiments described herein. It should be understood that both the general description above as the following detailed description are illustrative and explanatory only and are not intended to provide further explanation of the described and claimed embodiments.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the illustrative embodiments herein, an improved food grade lubricant composition is provided that can be particularly effective in reducing sludge and varnish formation, and can meet the requirements of Hl and / or H-2 for used in food processing industries. Illustrative food grade lubricants are also suitable to provide good wear protection, adequate protection against rust and corrosion, and good foam and air release properties. As discussed above, the lubricant composition includes a food grade base oil. The base oil for use in the food grade lubricating oils described herein can be selected from food grade hydrocarbon oils such as food grade mineral oil, food grade polybutene, food grade hydrogenated polybutene, food grade polyol esters, food grade diesters, food grade hydrogenated poly (alpha olefin) with an alpha olefin monomer of not less than 6 carbon atoms and a wide variety of vegetable oils. The base oil must be substantially odorless, colorless and tasteless and comply with USDA H-1 and / or H-2 specifications and requirements for use in food processing plants and other applications. In an illustrative embodiment, the base oil can be a mineral oil such as a technical grade white oil made from selected lubricant base supply materials. The food grade mineral oil can also be a white mineral oil that meets the strictest requirements of the United States Pharmacopeia (USP) or a light mineral oil that meets the strictest requirements of the national form ( NF, for its acronym in English). These food-grade mineral oils are often directly derived from crude oil through the processing steps of distillation, extraction, wax removal and severe hydrotreating. Suitable base oils, derived from other media, are food grade polybutene, food grade hydrogenated polybutene, food grade polyol esters, food grade diesters and poly (alpha olefin) hydrogenated food grade with an alpha olefin monomer of not less than 6 carbon atoms. Vegetable oils can also be used as the base oil component, either alone or in combination with the previous oils. Suitable vegetable oils may include, but are limited to, rape seed oil, hump oil, stick oil, castor oil, wood oil, flaxseed oil, olive oil, peanut oil, rope oil , coconut oil, soybean oil and mixtures thereof. Oils derived from meat products such as lard oil, bait oil, mink oil and the like are avoided for lubricant applications that meet the requirements of Kosher and / or Halal. The base oil comprises approximately 85. 0% to 99.9% by weight of the lubricant composition containing additives to provide a product having a viscosity ranging from 10 cSt at 40 ° C to 1000 cSt at 40 ° C. The additives used can suitably meet the HX-1 criteria to provide H-1 food grade lubricant compositions and meet the criteria of HX-2 to provide food grade lubricant compositions of H-2.

Anti-wear additives The anti-wear additives that can be used in the compositions described herein include food-grade oil-soluble sulfur and / or phosphorus-containing compounds and neutralized alkyl phosphate esters and mixtures of the foregoing. A sulfur and / or phosphorus compound that can be used is triphenyl phosphorothioate. Other materials containing sulfur and / or phosphorus that are not currently approved for food grade use include: zinc dialkyldithiophosphate, zinc dithiocarbamate, amine dithiocarbamate and methylene bis-dithiocarbamate. Any of the above compounds, with approval of HX-1, would be an appropriate anti-wear additive. A neutralized alkyl phosphate ester component can include a component containing a mixture of mono- and di-C4-C8 alkyl phosphate esters and / or polyphosphate esters that have been neutralized with an unbranched chain amine. The non-branched chain amines can be selected from tetramethylnonilamines, C-C4 alkylamines and the like. The food grade lubricant may contain from about 0.1 to about 0.5 of the anti-wear additive based on the total weight of the lubricant composition. For a food grade lubricant that containing the triphenyl phosphorothioate component and the neutralized alkyl phosphate ester wear reducing agents, the anti-wear additive component of the composition may include from about 0 wt.% to about 50 wt.% of the triphenyl phosphorothioate component and of about 35% by weight to about 100% by weight neutralized alkyl phosphate ester. One criterion for the anti-wear additive is that the additive is an anti-wear additive promoting no mud formation. Conventional antiwear agents typically include a neutralized dialkyl phosphate that has been neutralized with a primary C12-C14 t-alkylamine. Surprisingly, food-grade lubricants containing anti-wear additives that have not been neutralized with a branched alkylamine exhibit reduced mud / varnish formation tendencies compared to lubricants containing an anti-wear additive which is neutralized with a C12-C14 primary alkylamine.

Antioxidant Additives Antioxidant additives that can be used as a component of the food grade lubricant composition include phenolic and amine antioxidants and mixtures thereof. Phenolic antioxidants that can be used include, but are not limited to, sterically hindered, oil-soluble, food-grade phenols and thiophenols. Included within the definition of phenolic and thiophenolic antioxidants are the sterically hindered phenols such as phenols and hindered bis-phenols., Hindered 4'-thiobisphenols, hindered 4-hydroxy-acid and 4-thiobenzoic esters and dithioesters, and alkylenoic esters of hindered bis (-hydroxy acid and 4-hydroxy acid and 4-thiolbenzoic acid) esters. The phenolic portion can be substituted in both positions ortho to the hydroxy or thiol groups with alkyl groups that sterically prevent these groups. These alkyl substituents usually have 3 to 10 carbons, suitably 4 to 8 carbons, with an alkyl group which is generally branched instead of straight chain (e.g., t-butyl, t-amyl, etc.). The first group of hindered phenolic antioxidants is the individual hindered phenols. Examples of these compounds include 2,6-bi-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-amyl-p-cresol and 2-tert-butyl-6. -ter-amyl-p-cresol. A second group of hindered phenolic antioxidants is hindered bisphenols. Examples of these compounds include 4,4'-methylene bis (2,6-bi-tert-butylphenol), 4, '-dimethylene bis (2,6-di-tert-but-ylphenol), 4,4'-trimethylene bis (2,2-di-ter-araylphenol), and 4,4' -trimethylene bis (2,6) -di-tert-butylphenol). Another group of hindered phenolic antioxidants is the 4,4'-thio bis-phenols hindered. Examples of these compounds include 4,4'-thio bis (2,6-di-sec-butylphenol), 4,4'-thio bis (2-tert-butyl-6-isopropylphenol), and 4,4'-thio bis (2-methyl-6-t-butylphenol). A fourth group of hindered phenolic antioxidants is 4-alkoxyphenols. Examples of these compounds include butylated hydroxyanisole, butylated hydroxyphenetol and butylated hydroquinone. Any of the above compounds, with approval of HX-1, would be an adequate phenolic antioxidant. Butylated hydroxytoluene (BHT) is cost effective, commercially available and is approved by HX-1. The butylated hydroxytoluene may be present in a food grade lubricating oil in an amount of less than about 1% by weight and very typically is present in an amount ranging from about 0.1 to about 0.6% by weight of the grade lubricating oil composition. food Also, the food grade lubricant composition may contain less than 1% by weight of the phenolic antioxidant. The aromatic amine antioxidants soluble in Suitable food grade oils are naphthylphenylamines, alkylated phenylnaphthylamines, and alkylated diphenylamines. Examples of aromatic amine antioxidants include but are not limited to naphthylamines such as N-phenyl-alpha-naphthylamine, N-p-methyl-phenyl-alpha-naphthylamine, and diphenylamines such as di-sec-butyldiphenylamine. Di-isobornyl-di-phenylamine, and dioctyldiphenylamine. Any of the above compounds with approval of HX-1 may be a suitable aromatic amine antioxidant. Particularly suitable aromatic amine antioxidants are the alkylated and dialkylated diphenylamines, for example, the reaction products of the alkylation of n-phenylbenzenamine and 2,4,4-trimethylenzane. The resulting product may be a mixture of ortho, meta and para (octylphenyl) amine. Bis (octylphenyl) amine can also be referred to as dioctyldiphenylamine and is a food grade amine. Another food-grade diphenylamine is an octylated, butylated diphenylamine. The aromatic amine may be present in the lubricant composition in an amount of about 1% by weight of the lubricating oil composition. A suitable amount of alkylated diphenylamine can vary from about 0.05 to about 0.5% by weight of the total weight of the lubricant composition. The lubricant composition may typically contain only one antioxidant additive. Nevertheless, combinations of the above antioxidant additives may also be used. When a combination of the antioxidant additives is used, the phenolic and aromatic amine antioxidant components may vary in weight ratio from 20: 1 to 1:20, although an adequate ratio varies from 4: 1 to 1: 1.

Anti-rust additives The anti-rust additive component can include a combination of food-grade ionic and non-ionic active surface anti-rust ingredients. The total amount by weight of the ionic surface additive and nonionic additive needed to impart the desired degree of rust resistance should be significantly lower than any anti-rust additive independently. The ionic anti-rust lubricating additives that may be used in the compositions described herein may include food-grade phosphoric acid, mono- and di-hexyl ester compounds with tetramethylnonilamines, and IQ-CIQ alkylamines. Any rust-inhibiting compound with HX-1 approval could be a suitable anti-rust additive. Also, the acid phosphate amine salt used as an anti-wear additive can be used for its rust inhibiting properties as an additive. anti-rust The non-ionic anti-rust lubricating additives which may be used in the compositions described herein may include food grade fatty acids and their esters formed from the addition of sorbitan, glycerol or other polyhydric alcohols, or polyalkylene glycols. Other nonionic anti-rust lubricating additives may include food grade ethers from fatty alcohols alkoxylated with alkylene oxides, or alkoxylated sorbitan with alkylene oxides, or alkoxylated sorbitan esters with alkylene oxides. Examples of food grade nonionic anti-rust lubricating additives include: sorbitan monooleate, ethoxylated vegetable oil, isopropyl oleate, ethoxylated fatty acids, ethoxylated fatty alcohols, fatty glyceride esters, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan, glycerol monooleate, glycerol dioleate, glycerol monostearate, and glycerol distearate. Any of the above compounds, with approval of HX-1, would be a suitable anti-rust additive. The food grade anti-rust additive may comprise less than about 1% by weight of the food grade lubricating oil and may comprise from about 0.01 to about 0.3% by weight of the food grade lubricating oil. food-grade lubricating oil.

Corrosion inhibiting additive In some embodiments, corrosion inhibitors may constitute another class of suitable additives to be included in the compositions described herein. These compounds include food-grade tlazoles, triazoles and thiadiazoles. Examples of such compounds include benzotriazole, tolyltriazole, octyl riazole, decyltriazole, dodecyl-riazole, 2-mercapto-benzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbyl-1, 3-thiadiazoles , 2-mercapto-5-hydrocarbyldithio-l, 3-4-thiadiazoles, 2, 5-bis (hydrocarbyl) -1, 3, -thiadiazoles, and 2,5-bis (hydrocarbyldithio) -1, 3, 4-thiadiazoles . Suitable compounds include 1, 3, 4-thiadiazoles, a number of which are available as articles of commerce, combinations of triazoles such as tolyltriazole with 1, 3, 5-thiadiazole such as 2, 5-bis (alkyldithium) -1, 3, -thiadiazole and bis-alkyl-arylalkylbenzotriazolalkylamines such as N, N-bis (2-ethyl) ar-methyl-lH-benzotriazole-1-methanamine. The amount of corrosion inhibitor in the food grade formulations described herein may vary from about 0.01 to about 0.5% by weight based on the total weight of the lubricant composition.

Antifoam Additive In some embodiments, a foam inhibitor can form another component suitable for use in food grade compositions. The foam inhibitors can be selected from silicones, polyacrylates, methacrylates, surfactants and the like which meet the approval criteria of HX-1. The amount of antifoam agent in the food grade formulations described herein may vary from about 0.0025 wt% to about 0.01 wt% based on the total weight of the food grade lubricant composition.

Conservative Additives Suitable food grade preservatives include, but are not limited to vitamin E (α-tocopherol) and / or C2-C6 alkyl hydroxylbenzoate such as propyl p-hydroxylbenzoate. The amount of preservative in the lubricant composition can vary from about 0.001 to about 0.1% by weight of the total weight of the food grade lubricant composition. The additives used in the formulation of the compositions described herein can be mixed in base oil individually or in several subcombinations. However, it is appropriate to mix all the components that you use presently an additive concentrate (ie, additives plus a diluent, such as base oil). The use of a concentrate takes advantage of the mutual compatibility provided by the combination of ingredients when it is in the form of an additive concentrate. As well, the use of a concentrate reduces the mixing time and reduces the possibility of mixing errors. In the following table 1, the formulations for food grade lubricant compositions (samples 1-4) and for food grade lubricant compositions are given in accordance with illustrative embodiments described herein (samples 5-8). Table 2 compares the test results of the fluid compositions.

Table 1 Component Sample 1 Sample 2 Sample 3 Sample 4 Base oil 90 90 90 90 Agent 0.0 0.0 0.02 0.02 Anti-foam Agent anti0.20 0.15 0.0 0.0 conventional wear Component Sample 1 Sample 2 Sample 3 Sample 4 Agent anti0.0 0.0 0.15 0.15 non-mud-forming wear Phosphorothioate 0.20fps 0.20 0.20 0.20g Rifenil Vitamin E 0.01 0.01 0.01 0.01 Conservative 0.01 0.01 0.01 0.01 Antioxidant 1 0.20 0.20 Antioxidant 2 0.50 0.50 Inhibitor 0.10 0.10 0.10 0.10 corrosion Inhibitor 0.05 0.05 0.05 0.05 rust Table 2 Results of Sample 1 Sample 2 Sample 3 Sample 4 test CCMA test Weight of sludge 39.11 39.72 9.4 11.68 (mg / 100, ml) Test of 11 12 past scratches of FZG passed Results of Sample 1 Sample 2 Sample 3 Sample 4 test Wear of 4 0.28 0.27 balls 20 Kg / 1475 rpm / 1 hr / environment Wear of 4 0.47 0.46 balls 20 Kg / 1475 rpm / 1 hr / room As shown in Table 2, the fluid compositions according to the description (samples 3-4) provide relatively low degree results of less than 15 mg / 100 ml in the CCMA test versus a limit of 25 mg / 100 ml. . In comparison, the use of a conventional anti-wear agent (samples 1-2) showed grade results that were much higher than samples 3-4 and were above 25 mg / 100 ml. Beakers containing samples 1-2 had much more varnish in them than the beakers in samples 3-4. Scratch and wear data from FZG for samples 3-4 indicated that, even with low mud, adequate wear protection can be obtained by the formulations of samples 3-4 that contain the anti-wear agent that does not form mud. The above modalities are susceptible of considerable variation in their practice. Accordingly, the modalities are not limited to the specified exemptions specified above. Rather, the above embodiments are within the spirit and scope of the appended claims, which include the equivalents thereof available as legal material. The applicants do not intend to dedicate any modality described to the public, and to the extent that any modifications or alterations described may not fall literally within the scope of the claims, they are considered part of it under the doctrine of equivalents. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property. A food-grade lubricant composition characterized in that it comprises: a larger amount of food-grade base oil and a minor amount of at least one additive composition comprising one or more non-sludge-promoting wear reducing agents, wherein the lubricant composition has lower mud formation tendencies than a lubricant composition containing an enamel wear reducing agent. 2. The food grade lubricant composition according to claim 1, characterized in that one or more non-sludge-promoting wear reducing agents are selected from the group consisting of triphenyl phosphorothionates, amine-neutralized phosphoric acid esters, and mixtures thereof, wherein the amine is an unbranched chain amine. 3. The food grade lubricant composition according to claim 1, characterized in that the food grade base oil comprises an oil selected from the group consisting of white oil, oils, vegetables and mixtures thereof. 4. The food grade lubricant composition according to claim 1, characterized in that the additive further comprises at least one antioxidant selected from the group consisting of amine antioxidants, phenolic antioxidants and mixtures thereof. 5. The food grade lubricant composition according to claim 1, characterized in that the wear reducing agent comprises a mixture of triphenyl phosphorothionate and amine-neutralized phosphoric acid esters, wherein the amine is an unbranched chain amine. 6. The food grade lubricant composition according to claim 1, characterized in that the additive composition further comprises a methacrylate antifoam agent. The food grade lubricant composition according to claim 1, characterized in that it comprises a component selected from the group consisting of a preservative, a corrosion inhibitor and a rust inhibitor. 8. The food-grade lubricant composition according to claim 1, characterized in that the larger amount of food-grade base oil comprises from about 85 to about 99.9% by weight. weight based on the total weight of base oil and additive composition. 9. The food grade lubricant composition according to claim 1, characterized in that the additive composition satisfies the approval criteria of HX-1. 10. The food-grade lubricant composition according to claim 1, characterized in that the lubricant composition is devoid of base oils and additives derived from animals. 11. A method of operation of food processing machinery characterized in that it comprises: providing the machinery with a food-grade lubricant comprising a larger amount of food-grade base oil and a minor amount of at least one additive composition comprising one or more non-sludge-promoting wear reducing agents, wherein the lubricant composition has lower sludge formation tendencies than a lubricant composition containing a conventional wear reducing agent; and operate the machinery. The method according to claim 11, characterized in that one or more non-sludge-promoting wear reducing agents is selected from the group consisting of triphenyl phosphorothionate, esters of phosphoric acid neutralized with amine and mixtures thereof, wherein the amine is an unbranched chain amine. The method according to claim 11, characterized in that the food grade base oil comprises an oil selected from the group consisting of white oil, vegetable oils and mixtures thereof. The method according to claim 11, characterized in that the additive further comprises at least one antioxidant selected from the group consisting of amine antioxidants, phenolic antioxidants and mixtures thereof. The method according to claim 11, characterized in that the wear reducing agent comprises a mixture of triphenyl phosphorothionate and amine-neutralized phosphoric acid esters, wherein the amine is an unbranched chain amine. 16. The method according to claim 11, characterized in that the additive composition further comprises a methacrylate antifoam agent. The method according to claim 11, characterized in that the additive composition further comprises a component selected from the group consisting of a preservative, a corrosion inhibitor and an inhibitor of rust 18. The method according to claim 11, characterized in that the larger amount of food-grade base oil comprises from about 85 to about 99.9% by weight based on the total weight of base oil and additive composition.