Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
1994-09-01
2002-04-16
Medley, Margaret (Department: 1714)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S465000, C508S476000, C508S500000, C508S503000
Reexamination Certificate
active
06372698
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to chain conveyor lubricants which form clear solutions in water and which contain amphoteric compounds corresponding to general formula (I), organic carboxylic acids and, optionally, water and additives and/or auxiliaries.
The invention also relates to the use of such lubricant combinations as chain conveyor lubricants in the food industry. More particularly, the lubricants according to the invention are used for lubricating, cleaning and disinfecting automatic chain conveyors of the type used in the packaging of foods, preferably beverages, in glass and plastic bottles, cans, glasses, barrels, kegs, paper and cardboard containers and the like.
2. Statement of Related Art
In bottle cellars and barrel cellars of beverage factories and in the packaging of foods, plate-type conveyor belts or chain conveyors are normally used for transporting the corresponding vessels, being lubricated and kept clean with suitable water-based lubricant preparations applied by dip lubrication or by automatic belt lubrication systems.
Whereas, in dip lubrication systems, the choice of the lubricant does not present any problems so far as performance properties are concerned, the precipitation of poorly soluble salts together with microbiological deposits in the nozzles and filters of centralized lubrication systems can seriously affect the continuous packaging of foods, particularly beverages, so that the systems always have to be switched off and cleaned after a certain period of operation.
The chain lubricants hitherto used for lubrication are based on the one hand on fatty acids in the form of their water-soluble alkali metal or alkanolamine salts or on fatty amines in the form of their organic or inorganic salts.
DE-A-23 13 330 describes soap-based lubricants containing aqueous mixtures of C
16-18
fatty acid salts and surfactants.
Apart from these soap-based lubricants, lubricants based on primary fatty amines are otherwise mainly used. Thus, DE-A-36 31 953 describes a process for lubricating chain-type bottle conveyors in bottling plants, more particularly in breweries, and for cleaning the conveyors with a liquid cleaner which is characterized in that the chain-type bottle conveyors are lubricated with conveyor lubricants based on neutralized primary fatty amines which preferably contain 12 to 18 carbon atoms and an unsaturated component of more than 10% and in that the bottle conveyors are cleaned with cationic cleaning preparations based on the quaternary ammonium compounds, such as alkyl trimethyl ammonium chloride, dialkyl dimethyl ammonium chloride and alkyl dimethyl benzyl ammonium chloride, or organic acids.
The main disadvantages of these fatty amines are: the reaction with anions present in the water, more particularly sulfates, bicarbonates, phosphates and carbonates from alkaline waters and other water ingredients; a strong reaction with carbonic acid dissolved in water to form poorly soluble ammonium carbonates, for example in the case of beverages containing carbon dioxide; solubilizers have to be used; the spraying and distribution system has to be cleaned at regular intervals; otherwise the system as a whole blocks up and thus becomes unusable.
In the case of lubricants based on primary fatty amines, continuous 24-hour operation is not possible. Where primary fatty amines are used as lubricants, the plants can only be operated with minimal flexibility; in many cases, this process cannot be applied at all because premixing tanks are often present in existing plants. The use of primary fatty amines and the two process steps which it entails—on the one hand lubrication, on the other hand cleaning—involves high capital investment on equipment. Finally, the use of primary amines and lower alkanecarboxylic acids (for example acetic acid), which are necessary for the cleaning step, is accompanied by serious odor emission.
Accordingly, the main disadvantages of the processes mentioned above lie on the one hand in the marked dependence on water of the soap-based lubricants and in the need for regular cleaning of the system where lubricants based on primary amines are used. The precipitations encountered in both known processes have to be removed at the same time. A simple acid/base reaction is used for this purpose. In the case of soap products based on fatty acids, alkaline cleaners containing complexing agents are used for this reaction; in the case of products based on primary fatty amines, organic or inorganic acids are used as technical equivalents to perform the cleaning function.
Finally, chain lubricants without any of the disadvantages mentioned above are known from the prior art. Thus, EP-A-0 044 458 describes lubricant preparations which are substantially free from fatty acid soaps and which in addition contain a carboxylated nonionic surfactant and an acyl sarcosinate. The pH value of these products is in the range from 7 to 11 and, accordingly, is preferably in the neutral to alkaline range.
Finally, DE-A-38 31 448 relates to water-containing, soapless lubricant preparations which form clear solutions in water, to a process for their production and to their use in particular as lubricants for the transport of glass bottles or polyethylene terephthalate bottles. The substantially neutral water-containing lubricant preparations (pH 6 to 8) contain alkyl benzenesulfonates, alkoxylated alkanol phosphates and alkanecarboxylic acids, optionally in addition to typical solubilizers, solvents, foam inhibitors and disinfectants.
Unfortunately, the two products described above are attended by the following three disadvantages:
1. They are microbiologically unfavorable because they create excellent growth conditions for micro-organisms.
2. In addition, they show minimal cleaning power.
3. Finally, their foaming behavior is difficult to control.
DE-A-39 05 548 describes lubricants containing at least one secondary and/or tertiary amine and/or salts of such amines. Unfortunately, these conveyor hygiene products have been found in practice to exhibit certain problems on account of the skin irritation observed in a few cases which was attributed to these products and on account of the formation of toxic secondary products in the event of careless handling (alkalization). On account of their poor wetting effect, these hydrophobic compounds can only be used in the optimal operational state of a conveyor lubrication system. The compounds are neutralized by organic impurities or acids, for example by the introduction of phosphate.
U.S. Pat. No. 3,574,100 describes lubricant compositions containing amphoteric compounds which are named in this document as N-fatty alkyl-&bgr;-aminopropionates and N-fatty alkyl-&bgr;-iminodipropionates.
However, where these compounds are used in lubricants, relative high friction coefficients are observed.
In addition, their ability to form clear solutions in water is inadequate for use in centralized lubrication systems in the food industry, more particularly permanently installed automatic systems.
DESCRIPTION OF THE INVENTION
Accordingly, the problem addressed by the present invention was to provide new improved lubricant preparations, more particularly chain conveyor lubricants forming clear solutions in water, which would not be attended by the disadvantages of the prior art. The lubricants according to the invention have a good coefficient of friction, i.e. an excellent lubricating effect, generate little foam and combine an excellent cleaning effect with high microbicidal activity.
The present invention relates to chain conveyor lubricants forming clear solutions in water and containing in combination
a) at least one compound corresponding to general formula (I):
in which
R
1
is a saturated or mono- or polyunsaturated, linear or branched alkyl group containing 6 to 22 carbon atoms which may optionally be substituted by —OH, —NH2, —NH—, —CO—, halogen or a carboxyl group,
R
2
is a carboxyl group containing 2 to 7 carbon atoms,
M is hydrogen, alkali metal, ammonium, an alky
Strothoff Werner
Winkelmann Birgit
Ecolab Inc.
Henkel-Ecolab GmbH & Co. OHG
Medley Margaret
Sorensen Andrew D.
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