WO2000036057A1

WO2000036057A1 - Method for lubricating conveyor chains used in the food industry

Info

Publication number: WO2000036057A1
Application number: PCT/EP1999/009402
Authority: WO
Inventors: Michael Schneider; Harald Kluschanzoff
Original assignee: Henkel Ecolab Gmbh & Co. Ohg
Priority date: 1998-12-11
Filing date: 1999-12-02
Publication date: 2000-06-22
Also published as: AU1779600A; DE19857236A1

Abstract

The invention relates to a method for lubricating conveyor chains, especially those used for conveying containers (bottles) in filling systems in the food industry; and to concentrates for use in this method. Alkoxylated alkyl or aryldi- or polyamines that carry 2 to 200 alkoxy groups are used as the lubricating components.

Description

"Process for the lubrication of transport chains in the food industry"

The present invention relates to a method for the lubrication of transport chains, such as are used in particular for the transport of containers in filling plants in the food industry, the chains being brought into contact with aqueous solutions of amine active substances.

In the food industry, in particular in beverage companies, the containers to be filled in the filling plants are transported with conveyors of various designs and materials, for example plate conveyor belts or chain-like arrangements, which are generally referred to below as transport chains. The transporters establish the connection between the various optional treatment stages of the filling process such as B. Unpacker, bottle washer, filler, capper, labeler, packer, etc. The containers can be of various shapes, in particular glass and plastic bottles, cans, glasses, barrels, beverage containers (KEG), paper and cardboard containers. To ensure trouble-free operation, these chains must be lubricated in a suitable manner so that excessive friction against the containers is avoided. Diluted aqueous solutions containing suitable anti-friction agents are usually used for lubrication. The transport chains are brought into contact with these aqueous solutions, for example by immersion or spraying, in which case one speaks of immersion lubrication systems or automatic belt lubrication systems or central chain lubrication systems. In the case of central lubrication systems in particular, failures of poorly soluble residues and microbiological deposits in the nozzles and filters of the central lubrication systems can considerably disrupt the continuous operation of filling foodstuffs, in particular beverages. The result is that the systems must always be switched off and cleaned after a certain period of operation.

The chain lubricants previously used as lubricants are based on the one hand on fatty acids in the form of their water-soluble alkali or alkanolamine salts or on fatty amines, preferably in the form of their organic or inorganic salts.

While both substance classes can be used without problems in splash lubrication, they show a number of disadvantages in the central chain lubrication systems that are common today. For example, DE-A-23 13 330 describes soap-based lubricants, the aqueous mixtures of Ciss-Cig fatty acid salts and surface-active agents

Contain substances. Such soap-based lubricants have the following disadvantages:

1. There is a reaction with the water hardness, ie the alkaline earth ions, and other water constituents with the formation of poorly soluble metal soaps, the so-called primary alkaline earth soaps.

2. There is a reaction between these soap-based lubricants and carbon dioxide dissolved in water or the product to be filled.

3. The application solution created in this way is always germ-demanding.

4. When hard water is used, ion exchangers are required for water softening, which means an additional source of germs (and therefore can hardly be found in practice), or the use of products containing high levels of complexing agents, which in turn is ecologically questionable. 5. There is increased foam formation, which is particularly problematic

Bottle-Inspector (automatic bottle control) can cause and wets the transport containers.

6. Most of these products contain solvents.

7. The cleaning effect of these products is poor, so that a separate discontinuous cleaning is always necessary.

8. Such soap-based lubricant preparations show a pH-dependent performance behavior.

9. Soap-based lubricant preparations continue to be dependent on water temperature.

10. Soap-based lubricants only have a low storage stability, especially at low temperatures.

11. The EDTA (ethylenediaminetetraacetate) contained in many products is known to be poorly biodegradable.

12. Such soap-based lubricant preparations are not suitable for all transport goods made of plastic, since in many cases stress corrosion cracking on the transport goods occurs when these agents are used.

In addition to these soap-based lubricants, those based on fatty amines are mainly used. For example, DE-A-36 31 953 describes a method for lubricating chain-shaped bottle conveyor belts in beverage bottling plants, in particular in breweries, and for cleaning the belts using a liquid cleaning agent, which is characterized in that the chain-shaped bottle conveyor belts are used with belt lubricants based on neutralized primary Lubricates fatty amines, which preferably have 12 to 18 carbon atoms and contain an unsaturated fraction of more than 10%.

From EP-A-0 372 628 are fatty amine derivatives of the formulas

known as a lubricant, wherein

R is a saturated or unsaturated, branched or linear alkyl group with 8 to 22 C atoms;

R ^ hydrogen, an alkyl or hydroxyalkyl group having 1 to 4 carbon atoms or

-A-NH ₂ ; A is a linear or branched alkylene group with 1 to 8 carbon atoms; and

A * denotes a linear or branched alkylene group with 2 to 4 carbon atoms.

In addition, DE-A-39 05 548 discloses lubricants based on N-alkylated fatty amine derivatives which contain at least one secondary and / or tertiary amine.

The main disadvantages of these lubricants are the reaction with anions in the water, especially with sulfates, bicarbonates, phosphates and carbonates from alkaline waters, as well as other water components.

In addition, these fatty amine-based lubricants show unsatisfactory foaming behavior. For example, the lubricants of EP-A-0 327 628 tend to form too much foam, as a result of which the transported goods are wetted too much. Lubricants according to DE-A-39 05 548 have a rather poor wetting behavior, which leads to the applied lubricating film running off too quickly. The main disadvantages of the above-mentioned lubricants are, on the one hand, the strong water dependency of the soap-based lubricants and, on the other hand, the regularly necessary system cleaning when using lubricants based on fatty amines, which is also caused by the water content. The precipitates that occur in both prior art processes must be removed. A simple acid-base reaction is used for removal. In the case of fatty acid-based soap products, alkaline, complexing agent-containing cleaners are used for this, and organic or inorganic acids are used as technical equivalents for this purpose in products based on fatty amines as cleaners.

Suitable lubricants should have a good coefficient of friction, i.e. an excellent lubricating effect, a metered foam behavior, a good solubility in clear water, a good cleaning effect and a good microbicidal effect.

For the purposes of the present invention, the term “clear water solubility” is coupled with the insensitivity of the lubricant constituents to anions contained in natural water, such as sulfate, bicarbonate and the like. If, for example, the clear water solubility of a lubricant formulation is not very pronounced, such formulations can react with the water constituents when the system is shut down for a longer period, for example over the course of a weekend. The resulting precipitations and cloudiness in the lubricant's application solutions lead to clogging of the filters and nozzles of the belt lubrication system in the short to medium term.

WO 94/03562 relates to a lubricant concentrate based on fatty amines and, if appropriate, customary diluents or auxiliaries or additives, characterized in that it contains at least one polyamine derivative of a fatty amine and / or a salt of such an amine, the proportion of which is mentioned Polyamine derivatives of fatty amines on the total formulation is 1 to 100% by weight.

These lubricant concentrates, in their form diluted with water to the application concentration, for example in the form of aqueous solutions containing 0.02% by weight of the amines, have excellent clear water solubility.

According to a preferred embodiment of the invention described in WO 94/03562, the lubricant concentrate contains at least one polyamine derivative of a fatty amine of the general formula

RA- (CH ₂ ) _k -NH - [(CH ₂ ) ₁ -NH] _y - (CH ₂ ) _m -NH ₂ ^• (H + X ^

in which

R is a substituted or unsubstituted, linear or branched, saturated or mono- or polyunsaturated alkyl radical having 6 to 22 carbon atoms, the substituents being selected from amino, imino, hydroxy, halogen and carboxy, or a substituted or unsubstituted phenyl radical, where the Substituents are selected from amino, imino, hydroxyl, halogen, carboxy and a linear or branched, saturated or mono- or polyunsaturated alkyl radical having 6 to 22 carbon atoms;

A represents either -NH- or -O-,

X ^"is an anion of an inorganic or organic acid, k, 1, m is independently an integer in the range from 1 to 6; y in the case A = -NH- 0, 1, 2 or 3 and in the case A = - Is O- 1, 2, 3 or 4, n is an integer from 0 to 6. It is known in the prior art to use alkoxylation products of amines, in particular fatty amines, in chain lubricants. On the one hand, these alkoxylation products serve to improve the lubricating effect of other lubricating components. For example, DE 196 42 598 describes a lubricant concentrate whose lubricating effect is based on a combination of one or more amines, one or more ether carboxylic acids and one or more polyethylene glycols. Some of the amines can be present in oxyalkylated form, but according to the disclosure of this document apparently only in connection with nonalkoxylated amines. EP-A-372 628 describes chain lubricants which contain either alkyl diamines or aminocarboxylic acids as lubricating components. In addition to these lubricating components, these lubricants can contain dispersants, which can be selected from triethanolamine and alkoxylated fatty alkyl monoamines or diamines. WO 95/26389 describes chain lubricants based on diamines which, in addition to the alkyldiamine responsible for the lubricating action, contain a water-soluble hydrotrope which is selected from the group consisting of ethoxylated alkylamines having at least 6 carbon atoms in the alkyl group, nonionic surfactants and mixtures thereof. In the last two documents mentioned, the alkoxylated amines therefore take on the role of auxiliaries such as dispersants or hydrotropes. In the aforementioned DE 196 42 598, the alkoxylated amines are used at most as a supporting component for the lubricating effect, but not as the main component which essentially brings about the lubricating effect.

No chain lubricants of the prior art perform all the tasks placed on such a product equally well. There is therefore a need for further chain lubricants with improved properties or for processes for lubricating transport chains in the food industry which are improved compared to previous processes. Accordingly, the invention relates to a process for the lubrication of transport chains in the food industry, in which the transport chains are brought into contact with an aqueous solution during operation, characterized in that this aqueous solution as a friction-reducing agent has at least one alkoxylated polyamine in an amount of 0.001 to Contains 1 wt .-%, wherein this alkoxylated polyamine is selected from the group of compounds with the following formulas I, II and III:

(CH ₂ CHX ¹ 0) _a Y ¹ (CH ₂ CHX ² -0) _b Y ²

(I)

with the following meaning of the abbreviations and indices:

R ¹ : phenyl, alkylphenyl or a linear or branched, saturated or unsaturated alkyl group with 7 to 22 carbon atoms,

A: oxygen, a CH ₂ group or the group -N-

(CH ₂ -CHX ⁵ 0) _e Y ⁵ X, X, ... X: each independently of one another hydrogen or a methyl group,

Y 1, Y? , ... Y 5. each independently of one another hydrogen or an alkyl group having 1 to 4 carbon atoms k, 1, m: each independently an integer from 2 to 6 p: 0, 1, 2 or 3, where p is preferably not 0 when A represents a (CH ₂ ) group, a, b, c, d, e: 0 or integers with the proviso that a + b + c + d + e = is in a range between 2 and 200;

with the following meaning of the abbreviations and indices:

R ² , R ³ : phenyl, alkylphenyl or a linear or branched saturated or unsaturated alkyl group with 7 to 21 C atoms,

X ¹ , X ² , X ³ : meaning as in formula I,

Y ¹ , Y ² , Y ³ : meaning as in formula I, k, 1: meaning as in formula I, x, y, z: 0 or integers with the proviso that in formula II x + y and in formula

III x + y + z are in the range 2 to 200.

In the general formulas I, II and III mentioned above, the following radicals are suitable as substituents R ¹ , R ² and R ³ : n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n -Dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, n-uneicosyl and for R ¹ also n-docosyl and the branched chain isomers the aforementioned Alkyl residues. Instead of the saturated alkyl radicals, R ¹ , R ² and R ^{3 can} also mean the corresponding - mono- or poly-unsaturated alkyl radicals, which can also be linear or branched. The radicals mentioned above can also be substituted, one or more amine, imine, hydroxyl, halogen or carboxy groups being suitable as substituents. In addition, R ¹ , R ² and R ^{3 can} also mean phenyl radicals which can likewise be substituted by one or more amine, imine, hydroxyl, halogen or carboxy groups. Alkylphenyl radicals are also suitable for R ¹ , R ² and R ³ , where the alkyl radical contains 7 to 21 carbon atoms and can also be linear or branched, saturated or mono- or polyunsaturated. In all cases, chlorine or bromine are preferred as halogen substituents.

The non-alkoxylated amines which are suitable as starting products for the alkoxylation are known in the prior art, for example as components of belt lubricants. Examples of this are given in the literature mentioned above. According to known processes, the alkoxylated products which can be used in the process according to the invention can be obtained therefrom by reaction with ethylene oxide and / or propylene oxide in the desired molar ratio.

The process according to the invention is preferably characterized in that in formula I the sum of a, b, c, d, e, in formula II the sum of x and y and in formula III the sum of x, y, z in the range 3 to 50 and preferably in the range 5 to 20.

It is further preferred that in the formulas I, II and III the indices k, 1, m each independently represent 2 or 3, the formulas I, II and III representing the radicals X, X ... X being hydrogen. Accordingly, the use of the ethoxylation products is preferred, but propoxylation products or mixed ethoxylation / propoxylation products are also used can be. In the case of mixed ethoxylation / propoxylation products, it may be advantageous due to the foaming behavior to use products which were first ethoxylated and then propoxylated.

Irrespective of this, the groups introduced by the alkoxylation can either end with an -OH group or be etherified again with an alcohol having 1 to 4 carbon atoms, that is to say end group-capped. However, the alkoxylation products which are not end-capped are preferably used. In formulas I, II and III this means that the radicals Y ¹ , Y ² ... Y ^{5 are} preferably hydrogen.

Preferably, the inventive method is characterized in that at least one compound of formula I is contained in the aqueous solution as a drag reducing agent, wherein A preferably has the meaning of - N (CH ₂ -CHX ⁵ 0) _e Y ⁵ -, and p has the particular Has values of 0 or 1.

Compared to the lubrication processes specified in documents DE 196 42 598, EP-A-372 628 and WO 95/26389, the process according to the invention is distinguished in that the alkoxylated amines of the general formulas I, II and III are the main carriers of the lubrication action, if not can even be used as the only friction-reducing component. In contrast, in the three documents mentioned in the previous sentence, the lubricating effect is achieved by other friction-reducing connections. Accordingly, the process according to the invention is preferably characterized in that the aqueous solution brought into contact with the transport chain is free from non-alkoxylated monoamines and from non-alkoxylated diamines and that it contains no ether carboxylic acids and / or polyethylene glycols.

The process according to the invention is preferably carried out in such a way that the alkoxylated polyamines used as friction-reducing active ingredients in the aqueous solution in a concentration between 0.003 and 0.1 wt .-%, preferably between 0.005 and 0.05 wt .-% are contained.

The aqueous solution of the alkoxylated polyamines brought into contact with the transport chain preferably has a pH between about 5 and about 8. If acids have to be added to adjust this pH (so that the alkoxylation products of the amines to be used according to the invention are at least partially in Salt form), different acids tTX ^" can be used for this.

The anion X "here can mean an anion of any inorganic or organic acid. What is important for the selection of this acid in the sense of the present invention is only that the acid or its anion in conjunction with the alkoxylation products of the general formulas I, II and III does not lead to precipitation and thus impairs the clear water solubility of the lubricant In individual cases, the expert will make a suitable selection based on simple tests.

Those acids whose anion X "is selected from the group amidosulfonate, nitrate, halide, hydrogen sulfate, sulfate,

Hydrogen carbonate, carbonate, phosphate or R -COO ", where the radical R ^{4 represents} hydrogen, a substituted or unsubstituted, linear or branched alkyl radical having 1 to 20 C atoms or alkenyl radical having 2 to 20 C atoms, the substituents being selected are from one or more of the residues

Hydroxy, amino, imino and carboxy. Anion X "thus - in addition to the inorganic anions already mentioned - also come from anions of organic acids

Type R ⁴ -COO "in question. As examples of organic anions X" of type R ⁴ -

COO "may be mentioned in particular: formate, acetate, glycolate, oleate, lactate, Gluconate, citrate and glutamate. For practical reasons, it is preferred

Formic acid or acetic acid used.

Belt lubricants are preferably sold as concentrates, in which the friction-reducing component is more or less enriched. The higher the concentration of the friction-reducing component in the concentrate, the more economical it is to transport such concentrates from the manufacturer to the user, since the less water has to be transported. At the user, the concentrates are diluted to the application concentration and applied to the transport chains. This also applies to the process according to the invention, which is accordingly characterized in that the aqueous solution brought into contact with the transport chain is prepared by diluting a concentrate with water, the concentrate or the friction-reducing active ingredients in a correspondingly higher concentration together with others in such a concentration Contains conventional additives and additives. The desired pH of the ready-to-use aqueous solution can be adjusted by adding the required amount of acid only when the concentrate is diluted. This can be done, for example, by first adding one of the abovementioned acids, in particular acetic acid, to the water used to dilute the concentrate, for example to initially set a pH in the range from about 3 to about 6. By adding the alkaline belt lubricant to the water, the desired pH is then set.

In a further aspect, the invention also includes the concentrate of the belt lubricant, the dilute aqueous solution of which can be used in the process according to the invention. Accordingly, the invention also relates to a concentrate for use in a process according to claim 10, containing, as friction-reducing active ingredients, one or more of the compounds of general formulas I, II and III mentioned in claim 1 in amounts between 1 and 100 % By weight, preferably in amounts between 2 and 90% by weight and in particular in

Amounts between 5 and 90% by weight, with a remainder consisting of 100% by weight of water and / or other active substances and auxiliaries.

Accordingly, the concentrates of the alkoxylated amines to be used in the process according to the invention can contain these friction-reducing active ingredients in highly concentrated form, for example in concentrations above about 60% by weight. In suitable cases, the alkoxylated amines can also be in pure form, i.e. H. are marketed and used as "100% concentrate", provided that they can be diluted with water to the desired application concentration sufficiently quickly during use. In general, the concentration of the alkoxylated amines in the concentrate will be adjusted so that it ranges between about 2 and about 90% by weight and in particular between about 5 and about 90% by weight If no dosing devices are available which can dilute the highly concentrated products to the application concentration, concentrations in the lower range of this range, for example between about 5 and about 40% by weight may be preferred, for industrial metering devices it may be advantageous for the lubricant concentrates to have a dynamic viscosity of less than 300 mPa.s, in particular less than 150 mPa.s and particularly preferably in the range from 20 to 100 mPa.s - each at 20 ° C - to ensure their pumpability The viscosity is adjusted to the values mentioned, if appropriate, by adding suitable amounts of the diluent water or a solubilizer.

If concentrates are used whose concentration of the alkoxylated amines is in the upper range of the above-mentioned concentration range, that is to say in the range from about 50 to 100% by weight and in particular from about 60 to about 90% by weight, the dilute is prepared from this Ready-to-use aqueous lubricant solution preferably as follows: 2 or more mixing reactors working in parallel are provided. In the reactors there is water, which is acidified with an organic acid, preferably acetic acid, to a pH of 3 to 6, and the required amount of concentrate is added. Mix for a period in the range of about 1 to about 30 minutes, preferably from about 10 to about 20 minutes, using an agitator. The reactors are used alternately as a mixing reactor or as a storage container for the ready-to-use chain lubricant solution. Mixing reactors are expediently provided, the size of which is adapted to the consumption of the chain lubricant solution.

In particular, the invention relates to a concentrate for use in a method according to claim 10, which is free of non-alkoxylated monoamines and non-alkoxylated diamines and which contains no ether carboxylic acids and / or polyethylene glycols.

The concentrates can contain further auxiliaries and / or additives. Auxiliaries and / or additives according to the present invention are, in particular, solubilizers, for example alcohols, polyalcohols, ethers or polyethers, in particular isopropanol, butyl glycol, butyl diglycol or ethylene glycol ether. The amount of solubilizer to be used depends in each case on the amine used, the person skilled in the art will determine the required amount of solubilizer by trying out in individual cases. In general, additions to solubilizers in the range from 5 to 20% by weight, based on the overall formulation, are sufficient. If polyethers in the form of polyethylene glycols are to be used as auxiliaries, the concentrate is kept free of ether carboxylic acids.

Auxiliaries and / or additives according to the present invention are furthermore, in particular, nonionic and / or amphoteric surfactants, for example alkoxylated fatty amines, fatty alcohols and alkoxylated fatty alcohols. These surfactants can improve the wetting of the chains and plate conveyor belts, provided this should be necessary in individual cases. In general, surfactant additives

A range of 1 to 5% by weight, based on the total formulation, is sufficient for this.

Claims

claims

A process for the lubrication of transport chains in the food industry, in which the transport chains are brought into contact with an aqueous solution during operation, characterized in that this aqueous solution as an anti-friction agent has at least one alkoxylated polyamine in an amount of 0.001 to 1% by weight. contains, wherein this alkoxylated polyamine is selected from the group of compounds with the following formulas I, II and III:

(CH ₂ CHX ³ 0) _c Y ³

R ^A A - CH ^ - N - KCi Jr ^ f -] _P - (CH ₂ ) _m -:

(CH ^ HX ^ Y ⁴

(CH ₂ CHX ¹ 0) _a Y ¹ (CH ₂ CHX ² -0) _b Y ²

(I)

with the following meaning of the abbreviations and indices:

A: oxygen, a CH ₂ group or the group -N-

1 9 * ϊ

Y, Y, ... Y: each independently of one another hydrogen or one

Alkyl group with 1 to 4 carbon atoms k, 1, m: each independently of one another an integer from 2 to 6 p: 0, 1, 2 or 3, preferably not being 0 if A is a (CH ₂ ) group stands, a, b, c, d, e: 0 or integers with the proviso that a + b + c + d + e = is in a range between 2 and 200;

R ³ -CO-NIt (III)

with the following meaning of the abbreviations and indices:

9

R, R: phenyl, alkylphenyl or a linear or branched saturated or unsaturated alkyl group with 7 to 21 C atoms,

X ¹ , X ² , X ³ : meaning as in formula I,

Y ¹ , Y ² , Y ³ : meaning as in formula I, k, 1: meaning as in formula I, x, y, z: 0 or integers with the proviso that in formula II x + y and in

Formula III x + y + z are in the range 2 to 200.

2. The method according to claim 1, characterized in that in formula I the sum of a, b, c, d, e, in formula II the sum of x and y and in formula III the sum of x, y, z in the range 3 to 50 and preferably in the range 5 to 20.

3. The method according to any one of claims 1 or 2, characterized in that in the formulas I, II and III, the indices k, 1, m each independently represent 2 or 3.

4. The method according to any one of claims 1 to 3, characterized in that in the formulas I, II and III, the radicals X ¹ , X ² , ... X ^{5 represent} hydrogen.

5. The method according to any one of claims 1 to 4, characterized in that in the formulas I, II, III, the radicals Y ¹ , Y ² , ... Y ^{5 represent} hydrogen.

6. The method according to any one of claims 1 to 5, characterized in that at least one compound of formula I is contained in the aqueous solution as a friction-reducing active ingredient, wherein A preferably has the meaning of -N (CH ₂ -CHX ⁵ 0) _e Y ⁵ - and p has in particular the values 0 or 1.

7. The method according to any one of claims 1 to 6, characterized in that the aqueous solution brought into contact with the transport chain is free of non-alkoxylated monoamines and non-alkoxylated diamines and that it contains no ether carboxylic acids and / or polyethylene glycols.

8. The method according to any one of claims 1 to 7, characterized in that the alkoxylated polyamines used as friction-reducing agents in the aqueous solution in a concentration between 0.003 and 0.1 wt .-%, preferably between 0.005 and 0.05 wt .-% % are included.

9. The method according to any one of claims 1 to 8, characterized in that the aqueous solution of the alkoxylated polyamines brought into contact with the transport chain has a pH between 5 and 8.

10. The method according to any one of claims 1 to 9, characterized in that the aqueous solution brought into contact with the transport chain is prepared by diluting a concentrate with water, the concentrate or the friction-reducing active ingredients in a correspondingly higher concentration together with far in contains such additives and conventional additives.

11. Concentrate for use in a process according to Anspmch 10, containing as friction-reducing active ingredients one or more of the compounds of general formulas I, II and III mentioned in Anspmch 1 in amounts between 1 and 100% by weight, preferably in amounts between 2 and 90% by weight and in particular in amounts between 5 and 90% by weight, a remainder consisting of 100% by weight of water and / or other active substances and auxiliaries.

12. Concentrate according to Anspmch 11, characterized in that it is free from non-alkoxylated monoamines and from non-alkoxylated diamines and that it contains no ether carboxylic acids and / or polyethylene glycols.