WO1995019413A1

WO1995019413A1 - Lubricant compositions

Info

Publication number: WO1995019413A1
Application number: PCT/CA1995/000025
Authority: WO
Inventors: James Taylour; Clare Grisdale
Original assignee: Unilever N.V.
Priority date: 1994-01-12
Filing date: 1995-01-12
Publication date: 1995-07-20
Also published as: EP0739407A1; PL315523A1; CA2180326A1; GB2285630A; GB9400437D0; NZ278034A; MX9602747A; AU680095B2; BR9506487A; ZA95220B; JPH09508153A; AU1411395A

Abstract

A high pH concentrate which upon dilution with water forms a lubricant composition for use in lubricating conveyor track, said concentrate having a pH of 7 to 11 comprising the following components: (a) (i) an alkylamine dicarboxylate compound of general formula (I), wherein R1 is a C8 to C18 saturated or unsaturated alkyl group, including mixtures of such alkyl groups, n is an integer of from 1 to 12, preferably n is 2, and each of M1 and M2, which may be the same or different, independently represents hydrogen or a Group I metal, typically sodium or potassium, and with the proviso that the distribution of alkyl chain lengths of the group R1 is such that components (a) and (b) remain in solution; and/or (ii) a compound of general formula (II), wherein R1 is a C8 to C18 alkyl group as defined above, R2 represents hydrogen or -(CH2)m -OH wherein m is an integer of from 2 to 12, and each of Y1 and Y2 which may be the same or different, is independently selected from -CH2 OH, -COOOM3O and -CH¿2COO?OM3O, wherein M¿3? is hydrogen or a Group I metal, typically sodium or potassium; (b) a cyclic imidazoline of general formula (III), wherein R3 is a C7 to C20 saturated or unsaturated alkyl group; and (c) a C12 to C18 saturated or unsaturated alkyl sulphonate anionic surfactant, and (d) optionally, a pH reducing agent to provide said pH in the range of 7 to 11.

Description

LUBRICANT COMPOSITIONS

Field of the Invention

The present invention relates to lubricant compositions, and more specifically to lubricant compositions for use in lubricating the tracks which convey bottles, cans and similar containers and packages for beverages from one station to another in a bottling plant.

Background of the Invention Beverages are sold in a variety of containers such as glass bottles, plastics bottles, plastics containers, cans, or waxed carton packs. These containers are conveyed through a number of stations in a plant where they are filled with the desired beverage; the containers are conveyed from one station to another by a track which is usually of stainless steel when the containers are glass bottles, or of a plastics material such as an acetal resin (sold under the name Delrin) when the containers are other than glass bottles. Such tracks will hereinafter be referred to as "conveyor track".

When the containers are being filled with beverage at a filling station on the bottling plant, they are kept at a fixed position under the filling station while the conveyor track continues to move forwards below the container. In addition, blockage of the path along which the containers are travelling can occur if a container falls over or gets jammed. In such instances it is important that the conveyor track is properly lubricated so that the track can continue to move even though the containers on the track are temporarily prevented from advancing.

In order to ensure smooth operation of the filling process, it is imperative to ensure that the conveyor track is properly lubricated and cleaned. If the conveyor track is not properly lubricated, the containers can easily fall over or fail to stop moving when they reach the appropriate station in the plant. This can cause serious disruption to the efficient operation of the filling process.

Lubricant compositions which are currently used for lubricating and cleaning conveyor track are generally of three main types:

(i) compositions based on fatty acids, (ii) compositions based on fatty amines, and (iii) compositions based on phosphate esters. Aqueous solutions of fatty acids are not suitable for use in areas of hard water, unless they are stabilized by the incorporation of a complexing agent such as ethylenediamine tetra-acetic acid (EDTA) .

A further problem which we have encountered with compositions based on fatty acids or amines or on phosphate esters is that these known formulations are very aggressive to the coloring pigments used to label the surfaces of the containers, particularly steel and aluminum cans used in the beverage industry. We have found that these known lubricating compositions have a marked tendency to leach the printed matter printed an the surface of the containers.

U.S. Patent 3,574,100 describes a conveyer track lubricant composition which comprises an aqueous solution of (a) a phosphate ester of an oleyl alcohol ethoxylate and (b) a water soluble amphoteric compound.

We have now produced a new lubricating composition for use in lubricating conveyor track which has the advantage that it does not cause fading of the colors in the printed matter on the containers which are being processed through the filling plant. The lubricant compositions of the present invention can also be used in areas of hard water. Summary of the Invention According to one aspect of the present invention, there is provided a high pH concentrate which upon dilution with water forms a print compatible lubricant composition for use as a lubricant for conveyor track, said concentrate comprising the following components:- (a) (i) an alkylamine dicarboxylate compound of general formula (I)

wherein R, is a C₈ to C^ saturated or unsaturated alkyl group, including mixtures of such alkyl groups, n is an integer of from 1 to 12, preferably n is 2, and each of M, and M₂, which may be the same or different, independently represents hydrogen or a Group I metal, typically sodium or potassium, and with the proviso that the distribution of alkyl chain lengths of the group W is such that components (a) and (b) remain in solution; and/or (ii) a compound of general formula (II)

O R₂

wherein W is a C₈ to C₁₈ alkyl group as defined above, R₂ represents hydrogen or -(CH₂)_m -OH wherein m is an integer of from 2 to 12, and each of Yj and Y₂ which may be the same or different, is independently selected from -CH₂ OH, -C00^θM₃ ^θ and -CH₂COO^θM₃ ^®, wherein M₃ is hydrogen or a Group I metal, typically sodium or potassium; (b) a cyclic imidazoline of the general formula

(III)

wherein R₃ is a C-* to C^ saturated or unsaturated alkyl group;

(c) a C₁₂ to C_lg saturated or unsaturated alkyl sulphonate anionic surfactant, and

(d) optionally, a pH reducing agent to provide said pH in the range of 7 to 11. DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION In the group R, of component (a) , the distribution of alkyl chain lengths must be such that the product is stable and components (a) and (b) do not come out of solution. This is achieved, for example, if the alkyl chain of the group R_j is predominantly a C₁₂ alkyl group, e.g., a mixture of alkyl groups as obtained from coconut acid, or a mixture of an unsaturated C₁₈ alkyl group (ie oleyl) with said predominantly C₁₂ alkyl mixture. Thus, when component (a) is an alkylamine dicarboxylate of formula (I) , it is preferably a salt of coco-amine dipropionate, or a mixture of said coco-amine salt, with a salt of oleyl-amine dipropionate. These salts are typically the mono sodium salts.

These alkylamine dicarboxylate compounds may often be referred to in the art as alkyl betaine compounds and are intended to be interchangeable insofar as describing various aspects of the invention.

In a particularly preferred embodiment of the concentrate of the present invention, component (a) comprises a mixture of the said oleyl- and coco-amine dipropionate salts, preferably in a 1:2 weight ratio of oleyl-amine dipropionate: coco-amine dipropionate. The coco-amine dipropionate salt is derived from coconut acid, which acid is a mixture of long chain fatty acids having chain lengths varying from C₈ to C₁₈, with a preponderance of C₁₀, C_n and C₁₄. When component (a) is a compound of formula (II) , it is preferably a compound of said formula in which R, is an oleyl-group or a coco-group as defined above, R₂ is a -CH₂CH₂OH group and Yi and Y₂ are as defined above. A particularly preferred compound of formula (II) is a compound of the formula:

CH₂CH₂COO^θNa^θ

(Coco) - C - N - CH₂CH₂ - N

II I CH₂CH₂COO^θNa^® O CH₂CH₂OH

Compounds of general formula (I) and general formula (II) are commercially available. For example, the oleyl- amine dipropionate and coco-amine dipropionate salts mentioned above are sold by Lakeland Laboratories Ltd of Manchester, England as oleyl betaine - Lakeland ODA - (monosodium salt of oleyl a ine dipropionate) and coca betaine - Lakeland AMA - (monosodium salt of coca amine dipropionate) . These materials are sold as 30% active solutions.

Compounds of general formula (II) are available from Rhone Poulenc and sold under-the MIRANOL trade name. These materials are sold as solutions which are 37-45% active. Typically, component (a) is used in an active amount of from 0.4 to 18 wt%, based on the total weight of the concentrate. More preferably, the active amount of component (a) used to form the concentrate of the present invention ranges from 3.8 to 13 wt%. These ranges apply whether component (a) is an alkylamine dicarboxylate of general formula (I) or a compound of general formula (II). Component (b) is a cyclic imidazoline of general formula (III) as defined above. In these compounds, R₃ is preferably a saturated or unsaturated O, to C₁₈ alkyl group, more preferably an unsaturated C₁₇ alkyl group. Typically, the cyclic imidazoline is used in an active amount of from 0.35 to 14 wt%, based on the total weight of the concentrate. More preferably, the active amount of the cyclic imidazoline compound used to form the concentrate ranges from 3 to 10 wt%, based on the total weight of the concentrate.

Materials of general formula (III) are also commercially available. For example, an imidazoline of this type in which R₃ is an unsaturated C₁₇ alkyl group is supplied by Lakeland Laboratories Ltd as Imidazoline 180H. This material is sold as a liquid which is typically 65-71% active, with an average activity of 68%.

Component (c) is an alkyl sulphonate anionic surfactant and is preferably an oleyl sulphonate anionic surfactant. Surfactants of this general type are commercially available materials. For example, the oleyl sulphonate anionic surfactant mentioned above is sold by Hoechst AG as Hostapur OS and is sold as a 40% active solution.

Typically, the alkyl sulphonate anionic surfactant is present in the concentrate in an active amount of from 0.2 to 5 wt%, based on the total weight of the concentrate. In preferred compositions the active amount of the alkyl sulphonate anionic surfactant ranges from 0.2 to 1 wt%, based on the total weight of the concentrate.

Components (a) and (b) are incorporated in the present compositions to provide the desired lubrication properties. Preferably the active weight ratio of component (a) to component (b) is 0.9-1.4:1. The alkyl sulphonate surfactant - component (c) - is included in the present compositions as a hydrotrope, i.e. it acts to stabilize the formulation thereby to prevent phase separation, particularly of the dilute solutions which are produced when the concentrate is diluted with water. The alkyl sulphonate surfactant does not play any active role in the lubrication process nor does it appear to have any function in preventing leaching of pigment from the printing inks used on containers which are conveyed through bottling plants.

We have found that it is possible to include a further component in the concentrates of the present invention. We have found that if one incorporates up to 3 wt%, based on the total weight of the concentrate, of (d) a non-ionic surfactant which is a linear or branched alkoxylated alcohol or alkoxylated phenol, each having from 5 to 20 units of ethoxylation, in the concentrate of the invention, the soil handling characteristics of the resultant lubricant compositions are improved. This surfactant appears to play no part in lubrication, in the stability of the composition, nor in protecting the pigment on the printed surface of the container. A preferred such non-ionic surfactant is an iso-C - C₁₅ alcohol which has 12 units of ethoxylation. These surfactants are available commercially; for example a material of this type is sold by BASF AG as Lutensol T0129 and is said to be 88% active. When a non-ionic surfactant of this type is incorporated as component (d) in the concentrates of the present invention, it is usually present in an active amount of from 0.5 to 10 wt%, preferably from 1 to 5 wt%, based on the total weight of the concentrate. The concentrates of the present invention are typically prepared by dissolving the cyclic imidazoline (component b) in a mixture of water and isopropanol. The solution is stirred until the imidazoline has dissolved, whereupon component (a) is then introduced. When component (a) comprises a mixture of oleylamine dicarboxylate and coco-amine dicarboxylate, the procedure is that the oleylamine dicarboxylate is introduced first and the solution is stirred gently and heated up to a temperature of about 60°C until a viscous slurry is obtained (usually about 1/2 hour) .

Finally the oleyl sulphonate surfactant (component c) is added to the formulation.

The pH of the formulation can be varied from 7 to 11 depending on the properties required. We have observed that at lower pH values for the concentrate good lubrication with drag coefficients of 0.15 - 0.16 are realized. However, better pigment compatibility is observed at the high pH values. A pH value of about 9 to 11 is preferred for optimum pigment compatibility.

To lower the pH of the formulation, as needed, a suitable acid is added. We have found that addition of a simple acid such as acetic acid results in an unstable product. We have found that acids which have hydrotropic properties are suitable. Examples of such hydrotropic acids are caprylic acid and neodecanoic acid. Neodecanoic acid is preferred; surprisingly, the resultant product remains stable in hard water. Use of caprylic acid results in a product that is not stable to hard water.

According to a further aspect of the present invention there is provided a lubricant composition for use as a lubricant for conveyor track, said lubricant composition comprising a concentrate as defined above diluted with from 80.00 to 99.99 parts by volume of water. More typically, the concentrates of the present invention are diluted with from 99.0 to 99.9 parts by volume of water.

The compositions of the present invention are usually sold as concentrates and are diluted for use as conveyor track lubricants.

Typical use concentrations of the formulation would be from 0.1 to 1% vol/vol made up in water. The exact concentration depends on factors such as the speed of the conveyor track, the type of package or container being carried by the track, the total loading on the conveyor track and the amount of soiling caused by spillage.

Dilution of the lubricant concentrate is normally performed at a central dispenser, and the diluted lubricant composition is then pumped to spray nozzles at the point of use. There are some areas of the conveyor track that require very little lubricant. Typically these are the zones before the filler and before the pasteurizer. In these regions secondary dilution is often employed. Lubricant is likely to be at its highest use concentration at the filler.

The lubricant solutions are typically sprayed onto the conveyor from fan jet nozzles placed at the start of each length of track. For particularly long runs, secondary spray jets may be positioned along the length of the track.

In areas of heavy soiling it may be necessary to continually spray lubricant onto the track. However, in most instances timers are employed to vary the dosing rate. Typically on and off times will be between 10 and 90 seconds. Off times will not always equal on times. Also it is likely that throughout a plant timer settings will vary.

In some applications, a final water wash jet will be placed at the end of a bottle/can filling track. This will wash residues of lubricant from the package before crating and dispatching.

Excess lubricant will be allowed to fall from the track either to the floor or suitable drip trays. In either event it will eventually enter the drainage and water treatment systems.

As has been stated above, we have found that the lubricant compositions of the present invention have the particular advantage that they are compatible with can print, i.e. they do not rapidly leach print from the surface of containers being carried by conveyor track which is being lubricated by the said lubricant compositions. Furthermore the lubricant compositions of the invention can also be used in areas of hard water without any apparent adverse effects.

The present invention is illustrated by the following Examples:

EXAMPLE 1

A concentrate suitable for use upon dilution with water as a conveyor track lubricant was formulated in the following manner from the components set out in the Table below:-

Raw %wt/wt Bulk % Active Material Concentration in formulation

Imidazoline 180H 5.4 3.7

Lakeland ODA 5.7 1.7

Lakeland AMA 10.4 3.1

Hostapur OS 1.0 0.4

Isopropyl Alcohol 5.7 5.7

Soft Water (<5ppm 71.8 71.8

CaC0₃)

Referring to the Table, Imidazoline 180H is a compound of general formula (III) in which R₃ is an unsaturated C₁₇ alkyl group and is supplied by Lakeland Laboratories Ltd as a liquid which is 65-71% active.

Lakeland ODA is an oleylamine dipropionate (mono sodium salt) , i.e. a compound of general formula (I) , sold by Lakeland Laboratories Ltd as a 30% active solution.

Lakeland AMA is a coco-amine dipropionate (mono sodium salt) , i.e. a compound of general formula (I) , sold by Lakeland Laboratories Ltd as a 30% active solution.

Hostapur OS is an oleyl sulphonate anionic surfactant i.e. component (c) - sold by Hoechst AG as a 40% active material. Imidazoline 180H (component c) was added to a mixture of the isopropyl alcohol and soft water. The resultant solution was stirred until the imidazoline was fully dissolved. Lakeland ODA (component (a) : oleyl amine dipropionate) was then added to the solution and stirred for up to 30 minutes with gentle heating at up to 60°C. During this mixing process, the mixing vessel was sealed to prevent loss of volatile material. The resultant product was a viscous slurry.

Lakeland AMA (component (a) : coco-amine dipropionate) was added to the slurry and stirred until the mixture had cooled to room temperature. The mixture at this stage was a clear solution. Finally, Hostapur OS (component (b) : anionic surfactant) was added to the solution.

The resultant formulation had a pH between 10 and 11. The product was found to be stable when diluted to 1% in hard water and did not cause fading of the printing inks used on the surfaces of printed aluminum cans, i.e. the formulation is compatible with the printing on aluminum cans.

The product formulation shown in the Table above is typically diluted in water for use as a conveyor track lubricant. Typical use concentrations are from 0.1 to 1% vol/vol.

EXAMPLE 2

Following the procedure described in Example 1, an alternative aqueous concentrate formulation was prepared from the components set out in the Table below:- Raw %wt/wt Bulk %Active Material Concentration in formulation

Imidazoline 180H 5.4 3.7 Lakeland ODA 5.4 1.7 Miranol C2MSF 10.0 3.9 Hostapur OS 1.0 0.4 Isopropyl Alcohol 5.7 5.7 Soft Water 72.5 72.5

Apart from Miranol C2MSF, the components are the same as those described in Example 1. Miranol C2MSF is a compound of general formula (II) of the structure

CH₂CH₂COO^θNa^θ

CH₂CH₂COO^θNa^θ

O CH₂CH₂OH

and is supplied by Rhone Poulenc as a solution which is said to be 39% active.

As will be seen, this formulation is similar to that described in Example 1, except that the Lakeland AMA material (i.e. the coco-amine dipropionate) is replaced by the Miranol C2MSF material described above.

The properties of the resultant formulation were very similar to those of the formulation of Example 1.

Example 3 Tests were conducted to evaluate the ink compatibility of the various lubricant compositions of this invention as well as their lubricity at various pH levels.

The lubricity of the test composition was measured using an apparatus which comprised a moving conveyor on top of which a stationary load cell is mounted. A dynamic load is positioned upstream of the load cell and a static load is positioned upstream of the dynamic load. In order to test the lubricity or drag coefficient μ, a four kilogram glass bottle was positioned on the conveyor and represented the dynamic load, whereas the static load consisted of ten 600 gram glass bottles. The drag coefficient was calculated on the basis of; M = drag (g) weight of dynamic load (g)

For aluminum cans, the dynamic load was replaced with cans to give a load of 3.6 kilograms and the static load consisted of ten aluminum/steel cans. The drag coefficient was calculated in accordance with the above formula. The durability of the lubricant composition was also evaluated. Durability is measured as the time taken for the drag coefficient to increase to 0.25 after disconnection of the lubricant supply to the conveyor whilst continuous dosing of the conveyor with water is continued over that period of monitoring. Both the drag coefficient and durability are a measure of lubricant effectiveness. A good lubricant has a low drag coefficient, a high durability rating and quickly reaches equilibrium lubrication. In order to test the print compatibility of the various lubricants of this invention with ink that is used in marking aluminum cans or steel cans, the following ink compatibility test was conducted.

This is an aggressive test method that we believe mimics the conditions that a beverage can would experience in a pasteurizer. In detail, test strips were cut from aluminum beverage cans printed predominantly with red ink. Each strip had dimensions of approximately 20 mm by 80 mm. Contact of the strips with lubricant was achieved by placing strips into lubricant solutions at 65°C. Furthermore, these solutions were made up to a concentration of approximately ten times the expected maximum use concentration. For this type of formulation, we expect the maximum use concentration to be about 0.5% wt/wt, hence test solutions were made to 5.0% wt/wt in soft water (< 10 ppm calcium carbonate) . Contact time was taken between 1 and 24 hours during which time the temperature was maintained at 65°C. At the end of the duration, the strip was removed from the solution and compared qualitatively against a control formulation that was known to be benign towards the ink. Arbitrary units were assigned to reflect the degree of aggressive removal of print pigment. A lower unit value indicates mild, if any, pigment removal, whereas a higher unit value indicates an aggressive pigment removal. The control standard establishes that a score of 1 indicates a benign action, whereas a score of 4 indicates an unacceptable aggressive action by the lubricant. Formulations of Example 1 were tested and identified by the composition numbers D853; D854; D855 and D856. The only difference in each composition is that the pH was adjusted to the level noted in the following Table 1.

TABLE 1

D853 D854 D855 D856 Control pH 6.0 7.2 9.5 10.2 — μ 0.15-0.17 0.15-0.17 0.16-0.18 0.15-0.17 -

Durability/ 42.0 24.0 18.0 18.0 - Seconds

Time to reach 3 3 7 15 — equilibrium minutes minutes minutes minutes lubrication

Qualitative 4 3 2 1 1-2 Ink

Compatibility Rating pH INCREASING → Ink Compatibility Increasing → «- Lubricant Efficacy INCREASING

From the above Table, it is apparent that acceptable print compatibility was achieved with formulations D856 and D855. The formulation of D854 with a pH of 7.2 is understood to be at the outermost edge of print compatibility acceptability, although from Table 1, it is apparent that a pH of about 9.5 and about 10.2 for the formulation are far superior. As is understood by those skilled in the art, evaluation of lubrication performance depends on the drag coefficient, durability and time to reach equilibrium value of μ. From Table 1, we can see that as pH decreases, lubrication performance decreases. The drag coefficient is reasonably consistent for the various selected pH with a slight increase being noted at a pH of 9.5, but dropping back to a level corresponding to the lower pHs when the pH is increased above 9.5. It is understood, however, that, in measuring drag coefficient, the slight increase at a pH of 9.5 may be due to a particular procedure with that composition and should not be interpreted as indicating any special circumstance for the pH lubricity value at 9.5. However, in considering the values for durability and time to react equilibrium value for μ. Table 1 demonstrates the above increase in lubrication performance with decreasing pH, but it is apparent that the higher pH composition still constitutes good lubricants. Example 4

In order to further evaluate print compatibility of the lubricant compositions of this invention, a second technique for testing print compatibility was undertaken. The revised method required a modification of the method defined in Example 3 to provide a more quantitative way of assessing print compatibility. This was achieved by using the same aluminum beverage cans used in the previous method, filling them with water and placing them completely in a ten times working concentration of the lubricant. Excess fluid was allowed to drain from the paper and then carefully wrapped around the hot can. The can was maintained at 65°C by placing in an insulated box for a contact time of 45 minutes. The blotting paper was then allowed to air dry and compared qualitatively against the control formulation. As with the previous test method, the scoring of the lubricant's aggressive nature for removing print pigment was evaluated in a similar manner.

The results of the test including also measuring of drag coefficient were undertaken and summarized in the following Table 2.

TABLE 2

«- Lubricant Efficacy INCREASING Ink Compatibility ACCEPTABLE

From the above Table 2, it is apparent that preferred compositions of the invention having a pH of 9.5 and 10.5 have acceptable ink compatibility with very high durabilities and very acceptable drag coefficients. From the results of Tables 1 and 2, it is apparent that a suitable lubricant, in accordance with the composition of this invention, can be provided with a pH preferably from 9 to 11 to yield ink compatibility in accordance with the test techniques.

Claims

1. A high pH concentrate which upon dilution with water forms a print compatible lubricant composition for use in lubricating conveyor track, said concentrate having a pH of 7 to 11 and comprising the following components:- (a) (i) an alkylamine dicarboxylate compound of general formula (I)

(CH₂)_n COO^θM.^Θ R_! - N (I)

"^"^(CH₂)_n COO^θM₂ ^θ

wherein R_! is a C₈ to C₁₈ saturated or unsaturated alkyl group, including mixtures of such alkyl groups, n is an integer of from 1 to 12, preferably n is

2, and each of M, and M₂, which may be the same or different, independently represents hydrogen or a Group I metal, typically sodium or potassium, and with the proviso that the distribution of alkyl chain lengths of the group R, is such that components (a) and (b) remain in solution; and/or (ii) a compound of general formula (II)

R,

wherein Rj is a C₈ to C₁₈ alkyl group as defined above, R₂ represents hydrogen or -(CH₂)_m -OH wherein m is an integer of from 2 to 12, and each of Yj and Y which may be the same or different, is independently selected from -CH₂ OH, -C00^θM₃ ^® and -CH₂COO^θM₃ ^θ, wherein M₃ is hydrogen or a Group I metal, typically sodium or potassium; (b) a cyclic imidazoline of the general formula

(III)

wherein R₃ is a C, to C₂₀ saturated or unsaturated alkyl group;

(c) a C₁₂ to C₁₈ saturated or unsaturated alkyl sulphonate anionic surfactant- and

(d) optionally a pH reducing agent to provide said pH in the range of 7 to 11.

2. A concentrate according to Claim 1, wherein component (a) comprises a salt of coco-amine dipropionate, or a mixture of said coco-amine dipropionate salt with a salt of oleylamine dipropionate.

3. A concentrate according to Claim 1 or Claim 2, wherein component (a) comprises a mixture of the mono sodium salts of oleylamine dipropionate and coco-amine dipropionate, preferably in a 1:2 ratio by weight of oleylamine dipropionate: coco-amine dipropionate.

4. A concentrate according to any one of the preceding claims, wherein component (a) comprises a compound of general formula (II) wherein ^ is an oleyl group or a coco group, R₂ is a -CH₂CH₂OH group and Y_j and Y₂ are as defined in claim 1.

5. A concentrate according to Claim 4, wherein component (a) comprises a compound of formula: CH₂CH₂COO^θNa*

(Coco) - C - N - CH₂CH₂ - N

II I CH,CH,C00^θNa^®

0 CH₂CH₂OH

6. A concentrate according to any one of the preceding claims, wherein component (a) is used in an active amount of from 0.4 to 18 wt%, based on the total weight of the concentrate, preferably from 3.8 to 13 wt%, based on the total weight of the concentrate.

7. A concentrate according to any one of the preceding claims, wherein component (b) comprises a cyclic imidazoline of general formula (III) in which R₃ is a saturated or unsaturated Cη to C₁₈ alkyl group, preferably an unsaturated C alkyl group.

8. A concentrate according to any one of the preceding claims, wherein the cyclic imidazoline (b) is used in an active amount of from 0.35 to 14 wt%, based an the total weight of the concentrate, preferably from 3 to 10 wt%, based on the total weight of the concentrate.

9. A concentrate according to any one of the preceding claims, wherein the alkyl sulphonate anionic surfactant is an oleyl sulphonate anionic surfactant.

10. A concentrate according to any one of the preceding claims, wherein the alkyl sulphonate anionic sulphonate surfactant is present in an active amount of from 0.2 to 5 wt%, based on the total weight of the concentrate, preferably from 0.2 to 1 wt%, based on the total weight of the concentrate.

11. A concentrate according to any one of the preceding claims, wherein the weight ratio of component (a) to component (b) in the concentrate is 0.9-1.4:1.

12. A concentrate according to any one of the preceding claims, further comprising a further component (d) which comprises a non-ionic surfactant which is a linear or branched alkoxylated alcohol or alkoxylated phenol, each having from 5 to 20 units of ethoxylation.

13. A concentrate according to Claim 12, wherein component (d) comprises an iso-C^ to C₁₅ alcohol having 12 units of ethoxylation.

14. A concentrate according to claim 12 or 13, wherein component (d) is present in an active amount of from 0.5 to 10 wt%, preferably from 1 to 5 wt%, based on the total weight of the concentrate.

15. A concentrate according to any one of the preceding claims, having a pH from 9 to 11 and most preferably 10 to 11.

16. A concentrate according to any one of the preceding claims wherein said pH reducing agent is a hydrotropic acid.

17. A concentrate according to any one of the preceding claims, said hydrotropic acid being selected from the group consisting of caprylic acid and neodecanoic acid.

18. A lubricant composition for conveyor track comprising a concentrate as claimed in any one of the preceding claims diluted with from 80.00 to 99.99 parts by volume of water.

19. A lubricant composition according to Claim 18, wherein the concentrate is diluted with from 99.0 to 99.9 parts by volume of water.