METHOD OF LUBRICATING A CONVEYOR BELT

1 . A method of lubricating a conveyor belt comprising the steps as follows:

a) a lubricant concentrate containing at least one fatty acid is employed in a dry lubrication process, wherein the pH-value of the lubricant concentrate is in the range of ≦4,

b) afterwards, a liquid composition is applied to the surface of the conveyor belt, wherein the pH-value of the liquid composition is in a range of ≧5, the liquid composition contains as component a) at least one base and the liquid composition contains as component b) at least one fatty acid.

2 . A method according to claim 1 , wherein in the lubricant concentrate the fatty acid is oleic acid.

3 . A method according to claim 1 , wherein the conveyor belt is partially or completely made of steel and/or the object transported on the conveyor belt is partially or completely made of glass.

4 . A method according to claim 1 , wherein the lubricant concentrate contains

0.1 to 25 wt.-% of at least one fatty acid,

0.1 to 25 wt.-% of at least one corrosion inhibitor,

0.1 to 25 wt.-% of at least one acid, and

5 to 95 wt.-% of water and/or at least one organic solvent.

5 . A method according to claim 1 , wherein the lubricant concentrate is applied onto the conveyor belt as an emulsion or a solution.

6 . A method according to claim 4 , wherein the corrosion inhibitor is at least one phosphate ester having the formula (I) or (II)

where R is an alkyl or alkylaryl group; n can (independently from another) equal from 1 to 10;

and/or at least one ethoxylated carboxylic acid containing a (C 4 -C 18 )-alkyl-fragment and 1 to 6 EO-fragments.

7 . A method according to claim 1 , wherein in the liquid composition, (in step b) the base is selected from an alkanol amine, an amine, ammonia, ammonia hydroxide, urea, an alkaline hydroxide, a buffer, a fatty amine, an alkoxylated fatty amine, a fatty amine oxide or an alkoxylated fatty amine oxide.

8 . A method according to claim 1 , wherein the liquid composition (in step b) contains a molar excess of the base versus the fatty acid.

9 . A method according to claim 8 , wherein in the liquid composition (in step b) the base is monoethanolamine (MEA), diethanolamine (DEA) or triethanolamine (TEA) and/or the fatty acid is oleic acid.

10 . A method according to claim 1 , wherein step b) is carried out for cleaning and optionally lubricating the conveyor belt.

11 . A method according to claim 1 , which method is carried out continuously with steps a) and b) in alternate order.

12 . A method according to claim 1 , wherein the operation time of step a) exceeds that of step b) by a factor of at least 20.

13 . A method according to claim 1 , wherein the pH-value of the lubricant concentrate employed in step a) is in the range of 1 to 3 and/or the pH-value of the liquid composition employed in step b) is in the range of 9 to 13.

14 . A method according to claim 1 , wherein the lubrication according to step a) is temporarily and/or in at least one section of the conveyor belt carried out as a wet lubrication process.

15 . A method according to claim 1 , wherein the liquid composition is employed as a use solution in step b).