Patent Application
20230383209
The present application claims benefit of priority under 35 U.S.C. 119(a) to European Patent Application No. 22175062.3, filed on May 24, 2022, and entitled, “BANDSCHMIERMITTELKONZENTRAT (translation: Belt Lubricant Concentrate).” That European patent application is incorporated herein by reference in its entirety.
The present invention relates to a belt lubricant concentrate and its use in the transport of packages on conveyor belts.
Belt lubricants are usually used for the transport of packages, such as bottles or cans, on conveyor belts.
Belt lubricants influence the sliding behaviour of the packages to be transported on conveyor belts. On the one hand, they reduce the coefficient of friction between the package and the conveyor belt so that signs of wear on the conveyor belts and the packages to be transported are significantly reduced. However, the friction must be at a minimum so that the packages can be conveyed on the conveyor belt.
Especially in the food industry, conveyor belts often remain in motion while the packages transported on them are prevented from being transported further by an obstacle (e.g., other packages or baffles). Without suitable belt lubricants, the friction arising thereby would lead to increased wear on the packages and the conveyor belts. In addition, delays caused by toppled packages could occur in the transport process, since the stability of packages located on conveyor belts is significantly reduced by increased friction between the package and the conveyor belt.
Especially in the food industry, it is furthermore crucial that the belt lubricant used is neither harmful to health nor detrimental to other hygiene measures (e.g., the use of chlorine dioxide). In addition, it is desirable to keep the amount of belt lubricant used as low as possible for economical and ecological reasons.
It is therefore an object of the present invention to provide a belt lubricant or, respectively, a belt lubricant concentrate which has to be used only in small quantities in order to generate a friction that is suitable for the transport of packages on conveyor belts. Furthermore, it is an object of the present invention that the belt lubricant or, respectively, the belt lubricant concentrate exhibits a lower consumption of chlorine dioxide than belt lubricants that are described in the prior art.
The present invention therefore relates to a belt lubricant concentrate comprising 15% by weight to 30% by weight of at least one monocarboxylic acid, 10% by weight to 25% by weight of at least one N-alkyl-1,3-propanediamine, 5% by weight to 15% by weight of at least one nonionic surfactant and water up to 100% by weight.
Surprisingly, it has been shown that a belt lubricant concentrate having the composition according to the invention has particularly advantageous properties compared to known belt lubricant concentrates. The belt lubricant concentrate according to the invention is sufficiently liquid at application temperatures of between 10 and 35° C. and therefore has good processing properties. In addition, it can be mixed with water in very small quantities and still has excellent properties with regard to the friction value. When diluted in water, the belt lubricant concentrate according to the invention exhibits a lower consumption of chlorine dioxide than belt lubricants described in the prior art. Since, in the food industry, chlorine dioxide in the process water is used for microbiological control, among other things, this is a particularly advantageous property of the belt lubricant concentrate according to the invention with regard to the consumption of chemicals.
A further aspect of the present invention relates to a ready-to-use belt lubricant comprising 0.01% by weight to 0.1% by weight of a belt lubricant concentrate according to the invention and water up to 100% by weight.
The belt lubricant concentrate according to the invention can be used at a concentration of from 0.01% by weight to 0.1% by weight. Before the belt lubricant is used on industrial plants, the belt lubricant concentrate according to the invention is diluted with water. The belt lubricant produced in this way can be applied to conveyor belts using a wide variety of methods such as, e.g., spray processes.
The low use of belt lubricant concentrate is beneficial in both ecological and economical terms.
Yet another aspect of the present invention relates to the use of a belt lubricant concentrate according to the present invention for chain and/or belt lubrication systems, preferably in the food industry.
The belt lubricant concentrate according to the invention can be used for lubricating chain and/or belt lubrication systems.
Another aspect of the present invention relates to a method of lubricating the travel of a container along a conveyor belt, comprising the application of a belt lubricant according to the present invention.
The belt lubricant concentrate according to the invention comprises 15% by weight to 30% by weight of at least one monocarboxylic acid, 10% by weight to 25% by weight of at least one N-alkyl-1,3-propanediamine, 5% by weight to 15% by weight of at least one nonionic surfactant and water up to 100% by weight.
According to the invention, it has been shown that the use of monocarboxylic acids is particularly advantageous in order to obtain a concentrate which is sufficiently stable and has a viscosity which enables further processing into a belt lubricant in a simple manner by mixing with water. It has indeed been shown that the predominant use of organic acids which have more than one carboxyl group in the concentration range according to the invention leads to an either solid or viscous concentrate which can hardly be processed further, if at all. In some cases, when a concentrate is diluted with organic acids comprising more than one carboxyl group, precipitations occur which no longer allow the diluted concentrate to be reused.
In addition, the selection of the organic acids influences the consumption of chlorine dioxide, i.e., the degradation of chlorine dioxide over time. The use of organic acids comprising more than one carboxyl group in belt lubricant concentrates, the latter being diluted into belt lubricants, results in a composition which has a higher consumption of chlorine dioxide than concentrates comprising at least one monocarboxylic acid. This means that chlorine dioxide in the process water or in the belt lubricant is degraded more quickly in the presence of organic acids comprising more than one carboxyl group.
The belt lubricant concentrate according to the invention can comprise one, two, three, four or more different monocarboxylic acids, the use of one, two or three different monocarboxylic acids being particularly preferred.
The at least one monocarboxylic acid, the at least one N-alkyl-1,3-propanediamine and the at least one nonionic surfactant are supplemented with water to make up 100% by weight, depending on their concentration in the final product. The water added can be deionized or distilled water.
According to a preferred embodiment of the present invention, the at least one monocarboxylic acid is selected from the group consisting of formic acid and lactic acid.
It has been shown according to the invention that it is particularly advantageous to provide formic acid and/or lactic acid in the belt lubricant concentrate according to the invention.
According to another preferred embodiment of the present invention, the alkyl group of the at least one N-alkyl-1,3-propanediamine is a C10-C24 alkyl group, preferably a C12-C22 alkyl group, more preferably a C14-C20 alkyl group, more preferably a C16-C20 alkyl group, particularly a C18 alkyl group.
In order to obtain a suitable friction value for the belt lubricant produced with the concentrate according to the invention, it is advantageous to use N-alkyl-1,3-propanediamines whose alkyl group has a certain length range. It has been shown according to the invention that particularly good results can be achieved with C10-C24 alkyl groups, with C16-C20 alkyl groups and in particular C18 alkyl groups being particularly preferred.
According to yet another preferred embodiment of the present invention, the at least one N-alkyl-1,3-propanediamine is N-octadecyl-propane-1,3-diamine.
According to a preferred embodiment of the present invention, the at least one nonionic surfactant is a polyalkylene glycol ether, which not only has a positive effect on lubrication, but also contributes to cleaning by allowing the rubbed-off parts to be flushed out better.
According to a further preferred embodiment of the present invention, the polyalkylene glycol ether has a degree of ethoxylation of between 15 and 30, preferably of between 20 and 30, more preferably of between 23 and 28, in particular of 25. Lutensol, in particular Lutensol AT25 and/or Lutensol FA12K, is used as a particularly preferred polyalkylene glycol ether.
According to a particularly preferred embodiment of the present invention, the concentrate comprises 18% by weight to 28% by weight, preferably 20% by weight to 25% by weight, of the at least one monocarboxylic acid.
According to a preferred embodiment of the present invention, the concentrate comprises 12% by weight to 22% by weight, preferably 15% by weight to 20% by weight, of the at least one N-alkyl-1,3-propanediamine.
According to a preferred embodiment of the present invention, the concentrate comprises 5% by weight to 12% by weight, preferably 7% by weight to 10% by weight, of the at least one nonionic surfactant.
According to a further preferred embodiment of the present invention, the concentrate comprises 10% by weight to 30% by weight, preferably 12% by weight to 25% by weight, of at least one alcohol and/or 5% by weight to 10% by weight, preferably 6% by weight to 8% by weight, of at least one glycol ether. In some cases, it can be advantageous to adjust the viscosity of the concentrate according to the invention using alcohol or, respectively, glycol ether in the specified amounts. This embodiment is particularly advantageous in applications in which the concentrate according to the invention is distributed via pump systems.
The belt lubricant according to the invention comprises 0.01% by weight to 0.1% by weight of a belt lubricant concentrate according to the invention and water up to 100% by weight. Preferably, the process water comprises 0.02% by weight to 0.09% by weight, preferably 0.02% by weight to 0.08% by weight, more preferably 0.02% by weight to 0.06% by weight, of the belt lubricant concentrate according to the invention.
The belt lubricant concentrate according to the invention is preferably diluted with water, preferably with deionized or ion-reduced water, prior to its use. Surprisingly, it has been shown that less of the belt lubricant concentrate according to the invention has to be used than with conventional concentrates in order to achieve the same or even a better friction value. In addition, the belt lubricant according to the invention is characterized in that it exhibits a lower consumption of chlorine dioxide than known belt lubricants. This is particularly advantageous if the belt lubricant according to the invention is mixed with chlorine dioxide or used in combination with process water containing chlorine dioxide.
According to a preferred embodiment of the present invention, the water is substantially deionized prior to the introduction of the belt lubricant concentrate according to the invention.
According to a preferred embodiment of the present invention, the belt lubricant comprises 0.01 mg/L to 1 mg/L, preferably 0.01 mg/L to 0.8 mg/L, more preferably 0.01 mg/L to 0.5 mg/L, of chlorine dioxide.
Chlorine dioxide is used as a biocide in the food industry, among other things.
A further aspect of the present invention relates to the use of a belt lubricant concentrate according to the invention for chain and/or belt lubrication systems, preferably in the food industry.
The belt lubricant concentrate or, respectively, the belt lubricant according to the invention is used for chain and/or belt lubrication systems.
Yet another aspect of the present invention relates to a method of lubricating the travel of a container along a conveyor belt, comprising the application of a belt lubricant according to the invention. Methods of applying belt lubricants to conveyor belts made of steel, for example, in particular of stainless steel, are well known to those skilled in the art. The most common method of applying belt lubricant is the spray process.
In the method according to the invention, the conveyor belt is preferably brought into contact with process water which comprises 0.01 mg/L to 1 mg/L, preferably 0.01 mg/L to 0.8 mg/L, more preferably 0.01 mg/L to 0.5 mg/L, of chlorine dioxide.
Above all, but not only, the control of biological growth (e.g., bacteria, algae) is of crucial importance in the food industry. In addition to physical measures, chemical compounds are usually also used for the control of biological growth. A frequently used compound in this process is chlorine dioxide. It has been found that among the ingredients of known belt lubricants especially chlorine dioxide is quickly degraded so that the biocidal effect of chlorine dioxide fails to take effect, or does so only to a very limited extent. Surprisingly, it has been found that the belt lubricant according to the invention exhibits a significantly lower consumption of chlorine dioxide (i.e., degradation of chlorine dioxide) than previously known belt lubricants. For this reason, the belt lubricant according to the invention is particularly suitable in industrial plants in which chlorine dioxide is used as a biocide in process water (e.g., pasteurization plants).
The present invention is explained in further detail on the basis of the following examples, but without being restricted to them.
In order to examine the impact of different organic acids and the acid/amine ratio on the solubility of concentrates based on N-alkyl-1,3-propanediamines (e.g., Duomeen O), the following compositions were tested:
Compositions 1 to 7 were prepared by mixing the ingredients as indicated in Table 1. The physical state of the compositions and the solubility after mixing with a water/ethanol mixture (2:1) (both at 20° C.) were examined. The results are listed in Table 2.
As can be seen from Table 2, compositions 3 and 5 were sparingly soluble and non-soluble, respectively. In addition to the monocarboxylic acids, both compositions also contain citric acid, a tricarboxylic acid. Composition 1 was also non-soluble in a water/ethanol mixture (2:1). With this composition, the ratio of formic acid to Duomeen O was 0.3. In composition 5, the ratio of organic acids to Duomeen O was 1:1. Since composition 5 was nevertheless non-soluble, the conclusion can be drawn that both the use of monocarboxylic acids and the ratio of them to the N-alkyl-1,3-propanediamine is essential for the solubility of the composition.
The friction value and the viscosity of compositions are crucial for their suitability as belt lubricants. In order to examine the impact of different acids on the friction value and on the viscosity, the following mixtures were prepared:
Formic acid, citric acid, acetic acid and lactic acid were used as the acid.
To determine the friction value, a 0.05% aqueous solution of the composition according to Table 3 was sprayed onto conveyor belts specially designed for this, using a pump. Approximately 30 litres of solution per hour were applied. With the help of a sensor connected to a T-Logg data logger, the measured values could be recorded in the MINISoft V7.18 software from GHM GROUP (Greisinger, Germany). The measurement time was 15 minutes, with a measuring point being recorded every second. By creating a calibration line, the measured signals could be converted into the frictional force and consequently the coefficient of friction. The coefficient of friction results from the ratio between the frictional force and the normal force.
For determining the viscosity, the technical rotational viscometer PCE-RVI 2 from PCE Instruments (Germany) comprising the spindle L2 was used. The viscosity was measured at 20° C. and a spindle speed of 60 rpm.
The measured data are represented in the following table:
As can be seen from Table 4, compositions which contain monocarboxylic acids have both low friction values and low viscosities. Compositions with high viscosities caused the spray nozzles to be clogged after a short time (less than 10 minutes). The composition containing citric acid had a viscosity which was too high.
The concentration of N-alkyl-1,3-propanediamine in the belt lubricant can influence the friction value thereof and was therefore examined more closely. The composition from Example 2, Table 3, was used, wherein 23% by weight of a monocarboxylic acid was used and was diluted with water to 100% by weight. The concentration of the components was maintained as outlined in Table 3, only the content of Duomeen O and the water content were adjusted according to Table 5. The friction value and the viscosity were determined analogously to Example 2. The results of the measurements are illustrated in the following table:
It can be seen from Table 5 that the use of less than 7% by weight of N-alkyl-1,3-propanediamine leads to an increased friction value. The viscosity increases with the content of N-alkyl-1,3-propanediamine.
The composition of the belt lubricant has a direct impact on the degradation of chlorine dioxide in an aqueous solution such as process water.
For determining the consumption of chlorine dioxide, TM CLEAROXID LIQUID (Thonhauser GmbH) was diluted to 2 ppm. 0.05, 0.1 and, respectively, 0.2% by weight of belt lubricant concentrate was added to this solution. The content of chlorine dioxide in the solution was determined after 5, 10 and 15 minutes by means of the test kit Chlorine Dioxide Test (Merck, Germany) and the photometer Spectroquant Prove 300 (Merck, Germany). The composition according to Table 3 with formic acid as the monocarboxylic acid (SD PLUS) or, respectively, formic acid and lactic acid as monocarboxylic acids (ratio 2:1) (SD PLUS 2), ECOLAB LUBODRIVE (from Ecolab), ECOLAB DRYEXX (from Ecolab), ECOLAB LUBODRIVE CD (from Ecolab) and water were used as the belt lubricant concentrate. The results of the measurements are listed in the following table (BL, belt lubricant):
It can be seen from Tables 6 and 7 that, by using compositions according to the invention, the consumption of chlorine dioxide can be significantly reduced in comparison to compositions not according to the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22175062.3 | May 2022 | EP | regional |
