AQUEOUS COMPOSITIONS

Abstract: Aqueous compositions for lubricating continuously moving conveyor systems, comprising octanoic acid soap and oleic acid soap and, optionally, anionic surfactant and/or sequestering agent, demonstrates an improvement in lubricity and an increased tolerance to bottling fluid contamination on PET bottling lines.

Description: Aqueous Compositions This invention is concerned with aqueous compositions. More particularly, this invention concerns aqueous compositions which are useful in or as conveyor lubricants. The aqueous compositions of the present invention comprise octanoic and oleic acid soaps. In conveyor systems employing bottling and capping operations, a clean and well lubricated conveyor surface may be required to enable progression of the bottles to be stopped during filling and capping whilst the conveyor track itself continues to move beneath the bottles. If the track surface is not clean and well lubricated, the bottles may fail to stop moving or may be knocked over, consequently resulting in disruption of the bottling line. Aqueous compositions have been used as lubricants to provide the slip and detergency required on such conveyor systems. For example, an aqueous lubricant composition, analysed in its concentrate form to comprise octanoic acid soap, oleic acid soap, anionic surfactant and sequestering agent, has been commercially available for this use in the United Kingdom for a number of years. However, in use, the lubricating compositions tend to become contaminated with bottling fluid, spilt or knocked onto the track, thereby reducing their lubricating efficiency. It is an object of the present to provide a conveyor lubricant having improved lubrication properties, particularly for lubricating PET bottling systems. It is yet a further object of the present invention to provide a conveyor lubricant composition having improved tolerance to bottling fluid contamination. In accordance with the present invention, there is provided an aqueous composition for lubricating continuously moving conveyor systems comprising octanoic acid soap and oleic acid soap and, optionally, anionic surfactant and/or sequestering agent, characterised in that the composition has a lubricant mobility height of at least 25.5cm and is obtainable by mixing 500 parts by weight water with 1 part by weight of a lubricant concentrate, wherein the lubricant concentrate is formed from 4.4% by weight KORTACID 0899 (an octanoic acid composition available from Akzo Chemicals), 10.8% by weight PRIOLENE 6900 (an oleic acid composition available from Unichema International ), 4.72% by weight AEROSOL OT100 (a dioctyl sodium sulpho succinate composition available from Cyanamid Of Great Britain ), 11.7 % by weight NERVANAID B.30 (a 30% solution of EDTA, present as its tetrasodium salt, available from Rhone-Poulenc ), 7.7% by weight Caustic Potash Liquor (a 48-51% aqueous KOH composition available from Gelpke & Bate Ltd, London ) and the balance water. Preferably, the composition comprises both anionic surfactant and sequestering agent. The aqueous lubricating compositions of the present invention demonstrate a surprising improvement in lubricity as evidenced by a surprising increase in lubricant mobility height, and an increased tolerance to bottling fluid contamination on PET bottling lines than commercially available conveyor lubricants. In another aspect, the present invention provides an aqueous composition for lubricating continuously moving conveyor systems comprising octanoic acid soap, oleic acid soap, anionic surfactant, and sequestering agent and is characterised in that the anionic surfactant is a di(Cs- c 12) a .l.ky.l sulpho succinic acid or salt thereof, preferably a di(C6-C10)alkyl sulpho succinate, and most preferably a dioctyl sodium sulpho succinate. The surfactant is preferably present in the composition in an amount of from 40 to 50 % by weight of the oleic acid. The compositions of the present invention have a lubricant mobility height of at least 25.5 cm, preferably 26 to 28cm. In yet another aspect, the present invention provides a lubricant concentrate comprising octanoic acid soap, oleic acid soap, anionic surfactant and sequestering agent and is characterised in that the anionic surfactant is a di(C6- C12)alkyl sulpho succinic acid or salt thereof, preferably a di(C6-CIO)alkyl sulpho succinate, and most preferably a dioctyl sodium sulpho succinate. Preferably, the surfactant is present in an amount of from 40% to 50% by weight of the oleic acid. A preferred lubricant concentrate is formed from 4 to 12 wt % octanoic acid, 4.5 to 15 wt % oleic acid, 1.8 to 6 wt % anionic surfactant, such as dioctyl sodium sulpho succinate, 2 to 5 wt % sequestering agent, such as EDTA, 3 to 6 wt % solubiliser, such as KOH, and the balance water. The concentrate may be diluted in proportion by weight of 1:100 to 1000 with water, preferably 1:400 to 600, more preferably 1:450 to 550 and most preferably 1:500. The oleic acid and/or oleic acid soap used in the lubricant concentrate may be obtained from any appropriate fatty acid source such as fatty acids of tall oil, coconut oil, sunflower oil, rape seed oil, tallow oil, soya bean oil, corn oil, cotton seed oil, palm oil and blends thereof. The preferred commercially available sources of oleic acid are PRIOLENE 6900 and 6921 available from Unichema International. The sequestering agents which may be employed in the composition of the present invention include those disclosed in US-A-3860521, though EDTA is the most preferred. A solubiliser, preferably KOH, may be added in the formation of the concentrates of t e present invention for saponification of the fatty acids present, although pre¬ formed fatty acid soaps may be used instead of the fatty acids. Other suitable solubilisers include sodium and ammonium hydroxide and mono-, di- or tri-ethanola ine or isopropanolamine. Typically, a stoichiometric excess of solubiliser is required, to maintain the pH of the concentrate above neutral. Preferably, the concentrate has a pH of from 8 to less than 12. Prior art compositions tend to have a pH of above 12. Other components typically found in conventional conveyor lubricants may also be added to the compositions and concentrates of the present invention, such as corrosion inhibitors and bacteriacides etc, without being detrimental to the advantageous properties of the composition. A nonionic surfactant or an alcoholic coupling agent are not essential components of the composition of the present invention. The compositions, and diluted concentrates, of the present invention are particularly useful as lubricants on conveyor systems carrying PET bottles. In accordance with another aspect of the present invention therefore, there is provided the use of the above compositions and diluted concentrates on conveyor systems carrying PET bottles. The invention will now be further described by way of reference to the following examples. In the examples, which are to be construed as illustrations, rather than limitative of the invention, all parts are by weight, absent contrary indications. Example I A lubricant concentrate of the present invention was prepared by mixing together the following components: KORTACID 0899 4.4 PRIOLENE 6900 10.8 AEROSOL OT100 4.72 NERVANAID B30 11.7 Caustic Potash Liquor 7.7 water 60.68 The concentrate was diluted in demineralised water to five hundred times dilution to form an aqueous composition of the present invention. Comparative Example I A commercially available lubricant concentrate was analysed and was found to comprise on a percent by weight basis the following components: The concentrate was diluted five hundred times with demineralised water, in accordance with the manufacturers instructions. The physical properties of the above compositions were then evaluated in accordance with the following tests. Lubricant Mobility Height: A 32 cm high, 1.5 1 PET bottle with a petaloid base, of the type which normally contains 1.5 1 of a carbonated soft drink, such as Tango orange drink available from Britvic Soft Drinks Limited, is filled with 1.5 1 of water and the lid secured . The bottle is then placed onto a stainless steel plate which has been thoroughly wetted with lubricant composition. Using an index finger, an attempt is made to push the bottle smoothly along the plate. The ability to push the bottle smoothly along the plate deminishes as the pushing finger is moved up the wall of the bottle. The height up the bottle wall of the highest point of contact between the finger and the side of the bottle is recorded when the bottle just begins to topple instead of sliding along the plate. This recorded height is the lubricant mobility height of the composition and is believed to be a direct indication of the lubricity of the composition evaluated. Foam Height Index and % Defoaming: 500ml of composition is carefully charged to a 1000ml glass measuring cylinder. The volume of the liquid is measured from the side of the cylinder (Vi). The composition is then agitated 30 times in 30 seconds using a perforated disk on a plunger. The disk is then removed and the volume of composition and foam measured from the side of the cylinder (V2) . The foam height index is calculated from V^-V^. A low foam height index is desirable. The cylinder is then left stationary for 2 hours when the final volume, Vf, of the composition and foam is recorded. The % defoaming is then calculated as: % defoaming = ( Vf-V^ / {V 2 -Vι ) ) x 100 A high % defoaming is desirable. Soil Tolerance: Compositions are contaminated with up to a few percent by weight of a carbonated soft drink (sold under the trade mark Diet Pepsi, available from Pepsi Cola) and the lubricant mobility height measured as above. The recorded figure for soil tolerance is the amount of soft drink present in the composition before any reduction in lubricity is recordable. A high soil tolerance is desirable. Stress Cracking: A PET bottle, as described above, is monitored for stress cracking after exposure to the composition for 24 hours. An acceptable composition should record no stress cracking over this period Haze: The composition is visually evaluated for its clarity. An acceptable composition should be clear. A comparison of the physical properties of compositions of the present invention with the properties of the dilute, commercially available lubricant is given in Table A Table A Test Stress Cracking Lubricant mobility height Haze Foam height index % defoaming Soil tolerance The superior lubricity and soil tolerance properties of the compositions of the present invention over the properties of the commercially available composition are surprising. The stress cracking, haze, foam height index and % defoaming properties of the composition of the present invention are comparable with those of the commercially available composition and must therefore be acceptable.

Claims: Claims 1. An aqueous composition for lubricating continuously moving conveyor systems comprising octanoic acid soap and oleic acid soap and, optionally, anionic surfactant and sequestering agent, characterised in that the composition has a lubricant mobility height of at least 25.5 cm and is obtainable by mixing 500 parts by weight water with 1 part by weight of a lubricant concentrate, wherein the lubricant concentrate is formed from 4.4% by weight KORTACID 0899 (an octanoic acid composition available from Akzo Chemicals), 10.8% by weight PRIOLENE 6900 (an oleic acid composition available from Unichema International ), 4.72% by weight AEROSOL OT100 (a dioctyl sodium sulpho succinate composition available from Cyanamid Of Great Britain ), 11.7% by weight NERVANAID B30 (a 30% solution of EDTA present as its tetrasodium salt, available from Rhone- Poulenc ), 7.7% by weight Caustic Potash Liquor (a 48-51% aqueous KOH composition available from Gelpke & Bate Ltd, London SW1) and the balance water. 2. An aqueous composition for lubricating continuously moving conveyor systems comprising octanoic acid soap, oleic acid soap, anionic surfactant, and sequestering agent, characterised in that the anionic surfactant is a di(Cg- C12)alkyl sulpho succinic acid or salt thereof, preferably a di(C6-C10)alkyl sulpho succinate, and most preferably a dioctyl sodium sulpho succinate. 3. A composition as claimed in claim 2, wherein the surfactant is present in the composition in an amount of from 40 to 50 % by weight of the oleic acid soap. 4. A lubricant concentrate formed from a mixture comprising octanoic acid, oleic acid, anionic surfactant and sequestering agent characterised in that the anionic surfactant is a di(C6-C12)alkyl sulpho succinic acid or salt thereof, preferably a di(C6-CIO)alkyl sulpho succinate, and most preferably a dioctyl sodium sulpho succinate. 5. A concentrate as claimed in claim 4, wherein the surfactant is present in an amount of from 40% to 50% by weight of the oleic acid. 6. A concentrate as claimed in claim 4 or claim 5, wherein the concentrate is obtained from 4 to 12 wt % octanoic acid, 4.5 to 15 wt % oleic acid, 1.8 to 6 wt % anionic surfactant, such as dioctyl sodium sulpho succinate, 2 to 5 wt % sequestering agent, such as EDTA, 3 to 6 wt % solubiliser, such as KOH, and the balance water. 7. A concentrate as claimed in any one of claims 4 to 6, wherein the concentrate has a pH of from 8 to 12. 8. A composition as claimed in claim 2 or claim 3, wherein the composition is obtained by diluting the concentrate of any one of claims 4 to 7 with water in proportion by weight of 1:100 to 1000, preferably 1:400 to 600, more preferably 1:450 to 550 and most preferably 1:500. 9. A composition or concentrate as claimed in the preceding claims, wherein the composition or concentrate comprises essentially no nonionic surfactant or alcoholic coupling agent. 10. Use of a composition as claimed in any one of claims 1 to 3, 8 or 9 as a lubricating composition on a PET bottling line. 11. A method of bottling a carbonated soft drink in a PET bottle characterised in that a composition as claimed in any one of claims 1 to 3, 8 or 9 is used as a lubricant on the bottling line. 12. A method as claimed in claim 11, wherein the carbonated soft drink is a cola drink.

Inventors: REVELL CHRISTOPHER, REVELL, CHRISTOPHER
Applicants: LAPORTE INDUSTRIES LTD, LAPORTE INDUSTRIES LIMITED
Application year: 1992
Main classification: C10M173
IPC codes: C10M173