CARBOXYLATED SURFACTANT CONTAINING LUBRICANTS, PRODUCTION AND USE

Abstract: A synergistic aqueous lubricant composition which comprises one or more carboxylated surfactants and one or more non-carboxylated surfactants, inter alia , is disclosed.

Description: This invention relates to carboxylated surfactant-containing lubricants and to the production and use thereof. Aqueous soap-based formulations are used as lubricants in numerous applications, in particular for providing slip and detergency on slat-, chain- or belt-type conveyors, for example, used for transporting items, such as bottles or cans, during a packaging operation. Generally, lubricating solutions are applied to such conveyors using pipe networks and suitable spray jets or nozzles. When used in hard water, soap-based lubricants generally require the addition of sequestering agents, such as EDTA, to reduce reaction between the soaps and the water hardness ions, e.g, Ca²⁺. If adequate steps are not taken, insoluble lime soaps may be formed and blockages of the lubricant distribution system may result. Lime soap dispersing agents are also commonly used so that, if the sequestrant is insufficient or exhausted, lime soap resulting will be dispersed rather than causing immediate blockages. Generally, lime soap-dispersing surfactants, which may be non-ionic, anionic or amphoteric, are included in soap-based formulations. It has now unexpectedly been found that the above problem may be obviated and lime soap dispersion may be significantly improved by the use of a certain type of anionic surfactant in addition to those surfactants normally used in soap-based lubricants. A surprising synergism has also been noted. The present invention relates to a synergistic aqueous lubricant composition which comprises one or more carboxylated surfactants and one or more non-carboxylated surfactants. Generally, the carboxylated surfactant component is used in an amount of up to 20% by weight of the formulation; preferably from 0.2 to 5%. Typically, the non-carboxylated surfactant component is also present in an amount of up to 20% by weight of the formulation, preferably from 2 to 15%. The preferred carboxylated surfactants correspond to the following general formula: R-(OC m H 2m ) n OR′COOX wherein: R represents a fatty group, typically C₁₀-C₁₈; preferably oleyl; R′ represents an alkylene group, typically _CH₂_ to _C₃H₆, preferably _CH₂_; X represents a cationic moiety, typically Na⁺, K⁺, NH₄⁺, H₃N⁺-CH₂CH₂OH, H₂N⁺(CH₂CH₂OH)₂ or HN⁺(CH₂CH₂OH)₃, preferably Na⁺; m represents an integer of from 2 to 4; and n represents an integer of from 1 to 20, preferably 4. Other preferred carboxylated surfactants include alkyl phenol alkoxylated, preferably ethoxylated, carboxylates, which may correspond to the following general formula: wherein R′; X; m and n are as defined above; and R″ represents a C₆-C₂₀ alkyl group, typically C₉H₁₉, which is preferably in the para-position. In accordance with the present invention, one or more other conventional components may also be used in conventional amounts. More particularly, there may be present up to 30% by weight of the formulation, of one of more soaps and/or up to 15% by weight of the formulation of one or more sequestrants and/or one or more solvents and/or one or more hydrotropes and/or one of more bacteriostats. The compositions according to the present invention may be produced by mixing the components. Generally, the present compositions are diluted with water before use. This may be done in the conventional manner by premixing lubricant and water before dispensing or by directly injecting undiluted lubricant into a flowing stream and allowing the lubricant to mix slowly as it flows through the distribution pipework. An in-use solution in accordance with the present invention may typically be obtained by dilution in a weight ratio of from 3: 10 to 1: 1000, preferably from 1: 10 to 1: 500. The present invention further relates to such production. The compositions or more usually the solutions in accordance with the present invention may be used for lubricating and/or cleaning in numerous applications. Generally, they are used in the conventional manner. They are particularly suitable for lubricating and/or cleaning slat-, chain- or belt-type conveyors and are advantageously used in food/beverage and pharmaceutical fields. Such processes are encompassed by the present invention. The present invention may be illustrated by means of lime soap deposition tests using the test rig illustrated in Figure 1 of the accompanying drawing. The pump 10 delivers a constant flow of 600 ml/min of water from tank 11 at a pressure of 15 psi (approx. 1.05 kg/sq cm) indicated by pressure gauge 13 into six water lines 12, 14, 16, 18, 20 and 22. Formulated product is withdrawn from respective reservoirs 24, 26, 28, 30, 32 and 34 by pumps 25, 27, 29, 31 and 33 pumps and dosed into each respective line through "T" junctions 36, 38, 40, 42, 44 and 46; 10 ml at a time, at 2 minute intervals. Each line terminates 25 meters after the injection point at a respective column 48, 50, 52, 54, 56 and 58 containing 15 grams of stainless steel mesh 60 which acts as a lime soap adsorbant. After a given weight of product has been injected into the system, the stainless steel mesh is removed from the column and treated with a measured mixture of EDTA and sodium hydroxide to dissolve any adsorbed lime soap. Re-dissolved lime soap is measured as Ca²⁺ ion by atomic absorption spectroscopy. Formulated products which have been used to test surfactants for lime soap dispersion/adhesion prevention properties by the above method are prepared to the following base formulation: The above constituents are added in descending order with a thorough mixing. The above ingredients are generally added in descending order with thorough mixing.

Claims: 1. An aqueous soap-based lubricant concentrate characterised in that it comprises: (i) a soap lubricant; (ii) a carboxylated surfactant corresponding to one of the following general formulae: or wherein: R represents a fatty group; R′ represents an alkylene group; R″ represents a C₆-C₂₀ alkyl group; X represents a cationic moiety; m represents an integer of from 2 to 4; and n represents an integer of from 1 to 20; or mixtures thereof; (iii) a non-carboxylated surfactant; and (iv) an aqueous diluent. 2. A lubricant as claimed in claim 1 wherein R represents a C₁₀-C₁₈ fatty group; R′ represents _CH₂_ to _C₃H₆_; X represents Na⁺, K⁺, NH₄⁺, H₃N⁺-CH₂CH₂OH, H₂N⁺(CH₂CH₂OH)₂ or HN⁺(CH₂CH₂OH)₃. 3. A lubricant as claimed in claim 1 or claim 2 wherein R represents oleyl; r′ represents _CH₂_; X represents Na⁺ and n represents 4. 4. A lubricant as claimed in any of claims 1 to 3 wherein R″ represents C₉H₁₉ and m represents 2. 5. A lubricant as claimed in any of claims 1 to 4 wherein r″ represents C₉H₁₉ in the para-position. 6. A lubricant as claimed in any of claims 1 to 5 wherein the carboxylated surfactant (ii) corresponds to general formula (a). 7. A lubricant as claimed in any of claims 1 to 6 wherein up to 20%, by weight, of the carboxylated surfactant (ii) is present. 8. A lubricant as claimed in claim 7 wherein from 0.2 to 5%, by weight, of the carboxylated surfactant (ii) is present. 9. A lubricant as claimed in any of claims 1 to 8 wherein up to 20%, by weight, of the non-carboxylated surfactant (iii) is present. 10. A lubricant as claimed in claim 9 wherein from 2 to 15%, by weight, of the non-carboxylated surfactant (iii) is present. 11. A lubricant as claimed in any of claims 1 to 10 wherein up to 30%, by weight, of the soap lubricant (i) is present. 12. A lubricant as claimed in any of claims 1 to 11 wherein up to 15%, by weight, of a sequestrant is also present. 13. An in-use solution characterised in that it comprises a lubricant as claimed in any of claims 1 to 12 diluted with water in a weight ratio of from 3: 10 to 1: 1000. 14. A solution as claimed in claim 13 wherein the ratio is from 1: 10 to 1: 500.

Inventors: DENTON, JEFFREY, SINGH, MANJIT
Applicants: DIVERSEY CORPORATION
Application year: 1987
Main classification: C10M173
IPC codes: C02F9, C10M173