WO2006010375A1

WO2006010375A1 - Formulation for degreasing metal comprising a demulsifyiing agent, use of the agent, and process for degreasing metal.

Info

Publication number: WO2006010375A1
Application number: PCT/EP2004/008433
Authority: WO
Inventors: Dalibor Satrapa
Original assignee: Rhodia Chimie
Priority date: 2004-07-27
Filing date: 2004-07-27
Publication date: 2006-02-02

Abstract

The invention relates to a formulation for degreasing metal, comprising metal degreasing agents and a demulsifying agent, wherein the demulsifying agent is a compound having one of the following formulae (I) or (II): R-CO-NH-CH2-CH2-[EO]m-OH (I) R-CO-N[CH2-CH2-[EO]n-OH][CH2-CH2-[EO]n'-OH] (II) wherein: - R is a linear or branched, saturated or unsaturated C7-C22 hydrocarbon group, optionally carrying at least one hydroxyl group, - EO represents a group having formula -O-CH2-CH2-, - m, n and n', identical or different, are average numbers different from 0, - n+n' is of from 1 to 50, and - m is of from 1 to 50.

Description

Formulation for degreasing metal comprising a demulsifying agent, use of the agent, and process for degreasing metal

BACKGROUND OF THE INVENTION

The invention relates to a formulation for degreasing metal, comprising degreasing agents and a demulsifying agent.

Metal working requires the use of lubricants such as oils. The oil used during working operations needs to be removed by an appropriate treatment. It is referred to metal degreasing. For example, metal parts or plates often have, after working operation, an oil layer to be removed by a degreasing treatment.

For degreasing, aqueous compositions comprising a degreasing formulation can be used. Accordingly, oil-soiled metal is treated with an aqueous composition comprising a formulation having degreasing agents and a demulsifier, to obtain an emulsion of oil in water that will phase- separate. Then the phases are separated to recover and optionally re-use the oil and the aqueous composition.

Using ethoxylated amines as demulsifiers is known. However these compounds have a low biodegradability and their use at least in some areas might be banned in some countries. Therefore there is a need for a replacement solution, involving using replacement compounds preferably having a higher biodegradability, while delivering properties that are still interesting.

Some ethoxylated amides (or "superamides") compounds, and their use as surfactants or emulsifiers have been described in patents or patent applications including DE1916263, DT 2605502, DE 19650357. These documents describe very specific or modified ethoxylated amides, and/or their use in areas different from metal treatment, and/or as providing emulsification properties.

BRIEF SUMMARY OF THE INVENTION

The invention addresses at least some of the above-mentioned problems. Accordingly, the invention provides a formulation for degreasing metal, comprising metal degreasing agents and a demulsifying agent, wherein the demusifying agent is a compound having one of the following formulae (I) or (II):

R-CO-N H-CH₂-CH₂-[EO]_m-OH (I) R-CO-N[CH₂-CH₂-[EO]_n-OH][CH₂-CH₂-[EO]_n-OH] (II) wherein: - R is a linear or branched, saturated or unsaturated C₇-C₂₂ hydrocarbon group, optionally carrying at least one hydroxyl group, - EO represents a group having formula -0-CH₂-CH₂-,

- m, n and n', identical or different, are average numbers different from 0,

- n+n' is of from 1 to 50, and

- m is of from 1 to 50.

The invention also relates to the use of the above compounds as demulsifying agents, and advantageously as biodegradable demulsifying agents.

The invention also relates to a process for degreasing metal parts or plates with an aqueous compositions, comprising the following steps: a) treating oil-soiled metal plates with an aqueous composition comprising the formulation above, to obtain an oil-soiled composition comprising emulsified oil in water, b) subsequently or simultaneously allowing a phase separation of an oil phase comprising the oil, and of an aqueous phase, c) recovering separately the oil phase and the aqueous phase, d) optionally, re-using totally at least one of the recovered phase or ingredients therefrom.

DETAILED DESCRIPTION OF THE INVENTION

Demulsifving agent

The demulsifying agent is a compound having formula (I) or formula (II) above. The demulsifying agent can also be a mixture compounds of formula (I) and formula (II).

In formulae (I) and (II) m, n and n¹ are average numbers. These numbers result from an ethoxylation process (reaction with ethylene oxide). Thus, numbers m and n+n' might be considered as the number of moles of ethylene oxide per mole of reagent to be ethoxylated.

R is preferably a C₇-C₂₂ linear or branched, saturated or unsaturated hydrocarbon group, preferably a Ci₀-C₁₆ linear or branched linear or branched, saturated or unsaturated, hydrocarbon group, and more preferably a C₁₂-C₁₄ linear or branched linear or branched, saturated or unsaturated, hydrocarbon group (for example a "coco" group). R groups are usually actually a mixture of different groups having different numbers of carbon atoms, being linear or branched, and having different numbers of insaturations. These mixtures come from the reagents used to prepare them, which are actually distillation cuts and/or have a natural origin. In the present specification the number of carbon atoms in the R group refers to the number of carbon atoms of the two most represented species. More precisely, group R can derive from fatty acids or oils of animal or plant origin. Examples of C-_I0-C₂₂ saturated fatty acids that can be cited include lauric acid, capric acid, decanoic acid, stearic acid, isostearic acid, gadoleic acid, myristic acid and mixtures thereof.

Non limiting examples of C₁₀-C₂₂ fatty acids carrying at least one ethylenically unsaturated bond that can be cited are linderic acid, myristoleic acid, palmitoleic acid, oleic acid, petroselenic acid, doeglic acid, erucic acid, linoleic acid, Iinolenic acid, isanic acid, stearodonic acid, arachidonic acid, chypanodonic acid, ricinoleic acid and mixtures thereof.

Of the above acids, group R can derive from fatty acids selected from palmitoleic acid, oleic acid, petroselenic acid, erucic acid, linoleic acid, Iinolenic acid, ricinoleic acid and mixtures thereof. Oils from which group R can derive include oils of animal or plant origin.

Suitable animal oils that can be cited include sperm whale oil, dolphin oil, whale oil, seal oil, sardine oil, herring oil, dogfish oil, cod liver oil; calves' foot oil and beef, pork, horse or sheep fat (tallow).

Examples of oils of plant origin that can be mentioned include rapeseed oil, sunflower seed oil, peanut oil, olive oil, walnut oil, com oil, soya oil, linseed oil, hemp oil, grapeseed oil, coprah oil, palm oil, cottonseed oil, babassu oil, jojoba oil, sesame seed oil, castor oil and coriander oil. R preferably derives from rapeseed.

Finally, group R can derive from products resulting from alcoholysis reactions, more precisely methanolysis of the above oils.

Advantageously n+n', or m, is of from 5 to 30, preferably of from 10 to 25.

In a preferred embodiment the demulsifying agent has formula (II), with R being a C₁₂-C₁₄ hydrocarbon group, and n+n' being of from 5 to 30, preferably of from 10 to 25, more preferably of from 16 to 25, even more preferably of from 16 to 20.

The demulsifying agent can be prepared by a process comprising the following steps: a) reacting a fatty acid R-COOH or a fatty acid ester of formula R-COOR' wherein R' is an alkyl group, preferably a methyl group, with an alkanolamine formula NH₂-CH₂-CH₂-OH (monoethanol amine, «MEA», route for compounds of formula (I)) or NH-(CH₂-CH₂-OH)₂ (diethanol amide, «DEA», route for compounds of formula (II)), optionally in the presence of a basic compound, b) ethoxylating by reacting the product obtained at the end of step a) with ethylene oxide.

Step a) is carried out in the presence of a fatty acid or fatty acid ester or a mixture of such compounds.The fatty acids described in the definition of group R, the esters thereof, can be used and the list will not be repeated here. It should be noted that this first step can advantageously be carried out from the products resulting from alcoholysis reactions (more particularly methanolysis) of oils of animal or plant origin, in particular selected from those mentioned above.

More particularly, the mole ratio of the alkanolamine to the ester is in the range 0.8 to 1.2. A ratio that is close to stoichiometry is suitable (between 1 and 1.1). Step a) can be carried out in the presence or absence of a basic catalyst. Preferably, such a compound is employed. More particularly, this latter is selected from alkali metal alcoholates such as sodium methylate, sodium ethylate, potassium methylate or potassium ethylate. It is also possible to use alkali metal hydroxides such as sodium or potassium hydroxide; or alkali metal carbonates such as sodium carbonate or potassium carbonate. The quantity of this catalyst, if present, is normally in the range 0.01 % to 5% by weight with respect to the product of step a).

The reaction temperature is generally in the range 5O⁰C to 15O⁰C. It is advantageously higher than the boiling point of the alcohol produced during the reaction to eliminate that alcohol as it appears in the mixture. Once the reaction has been carried out, step b) is carried out. It should be noted that a step for purifying the product obtained is not obligatory.

The reaction of step b) can carried out under basic conditions, for example by employing a basic catalyst of the type used in step a). It is also possible to envisage said reaction being carried out in the presence of a Lewis acid such as titanium trichloride or boron trifluoride. The number of moles of ethylene oxide introduced is such that it allows having numbers m or n+n', as mentioned above.

The temperature at which the reaction is carried out is normally of between 8O⁰C and 18O⁰C.

Preferably, it is carried out in an atmosphere that is inert under the reaction conditions (for example nitrogen).

It is also possible to envisage carrying out the reaction in the presence of a solvent. This latter is selected from compounds that are inert under the reaction conditions. Suitable compounds that can be cited are aromatic or non aromatic hydrocarbon solvents such as hexane, toluene or xylene. It is also possible to use halogenated solvents such as chloroform, or cyclic or non cyclic ether type solvents such as dibutylether or tetrahydrofuran.

Preferably, steps b) is carried out under basic conditions. More particularly, the quantity of base required for the this step is added at the beginning of the first step. Normally, the amount of base is between O.5%o and 0.7% by weight with respect to the product obtained in step a).

The excess base remaining in the medium is preferably neutralized. To this end, the reaction medium is brought into contact with an acid that can be selected from organic acids such as carboxylic acids, more particularly acetic acid, for example; or sulphonic acids such as dodecylbenzene sulphonic acid.

It is also possible to use a mineral acid such as hydrochloric acid or sulphuric acid. By way of illustration, the quantity of acid used is such that the pH of a mixture comprising 5 g of product supplemented with 45 g of ethanol and 50 g of water is in the range 8 to 11.

Biodegradability

The demulsifying agent has preferably a biodegradability of at least 60% according to a respirometric test as defined in OECD Guidelines for testing chemicals 301 B: CO₂ Evolution Test (17 July 1992). The test is often referred to as OECD 301 B". The demulsifying agent has more preferably a biodegradability of at least 70%.

Formulation

The formulation according to the invention comprises the demulsifying agent and metal degreasing agents. The formulation can also comprise water. For example the amount of water in the formulation can be of from 0 to 70%. The formulation can be in a powder form as well as in a liquid form.

The formulation can be diluted in water by the user, to obtain an aqueous composition comprising the formulation, for example in metal working facilities.

The formulation comprises degreasing agents, further to the demulsifying compounds.

Degreasing agents that can be used in the formulation are known by the one skilled in the art. For example the formulation can comprise surfactants, and/or alkaline bases, and/or solvents. These ingredients, and mixtures thereof are considered as degreasing agents. The surfactants can be anionic, cationic, amphoteric, non ionic surfactants, or mixtures thereof. Non ionic surfactants are usually preferred. Useful anionic surfactants include:

- alkyl ester sulphonat.es of formula R-CH(SO3M)-COOR', where R represents a Cβ-20. preferably

C1O-C16_> ^alky' radical, R' a C-|-C6, preferably C1-C3, alkyl radical and M an alkali metal cation (sodium, potassium or lithium), a substituted or unsubstituted ammonium (methyl-, dimethyl-, trimethyl- or tetramethylammonium, dimethylpiperidinium, and the like) cation or a cation derived from an alkanolamine (monoethanolamine, diethanolamine, triethanolamine, and the like). Mention may very particularly be made of the methyl ester sulphonates for which the R radical is a

C14-C16 radical; - alkyl sulphates of formula ROSO3M, where R represents a C5-C24, preferably C10-C-I8, alkyl or hydroxyalkyl radical, M representing a hydrogen atom or a cation with the same definition as above, and their ethoxylated (EO) and/or propoxylated (PO) derivatives exhibiting an average of 0.5 to 30, preferably of 0.5 to 10, EO and/or PO units;

- alkylamide sulphates of formula RCONHROSO3M, where R represents a C2-C22, preferably C6-C20. ^{alkyl rac}''^cal. ^RI represents a C2-C3 alkyl radical, M representing a hydrogen atom or a cation with the same definition as above, and their ethoxylated (EO) and/or propoxylated (PO) derivatives exhibiting an average of 0.5 to 60 EO and/or PO units;

- salts of saturated or unsaturated C8-C24, preferably C14-C2O. fatty acids, C9-C20 alkylbenzenesulphonates, primary or secondary C8-C22 alkylsulphonates, alkylglycerol sulphonates, the sulphonated polycarboxylic acids disclosed in GB-A-1 ,082,179, paraffin sulphonates, N-acyl-N-alkyltaurates, alkyl phosphates, isethionates, alkylsuccinamates, alkylsulphosuccinates, the monoesters or diesters of sulphosuccinates, N-acylsarcosinates, alkylglycoside sulphates or polyethoxycarboxylates

- the cation being an alkali metal (sodium, potassium, lithium), a substituted or unsubstituted ammonium residue (methyl-, dimethyl-, trimethyl- or tetramethylammonium, dimethylpiperidinium, and the like) or a residue derived from an alkanolamine (monoethanolamine, diethanolamine, triethanolamine, and the like).

Useful non ionic surfactants include:

- polyoxyalkylenated (polyoxyethylenated, polyoxypropylenated or polyoxybutylenated) alkylphenols, the alkyl substituent of which is C6-C12, comprising from 5 to 25 oxyalkylene units; mention may be made, by way of example, of Triton X-45, Triton X-114, Triton X-100 or Triton X-102, sold by Rohm & Haas Co.;

- glucosamides, glucamides or glycerolamides;

- polyoxyalkylenated C8-C22 aliphatic alcohols comprising from 1 to 25 oxyalkylene (oxyethylene or oxypropylene) units; mention may be made, by way of example, of Tergitol 15-S-9 or Tergitol 24-L-6 NMW, sold by Union Carbide Corp., Neodol 45-9, Neodol 23-65, Neodol 45-7 or Neodol 45-4, sold by Shell Chemical Co., or Kyro EOB, sold by The Procter & Gamble Co.;

- the products resulting from the condensation of ethylene oxide, the compound resulting from the condensation of propylene oxide with propylene glycol, such as the PIuronics sold by BASF;

- the products resulting from the condensation of ethylene oxide, the compound resulting from the condensation of propylene oxide with ethylenediamine, such as the Tetronics sold by BASF;

- amine oxides, such as (C10-C18 alkyl)dimethylamine oxides or (Cβ-C22 alkoxy)ethyldihydroxyethylamine oxides;

- the alkylpolyglycosides disclosed in US-A-4,565,647;

- C8-C20 fatty acid amides; - ethoxylated fatty acids. The alkaline base can comprises the following compounds, or mixtures thereof:

- pH control agent such as a hydroxide, carbonate, sesquicarbonate, or alkali metal or alkaline- earth metal bicarbonate, for example Potassium hydroxide, Sodium Hydroxide or mixtures thereof,

- polyphosphates such as a tripolyphosphate, pyrophosphate, orthophosphate or hexametaphosphate of an alkali metal, alkaline-earth metal, N(R₄ ⁺) type ammonium where R represents hydrogen, a C₁-C₄ alkyl radical that may optionally contain an oxygen atom,

- alkali metal silicate or metasilicates such as alkali metal metasilicates, anhydrous or otherwise, or mixtures thereof.

The concentration of alkaline base in the aqueous composition after dilution can be of from 1 to 100 g/l, more particularly of from 5 to 20 g/l.

The pH of the aqueous composition can be of from 6 to 14, and preferably of above 9. The alkaline base, or further bases or acids, can be used to trigger the pH.

The amount of demulsifying agent compared to the sum of the amounts of the surfactants and demulsifying agent is preferably of from 20 to 80% by weight. The amount of demulsifying agent after dilution in water can be for example of from 0.2 g/L (20% of 1 g/L) to 2,4 g/L (80% of 3 g/L). Dilution rates can typically of from 1 to 300 to 1 to 1000.

The formulation can also comprise: - hydrotropic electrolytes such as benzenesulphonates, mono- or di-alkyl (Ci-C₄) benzene sulphonates, toluene-, xylene- or cumene-sulphonates, alcohols or glycols, phosphate esters,

- sequestrating agent such as nitriloacetic acid, ethylenediamine tetraacetic acid, ethylenediamine tetramethylphosphonic acid, nitrilotrimethylene phosphonic acid or salts thereof,

- buffer agents such as alkanolamines, ethylenediamine, - metal corrosion inhibitors,

- defoaming agents.

The formulations can especially comprise:

- of the order of 0 to 2%, generally of 0.01 to 1%, by weight (in the aqueous solution) of at least one anionic or nonionic detergent surface-active agent, such as (C8-Ci6)alkylbenzenesulphonates, (C8-C2θ)a'kyl sulphates, ethoxylated alkylphenols, ethoxylated fatty alcohols, or block polymers of ethylene oxide and of propylene oxide,

- of the order of 5 to 20% by weight (in the aqueous solution) of at least one hydrotropic electrolyte, such as benzenesulphonates, mono- or di(Ci-C4)alkylbenzene sulphonates, or toluene-, xylene- or cumenesulphonates, - other hydrotropic agents, such as alcohols and glycols, - of the order of 5 to 25% by weight (in the aqueous solution) of at least one sequestering agent, such as nitriloacetic acid, ethylenediaminetetraacetic acid, ethylenediaminetetramethylenephosphonic acid, nitrilotrimethylenephosphonic acid or their salts,

- buffer agents, such as alkanolamines, ethylene-diamine, and the like.

For example, a formulation in a powder form can comprise:

- from 25% to 50% by weight of a sodium metasilicate,

- from 10% to 25% by weight of NaOH,

- from 10% to 25% by weight of Sodium Carbonate, - from 2,5% to 10% by weight of the demulsifying agent, and

- from 1% to 2,5% by weight of alkylbenzene sulfonates, such as sodium alkylbenzene sulfonates, for example sodium dodecylbenzene sulfonate.

Process for degreasing metal The invention also relates to a process for degreasing metal wherein the demulsifying agent is used. The process involves treating metal, such as metal parts or plates, with an aqueous composition comprising the formulation diluted in water, and optionally further ingredients. For example, the process for degreasing metal can be used in processes including the following: - Vehicles metal body parts cleaning,

- Metal parts cleaning,

- Metal strip cleaning / Coil cleaning,

- Air condition / heat exchanger cleaning, and

- Paint box cleaning.

The process can comprise the following steps: a) treating oil-soiled metal parts or plates with an aqueous composition comprising the formulation above, to obtain an oil-soiled composition comprising emulsified oil in water, b) subsequently or simultaneously allowing a phase separation of an oil phase comprising the oil, and of an aqueous phase, c) recovering separately the oil phase and the aqueous phase, d) optionally, re-using totally at least one of the recovered phase or ingredients therefrom.

According to a preferred embodiment, step a) treating is performed by dipping the metal parts or plates in an aqueous bath comprising the formulation. Dipping can be performed for example at temperatures of from 45 to 7O⁰C. According other embodiments, step a) treating can be performed by spraying the metal parts or plates with the aqueous composition. Some details or advantages of the invention are further described in the non-limiting examples below.

EXAMPLES Ingredients

- Demulsifier 1: compound having formula (II), wherein R is a C₁₂-C₁₄ "coco" group, and n+n' is of about 18.

- Demulsifier 2: GN 8361 , marketed by Zschimmer & Schwarz, a coco ethoxylated amine, having about 8 EO groups. This is a comparative demulsifier.

- Metal Degreasing mixture: Gardoclean S 5166, marketed by Chemetall.

- Oil: Anticorit RP 4107S, marketed by Fuchs Petrolub.

In the examples, "C" stands for comparative

Example 1 : Formulation

2 g/l of demulsifiers are added at 60⁰C to a solution of 5,6 % (weight %) Gardoclean S 5166. All give a clear solution.

Formulation 1 : 2 g/l of demulsifier 1 Formulation 2C: 2 g/l of demulsifier 2

Example 2: Dip cleaning

Oily metal panels (panels covered with a 20μm thick layer of the oil, oil being applied just before the test) are degreased by dipping 5 minutes in the above described formulations.

Results:

With formulation 1 , the metal panels are wetted with water at 95%.

With formulation 2C, the metal panels are wetted with water at 100%.

Thus, the compounds according to the invention do not decrease significantly the cleaning.

Example 3: Demulsification

2 g/l of the oil is added with stirring into the formulations described in Example 1. An emulsion is formed.

The oil separation from the emulsion is tested by storing 11 in a round neck balloon for 16 hours at 50⁰C. Then quantity of separated oil (demulsification) is visually evaluated in the neck (thickness of the oil layer). The demulsification with formulation 1 and formulation 2C is quite similar.

Example 4 Biodegradability Demulsifier 1 has a biodegradability of 78% as defined by OECD 301 B respirometric test, within 28 days and readily biodegradable.

Demulsifier 2 has a biodegradability of lower than 60% as defined by OECD 301 B respirometric test.

Claims

1. A formulation for degreasing metal, comprising metal degreasing agents and a demulsifying agent, wherein the demulsifying agent is a compound having one of the following formulae (I) or (II):

R-CO-NH-CH₂-CH₂-[EO]_m-OH (I) R-CO-N[CH₂-CH₂-[EO]_n-OH][CH₂-CH₂-[EO]_n-OH] (II) wherein:

- R is a linear or branched, saturated or unsaturated C₇-C₂₂ hydrocarbon group, optionally carrying at least one hydroxyl group,

- EO represents a group having formula -0-CH₂-CH₂-,

- m, n and n', identical or different, are average numbers different from O,

- n+n' is of from 1 to 50, and

- m is of from 1 to 50.

2. A formulation according to claim 1 , wherein:

- the demulsifying agent is a compound having formula (II)

- R is a Ci₂-C₁₄ hydrocarbon group, - n+n' is of from 16 to 25.

3. A formulation according to one of the preceding claims, wherein the metal degreasing agents comprise at least one non ionic or anionic surfactant.

4. Use as a demulsifying agent, of a compound having one of the following formulae (I) or (II): R-CO-NH-CH₂-CH₂-[EO]_1T1-OH (I)

R-CO-N[CH₂-CH₂-[EO]_n-OH][CH₂-CH₂-[EO]_n-OH] (II) wherein:

- R is a linear or branched, saturated or unsaturated C₇-C₂₂ hydrocarbon group, optionally carrying at least one hydroxyl group, - EO represents a group having formula -0-CH₂-CH₂-,

- m, n and n', identical or different, are average numbers different from O,

- n+n' is of from 1 to 50, and

- m is of from 1 to 50.

5. Use according to claim 4, wherein the demulsifying agent is also used as a biodegradable agent.

6. Use according one of claims 4 to 5, in a formulation for degreasing metals.

7. A process for degreasing metal plates panels or sheets with an aqueous compositions, comprising the following steps: a) treating oil-soiled metal parts or plates, with an aqueous composition comprising the formulation according to one of claims 1 to 3, to obtain an oil-soiled composition comprising emulsified oil in water, b) subsequently or simultaneously allowing a phase separation of an oil phase comprising the oil, and of an aqueous phase, c) recovering separately the oil phase and the aqueous phase, d) optionally, re-using totally at least one of the recovered phase or ingredients therefrom.

8. A process according to the preceding claim, wherein in step a) treating is performed by dipping the metal parts or plates in an aqueous bath comprising the formulation.