CZ20011852A3 - Metal treatment and cleaning process - Google Patents

Abstract

The invention relates to a method for the metal-cutting machining of metals using an aqueous cutting fluid which is followed by cleaning of the machined metal parts with an aqueous cleaning solution. The invention is characterized in that a) as cutting fluid for the metal-cutting machining an aqueous solution is used which contains corrosion inhibitors as well as polyglycol monoether and/or polyglycol diether; and b) as cleaning solution an aqueous solution is used which contains cleaning substances and the same corrosion inhibitors as the cutting fluid.

Description

Method of working and cleaning of metals

Technical field

The invention is in the field of metal machining and relates to the following steps: metal machining by chip separation and subsequent cleaning with corrosion protection. In this context, "metal cutting by metal" is understood to mean machining processes in which the shape of the metal material is changed by cutting the metal tool from the metal material to be cut. Drilling, turning, milling and grinding are examples of such metal cutting by chip separation. For such machining processes, both the tool and the workpiece are required to be rinsed with coolant and lubricant. It has the task of: lubricating the working tool to prevent welding and overheating, dissipating the heat generated and deburring the chips or other metal particles formed. In doing so, it must have properties that prevent corrosion of the working material.

BACKGROUND OF THE INVENTION

Oils, oil-in-water emulsions or water-soluble coolants and lubricants, which consist of only one aqueous solution, are known in the art as coolants and lubricants. In the present invention, these are water-soluble lubricating fluids, i.e. coolants and lubricating fluids, which contain no water-insoluble components, for example oils.

In the sequence of machining of the metal material, the metal material is usually cleaned after chip removal. This is intended to remove, in particular, the remnants of this to this to this to it to this to it to this to

- ······················· Other cooling and lubricating fluids, but also other impurities and adhering metal particles. The property of the coolant and lubricant used for machining metals prior to cleaning plays a role for the selected cleaning agent only if the cleaning agent has to remove it. The total coolant and lubricant is a 'dirt load' for the detergent, making the detergent unnecessary over time. Depending on the coolant and lubricant load, the detergent must either be refilled with new cleaning active ingredients, regenerated by bath maintenance measures, or discarded and used a new one. This leads to a high consumption of detergent active ingredients which must be discarded after the shelf life of the detergent. This entails environmental burdens and is economically advantageous due to the desired use of the substances.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of combining metal cutting by chip separation using an aqueous cooling liquid and subsequent cleaning of the machined metal parts with an aqueous detergent solution, wherein the components contained in the cooling liquid and the aqueous detergent solution are in the coolant, they supplement or at least do not adversely affect the detergent solution. According to this concept, the coolant for the cleaning solution does not represent any "contamination load" but rather complements it. This allows less active substance consumption for the cleaning solution. The shelf life of the cleaning solution will be extended without any bath maintenance measures. Reduced material consumption and lower disposal costs will make the environment easier and cheaper.

The invention is based on aqueous coolants and lubricants which contain polyglycol monoether and / or polyglycol ether as lubricants. In addition, aqueous coolants and lubricants contain corrosion inhibitors.

German Patent Application DE 197 23 990.0 also discloses metal cleaning compositions which contain glycol monoether of the general formula as active cleaning ingredients.

- 3 RO- (CH ₂ -CH (CH ₃ ) -O) _n -H wherein R is C 1 -C 4 alkyl or phenyl and n is from 1 to 5. These glycol monoethers are used in combination with cationic surfactants in a weight ratio of glycol monoether to cationic surfactant of 8: 1 and 100: 1. Preferably, the cleaning composition contains corrosion inhibitors as further active ingredients.

SUMMARY OF THE INVENTION

The object of the invention is solved by a method of metal machining by chip separation using an aqueous cooling and lubricating liquid and subsequent cleaning of the machined metal parts with an aqueous cleaning solution, characterized in that:

(a) an aqueous solution containing corrosion inhibitors and a polyglycol monoether and / or polyglycol diether is used as a metal-cutting coolant and cooling agent; and

(b) an aqueous solution containing active cleaners and the same corrosion inhibitors as the coolant and lubricant is used as the cleaning solution.

The essence of the invention is, on the one hand, that the aqueous (= water-soluble) cooling and lubricating liquid contains the same corrosion inhibitors as the cleaning solution. If the coolant and lubricant are incorporated into the cleaning solution, the corrosion inhibitors of the coolant and lubricant do not present any contamination for the cleaning solution. They more or less supplement the contents of the cleaning solution with corrosion inhibitors. They compensate for the loss of corrosion inhibitors that are carried away from the cleaning solution by the cleaned workpieces. Therefore, to a reduced extent, ideally • · · · • ·

it does not require that the corrosion inhibitor content of the cleaning solution be replenished.

On the other hand, polyglycol monoethers or polyglycol monoethers are selected. lubricating polyglycol diethers to be compatible with the components of the cleaning solution. Thus, they neither cause a loss of cleaning effect nor reduce the effectiveness of the corrosion inhibitors of the cleaning solution. Thus, they do not present any contamination for the cleaning solution and cause no bath maintenance measures necessary to remove them. During operation, the stationary content of these components is more or less set during operation, since the same amounts of lubricant are introduced into the cleaning solution in equilibrium as the cleaned workpieces are carried.

In this case, the polyglycol monoethers and the polyglycol monoethers are optionally present. polyglycol diethers as such, which are used as lubricant components in the coolant and lubricant, are known for such applications and are commercially available. In doing so, polyglycol monoethers are also often shortened, but incorrectly referred to as 'polyglycols'. They are obtained by reacting suitable starter molecules, for example monohydric or polyhydric alcohols having 1 to 5 carbon atoms, with ethylene oxide and / or propylene oxide. This produces a polyethylene glycol, polypropylene glycol or mixed chain wherein the alkylene oxide units bind to the polyethers after the chain is opened. The term "polyglycols" generally ignores these ether compounds. When referring to polyglycol ethers, it is meant that polyglycols do not carry an OH group at each end of the chain, but form an ether with an alcohol at one end of the chain. However, this designation does not distinguish whether only one end of the chain or whether both ends of the chain form an ether with the alcohol. For the purposes of the present invention, the following terms are used: polyglycol monoether are oligomeric or polymeric polyalkylene glycol chains that form an ether at one end with an alcohol. Correspondingly, the terms glycol diether and " polyglycol diether oligomeric or polymeric alkylene glycol chains that form an ether at both ends with an alcohol. It is not desirable for the molecules to carry the same alcohol group at both ends. The term glycol diether or the term "

Therefore, the polyglycol diether also corresponds to a technically feasible technically suitable polyglycol diether. end-capped glycol ether polyglycol ether '.

The aqueous cooling and lubricating liquid used according to the invention preferably contains those polyglycol monoethers and / or polyglycol diethers which are obtained by ethoxylation and / or propoxylation with monohydric or polyhydric alcohols having 1 to 5 carbon atoms. alcohols having 1 to 6 carbon atoms. The polyglycol monoethers or polyglycol ether ethers preferably have an average molecular weight in the range from 500 to 25,000.

The corrosion inhibitors used according to the invention both in the aqueous cooling and lubricating liquid and in the aqueous cleaning solution are preferably selected from alkanolamines and / or salts of branched or unbranched, saturated or unsaturated aliphatic mono- or dicarboxylic acids having 6 to 10 atoms C and / or aromatic carboxylic acids having 7 to 10 carbon atoms. When referring to carboxylic acid salts, this may on the one hand mean that the alkanolamine salts of carboxylic acids are used directly. This is equivalent to a mixture of alkanolamines and carboxylic acids that interact with each other to form a salt. Furthermore, alkanolamines per se and carboxylic acids as alkali metal salts can be used. Equivalent to the alkaline earth salts of carboxylic acids are mixtures of carboxylic acids and alkali metal hydroxides. Depending on the pH of the aqueous cooling and lubricating liquid or aqueous cleaning solution used, alkanolamines and / or carboxylic acids exist as an equilibrium mixture of neutral molecules and cations in the case of alkanolamines or alkanolamines. anions in the case of carboxylic acids.

Preferably, the useful aqueous cooling and lubricating liquid comprises 2 to 15 g / l polyglycol monoether and / or polyglycol diether and 8 to 40 g / l corrosion inhibitors. As further components, the aqueous cooling and lubricating liquid may additionally contain emulsifiers, buffers, surfactants and / or biocides. Its pH preferably lies in the range between about 6 and about 9.5.

• · · · · · · · · · · ·

- θ - ······· ····· ·

For metal cutting applications, the aqueous cooling and lubricating capsule can in principle be mixed in situ by dissolving the individual components at the desired concentrations in water. It is, however, technically common for an aqueous cooling and lubricating liquid to be marketed in the form of an aqueous concentrate which contains the individual active ingredients in the correct amount, but in concentrated form. For use, this concentrate must be diluted with water to the applicable concentrations on site. In this case, the concentrate can be a one-component concentrate; It contains all active substances of cooling and lubricating liquids. However, the concentrate may also be marketed in the form of two or more separate containers containing certain components or components. combination of ingredients. This allows the use of coolant and lubricant to dispense the components separately from each other when consumed or discharged in different proportions. For example, the coolant and lubricant may be marketed as a concentrate containing both about 50 to 300 g / l of polyglycol ether and / or about 50 to 600 g / l of said corrosion inhibitors and optionally other active and excipients. Separate polyglycol ether and / or polyglycol diether concentrates on the one hand and corrosion inhibitors on the other hand can be used to introduce or replenish the aqueous cooling and lubricating liquids used. In this case, optionally used active and auxiliary substances such as emulsifiers, buffers, surfactants and / or biocides, preferably those concentrate components containing polyglycol monoether and / or polyglycol diether, are added together. The second concentrate is then an aqueous solution of the corrosion inhibitor. This concept has the advantage that the corrosion inhibitor concentrate can be used both to replenish the coolant and lubricant as well as to replenish the aqueous cleaning solution.

In principle, an aqueous cleaning solution can also be prepared by dissolving the individual active ingredients with water on site. As with the coolant and lubricant, however, it is also advantageously provided here that the concentrates of the cleaning solution are placed on the market, which are diluted on site with water in the desired proportions.

The concentrate may contain all active and auxiliary substances in the correct relative relative proportions to one another. Pursuant • · · ·

It is advantageous to prepare an aqueous cleaning solution which contains cleaning active ingredients and other optional active and auxiliary substances, but not corrosion inhibitors. To adjust the corrosion inhibitor content of the aqueous cleaning solution to be used, the same concentrate can be used to deploy or dispense the same. to replenish used aqueous coolant and lubricant. This concept, bringing together a total of three concentrated products for coolant and lubricant and cleaning solution, will increase the flexibility of replenishment of individual components and lead to particularly economical use of substances.

The active cleaning agents in the cleaning solution are preferably selected from anionic surfactants, nonionic surfactants, cationic surfactants and glycol monoethers of the general formula

RO- (CH ₂ -CH (CH ₃ ) -O) _n -H, wherein R is C 1 -C 5 alkyl or phenyl, and _n is from 1 to 5, preferably from 1 to 3.

Possible glycol monoethers include: tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, dipropylene glycol n-nutyl ether, tripropylene glycol n-butyl ether and propylene glycol phenylether. Tripropylene glycol monomethyl ether and tripropylene glycol n-butyl ether are particularly preferred.

Preferably it comprises a cleaning solution

a) a glycol monoether of the formula RO- (CH 2 -CH (CH 3) -O) _n -H, wherein R is a C 1 -C 5 alkyl radical or a phenyl radical and n is a number from 1 to 5, preferably from 1 to 3 , and · ** · ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** · ···· ···· ··· ·· ··· ·· ···

b) a cationic surfactant in a) to b) ratio by weight of between 5: 1 and 100: 1. Preferably, the weight ratio of glycol monoether and cationic surfactant in the detergent composition is between 8: 1 and 25: 1.

The cationic surfactants used optionally in the cleaning solution are preferably selected from quaternary ammonium compounds of the general formula

R ¹ - (CHOH-CHR ² ) n N ⁺ R ³ R ⁴ R ⁵ X ', where it may be

R ¹ a linear or branched alkyl radical having 1 to 22 C atoms,

R ² is hydrogen or a linear or branched alkyl radical having 1 to 22 C atoms, wherein the total number of carbon atoms of the radicals R ¹ and R ² ranges from 10 to 22, n = 0 or 1,

R ₃ and R ₄ are independently a methyl, ethyl, 2-hydroxyethyl or hydroxypropyl,

R ₅ is an alkyl radical of 1 to 12 atoms, a benzyl radical or an alkylphenyl radical of 1 to 3 C atoms in the alkyl radical, and wherein the total number of carbon atoms of the quaternary ammonium cations is at least 9 and at least one of R ¹ and R ⁵ has more than 4 carbon atoms; and

X 1 is a halide, methyl sulfate or anion of an aliphatic or aromatic organic acid with up to 15 C atoms.

- 9 9 9 9 99 99 9 99 9 9 9 9 9 9 9 9 99

9 «9 9

9 9 99 9 9 99 999

Hereby, priority of such cationic surfactants in which R ³ and R ⁴ is a methyl group and R ⁵ is a benzyl group.

Examples of such surfactants are the lauryl-dimethyl-benzyl-ammonium salts or the 2-hydroxydodecyl-dimethyl-benzyl-ammonium salts. Suitable anions X in these salts are, for example, halides, in particular chloride, or anions of organic acids such as acetate, propionate, lactate or benzoate ions.

Preferably, the cleaning solution used contains 1 to 15 g / l of said corrosion inhibitors.

The active detergent content of the cleaning solution to be used is preferably 0.1 to 5.0 g / l. In particular, the cleaning solution preferably contains 0.1 to 4.0 g / l of said glycol monoether and 0.001 to 0.5 g / l of said cationic surfactant.

Typically, the cleaning solution may additionally contain builder substances, biocides and / or complexing agents. Examples of builder substances are alkali metal o-phosphates, polyphosphates, silicates, borates, carbonates, polyacrylates and gluconates. These builder substances partly have complex properties and thus act as a water softener. Instead of these or in addition to these, stronger complexing agents such as 1-hydroxyethane-

1,1-diphosphonic acid or 2-phosphonobutane-1,2,4-tricarboxylic acid. Further suitable are ethylenediaminetetraacetates or nitrilotriacetates.

Preferably, the cleaning solution is formulated as a so-called neutral cleaning agent. The usual pH of this so-called neutral detergent is in the range of 6.5 to 9.

♦ · · ♦ «« · 4 4 · · · 4 · 4 · 4 · 44 • 44 • 4 • 4 4444 44 • 4 4 4 44444 • 4 4 4 4 44

4444 444 44 444 444

The temperature of the cleaning solution is preferably in the range from 15 to 80 ° C. In this case, the cleaning can be carried out in a dipping device or in a spraying device. Spray cleaning is particularly effective, so that cleaning preferably takes place in the spray device. For preferred use in a spraying device, the above-described glycol monoethers, preferably in combination with said cationic surfactants, are chosen as active cleaning agents for the cleaning solution. These are particularly low foaming and can be used for spray cleaning over the entire temperature range mentioned.

• *

Examples of embodiments of the invention

For example, an aqueous cooling and lubricating liquid having the following composition may be used for the metal cutting phase of the chip separation:

Example 1:

3.41 g Monoethanolamine

9.79 g Triethanolamine

5.28 g Sebacic acid

3,57 g Polyethylene / propylene glycol ether (starting molecule: pentaerythritol), molecular weight 15.000

1.70 g 6 - ((((4-methylphenyl) -sulfonyl) -amino) -hexanoic acid)

1.79 g Glycerin

2.14 g Caprylic acid

0.07 g 1H, 2,3-Benztriazole

1.79 g of boric acid

Residue up to 1000 ml: make up with water.

Example 2:

3.00 g Monoethanolamine

11.00 g Triethanolain

5.28 g Sebacic acid

7.50 g Polyethylene (propylene glycol ether (starting molecule: petaerythrite)), molecular weight 15.000 ·· φ · · · · · · · · ·

Φ · · φ · φ φ φ φ φ φ φ φ φ

- 12 - ···· ♦ ·· · · ··· ·· ·

2.85 g 6 - (((4-methylphenyl) -sulfonyl) -amino) -hexanoic acid

4.20 g Glycerin

0.12 g 1H, 2,3-Benztriazole

Residue up to 1000 ml: make up with water.

It can be obtained by suitable dilution of an aqueous concentrate containing about 50 to 300 g / l polyglycol monoether and / or polyglycol diether and about 50 to 600 g / l corrosion inhibitor.

The aqueous cleaning solution used in the process of the invention may, for example, have the following composition:

Example for cleaning solution (example 3):

0.60 g Monoethanolamine

2.70 g Triethanolamine

1.79 g Sebacic acid

0.27 g Tripropylene glycol monomethyl ether

0.01 g of 2-hydroxy-dodecyl-dimethyl-benzyl-ammonium benzoate

Residue up to 1000 ml: make up with water.

Also, a cleaning solution is prepared on site by dissolving the concentrate with water. The dilution factor of the concentrate preferably lies in the range of about 1: 200 to about 1:20. A concentrate which contains all the components of the cleaning solution in appropriate weight ratios can be used to introduce a new cleaning bath. However, it is recommended to use a concentrate that contains little or no inhibitors to supplement the cleaning solution with the active cleaning active ingredients. 99 ·· · · · · · ·

»» »··

- J O - Corrosion as they are clogged into the cleaning solution by coolant and lubricant and thus replenish.

The following test performs the effect of cleaning a non-loaded and coolant-loaded cleaning agent:

St 1405 grade steel sheets are manually pre-cleaned with a surfactant solution and contaminated with a test impurity consisting of carbon black, graphite, fatty acid triglyceride and a hydrocarbon fraction. After 30 minutes of storage in an oven at 60 ° C, spray with a cleaning solution in a laboratory sprayer at 60 ° C for 2 minutes at 3 bar. To simulate extra foreign oils, the cleaning solution was previously mixed with 10 g / l Gerolub ^R 3005/7 (registered trademark of Henkel KGaA, Dusseldorf), a metastable O / W emulsion. After rinsing with water, the residual contamination is determined quantitatively by oxidation of the carbon remaining on the surface.

The cleaning effect ("Reinigungseffizienz") is the quotient of the removed contamination to the contamination before the cleaning attempt, also measured by the oxidation of the surface carbon, to imagine as a value in% multiplied by 100.

Example 4 Cleaning agent without coolant and lubricant

Composition of cleaning liquid

10.00 g Gerolub 3005/7

0.80 g Monoethanolamine

3.60 g Triethanolamine

2.38 g Sebacic acid

0.36 g Tripropylene glycol monomethyl ether

0.01 g of 2-hydroxy-dodecyl-dimethyl-benzyl-ammonium benzoate

- 14 make up to 1 l with water.

Cleaning efficiency: 94%

Example 5 A detergent loaded with an aqueous cooling and lubricating liquid

Composition of cleaning liquid

10.00 g Gerolub 3005/7

1.20 g Monoethanolamine

4.05 g Triethanolamine

2.38 g Sebacic acid

0.36 g Tripropylene glycol monomethyl ether

0.01 g of 2-hydroxy-dodecyl-dimethyl-benzyl-ammonium benzoate

0.89 g Polyethylene / propylene glycol ether (strentaerythritol), molecular weight 15.000

0.42 g 6 - (((4-methylphenyl) -sulfonyl) -amino) -hexanoic acid

0.45 g Glycerin

0.54 g Caprylic acid

0.03 g 1H, 2,3-Benzotriazole

Add 0,45 g of boric acid to 1 l with water.

Cleaning efficiency: 91%

- 15 Example 6: Cleaning agent loaded with aqueous quenching and lubricating liquid

Composition of cleaning liquid

10.00 g Gerolub 3005/7

1.00 g Monoethanolamine

4.10 g Triethanolamine

2.38 g Sebacic acid

0.36 g Tripropylene glycol monomethyl ether

0.01 g of 2-hydroxy-dodecyl-dimethyl-benzyl-ammonium benzoate

1.25 g Polyethylene / propylene glycol ether (starter molecule: pentaerythritol), molecular weight 15.000

0.48 g 6 - ((((4-methylphenyl) -sulfonyl) -amino) -hexanoic acid)

0.70 g Glycerin

Make 0,03 g 1H, 2,3-Benzotriazole to 1 l with water.

Cleaning efficiency: 88%

The results show a high cleaning effect despite the cooling agent and lubricant loading the detergent.

Claims (12)

Patent claims CLAIMS 1. A method of treating metals by separating chips using an aqueous cooling and lubricating liquid and subsequently cleaning the treated metal parts with an aqueous cleaning solution, characterized in that: (a) an aqueous solution containing corrosion inhibitors and a polyglycol monoether and / or polyglycol diether selected from ethoxylated and / or propoxylated monohydric or polyhydric alcohols having 1 to 5 atoms is used as the cooling and lubricating liquid for metal cutting by chip separation. C and their ethers with alcohols having 1 to 6 carbon atoms and having an average molar mass in the range of from 500 to 25000, and (b) an aqueous solution containing a glycol monoether of the general formula is used as the cleaning solution RO- (CH ₂ -CH (CH ₃ ) -O) _n -H, wherein R is C 1 -C 5 alkyl or phenyl, and n is from 1 to 5, and the same corrosion inhibitors as the coolant and lubricant. Method according to claim 1, characterized in that the corrosion inhibitors are selected from alkanolamines and / or salts of branched or unbranched, saturated or unsaturated aliphatic mono- or dicarboxylic acids having 6 to 10 carbon atoms and / or aromatic carboxylic acids having 7 to 10 carbon atoms. 10 C atoms 4 · ·· «« 4 4 4 4,444 • 4 «444« 44 · 4 44 ·· 44 44 4444 4 4 4 • • 4 4 44 · · ······ 4 «« 44 4 4 Method according to one or both of Claims 1 and 2, characterized in that the aqueous cooling and lubricating liquid comprises 2 to 15 g / l of polyglycol monoether and / or polyglycol diether and 8 to 40 g / l of corrosion inhibitors. The method of claim 3, wherein the aqueous cooling and lubricating liquid additionally comprises one or more substances selected from emulsifiers, buffers, surfactants and biocides. Method according to one or more of Claims 1 to 4, characterized in that the cleaning solution comprises (a) a glycol monoether of the general formula RO- (CH ₂ -CH (CH ₃ ) -O) _n -H, wherein R is C 1 -C 5 alkyl or phenyl, and n is from 1 to 5, and b) cationic surfactants in a) to b) weight ratio between 5: 1 and 100: 1. The process of claim 5, wherein the cleaning solution comprises glycol monoether and cationic surfactants in a weight ratio between 8: 1 and 25: 1. Method according to one or both of Claims 5 and 6, characterized in that the cationic surfactants are selected from quaternary ammonium 98 9 99 9 9 9 9 9 9 9 9 9 9 · 9 99 • 9 9 9 9 99 • 99999999 • 9 9 9 99 »• 99 999 99 · <·» 9 · compounds of the general formula R ¹ - (CHOH-CHR ² ) n N ⁺ R ³ R ⁴ R ⁵ X ', where R ¹ may be a linear or branched alkyl radical having 1 to 22 C atoms, R ² a hydrogen atom or a linear or branched alkyl radical having 1 to 22 carbon atoms 22 is C, wherein the total number of C atoms of R ¹ and R ² is in the range from 10 to 22, n = 0 or is 1, R ³ and R ⁴ are independently methyl, ethyl, 2-hydroxyethyl or hydroxypropyl, R ⁵ is C 1 -C 12 alkyl, benzyl or C 1 -C 3 alkylphenyl, and wherein the total number of carbon atoms of the quaternary ammonium cation is at least 9 and at least one of R ¹ and R ⁵ has more than 4 carbon atoms; and X‘is a halide, methyl sulfate or anion of an aliphatic or aromatic organic acid with up to 15 C atoms. 8. The method according to claim 7, characterized in that in the formula of the cationic surfactants, R ³ and R ⁴ is a methyl group and R ⁵ group is benzyl. The method according to one or more of claims 1 to 8, characterized in that the cleaning solution contains 1 to 15 g / l of corrosion inhibitors. Method according to one or more of Claims 1 to 9, characterized in that the cleaning solution contains 0.1 to 5 g / l of active cleaning substances. The method of claim 10, wherein the cleaning solution comprises 0.1 to 4.0 g / L glycol monoether and 0.001 to 0.5 g / L cationic surfactant. - 19 ·· 1 · «<<· · · t t t 9 9 9 9 9 9 9 9 · · »· · · · · Method according to one or more of claims 1 to 11, characterized in that the cleaning solution additionally comprises one or more substances selected from builder substances, biocides and complexing agents.