DE4201876A1 - Rolling oil used as lubricant or coolant - comprising mineral oils and carbonic acid ester(s) - Google Patents

Abstract

Rolling oil (I) based on mineral oils and carbonic acid esters comprise alkoxylated carbonic acid ester of formula (II): (where R1 and R2 = 6-38C alkyl; R3 and R4 = H or CH3; m and n = 0-50 where the sum of m and n is at least 1). Also claimed is the mfr. of rolling sheets using (I) comprising applying alkoxylated carbonic acid ester of formula (II) pref. as aq. emulsion on the rolling sheet or roller before and/or during thickness redn. of the sheet in the spraying process.

Description

The present invention relates to rolling oils containing Mineral oils and ethoxylated carbonic acid esters as well as the use ethoxylated carbonic acid ester as a lubricant component in rolling oils as well as a method for the production of rolled sheets, wherein rolling oils with ethoxylated carbonic acid esters can be used as lubricants.

Rolling oils and rolling emulsions are used for lubrication and cooling during rolling process used to reduce the thickness of thin sheets. When rolling is the formation of a uniform and at the same time sustainable and lubricating film between the roller and the rolling stock is necessary, because a never driger improves the lubrication in the roll gap, so that energy effort, frictional heat and roller wear can be reduced.

So far, mineral oils or natural fats or have been used as lubricants synthetic esters, alone or diluted with mineral oil, are used, whereby these were then advantageously used as aqueous emulsions, if cooling was desired during the rolling process. Thereby the mostly high water content (over 90% by weight) of the aqueous emulsion tion, which enables higher rolling speeds or strip throughputs are. However, it is difficult to adjust such aqueous emulsions that when used, an even, load-bearing and lubricious Film is formed and also the emulsion has sufficient stability points. As a criterion for the lubricating effect of the rolling oil emulsion  often the particle size of the emulsion is used because of larger oil droplets better coalition into a film.

A disadvantage has proven to be the case with the natural fats used to date or synthetic esters often their temperature behavior. Since the Lubricants from thin sheets are often used before further processing are removed by evaporation, the lubricant should have a certain Show temperature behavior. On the one hand it has to be at least that of Can withstand the rolling process occurring temperatures without decomposition (about 180 ° C) and on the other hand it should be at temperatures below 450 ° C be vaporizable without residue so that the residual carbon content on the Rolled sheet is low.

The oil from the European application EP-A-393749 as a lubricant of rolling known carbonate ester of straight or branched C ₆ - len ₃₀ -Alkoho overcome the disadvantage of the high evaporation point, but each show only moderate lubrication properties. In addition, the use of emulsifiers is required for their use as an aqueous emulsion. In the choice of emulsifiers one is limited in the carbonic acid esters according to EP-A-39 37 59. For example, in many cases, highly hydrophilic emulsifiers are no longer compatible with the nonpolar mineral oils and carbonic acid esters, so that segregation can occur. Such segregation is problematic for the application because uncertainties arise in the choice of concentration of the rolling oil.

The object of the present invention was to be rolling oils with lubricants to provide that, when used, especially as an aqueous emulsion, result in an even and load-bearing and lubricious film. Simultaneously The lubricants should either be transferred to the water ge emulsion without emulsifiers or at least better with these be tolerable. Another requirement was that the  Lubricants behave chemically neutral towards the rolled sheets, so for example, it does not corrode or change color the.

The task was solved by rolling oils based on mineral oils and Carbonic acid esters, characterized in that they are as carbonic acid esters alkoxylated carbonic acid esters of the general formula (I)

in which R 1 and R ^{2 are the} same or different and represent an alkyl radical having 6 to 38 carbon atoms,
R ³ and R ^{4 are the} same or different and represent a hydrogen or a methyl group
m and n are the same or different and mean zero or a number in the range from 1 to 50 on the condition that the sum of m + n is at least 1,
contain.

The alkoxylated carbonic acid esters of the general formula (I) are known compounds. It is proposed in the German patent application DE-B-12 42 569 to use carbonic acid esters, the alkyl residues of which may be interrupted by an oxygen atom, as foam-suppressing agents for foaming detergent and cleaning agent systems with ionic and / or nonionic surfactants. In the American patent documents US 33 32 980 and US 45 04 418 special alkoxylated carbonic acid esters are described as surfactants. These alkoxylated carbonic acid esters can be obtained by reacting phosgene with aliphatic alcohol according to J. Chem. Soc. 117, 708 (1920) or by reacting chloroformic acid esters with aliphatic alcohols (cf. J. Pract. Chem. 22, 353 (1880). Of course, in principle the alkoxylated carbonic acid esters can be transesterified using the same transesterification process as the non-alkoxylated carbonic acid esters, for example according to European application EP-A-89 709. The preferred synthesis access is the transesterification of carbonic acid alkyl esters whose alkyl radicals have 1 to 6 carbon atoms in the presence of basic catalysts such as sodium methoxide or alkali metal hydroxide with elimination of the volatile lower alcohol can be reacted, for example, according to the American patent US 36 32 828 dialkyl carbonates with polyethylene glycol monomethyl ethers or transesterified according to the cited patent US 45 04 418 diethyl carbonate with aliphatic alcohols and polyethylene glycol Produced carboxylated carbonic acid esters by dialkyl carbonates with C ₁ -C ₆ alkyl radicals with one or more alcohols of the formulas

R¹ 0 (-CH ₂ -CHR ³ 0) _n -H and
R ² 0 (-CH ₂ -CHR ⁴ 0) _m -H

with the meaning given for R¹, R ² , R ³ , R ⁴ , n and m transesterified. If several alcohols are used in the transesterification, so-called asymmetrical carbonic acid esters are formed because they carry different alkyl residues. If, on the other hand, only a certain alcohol is fully converted, symmetrical carbonic acid esters result. Dialkyl carbonates suitable for the transesterification are dimethyl, diethyl, di-n-propyl and diisopropyl carbonate. Suitable alcohols are aliphatic, aromatic and / or araliphatic alcohols, which may carry alkoxy groups. The alcohols can be saturated and / or unsaturated, straight-chain and / or branched. Saturated aliphatic alkanols and their adducts with 1 to 50 moles of ethylene oxide (R ³ and / or R ⁴ is a hydrogen) and / or propylene oxide (R ³ and / or R ^{4 are} a methyl group) are preferred. The alkoxylated alcohols can carry only ethoxy or only propoxy groups or both as well, and in the case of mixtures of ethoxy and propoxy groups both random and block arrangements are possible. Of the saturated aliphatic alkanols, particular preference is given to unbranched, primary alkanols which have 6 to 22 carbon atoms, such as capron, capryl, pearlagon, caprin, lauryl, myristol, palmityl, styrene, oleyl , Elaidyl, linoleyl, linolenyl and behenyl alcohol, and their addition products of ethylene oxide and / or propylene oxide. Other suitable alcohols are the so-called Guerbet alcohols, which are obtained from the primary alkanols by boiling in the presence of catalytic amounts of alkali metal hydroxide and heavy metal salts according to the Guerbet process and are primary alcohols branched in the alpha position (see EF Pratt, DG Kubler, J. Am. Chem. Soc. 76, (1954), pages 52-56). Of the Guerbetalko, 2-hexyldecanol obtained from n-octanol is particularly preferred.

For the purposes of the invention, preference is given to alkoxylated carbonic acid esters of the general formula (I) in which R 1 and R ^{2 are} an alkyl radical derived from an aliphatic saturated alcohol. Carbonic acid esters of the general formula (I) in which R 1 and R ^{2 are} an alkyl radical which is derived from aliphatic, saturated, unbranched, even-numbered alkanols having 6 to 22 carbon atoms, preferably having 10 to 16 carbon atoms, are very particularly preferred. Atoms. Of these, alkanols are preferred, which he will keep in the form of their technical mixtures, as they provide catalytic hydrogenation of fatty acid or fatty acid methyl ester mixtures from native fats or oils.

As already defined, the indices indicating the degree of alkoxylation n and m are 0 or a number in the range from 1 to 50, but with at least one alkoxy group must be present. Preferred in the sense of the inven are carbonic acid esters of the general formula (I), in which the Sum (m + n) is 2 to 20. The numbers given for n and m are medium Degrees of oxyalkylation, the molar amount of the alkylene oxides added corresponds. The preparation of the alkoxylation products of the Al  kohole takes place according to known methods at elevated temperature and he high pressure by alkoxylation of the alcohols in the presence of known Alkoxylation catalysts such as alkali metal alcoholate or calcined Hydrotalcite. Depending on the desired degree of alkoxylation (n + m) mol Alkylene oxide used per mole of alcohol.

For the purposes of the invention, preference is given to ethoxylated carbonic acid esters of the general formula (I) in which R ³ and / or R ^{4 are} hydrogen. Pure ethoxylated carbonic acid esters are particularly suitable, and preference is given to those with a narrow homolog distribution which have a narrowed range of degrees of ethoxylation. Such carbonic acid esters are made from ethoxylated alcohols of the type described. The ethoxylation of the alcohols themselves is known per se and can be carried out, for example, in the presence of calcined or hydrophobized hydrotalcite in accordance with German Offenlegungsschriften DE-A-38 43 713 or DE-A-40 10 606. In these ethoxylated carbonic acid esters with a narrow homolog distribution, in addition to the good lubricating properties, the stability of aqueous emulsions of the rolling oils has also proven to be advantageous.

Carbonic acid esters are very particularly preferred for the purposes of the invention general formula (I) in which R1 and R2 are an alkyl radical having 10 to 16 C atoms, R3 and R4 are hydrogen and m and n numbers in the range from 2 to 4 mean.

The alkoxylated carbonic acid esters of the general formula (I) are used in a mixture with mineral oils, alkoxylated carbonic acid esters and mineral oil being present in a ratio of 5: 1 to 1: 5. Suitable mineral oils, which can have a paraffinic, aromatic or naphthenic character, usually show a kinematic viscosity at 40 ° C of 5 to 100 mm ² s-1. The carbonic acid esters and the mineral oils can additionally contain further lubricants such as natural oils, lard oils, tallow oil, palm oil and coconut oil or synthetic esters such as pentaerythritol and trimethylol propane esters or phosphate esters or fatty amides or fatty amides or the non-alkoxylated carbonic acid esters according to European patent application EP- A-39 3749. Such non-alkoxylated carbonic acid esters can either be mixed with the alkoxylated carbonic acid esters or can be prepared more easily in situ. In this in-situ reaction one starts from a mixture of alkoxylated and non-alkoxylated alcohols of the type described and carries out a transesterification with the dialkyl carbonates in the manner described. This always creates mixtures with proportions of non-alkoxylated carbonic acid esters. This proportion can be increased if non-alkoxylated alcohols are used in increased amounts. Mixtures of non-alkoxylated carbonic acid esters and alkoxylated carbonic acid esters which are obtained by reacting short-chain dialkyl carbonates with mixtures of alkoxylated alcohols and non-alkoxylated alcohols in the range from 5: 1 to 1: 1 also belong to the scope of the invention. However, it is very particularly preferred to keep the proportion of non-alkoxylated esters as low as possible, if possible below 10% by weight, based on the carbonic ester fraction.

The rolling oils according to the invention can be used neat or advantageously in the form of aqueous emulsions. The emulsifiers can then be dispensed with for conversion into the aqueous emulsions if the proportion of non-ethoxylated carbonic acid esters is low. Otherwise, emulsifier additives in amounts of 1 to 15% by weight - based on mineral oil and carbonic acid ester - are recommended. Suitable emulsifiers can be normal nonionic or anionic surface-active compounds such as ethoxylated C ₁₂ -C ₂₂ alcohols,
optionally ethoxylated alkyl sulfates,
C ₁₂ -C ₂₂ carboxylic acids,
ethoxylated C ₁₂ -C ₂₂ carboxylic acids,
Mono-, di- and triglycerides of C ₁₂ -C ₂₂ carboxylic acids,
Polyglycerol esters, made from a polyglycerol with a degree of condensation between 2 and 20 and C ₈ -C ₂₂ carboxylic acids,
ethoxylated alkylphenols and / or mixtures thereof.

As further components, additives can be added to the rolling oils that Improve the wear and lubrication behavior of the rolling oil. Is recommended the use of so-called extreme pressure (EP) additives, which are known to the person skilled in the art are known for example from Ullmann's Encyklopadie der Technische Chemie Band 20 (1981), 552 to 556. Other optional additives are De-emulsifiers, antioxidants and / or viscostats known to the person skilled in the art improvement.

Particularly suitable rolling oils in the sense of the invention are those, the mine ralöl in amounts of 20 to 80 wt .-%, carbonic acid esters of the general For mel (I) in amounts of 19.8 to 60 wt .-%, emulsifiers in amounts of 0.1 to 10 wt .-% and EP additives in amounts of 0.1 to 10 wt .-% and given if further lubricants known from the prior art in quantities contain from 5 to 20 wt .-%, of course, the sum of the Be constituents is 100% by weight.

Another object of the present invention is the use of alkoxylated carbonic acid esters of the general formula (I) as lubricants middle component in rolling oils, preferably in the form of aqueous emulsions, preferably with a rolling oil content of 0.5 to 10% by weight, preferably from 1 to 5% by weight, based on the rolling oil emulsion.

The present invention also relates to a method for Manufacture of rolled sheets, mineral oils and mineral oils Carbonic acid esters are used, characterized in that alkoxy gated carbonic acid esters of the general formula (I), preferably in the form an aqueous emulsion on the sheet or on the roll before and / or  applied during the thickness reduction of the sheet by spraying will. The rolling oils according to the invention are very particularly preferred in Form of their aqueous emulsion in the cold rolling process for steel strip, and used in particular for the production of its thin sheet.

The rolling oils according to the invention have a medium to in emulsion form Large oil droplet size, which causes the formation of an even one Grease film is given. The stability of the aqueous emulsions so that there are no incompatibilities between mineral oil and fear carbonic acid ester or emulsifier and carbonic acid ester are. Apart from that, there is even no need for emulsifier additives, if the proportion of non-ethoxylated carbonic acid esters is low. Ultimately, these also show higher molecular weight alkoxylated carbonic acid esters better evaporation behavior than most previously used natural fats and a chemically neutral behavior towards the Rolled sheets.

1) Preparation of the ethoxylated carbonic acid esters, generally

2 moles of ethoxylated fatty alcohol were mixed with 1.5-1.7 moles of dimethyl carbonate and 0.5 mol% - based on fatty alcohol - of a 30 wt .-% methano Mix solution of sodium methoxide heated under a nitrogen atmosphere about 70 ° C. After 1 hour, the reaction temperature gradually decreased about 15 ° C per hour up to a maximum of 140 ° C and continuously a dimethyl distilled carbonate / methanol mixture. Then 2 hours in Water jet vacuum re-esterified at 140 ° C. After cooling to 90 ° C the product obtained was removed by 1% by weight to remove the catalyst Tonsil stirred for 1 hour and then filtered off cold.

Carbonic acid ester 1

649.2 mol of n-octanol (<94% by weight) with 4 mol of ethylene oxide (4 EO), 536 mol of dimethyl carbonate and 3.3 mol of sodium methoxide;
Characteristic data: hydroxyl number according to DIN 53 240 (OHZ) = 22.6

Carbonic acid ester 2

6,0 mol of C _12/14 fatty alcohol with 2.5 moles of EO distribution with reduced homologues, ie ethoxylation was calcined in the presence of hydro talcite (0.5 wt .-% on the reaction mixture) as a catalyst conducted 4.5 mol of dimethyl carbonate and 33 moles of sodium methoxide
Characteristic data: OH = 56

Carbonic acid ester 3

1,5 mol of C _12/14 fatty alcohol containing 2 EO and 1.5 mol of 2-hexyldecanol 2.3 mol of dimethyl carbonate and 16 mol of sodium methoxide
Characteristic data: OHZ = 16.7
Characteristics: OHZ = 50

Comparative Example V1

Carbonic acid ester of 50 mol% isotridecyl alcohol and 50 mol% oxo alcohol from Enichem (Lial ^R 125).

II) Tests The following parameters were examined Emulsion stability index (ESI)

20 g of rolling oil to be tested was heated to 45 ° C. with 380 g of water, and with a Braun standard mixer by 30 sec. Stir in an emulsion transferred to a separatory funnel. After 4 hours the 45 ml emulsion from the upper (A) and lower (B) part of the vagina funnel taken. The two emulsion samples were prepared by adding 5 g NaCl and 10 mol concentrated sulfuric acid and split to completion The emulsion splitting is kept at 100 ° C for 24 hours. The ESI value is calculated as

The values can be numbers from zero to 1, whereby the emulsion is all the more cheaper, is, the larger the value.

Droplet size distribution

The droplet size distribution of the emulsions was analyzed with Hil Fraunhofer diffraction (HELOS SYMPATEC). Determining the particles size distribution was done using interference patterns. The method gives up conclude about the size distribution of the droplets, the one at the time of measurement Flow through the measuring capillary. The emulsions were used for the measurement in  a suspension liquid (in this case deionized water) strong diluted (in the order of 1: 500) and then within measured about 10 sec. The x 10- shown in the following tables Value indicates that 10% of the droplets are sized below of the x 10 value. The x 90 value represents the diameter accordingly below which 90% of the emulsion droplets lie. The x 50 value corresponds to the median mean of the diameter.

Falex Pin and Vee Block Method according to ASTM D 2625-83, Method B

According to method B, the load (in Newton N) is increased and the moment (in N · m) determines or when the cross pin (pin) breaks off. It was with the standardized Falex Pin and Vee ßlock test machine worked, whereby first set 2224 N load, read the moment and after 5 Minutes was read again. From the next load of 3336 N onwards waited only 1 minute before reading. 3 were tested % By weight aqueous emulsions of the rolling oils.

III rolling oils

The carbonic acid esters 1 to 3 and V1 were used in the following rolling oil formulations tested (% by weight):

Rolling oil formulation A (% by weight)

35.12 naphthenic mineral oil
3.19 sulfurized lard oil
10.64 lard oil
51.06 carbonic acid esters according to Examples 2 and 3.

Rolling oil formulation B (% by weight)

35.12 naphthenic mineral oil
3.19 sulfurized lard oil
10.64 lard oil
51.06 carbonic acid ester according to Example 1.

Rolling oil recipe C (% by weight)

72.0 naphthenic mineral oil
3.0 nonylphenol with 4 EO
4.0 nonylphenol with 9 EO
21.0 carbonic acid esters according to Example 2 or according to V1.

Table 1

Droplet size distribution

In Table 1, U means a unimodal, B a bimodal and U _s a uni-modal distribution with shoulder.

Table 2

ESI values

From Table 2 it can be seen that all linear, ethoxylated carbons acid esters have a high stability; aqueous emulsions with strong ver branched carbonic acid esters (example 3) are worse.

Table 3

Falex test of rolling oil C with carbonic acid ester according to example 2

Table 4

Falex test of rolling oil C with carbonic acid ester according to V1

Claims (9)

1. rolling oils based on mineral oils and carbonic acid esters, characterized in that they are alkoxylated carbonic acid esters of the general formula (I) as carbonic acid esters in which R1 and R2 are the same or different and are an alkyl radical having 6 to 38 carbon atoms
R ³ and R ^{4 are the} same or different and represent a hydrogen or a methyl group
m and n are the same or different and mean zero or a number in the range from 1 to 50 on the condition that the sum of m + n is at least 1,
contain. 2. Rolling oils according to claim 1, characterized in that they contain alkoxylated carbonic acid esters of the general formula (I) in which R¹ and R ^{2 are} an alkyl radical derived from aliphatic saturated alcohols, preferably from unbranched primary alkanols having 6 to 22 carbon atoms , mean. 3. Rolling oils according to one of claims 1 or 2, characterized in that they contain alkoxylated carbonic acid esters of the general formula (I) in which the sum (m + n) is 2 to 20.   4. Rolling oils according to one of claims 1 to 3, characterized in that they contain alkoxylated carbonic acid esters of the general formula (I) in which R ³ and R ^{4 are} hydrogen. 5. Rolling oils according to one of claims 1 to 4, characterized in that they contain alkoxylated carbonic acid esters of the general formula (I), in which R¹ and R ^{2 are} an alkyl radical having 10 to 16 carbon atoms, R ³ and R ^{4 are} hydrogen and m and n mean numbers in the range from 2 to 4. 6. Rolling oils according to one of claims 1 to 5, characterized in that they alkoxylated carbonic acid esters and mineral oil and in proportions nits from 1: 5 to 5: 1 included. 7. Use of alkoxylated carbonic acid esters of the general formula (I) as a lubricant component in rolling oils. 8. Use according to claim 7, characterized in that the rolling oils in Form of aqueous emulsions are used. 9. Process for the production of rolled sheets, wherein rolling oils based on Mineral oils and carbonic acid esters are used records that alkoxylated carbonic acid esters of the general formula (I), preferably in the form of an aqueous emulsion, on the rolled sheet or on the roller before and / or during the thickness reduction of the Sheet metal can be applied by spraying.