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(11) | EP 1 123 968 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Aluminium and aluminium alloys cold rolling oil composition |
| (57) The present invention relates to an aluminium and aluminium alloys cold rolling oil
composition comprising a base stock oil and, based on the total weight of the composition,
from 0.01 to 5% by weight of a coumpound A having the formula X3-PO3, wherein each X is selected from the group consisting of alkylaryl, aryl-alkyl and aryl groups, wherein each alkyl group has from 3 to 24 carbon atoms and can include heteroatoms like oxygen, nitrogenous or sulfur; each aryl group has from 4 to 10 carbon atoms and can include heteroatoms like oxygen, nitrogen or sulphur; and the alkyl and aryl groups are unsubstitued or substitued with up to 3 halogen substituents. The invention also relates to a process for cold rolling aluminium and aluminium alloys sheets and to the use of the oil composition in an aluminium, aluminium alloys or non ferrous metals cold rolling process. |
[0001] The present invention relates to an aluminium and aluminium alloys cold rolling oil composition and to a process of cold rolling aluminium and aluminium alloy sheets.
[0002] The aluminium and aluminium alloys rolling industry expresses the need to maximize the efficiency of their rolled metal manufacturing process. In general terms, this means that there is a wish to operate at higher rolling speeds and to produce more marketable products per operating shift. Additionally, they also wish to minimize the number of passes through the mill taken to achieve a given level of reduction. Both these routes require that quality and surface finish be not compromised.
[0003] Further, since the final aluminium sheet may be used to wrap food articles or may come in contact with food, it is necessary that any composition used in the rolling process complies with the legal specifications relating to the food industry.
[0004] In addition, the final aluminium sheets must not be stained by the compositions used in the rolling process.
[0005] The invention thus provides an oil composition for aluminium and aluminium alloys cold rolling mills that affords the following customer benefits:
- lower rolling and reduced mill power (this allowing rolling harder non-ferrous alloys and/or allow higher reduction ratios);
- allows one or two pass(es) reduction versus conventional oil lubrication;
- improved rolled surface finish by minimizing the sticking tendency of the strip when performing decoiling after thermal treatment;
- non-stained surface; and
- the end product can safely be used with food products.
[0006] The invention is effective on any type of cold rolling, be it reversible or not, of the Sendzimir type (e.g. 1-2, 1-2-3, 1-2-3-4), or of Z-high type (e.g. 2-high, 4-high, 6-high), be it a reversible mill, a tandem mill, etc.
[0007] Especially, the invention is specially designed for aluminium and aluminium alloys for 2-high, 4-high and 6-high mills. The invention provides improved aluminium or aluminium alloy strip surface finish by minimizing the sticking tendency after thermal treatment of the rolled coils and excellent rolling capabilities by reducing the rolling force and mill power required when rolling harder copper alloys.
[0008] The International application n° WO 98/04657 relates to a process for cold-rolling aluminium comprising the provision on the surface of the aluminium of an organic lubricant which is selected from (i) an iso-paraffin hydrocarbon mixture, (ii) a mixture of iso-paraffinic and naphthenic hydrocarbons and (iii) a mixture of (i) and (ii).
[0009] The article of Zhang and Lenard in JSL (Journal of Synthetic Lubrication) 12-4 304 0265-6582 compares the effects of various lubricants on the magnitude and the variation of the roll-separating force during cold rolling of aluminium strips.
[0010] None of these documents provide information relating to the production of non-stained aluminium or aluminium alloy articles which can be satisfactorily used in the food industry.
[0011] Thus, the invention provides a aluminium and aluminium alloys cold rolling oil composition comprising a base stock oil and, based on the total weight of the composition, from 0.01 to 5% by weight of a coumpound A having the formula X3-PO3, wherein
each X is selected from the group consisting of alkyl-aryl, aryl-alkyl and aryl groups, wherein
each alkyl group has from 3 to 24 carbon atoms and can include heteroatoms like oxygen, nitrogenous or sulfur;
each aryl group has from 4 to 10 carbon atoms and can include heteroatoms like oxygen, nitrogen or sulphur; and
the alkyl and aryl groups are unsubstitued or substitued with up to 3 halogen substituents.
[0012] The alkyl groups can be linear or branched. Examples of alkyl groups include the propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, palmityl, stearyl and dodecanyl groups.
[0013] Examples of aryl groups include phenyl, naphtyl, anthracenyl, indenyl and thienyl groups. Among these groups phenyl is preferred.
[0016] The invention also provides a process for the preparation of an oil composition comprising blending the base stock and the other ingredients under stirring or with any mixing device.
[0017] In addition, the invention provides a cold rolling process for rolling aluminium and aluminium alloys sheets, comprising applying an effective amount of the oil composition of the invention.
[0018] Finally, the invention provides the use of the oil composition of the invention in aluminium and aluminium alloys cold rolling process.
[0019] The invention is now disclosed in more details in the following specification and in reference to the accompanying Figure 1, which is a graph representing the reduction ratio and the friction coefficient as a function of the additivation and the base oil type, when rolling an aluminium alloy.
[0021] The base stock oil is any oil typically used in the field of cold rolling. It can be paraffinic or naphthenic.
[0022] Paraffinic base oils are made from crude oils that have relatively high alkane contents (high paraffin and isoparaffin contents). Typical crudes are from the Middle East, North Sea, US mid-continent. The manufacturing process requires aromatics removal (usually by solvent extraction) and dewaxing. Paraffinic base oils are characterized by their good viscosity/temperature characteristics, i.e. high viscosity index, adequate low-temperature properties and good stability. They are often referred to as solvent neutrals, where solvent means that the base oil has been solvent-refined and neutral means that the oil is of neutral pH. An alternative designation is high viscosity index (HVI) base oil. They are available in full range of viscosities, from light spindle oils to viscous brightstock.
[0023] Naphthenic base oils have a naturally low pour point, are wax-free and have excellent solvent power. Solvent extraction and hydrotreatment can be used to reduce the polycyclic aromatic content.
[0024] In order to improve the cooling ability and to fulfil the stringent rolled metal quality constraints, very low viscosity base stocks have been developped for high speed cold rolling mills. Light petroleum fractions such as kerosene cut base oils are suitable for these applications. The kerosene type base stock is hydrotreated to improve its resistance to oxidation and to meet the non staining requirements during annealing and thermal degreasing. These base stocks are highly saturated paraffinic fractions that have been extracted sulphur, nitrogen, oxygen, heteroatoms that are naturally present in petroleum cuts.
[0025] The mineral oils and additives used in the invention are preferably those which can be safely used as a component of nonfood articles intended for use in contact with food. These oils and additives are described in 21 CFR Ch. 1 §178.3620 (a), (b) and (c) and 21 CFR Ch.1 § 178.3910 of the Food and Drug Administration, HHS.
[0026] The base oil typically has a viscosity from 1.2 to 6.0 cSt at 40°C and preferably from 1.6 to 3.0 cSt at 40°C. Viscosity can be adjusted by using a viscosity adjuster (such as kerosene), if needed.
[0027] The oil composition may comprise classical additives, such as surfactants, coupling agents or cosurfactants, friction- reducing agents or lubricity agents, corrosion inhibitors or anti-oxidants, extreme-pressure and anti-wear agents, anti-foaming agents, anti-rust agents.
[0029] Examples of corrosion inhibitors are hindered phenols and zinc dialkyldithiophosphates (ZDDP).
[0030] Examples of extreme-pressure and anti-wear agents are dilauryl phosphate, didodecyl phosphite, trialkylphosphate such as tri(2-ethylhexyl)phosphate, tricresylphosphate (TCP), zinc dialkyl(or diaryl)dithiophosphates (ZDDP), phospho-sulphurized fatty oils, zinc dialkyldithiocarbamate), mercaptobenzothiazole, sulphurized fatty oils, sulphurized terpenes, sulphurized oleic acid, alkyl and aryl polysulphides, sulphurized sperm oil, sulphurized mineral oil, sulphur chloride treated fatty oils, chlornaphta xanthate, cetyl chloride, chlorinated paraffinic oils, chlorinated paraffin wax sulphides, chlorinated paraffin wax, and zinc dialkyl(or diaryl)dithiophosphates (ZDDP), tricresylphosphate (TCP), trixylylphosphate (TXP), dilauryl phosphate, respectively.
[0031] Examples of corrosion inhibitors or anti-oxidants are radical scavengers such as phenolic antioxidants (sterically hindered), aminic antioxidants, organo-copper salts, hydroperoxides decomposers, butylated hydroxytoluene.
[0033] Examples of friction reducing agents or lubricity agents are fatty alcohols having a carbon number in the range from 12 to 18, fatty esters having a carbon number in the range from 12 to 18, like glycerol monooleate.
[0034] Further elements on base oils and additives can be found in "Chemistry And Technology Of Lubricants", R.M. Mortier and S.T. Orszulik, VCH Publishers, Inc, First published in 1992.
[0035] The aluminium alloys to which the invention applies are any alloys, including 1000, 2000, 3000, 5000, 6000, 7000 series.
[0036] The oil composition of the invention can also be used in another non ferrous metals cold rolling process.
[0037] The cold rolling process is the classical process. The oil temperature is generally maintained at a temperature below 70°C, preferably below 40°C. The process can be carried out on any rolling mill, such as of a 2 high, 4high, 6 high mill, in tandem, etc. The instant oil composition allows a significant reduction of the number of passes. With conventional prior art oils, the number of passes was typically 5. The oil composition of the invention allows lowering this number to 4 passes, which is a significant gain.
[0038] The following examples illustrate the invention without limiting it. All parts and ratios are given by weight.
Example
[0039] The following composition is prepared:
| Ingredients | Content (wt%) |
| Kerosene type base oil, aromatic free, high paraffin content, 1.7 cSt at 40°C | 95.6 |
| Lauryl alcohol | 1.0 |
| N-butyl stearate ester | 3.0 |
| Oleic acid | 0.1 |
| Tri(nonyl-phenyl)phosphite (TNPP)* | 0.3 |
| * TNPP is provided by CIBA GEIGY under the trademark TNPP IRGAFOS® |
[0040] The characteristics of said composition are set out in the following table :
| Physical properties | Unit | Method | Characteristics |
| Density at 15°C | kg/l | D1298 | 0.823 |
| Kinematic viscosity | CSt at 40°C | D445 | 1.80 |
| Flash point | °C | D93 | 94 |
| Distillation | °C | D86 | |
| temperature : | |||
| - initial boiling point | 222 | ||
| - when 50% are | 235 | ||
| distilled | |||
| - final boiling point | 245 | ||
| Sulfur content | ppm | ICP | < 1 |
| Saponification number | mg KOH/g | D94 | 6 |
[0042] The test mill is a reversing, single stand 4-high rolling mill with coiler and decoiler designed for 60 mm wide sheets, which can take up to 1.0 mm thick strips. The rolls have a length of 200 mm and a diameter of 100 mm.
[0043] The test conditions are as follows :
- rolling speed : 250 m/min
- rolled Al alloy : 1050
- rolling force at starting test conditions : 30 kg/cm2
- oil temperature : 45°C
- Al initial thickness : 100 µm
[0044] The reduction ratio and the friction coefficient are measured as a function of the additivation and the base oil type.
[0045] The following oils are tested :
- trial 1 (prior art) : non additivated aromatic free base oil, viscosity 1.7 cSt at 40°C;
- trial 2 : non additivated aromatic free base oil, viscosity 1.7 cSt at 40°C : trial 1 + 0.1% Irgafos TNPP;
- trial 3 : non additivated aromatic free base oil, viscosity 1.7 cSt at 40°C, trial 1 + 0.1% Irgafos TNPP + 1% lauryl alcohol;
- trial 4 : non additivated aromatic free base oil, viscosity 1.7 cSt at 40°C, trial 1 + 0.1% Irgafos TNPP + 1% lauryl alcohol + 0.1% oleic acid;
- trial 5 : non additivated aromatic free base oil, viscosity 1.7 cSt at 40°C, trial 1 + 0.1% Irgafos TNPP + 1% lauryl alcohol + 0.1% oleic acid + 3% n-butyl stearate ester;
- trial 6 : non additivated aromatic free base oil, viscosity 1.7 cSt at 40°C, trial 1 + 0.3% Irgafos TNPP + 1% lauryl alcohol + 0.1% oleic acid + 3% n-butyl stearate ester;
- trial 7 : conventional kerosene type base oil (aromatic content 10%), viscosity 1.7 cSt at 40°C, + 0.3% Irgafos TNPP + 1% lauryl alcohol + 0.1% oleic acid + 3% n-butyl stearate ester.
1. Aluminium and aluminium alloys cold rolling oil composition comprising a base stock
oil and, based on the total weight of the composition, from 0.01 to 5% by weight of
a coumpound A having the formula X3-PO3, wherein
each X is selected from the group consisting of alkyl-aryl, aryl-alkyl and aryl groups, wherein
each X is selected from the group consisting of alkyl-aryl, aryl-alkyl and aryl groups, wherein
each alkyl group has from 3 to 24 carbon atoms and can include heteroatoms like oxygen, nitrogenous or sulfur;
each aryl group has from 4 to 10 carbon atoms and can include heteroatoms like oxygen, nitrogen or sulphur; and
the alkyl and aryl groups are unsubstitued or substitued with up to 3 halogen substituents.
2. Oil composition according to claim 1, comprising, based on the total weight of the
composition, from 0.05 to 1.5% by weight of said compound A.
3. Oil composition according to claims 1 or 2 wherein the alkyl group has from 6 to 12
carbon atoms.
4. Oil composition according to any one of claims 1 to 3, wherein X is an alkyl-aryl
group.
5. Oil composition according to any one of claims 1 to 4, wherein the aryl group is a
phenyl group.
6. Oil composition according to any one of claims 1 to 5, wherein compound A is tri(nonyl-phenyl)
phosphite.
7. Oil composition according to any one of claims 1 to 6, further comprising a fatty
alcohol, preferably lauryl alcohol.
8. Oil composition according to any one of claims 1 to 7, further comprising a fatty
acid, preferably oleic acid.
9. Oil composition according to any one of claims 1 to 8, further comprising a fatty
ester, preferably n-butyl stearate ester.
10. Oil composition according to any one of claims 1 to 9, in which the base stock oil
has a viscosity comprised between 1.2 and 6.0 cSt at 40°C, preferably between 1.6
and 3.0 cSt at 40°C.
11. Oil composition according to any one of claims 1 to 10, which is adapted to be used
as a component of nonfood articles intended for use in contact with food.
12. Process for the preparation of an oil composition according to any one of claims 1
to 11, comprising blending the base stock and the other ingredients under stirring
or with any mixing device.
13. Cold rolling process for rolling aluminium and aluminium alloys sheets, comprising
applying an effective amount of the oil composition according to any one of claims
1 to 11.
14. Use of the oil composition according to any one of claims 1 to 11 in an aluminium
and aluminium alloys cold rolling process.
15. Use of the oil composition according to any one of claims 1 to 11 in a non ferrous
metals cold rolling process.