Additive mixture

Abstract

The present invention relates to new additive mixtures, processes for the production thereof and the use thereof for turbine oils.

Claims

1. An additive mixture comprising (a) one or more alkyl-substituted N--naphthyl-N-phenylamines of formula (I) ##STR00008## where R.sub.1=C.sub.10-C.sub.14 alkyl, (b) one or more alkyl-substituted diphenylamines of formula (II) ##STR00009## where R.sub.2 to R.sub.5=independently of one another H, C.sub.4-C.sub.9 alkyl, with the proviso that at least one of the radicals R.sub.2 to R.sub.5 is a C.sub.8 or C.sub.9 alkyl radical, (c) at least one sulfur-containing compound of formula (III) ##STR00010## where R=C.sub.8-C.sub.12 alkyl, (d) at least one benzotriazole of formula (IV) ##STR00011## oil (e), and at least one corrosion inhibitor, wherein the at least one corrosion inhibitor is a carboxamide (D) of formula (V) ##STR00012## where n=4-10.

2. The additive mixture according to claim 1, comprising at least one thiophosphate (g) of formula (VI) ##STR00013##

3. The additive mixture according to claim 1, comprising demulsifiers selected from the group of the polyglycols and/or defoamers selected from the group of polyacrylates.

4. The additive mixture according to claim 1, comprising: 35-90% by weight, of at least one alkyl-substituted N--naphthyl-N-phenylamine (a), 0.1-40% by weight, of at least one alkyl-substituted diphenylamine (b), 0.5-10% by weight, of at least one sulfur-containing compound (c), 0.5-10% by weight, of at least one benzotriazole (d), 0-30% by weight, of at least one oil (e), 5-15% by weight, of at least one corrosion inhibitor (f), the sum total of all constituents (a) to (f) being 100% by weight.

5. The additive mixture according to claim 1, comprising: 30-85% by weight, of at least one alkyl-substituted N--naphthyl-N-phenylamine (a), 0.1-30% by weight, of at least one alkyl-substituted diphenylamine (b), 0.5-5% by weight, of at least one sulfur-containing compound (c), 0.5-8% by weight, of at least one benzotriazole (d), 0-30% by weight, of at least one oil (e), 5-15% by weight, of at least one corrosion inhibitor (f), 0-5% by weight, of at least one thiophosphate (g), the sum total of constituents (a) to (g) being 100% by weight.

6. A process for producing an additive mixture according to claim 1 wherein components (a) to (d) and (e) to (g) are mixed at temperatures of 20-100 C.

7. A turbine oil comprising the additive mixture according to claim 1 in at least one base oil.

8. The turbine oil according to claim 7, wherein the proportion of the additive mixture in a base oil is 0.1-2% by weight, based on the turbine oil.

9. A method of incorporating the Use of an additive mixture according to claim 1 in a turbine oil.

10. The additive mixture according to claim 1 comprising: 50-70% by weight, of at least one alkyl-substituted N--naphthyl-N-phenylamine (a), 5-30% by weight, of at least one alkyl-substituted diphenylamine (b), 2.5-9% by weight, of at least one sulfur-containing compound (c), 4-9% by weight, of at least one benzotriazole (d), 15-25% by weight, of at least one oil (e), 5-15% by weight, of at least one corrosion inhibitor (f), the sum total of all constituents (a) to (f) being 100% by weight.

11. The additive mixture according to claim 1, comprising: 45-60% by weight, of at least one alkyl-substituted N--naphthyl-N-phenylamine (a), 5-20% by weight, of at least one alkyl-substituted diphenylamine (b), 2.5-4% by weight, of at least one sulfur-containing compound (c), 4-6% by weight, of at least one benzotriazole (d), 15-25% by weight, of at least one oil (e), 7-10% by weight, of at least one corrosion inhibitor (f), 1.5-3.5% by weight, of at least one thiophosphate (g), the sum total of constituents (a) to (g) being 100% by weight.

Description

EXAMPLES

(1) Production of the Additive Mixture

(2) Compounds (a) to (f) specified in Table 1 in the amounts (% by weight) indicated therein were mixed together at 70 C. until a homogeneous solution was obtained. The mixtures of Examples B to 0 are liquid. The mixture from Example A (comparative example in accordance with EP-A 1730101) is solid and therefore cannot be used in the oil without prior melting.

(3) Production of the Turbine Oil

(4) The previously produced additive mixtures in the amounts (% by weight) indicated in Table 1 were stirred at 70 C. into Yubase, a commercially available mineral base oil of API Group Ill from SK lubricants Co.

(5) TABLE-US-00001 TABLE 1 A (V) B C (V) D (V) [% by [% by [% by [% by Example weight] weight] weight] weight] (a1) APAN of formula (I) where R.sub.1 = 0.27 0.27 0.27 C.sub.10-C.sub.12 alkyl, proportion of C.sub.12 = 80% by weight (a2) APAN of formula (I) where R.sub.1 = 0.27 C.sub.8 alkyl (b) diphenylamine DPA of formula (II) 0.09 0.09 0.09 0.09 (substituted to an extent of 90% by weight by C.sub.4, C.sub.8) (c) S-compound of formula (III) = 0.015 0.015 0.039 2,5-dimercapto-1,3,4-thiadiazole (d) benzotriazole of formula (IV)* 0.024 0.024 0.06 (f) corrosion inhibitor of formula (V) 0.042 0.042 0.042 0.042 where n = 5.7 ASTM D 4636 Solid, not Passed Failed Failed usable Change in acid number +0.64 +0.04 +6.10 (mg KOH/g) Change in viscosity at 40 C. (cSt) +3.30 +1.0 +27.7 Change in weight of Al (mg/cm.sup.2) 0.0 +0.01 0.00 Change in weight of Fe (mg/cm.sup.2) +0.05 +0.04 0.00 Change in weight of Cu (mg/cm.sup.2) +0.11 +0.87 0.00 Change in weight of Mg (mg/cm.sup.2) +0.02 0.00 3.11 Change in weight of Cd (mg/cm.sup.2) 0.02 +0.03 17.29 Dry TOST in accordance with ASTM Passed D 7873 RPVOT - 0 h (min) in accordance with 2754 ASTM D 2272 RPVOT - 1000 h (min) in accordance 800 (29%) with ASTM D 2272 Sludge after 1000 h (mg/kg) 65 V = comparative example; RPVOT = Rotating Pressure Vessel Oxidation Test; *Mixture of N,N-bis(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine with methyl in position 4, 5 or 6 and N,N-bis(2-ethylhexyl)-methyl-2H-benzotriazole-1-methylamine with methyl in position 4 or 5 in a ratio of 68% by weight (1H) to 32% by weight (2H).

(6) A test in accordance with ASTM D 4636 is classed as failed for turbine oils if the change in weight of one of the metals (Al, Fe, Cu, Mg or Cd) is greater than 0.25 mg/cm.sup.2. A test in accordance with ASTM D 7873 is classed, inter alia, as passed if the RPVOT time after 1000 h is still at least 25% of the original RPVOT time and the sludge after 1000 h is below 100 mg/kg. The following standard tests were performed:

(7) The dry TOST in accordance with ASTM D 7873, as a standard test method for determining the oxidation stability and the formation of insoluble substances of turbine oils at 120 C. without inclusion of water (dry TOST method), and the oxidation test in accordance with ASTM D 4636.

(8) It has now surprisingly been found that the mixture according to the invention of components (a) to (d), see Example B, passes both the oxidation test in accordance with ASTM D 4636 and the dry TOST in accordance with ASTM D 7873 for turbine oils and has a good solubility in oil.

(9) It is evident from the comparative examples that these tests are not fulfilled as soon as one of the components of the mixture according to the invention is absent, or this mixture cannot be stirred into oil without prior work-up if a shorter-chain (C.sub.8) APAN is used as component (a).