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EP-4359495-B1 - O-ALKYLATED STERICALLY HINDERED ANTIOXIDANTS

EP4359495B1EP 4359495 B1EP4359495 B1EP 4359495B1EP-4359495-B1

Inventors

  • DONG, JUN
  • LEE, Jeonkyu
  • MULQUEEN, GERARD
  • KIM, Shinhyun

Dates

Publication Date
20260506
Application Date
20220622

Claims (18)

  1. A composition comprising i) a compound of the general formula (I) in which R 1 is a C7-C9 alkyl group; R 2 is a methyl group; R 3 is a tert-butyl group.
  2. The composition according to claim 1, wherein R 1 is an isooctyl group or a 2-ethylhexyl group or both.
  3. The composition according to claim 1 or 2, wherein the composition comprises at least 0.1 wt.-% of the compound of the general formula (I), based on the total weight of the composition.
  4. The composition according to claim 3, wherein the composition comprises at least 50 wt.-% of the compound of the general formula (I), based on the total weight of the composition.
  5. The composition according to anyone of claims 4, wherein the composition comprises at least 90 wt.-% of the compound of the general formula (I), based on the total weight of the composition.
  6. The composition according to anyone of claims 2 to 5, further comprising ii) isooctyl-3,5-di-tert-butyl-4-hydroxy-hydrocinnamate.
  7. The composition according to claim 6, wherein the composition comprises i) at least 0.01 wt.-% isooctyl-3,5-di-tert-butyl-4-methoxy-hydrocinnamate; ii) at least 25 wt.-% isooctyl-3,5-di-tert-butyl-4-hydroxy-hydrocinnamate; in each case based on the total weight of components i) and ii) in the composition.
  8. The composition according to claim 7, wherein the composition comprises iii) less than 5 wt.-% of compounds selected from the group consisting of diisooctyl-α-(3,5-di-tert-butyl-4-hydroxybenzyl)glutarate, di-tert-butylphenol, methyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate and isooctanol, based on the total weight of components i), ii) and iii) in the composition.
  9. The composition according to claim 8, wherein the composition comprises isooctyl-3,5-di-tert-butyl-4-methoxy-hydrocinnamate and diisooctyl-α-(3,5-di-tert-butyl-4-hydroxybenzyl)glutarate in a weight ratio of at least 2 : 1.
  10. The composition according to anyone of claims 6 to 9, wherein the composition comprises 1 to 50 wt.-% of the compound of the general formula (I), based on the total weight of the composition.
  11. The composition according to claim 10, wherein the composition comprises 2.5 to 35 wt.-% of the compound of the general formula (I), based on the total weight of the composition.
  12. The composition according to anyone of claims 6 to 11, wherein at least one of the following conditions (α1) to (α5) is fulfilled: (α 1) the composition has a cinematic viscosity (determined at a temperature of 40°C according to ASTM D 445) in the range from 60 to 300 cSt; (α2) the composition has a Gardner colour (determined according to ASTM D 1544) of less than 10 Gardner; (α3) the composition has water content (determined according to ASTM E 203) of less than 0.5 wt.-%; (α4) the composition has a specific gravity (determined at a temperature of 25°C according to ASTM D 1298) in the range from 0.900 to 1.020; (α5) the composition has a total acid number (as determined by the ASTM D664) of less than 5.0 mg KOH/g.
  13. The composition according to anyone of claims 1 to 12, wherein the total amount of component i) or the total amount of components i) and ii) in the composition is at least is at least 95 wt.-%, based on the total weight of the composition.
  14. The composition according to anyone of claims 1 to 11, wherein the composition is an additive blend and wherein the total amount of component i) or the total amount of components i) and ii) in the composition is in the range from 0.01 to 50 wt.-%, based on the total weight of the additive blend.
  15. The composition according to anyone of claims 1 to 11, wherein the composition is an engine oil comprising at least one base oil and wherein the total amount of component i) or the total amount of components i) and ii) in the composition is in the range from 0.01 to 5 wt.-%, based on the total weight of the engine oil .
  16. The composition according to anyone of claims 1 to 11, wherein the composition is a polymer composition comprising a polymer and wherein the total amount of component i) or the total amount of components i) and ii) in the composition is in the range from 0.01 to 5 wt.-%, based on the total weight of the polymer composition.
  17. Use of the composition according to anyone of claims 1 to 13 as an additive in additive blends, engine oils or polymer compositions.
  18. Use of a compound of the general formula (I) in which R 1 is a C7-C9 alkyl group; R 2 is a methyl group; R 3 is a tert-butyl group; as an additive in additive blends, engine oils or polymer compositions.

Description

[Technical Field] The present invention relates to a composition comprising O-alkylated sterically hindered antioxidants. The invention also relates to industrial products comprising such compositions and to the use of O-alkylated sterically hindered antioxidants as an additive in industrial products. [Background Art] As a main type of industrial products, lubricants, such as those used in a variety of machinery, are susceptible to oxidative deterioration during storage, transportation, and usage, particularly when such lubricants are exposed to high temperatures and iron catalytic environments, which greatly promote their oxidation. This oxidation, if not controlled, contributes to the formation of corrosive acidic products, sludge, varnishes, resins, and other oil-insoluble products, and may lead to a loss of designated physical and tribological properties of the lubricants. It is therefore a common practice to include an antioxidant in lubricants to prevent, at least to some extent, oxidation, so as to extend their useful life. Lubricant compositions containing various diarylamines or phenolic compounds as antioxidants are widely known in the art. US 5,892,097, for example, discloses the preparation of sterically hindered phenolic compounds and their use as antioxidants. These antioxidants are prepared by reacting an alcohol such as isooctanol with methyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate to form isooctyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate in a transesterification reaction. However, the antioxidative performance of the sterically hindered phenolic compounds obtained by such a reaction and known from the prior art can still be improved. US 3,717,611 A discloses a stabilized composition of a polymer normally susceptible to at least one of thermal and oxidative degradation in an unstabilized state and selected from the group consisting of polyolefins, polystyrenes, polyamides, polyesters, polyacetals, polyvinyl chloride, polyethers and natural synthetic rubbers, stabilized by the presence of a stabilizing amount of at least 2,6-di-tert.-butyl phenol ethers and esters. US 5,068,172 A discloses silver halide color photographic materials, and in particular relates to silver halide color photographic materials in which color fading in the magenta image and color changes in the non-image portions are prevented. US 2006/040833 A1 discloses stabilized lubricating oil compositions with improved oxidative performance. These lubricating oil compositions contain certain phenolic antioxidants, in combination with other antioxidants, which contribute to the improved performance. DATABASE REGISTRY (18 August 2017) discloses the compound "Ethyl-3-(1,1-dimethylethyl)-4-methoxy-5-methylbenzenepropanoate". DATABASE REGISTRY (24 August 2017) discloses the compound "Methyl-3-(1,1-dimethylethyl)-4-methoxy-5-methylbenzenepropanoate". DATABASE REGISTRY (2 February 2014) discloses the compound "Benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-ethoxy-methyl ester". DATABASE REGISTRY (1 January 2014) discloses the compound "Methyl 3,5-bis(1,1-dimethylethyl)-4-propoxybenzenepropanoate". DATABASE REGISTRY (27 December 2013) discloses the compound "Methyl 3,5-bis(1,1-dimethylethyl)-4-(1-methylethoxy)benzenepropanoate". [Disclosure] [Technical Problem] It is therefore an object of the present invention to overcome the disadvantages of the prior art associated with compositions that are used to improve the properties of industrial products such as engine oils, particularly with respect to their oxidative stability. In particular, it is an object of the present invention to provide a composition that, when being added as a separate additive or as a component in a so called "additive package" into a lubricant such as an engine oil, improves the properties of the lubricant, particularly with respect to the oxidative stability. A contribution to at least partly solving at least one, preferably more than one, of the above objects is made by the independent claims. The dependent claims provide preferred embodiments which contribute to at least partly solving at least one of the objects. [Technical Solution] A contribution to solving at least one of the objects according to the present invention is made a composition comprising i) a compound of the general formula (I) in which R1is a C7-C9 alkyl group, more preferably a linear or branched C8-alkyl group, most preferably a branched octyl group, wherein an isooctyl group or a 2-ethylhexyl group or both is/are most preferred;R2is a methyl group;R3is a tert-butyl group. Surprisingly, it has been discovered that O-alkylated sterically hindered compounds having the general formula (I) are particularly effective antioxidants, compared to their corresponding phenolic derivatives. Not only the pure or substantially pure O-alkylated sterically hindered compounds themself, preferably the pure O-methylated sterically hindered compounds, are effective antioxidants, but also mixtures of, f