JPS6340839B2 - - Google Patents

Description

[Detailed description of the invention]

The subject of the present invention relates to synthetic lubricants containing novel high-viscosity neutral complex esters of polyols and polymeric fatty acids and aliphatic monocarboxylic acids. Synthetic esters, so-called ester oils, have recently come to be used in increasingly large amounts as expensive lubricating oils. Thus, for example, diesters of dibasic carboxylic acids and monohydric alcohols, such as dioctyl sebacate or dinonyl adipate, or esters of polyols and monobasic acids, such as trimethylolpropane tripelargonate, are used as lubricants for aircraft turbines. It is proposed as. Recently, so-called complex esters have also been developed for this type of lubrication. The complex esters contain as esterification components, in addition to polyhydric alcohols such as trimethylolpropane or neopentyl glycol, monobasic carboxylic acids having 6 to 10 carbon atoms and dibasic acids such as sebacic acid or azelaic acid.
The good suitability of synthetic esters as lubricants is due to
This is due to the fact that the synthetic ester has a more favorable viscosity-temperature relationship than conventional lubricating oils based on mineral oils, and its freezing point is clearly lower when the viscosity is adjusted to be comparable. However, for many applications, high viscosity automatic transmission oils are required, for example having viscosity values of at least 14 cSt at 99°C (210°) or up to 150,000 cP at -26°C (-15°). New multi-field automatic transmission oil 80W
−90 (US Military Specification Mil−L2105C
), the known synthetic esters are not suitable due to their limited viscosity. Lubricating oils of sufficient viscosity based on mineral oils are produced by adding polymers, such as styrene-butadiene copolymers (DE 1811516). A disadvantage of adding polymers to increase the viscosity of automatic transmission oils is that the shear of the polymer increases. This significantly reduces the viscosity of the corresponding oil by shearing, ie by plastic destruction of the polymer.
Therefore, synthetic esters which, in addition to lower freezing points, have high viscosities and good viscosity-temperature relationships (high viscosity index) have become extremely important. By the way, (a) 2 to 4 primary hydroxy groups and 4 to 4 carbon atoms
(b) dimeric and/or trimer fatty acids prepared by polymerizing unsaturated fatty acids having 16 to 18 carbon atoms; and (c) branched aliphatic polyhydric alcohols having 10 carbon atoms. 6 to 16 straight-chain or branched saturated aliphatic monocarboxylic acids, the amount of hydroxy groups esterified by the monocarboxylic acids being 50
It has been found that a new neutral complex ester consisting of (~90%) satisfies the abovementioned requirements to a degree hitherto unachievable. High viscosity neutral complex esters according to the invention include all branched aliphatic polyols containing 2 to 4 primary hydroxyl groups and 4 to 10 carbon atoms as the alcohol component, such as neopentyl glycol, trimethylolethane, trimethyl Methylolpropane or pentaerythritol is present. Particular preference is given here to the trihydric alcohol trimethylolpropane. The polymeric fatty acids used are mixtures of dimer and trimer fatty acids produced by polymerizing unsaturated fatty acids having 16 to 18 carbon atoms. In this case, the mixture preferably contains 75% by weight or more of dimmer fatty acids. This polymeric fatty acid mixture may be prepared, for example, from an unsaturated fatty acid, such as oil acid, linoleic acid or linolenic acid, or from a fatty acid mixture containing unsaturated fatty acids, such as soybean oil or tallow oil, in a small amount of water at a temperature of about 200-300°C. and by thermal polymerization in the presence of mineral catalysts such as montmorillonite. The monocarboxylic acid component of the neutral complex ester in the present invention may consist of a linear or branched saturated aliphatic monocarboxylic acid having 6 to 16 carbon atoms.
Mention may be made, for example, of caproic acid, caprylic acid, capric acid, lauric acid, myristic acid or palmitic acid as well as mixtures thereof. Particularly suitable in this case are mixtures of fatty acids having 6 to 12 carbon atoms, which occur as precursor fatty acids, for example in the distillation of coconut oil fatty acids. Among branched monocarboxylic acids, the number of carbon atoms is 12 or more, which is branched at the α-position to the carboxyl group.
16 carboxylic acids are particularly preferred. Carboxylic acids of this type are prepared, for example, by subjecting unbranched saturated alcohols of average chain length to a Guerbet reaction and then oxidizing the resulting alcohols branched at the 2-position and having the same total number of carbon atoms. Isopalmitic acid prepared by oxidizing 2-hexyldecanol in this manner is used as the monocarboxylic acid component of the chain ester in this invention. Complex esters according to the invention consisting of a branched aliphatic polyol containing 2 to 4 primary hydroxy groups, a polymeric, in fact dimer, fatty acid and a linear or branched saturated aliphatic monocarboxylic acid are: It can be prepared in known esterification methods by heating the reactants (to 200 DEG C. in a nitrogen atmosphere) using an esterification catalyst such as tin powder, p-toluolsulfonic acid or others. Esterification can also be carried out in two steps. In this case, the alcohol component is first reacted with the dimer fatty acid, and after the partial reaction is completed, it is further esterified with a monocarboxylic acid. To purify the esterification product, it is treated with the addition of 1 to 5% by weight of activated bleaching earth. Any free monocarboxylic acid that may still be present is removed by distillation, thereby producing a complex ester with an acid number below 0.3. Owing to its excellent properties, namely high viscosity, low freezing point and favorable viscosity-temperature relationship, the neutral complex ester according to the invention is particularly suitable for use as a lubricant for the lubrication of automatic transmissions and two-stroke engines. The complex esters according to the invention may be present as the sole base oil in the final lubricant or may be mixed as a blend component with other products already known for this purpose. When used as mixed components in lubricants and automatic transmission oils, they can be mixed in any quantitative ratio, which is determined solely by the required properties, such as viscosity, freezing point, viscosity-temperature relationship. However, in general the content of complex esters in the final product does not fall below 10-30% by weight.
Various additives such as antioxidants and anticorrosion agents, dispersants, high pressure additives, defoamers, metal deactivators and
Other additives suitable for use in the preparation of synthetic ester-based lubricants may also be added in conventionally effective amounts. Next, the object of the present invention will be explained in detail based on examples, but the present invention is not limited thereto. Production example of neutral complex ester Trimethylolpropane 268g (2 mol), dimerized fatty acid 565g (approximately 1 mol) (dimerized fatty acid approximately 95
% by weight, a mixture consisting of about 4% by weight of trimerized fatty acids and about 1% by weight of non-polymerized unsaturated fatty acids) and
632 g (approximately 4 moles) of C ₆ -C ₁₂ fatty acids (approximately 5% by weight of C ₆ -fatty acids, approximately 45% by weight of C ₈ -fatty acids, as obtained by distillation of coconut oil fatty acids, approximately 45% by weight of C ₁₀ -fatty acids)
% by weight and about 5% by weight of C ₁₂ -fatty acids) in a dehydrator under nitrogen as carrier gas for 200 min.
heated to ℃. A mixture of tin powder and p-toluolsulfonic acid was used as the esterification catalyst.
At the end of the reaction at the same temperature but at reduced pressure (approximately
70mmHg) was further esterified. After cooling to 120°C, 1.5 g (about 1% by weight) of activated bleaching earth was added, and the mixture was heated again to 200°C, and excess monocarboxylic acid was distilled off in vacuo. The acid value of esterified product A (67% component esterified with monocarboxylic acid) was 0.28. The product has a viscosity of 628 cSt at 37.8°C (=100〓) and 57 cSt at 99°C (=210〓). The viscosity index is 164 and the freezing point is -38°C. The following complex esters, summarized in Table 1, were prepared according to the method described above.

[Table] Examples Degradation experiments were carried out at high temperatures using a lubricating oil produced based on the complex ester according to the present invention and a commercially available lubricating oil, and the compatibility of this oil with various packing materials was also tested. . SAE80 (American Society of Automotive Engineers Viscosity Number) when tested as a lubricant
commercially available single grade oil as well as SAE80−90
A multigrade oil according to the invention was used. The oil according to the invention had the following composition: Product D (1 mol of trimethylolpropane, 0.3 mol of dimer fatty acids (75%) and 2.4 mol of _C6 - _C12 -pre-fatty acids) 93.5% by weight Additives " Anglamol99” (Anglamol99:
(Trade name of lubricating oil additive manufactured by Lubrizol Corp., Cleveland, Ohio, USA) 6.5% by weight From the index of the oil according to the invention shown in Table 2, it can be seen that the additives used include freezing point depressants and VI- It is clear that no modifiers are included.

[Table] (a) Degradation experiment The lubricating oil to be tested was placed in a glass flask and
It was heated to 160-200° C. for an hour, with air being introduced in an amount of every 10 times during this time. Changes in viscosity and acid value were measured from samples degraded at 200°C. Viscosity change (%) at 99℃ (=210〓) according to the present invention
+33.2 +52.7 Increase in acid number 1.3 3.4 The lubricant according to the invention showed significantly less deterioration compared to the commercial product. The durability of the products aged at 160° C. was determined using an abrasion meter according to the Reichert method.
Wear was observed during steel-to-steel friction under a load of 1500kp/ ^mm2 (runway length 100m) Durability of commercially degraded specimens according to the invention (Kg/ ^cm2 )
1250 750 (b) Expansion ratio of packing materials Based on the provisions of DIN (German Industrial Standard) 53521, various packing materials were immersed in the tested lubricating oil heated to 100° C. for 70 hours. Subsequently, the weight increase of the packing material was measured.

Furthermore, this test shows that the lubricating oil according to the invention based on complex esters leads to more favorable results, ie a lower expansion of the tested packing materials than the known commercially available lubricating oils.

Claims (1)

[Scope of Claims] 1 (a) a branched aliphatic polyhydric alcohol having 2 to 4 primary hydroxy groups and 4 to 10 carbon atoms; (b) an unsaturated fatty acid having 16 to 18 carbon atoms; and (c) straight-chain or branched saturated aliphatic monocarboxylic acids having 6 to 16 carbon atoms, in which case the monocarboxylic acid The amount of esterified hydroxy groups is 50
~90%) as the sole base oil of the synthetic lubricant. 2. The synthetic lubricant according to claim 1, which contains the neutral complex ester according to claim 1 as a mixed component of a semi-synthetic lubricant. 3. The synthetic lubricant according to claim 1, which contains the neutral complex ester according to claim 1 as the sole base oil of automatic transmission oil. 4. The synthetic lubricant according to claim 1, which contains the neutral complex ester according to claim 1 as the sole base oil of a two-stroke engine oil.