KR950005698B1 - Lubricating oil composition - Google Patents

Abstract

The oil compsn. is produced by reacting a C3-20 (un)satd. fatty acid with a polyhydric alcohol of formula (I) in the organic acid or the organic tin catalyst at 180˜240 deg.C for 5˜24 hr to obtain a partially polymerized polyol ester, and adding 0.5˜5.0 wt.pt. of an phenylnaphthyl amine antionidant of formula (II), 0.1˜1.0 wt.pt. of an aryl phosphate abrasion resistance additive of formula (III), 0.5˜2.0 wt.pt. of a thickener, 0.02˜0.1 wt.pt. of a corrosion inhibitor and a proper amount of a defoamer to the polymerized polyol ester. In the formulas, R1 and R2 and eath C1-4 alkyl; R3 is C1-10 alkyl; R4 is c1-4 alkyl.

Description

Hydraulic Fluid Composition

The present invention relates to a lubricating oil composition and more particularly to a polyol ester hydraulic fluid having excellent lubricity.

To date, it is well known that various hydraulic hydraulic oils have been developed and used, and most of the oil-based oils are mineral oils. However, this petroleum hydraulic fluid is not suitable for high speed and high pressure equipment due to lack of lubricity, and because of the characteristics of the mineral oil, there is a high risk of fire. In addition, petroleum hydraulic fluids have a low viscosity index, which makes it difficult to maintain an appropriate viscosity due to a severe viscosity change due to temperature changes. To reinforce this, various polymers are used as viscosity index improvers. As a result of the breakdown, a sudden viscosity and viscosity index drop occur.

The present invention relates to a new type of hydraulic fluid that solves the determination of the conventional hydraulic fluid, and uses a polyol ester synthesized with monobasic premium fatty acid and polyhydric alcohol as a base. Polyol esters have a very high viscosity index and a high flash point so that they are not subject to the restrictions of use due to petroleum hydraulic fluids.

The polyol ester used in this invention is synthesize | combined using C6-C20 saturated or unsaturated fatty acid and the polyhydric alcohol of following formula (I). Here, the alkyl group of the fatty acid can be applied either linear or branched, and the selection should take into account the lubricity of the composition or other physical properties.

R ₁ and R ₂ are the same or different alkyl groups having 1 to 4 carbon atoms or (CH ₂ ) _n OH, n is an integer of 1 to 2;

The lubricating oil composition of this invention is obtained by mix | blending an appropriate amount of antioxidant, abrasion resistant additive, a midpoint agent, etc. with the synthesized polyol ester.

Specifically, the antioxidant has the best effect of the phenylnaphthylamine system (Formula II) and the amount is 0.5-5.0 parts by weight, preferably 1.0-3.0 parts by weight. In general, less than 0.5 parts by weight of the effect is very small, if greater than 5.0 parts by weight no significant improvement is recognized.

R ₃ is hydrogen or an alkyl group having 1 to 10 carbon atoms.

As an antiwear additive, the effect of an aryl phosphate system (form III) is the best, and the amount added is 0.1-1.0 parts by weight, preferably 0.3-0.5 parts by weight.

R ₄ may be the same as or different from each other as hydrogen or an alkyl group having 1 to ₄ carbon atoms.

As the thickener, an olefin copolymer, polymethacrylate, or the like may be used. A molecular weight of 100,000 or less, preferably of 50,000 or less polymethacrylate, which is excellent in shear stability and little in viscosity change, is suitable. The amount added depends on the target viscosity of the lubricating oil composition but is 0.5-2.0 parts by weight.

In the present invention, 0.02-0.10 parts by weight of corrosion inhibitor, antifoaming agent and the like may be added as necessary.

Example 1

[Production of Base]

1. Add 2.0 g of paratoluenesulfonic acid to a mixture of 645.6 g of oleic acid and 127.6 g of trimethylolpropane and react for 5 hours at 220 ° C. under a nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 736.4 g of an oleic acid ester of trimethylolpropane (hereinafter referred to as base 1) (yield: 95%). The properties of the ester are as follows.

Appearance: pale yellow transparent liquid Acid value: 2.7

Specific gravity: 0.925 Pour point: -30.0 ℃

Kinematic Viscosity: 43cSt (@ 40 ℃) Color: 2.0 (ASTM)

2. Add 2.0 g of paratoluenesulfonic acid to a mixture of 677.8 g of isostearic acid and 127.6 g of trimethylolpropane and react for 5 hours at 220 ° C. under a nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 767.0 g of isostearic acid ester of trimethylolpropane (hereinafter referred to as base 2) (yield: 95%). The properties of the ester are as follows.

Appearance: pale yellow transparent liquid Acid value: 2.5

Specific gravity: 0.925 Fluidity: -30.0 ℃

Kinematic Viscosity: 102cSt (@ 40 ℃) Color: 2.0 (ASTM)

3. Add 2.0 g of paratoluenesulfonic acid to a mixture of 302.2 g of caprylic acid and 127.6 g of trimethylolpropane and react for 5 hours at 220 ° C. under a nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 410.2 g of caprylic acid ester of trimethylolpropane (hereinafter referred to as base 3) (yield: 95%). The properties of the ester are as follows.

Appearance: pale yellow transparent liquid Acid value: 2.5

Specific gravity: 0.920 Pour point: -60.0 ℃

Kinematic Viscosity: 20cSt (@ 40 ℃) Color: 2.5 (ASTM)

4. Add 2.0 g of paratoluenesulfonic acid to a mixture of 645.6 g of oleic acid and 129.5 g of PENTAERYTHRITOL and react for 5 hours at 220 ° C. under a nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 738.2 g of an oleic acid ester of PENTAERYTHRITOL (hereinafter referred to as Base 4) (yield: 95%).

Appearance: pale yellow transparent liquid Acid value: 2.4

Specific gravity: 0.930 Pour point: -27.5 ℃

Kinematic Viscosity: 72cSt (@ 40 ℃) Color: 2.0 (ASTM)

5. Add 2.0 g of paratoluenesulfonic acid to a mixture of 677.8 g of isostearic acid and 129.5 g of PENTAERYTHRITOL and react for 5 hours at 220 ° C. under a nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 768.8 g of isostearic acid ester of PENTAERYTHRITOL (hereinafter referred to as "base 5") (yield: 95%).

Appearance: pale yellow colorless liquid acid value: 2.5

Specific gravity: 0.930 Pour point: -27.5 ℃

Kinematic Viscosity: 138cSt (@ 40 ℃) Color: 2.0 (ASTM)

6. Add 2.0 g of paratoluenesulfonic acid to a mixture of 645.6 g of oleic acid and 99.0 g of NEOPENTYLGLYCOL and react for 5 hours at 220 ° C. under nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 709.3 g of oleic acid ester of NEOPENTYLGLYCOL (hereinafter referred to as base 6) (yield: 95%).

Appearance: pale yellow transparent liquid Acid value: 2.8

Specific gravity: 0.926 Pour point: -30.0 ℃

Kinematic Viscosity: 29cSt (@ 40 ℃) Color: 2.5 (ASTM)

7. Add 2.0 g of paratoluenesulfonic acid to a mixture of 677.8 g of isostearic acid and 99.0 g of NEOPENTYLGLYCOL, and react for 5 hours at 220 ° C. under a nitrogen atmosphere (500 cc / min). When the acid value was 3.0 or less, the reaction was terminated to obtain 739.7 g of isostearic acid ester of NEOPENTYLGLYCOL (hereinafter referred to as "base 7") (yield: 95%).

Appearance: pale yellow transparent liquid Acid value: 2.6

Specific gravity: 0.926 Pour point: -30.0 ℃

Kinematic Viscosity: 85cSt (@ 40 ℃) Color: 2.5 (ASTM)

8. Add 2.0 g of paratoluenesulfonic acid to a mixture of 302.2 g of caprylic acid and 99.0 g of NEOPENTYLGLYCOL, and react for 5 hours at 220 DEG C under nitrogen atmosphere (500 cc / min).

When the acid value was 3.0 or less, the reaction was terminated to obtain 383.0 g of caprylic acid ester of NEOPENTYLGLYCOL (hereinafter referred to as "base 8") (yield: 95%).

Appearance: pale yellow transparent liquid Acid value: 2.7

Specific gravity: 0.920 Pour point: -45.0 ℃

Kinematic Viscosity: 15cSt (@ 40 ℃) Color: 3.0 (ASTM)

Example 2

[Manufacture of hydraulic oil]

About the base compound obtained in Example 1, it mix | blended as Table-2 and measured the property.

The results are shown in Table-3.

TABLE 2

Table 3

* Tester: Rotary Bomb Oxidation Stability Tester, Test Method: ASTM D2272

** Tester: FALEX Abrasion Resistance Tester, Test Method: ASTM D2670

*** Tester: Soda-type 4-ball tester (700rpm, ㎏ / ㎠), Test Method: KS M 2026

Claims (1)

Partial polymerization of a saturated or unsaturated fatty acid having 6 to 20 carbon atoms with a polyhydric alcohol of the following formula (I) under a nitrogen atmosphere at 180-240 ° C. for 5 to 24 hours under an organic acid, an organic acid or an organic tin catalyst. 0.5 to 5.0 parts by weight of a phenylnaphthylamine-based antioxidant of formula (II), 0.1 to 1.0 part by weight of an aryl phosphate antiwear additive of the following formula (II), and a thickener 0.5 to 2.0 to 94.0 to 99.9 parts by weight of a polyol ester. A hydraulic hydraulic oil composition prepared by adding a weight part, a corrosion inhibitor 0.02 to 0.1 part by weight, and an antifoaming amount. Wherein R ¹ R ² is the same or different alkyl group of 1 to 4 carbon atoms or (CH ₂ ) _n OH n is the same or different integer of 1 to 2 R ³ is hydrogen or alkyl group of 1 to 10 carbon atoms R ⁴ is the same Or an alkyl group having 1 to 4 carbon atoms different from each other.