JPH0734078A - Base oil of hydraulic oil for hydraulic elevator - Google Patents

Abstract

PURPOSE:To obtain the subject base oil capable of decreasing the odor while keeping the oxidation stability. CONSTITUTION:This base oil of a hydraulic oil for elevator containing mineral oil contains <=1.5wt.% of aromatic component. The base oil is incorporated with a phenolic additive (e.g. 2,6-di-t-butyl-4-methylphenol) in combination with an amine additive (e.g. p,p'-dioctyldiphenylamine) as antioxidants and an alkenylsuccinimide compound (e.g. alkenylsuccinimide) as a rust-proofing agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base oil for hydraulic oil used in hydraulic elevators.

[0002]

2. Description of the Related Art A base oil for hydraulic elevator hydraulic oil using mineral oil is prepared by treating crude oil by atmospheric distillation or vacuum distillation, which is a means for refining lubricating oil used in ordinary petroleum refining industry. A distillate having the required degree of refinement is obtained by known means such as furfural extraction, hydrorefining, dewaxing, and, if necessary, whiteness treatment.

The hydraulic oil used in the hydraulic jack for driving the hydraulic elevator has a kinematic viscosity of 20 to 10 at an oil temperature of 40 ° C.
Although the range of 0 cSt is used, the required refining degree is about 65% by weight of paraffin and about 30% by weight of naphthene in the base oil.
% By weight, about 5% by weight of aroma, about 0.1% by weight of sulfide and about 10 ppm of nitrogen.

It is widely known that the composition of such mineral oil itself contributes to oxidative stability, and conversely, pure saturated hydrocarbon or white oil is said to have extremely low oxidative stability. Therefore, although the base oil was constituted by the above-mentioned composition, among these components, the highly volatile soft components of the aroma, sulfide and nitrogen components formed the odor of the base oil itself as a mineral oil odor. In order to reduce this odor, JP-A-3-12
In 2195, it is proposed to reduce the amount of evaporation by precision distillation, but the composition in the base oil was as described above.

[0005]

However, in a structure such as the hydraulic jack used in a hydraulic elevator in which the outer wall surface of the plunger to which the hydraulic fluid is adhered is exposed to the outside air during operation, the odor volatilized from the oil film on the outer wall surface of the plunger is removed. The components are released to the outside air and deteriorate the surrounding environment. In particular, in a hydraulic elevator, an ordinary person may approach the hydraulic device portion, and the odor of the hydraulic fluid causes discomfort to the people around. For example, even with hydraulic oil prepared using additives with low odor, the base oil itself has an odor, and there is a problem that mineral oil odor drifts immediately after the hydraulic oil is delivered, and no fundamental countermeasures have been taken. It was the current situation. Further, it has been widely known that the composition itself of the mineral oil as described above contributes to the oxidation stability.

An object of the present invention is to provide a base oil for hydraulic oil for hydraulic elevators, which can reduce odor without lowering oxidation stability.

[0007]

In order to achieve the above object, the present invention provides a base oil for hydraulic elevator hydraulic oil using mineral oil, wherein the aroma content in the base oil is 1.5% by weight or less. It is characterized by having done.

[0008]

The base oil of the hydraulic oil for hydraulic elevators according to the present invention is used in an accelerated deterioration test which is widely performed to confirm the oxidation stability. It is known that the rate of increase in absorbance, which indicates an increase in oxidation products, increases in the region up to%. Based on this, it is predicted that the rate of increase in absorbance increases with the decrease in aroma content, and oxidation stability increases. Although it was thought that the aroma content would decrease, setting the aroma content to 1.5% by weight or less shows that the rate of increase in absorbance tends to decrease and exceeds the oxidation stability of a general mineral oil content of 5% by weight. ,
At the same time, the odor can be reduced.

[0009]

EXAMPLES Examples of the present invention will be specifically described below.
FIG. 1 is a diagram showing Examples 1 to 6 according to the present invention together with Comparative Examples 7 to 10. As the base oil, as shown in FIG. 1, a mineral oil having a kinematic viscosity of 40 ° C. and having an aromatic component as an aromatic component, a sulfide component and a nitrogen component of each numeral is used.

As the additives to be added to this base oil, an antioxidant and a rust preventive were selected as follows. That is, as antioxidants, two antioxidants that are amine-based additives that produce a synergistic effect with phenol-based additives that have high antioxidant ability, and 2,6-di-t-Carryy 4-methylphenol as a phenol-based additive and amine-based additives Was selected as p-p'-dioctyldiphenylamine. As a rust preventive agent,
Since alkenyl succinic acid has a high odor both in the ester type and the imide type, an imide type alkenyl succinimide, which has been confirmed to have a synergistic effect with a phosphoric acid type antiwear additive not introduced in this example, was selected. In addition, when compounding these antioxidant and rust preventive additives into the base oil, stirring was carried out at 1500 rpm in an oil bath at 60 ° C. for 1 hour continuously.

The physical properties of each hydraulic oil were evaluated based on the following.

The base oil component is n- for analysis of aromatic components.
The d-m ring analysis was carried out, and the sulfide system and the nitrogen system were measured by ion chromatography analysis. The kinematic viscosity is JIS K 2
According to 283, kinematic viscosity at 40 ° C was measured. Furthermore, the evaporation loss is measured by thermogravimetry with about 30 mg of sample placed in an aluminum cell with an internal diameter of φ6 mm and a depth of 1.5 mm, and increasing the temperature from room temperature by 2 ° C./min to 250 ° C. in a nitrogen atmosphere. did.

In the odor sensory test as an evaluation test, the strength of the odor was sensory measured by 12 testers. Tested by the 6-level odor intensity display method that is usually used in odor tests, the maximum and minimum evaluation points of 12 examiners were deleted one by one from both limits, and the average odor of 10 examiners was deleted. The strength score was evaluated. A low score indicates low odor, and a high score indicates high odor. 6-level odor intensity is 0: no odor, 1: odor that can be perceived as a sickness, 2: weak odor that allows you to know what odor it is, 3: odor that can be easily perceived, 4: strong odor, 5: intense odor .

30 ml of the sample was sealed in a screw cap bottle having a mouth of 27 mm in diameter and a capacity of 50 ml, the bottle was shaken violently, and then the bottle lid was opened to smell the odor, and the 6-stage odor intensity was evaluated. Rounds the odor intensity average to 1
O is marked as good up to the point, and X is marked as the other points have odor.

In the accelerated deterioration test, 50 g of the sample was pre-polished to expose a new metal surface, and the polished skin was degreased with diethyl ether. A spirally wound 3 m copper wire was inserted into the sample. Put in a 200 ml glass bottle, and then put the glass bottle in a copper container that can be pressure-sealed with oxygen.
It is sealed at a pressure of MPa, and the copper container itself is placed in an oil bath using silicon oil of 150 ° C with a 30 ° inclination, and the copper container is rotated at 100 rpm to heat the sample in the glass container while stirring. Deterioration was performed continuously for 1 hour. The increase of the organic deterioration product of this sample was measured by an infrared absorption measuring instrument, and the infrared absorption increasing rate of the oil at the time of new oil and after deterioration was measured and evaluated. Infrared absorption wavelength has a high rate of increase 1
The wavelength is shown at 790 cm Kaiser (unit: _~ ¹ ).

Those marked with a circle in the evaluation in the examples have an infrared absorption increase rate of not more than the infrared absorption increase rate of the reference oil of Comparative Example 10, which is superior to the current oil in oxidation stability. I have decided. If the rate of increase exceeds that of the current oil, the performance is evaluated to be poorer and marked with an X.

The shell four-ball wear test is ASTM D27.
According to the 83 shell four-ball wear test method, the test conditions were a vertical axis rotation speed of 1800 rpm, a load of 30 kg, a test time of 30 minutes, and a test temperature of room temperature. A precision sphere was used. In each of the examples and the comparative examples, R & O containing only the antioxidant and the rust preventive is added.
Since it is a type general mineral oil, the wear scar system is 0.48 to 0.
It is estimated to be 52 mm.

The RBOT deterioration test is conducted according to JIS K251.
The rotating cylinder oxidative stability test method of 4 was followed. It is presumed that the oxidative deterioration reaction can be suppressed by the amount of the impurities removed, and it can be presumed that the Example can obtain an extremely high RBOT value as compared with the Comparative Example.

As an economic evaluation, if the base oil cost was within twice the comparative example 10 as a reference, there was no problem in practical use and it was judged as good and marked with a circle. It was evaluated that the cost was more than twice as large as the ranking cost, but a cross was added, but this can be arbitrarily determined.

Next, the test results and evaluation results for various evaluation items shown in FIG. 1 will be described. The odor sensory test by human nose shows that the odor is extremely low when the aroma content is 1.5% by weight or less. Further, in the accelerated deterioration test result for confirming the oxidation stability, in the range from 5% by weight to 3% by weight, which is the aroma content rate of general mineral oil,
The rate of increase in absorbance showing an increase in oxidation products is increasing, but this tendency is that contrary to the conventional expectation, if the content exceeds 3% by weight and the content further decreases, the rate of increase in absorbance tends to decrease. It was found that the content of 1.5% by weight exceeds the oxidation stability of the content of general mineral oil of 5% by weight. Therefore, the aroma content is 1.5 in the oxidation stability.
It is preferably not more than weight%. However, when the aroma content is 0.5% by weight or less, it tends to level off, and further improvement in the degree of purification has no effect on oxidative stability. Therefore, considering economic efficiency, the aroma content rate is 0.5 to 1.5.
It is preferably used in the range of weight%.

Further, the degree of consumption of the antioxidant for knowing the life of the hydraulic oil is reduced if a predetermined antioxidant measure is taken by lowering the aroma content rate, and the residual amount of the antioxidant is increased.
The reduction of the aroma content in the base oil is preferable also in the residual amount of the antioxidant. However, a highly refined base oil represented by fluid paraffin has a high economic burden compared to its performance, and in consideration of economic aspects, the aroma content has a lower limit of 0.5% by weight. It is preferably within the range.

Thus, the aroma content of the base oil is 1.5.
When the content is less than or equal to% by weight, the content ratio of aroma components and the like in the base oil decreases by increasing the degree of refinement of hydrogenation.
The odor can be kept low by increasing the degree of purification of hydrogenation. In addition, the refinement of hydrogenation for removing mineral oil odorous components such as aromas can reduce the evaporation amount of mineral oil odorous components from the oil film on the outer wall of the plunger.
It is also preferable to reduce odor rather than evaporation.

Thus, as shown in FIG. 1, Examples 1 to 6
The base oils shown in 1) are excellent in terms of evaporation amount, odor sensory test, oxidation stability by accelerated deterioration test, wear resistance, and antioxidant life, and the results of oxidation stability by accelerated test show that hydrogen addition The improvement in the degree of refinement due to will not be overlooked. In this way, the base oil having an aroma content of 1.5% by weight or less can surely have a low odor, and since the evaporation amount is suppressed to a low level, it can be removed from the outer wall surface of the plunger. It is possible to provide a low odor hydraulic oil that corresponds to the environment in the elevator by suppressing the evaporation amount of. Furthermore, the effect of the antioxidant is caused by the good degree of refinement of the base oil, and the deterioration of the base oil is suppressed to a low level,
Compared with conventional hydraulic oils that use mineral oil as a base oil, the life with low odor and the service life can be significantly extended.

[0024]

As described above, the base oil of the hydraulic elevator hydraulic oil of the present invention can suppress the odor of mineral oil without impairing the original performance of the base oil, and can suppress the oxidative deterioration to a long time. The low odor can be maintained even when used, and the environment around the hydraulic elevator can be kept comfortable even after long-term use.

[Brief description of drawings]

FIG. 1 is a diagram showing characteristics and evaluation results of a hydraulic oil for hydraulic elevator according to an embodiment of the present invention in a base oil.

Claims (1)

[Claims] 1. A base oil of a hydraulic elevator hydraulic oil using mineral oil, wherein the aroma content in the base oil is 1.5% by weight or less.