JPH08120291A - Hydraulic fluid composition - Google Patents

Abstract

PURPOSE: To obtain a hydraulic fluid which enables a hydraulic system to be used safely and comfortably in the fields of family life and wellfare and neither causes fire nor affects a human body or the environment even if it leaks by any chance, i.e., is excellent in flame retardance, biodegradability, and safety of living organisms. CONSTITUTION: A hydraulic fluid compsn. excellent in flame retardance, biodegradability, and safety is prepd. by compounding a base fluid comprising 30-90wt.% propylene glycol, 0-50wt.% glycerin, and 10-60wt.% water with 0.1-2wt.% salt of an 8-14C satd. fatty acid.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The hydraulic fluid composition of the present invention is preferentially used in environmental conditions where safety, fire safety and environmental pollution are problems, such as general households, medical / welfare facilities, entertainment / play facilities, etc. Used. It is used as a lubricating fluid that is kind to the earth and the environment, and to living things and humans, especially for hydraulic drive.

[0002]

2. Description of the Related Art Hydraulic drives are widely used in various industrial machines such as mining industry, manufacturing industry and construction industry due to their characteristics. As the driving fluid, various fluids such as mineral oil are used.

In recent years, the independence and social participation of the elderly and the disabled,
The development and use of devices to reduce the burden on home caregivers and welfare workers, which increases with the aging of the population, are advancing. Due to advantages such as power density, it is desired to expand the use of hydraulic drive to general household and welfare fields. Currently, hydraulic fluids used for general industry are used as hydraulic fluids for these household appliances (home elevators, etc.) and medical welfare equipment (movable beds, etc.). However, if these hydraulic fluids leak, there is a risk of fire, an unpleasant odor, and a harmful effect on the human body and the environment.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to use a hydraulic system safely and comfortably in the home and welfare fields.
Even if it leaks, it is to provide a hydraulic fluid that has no fire accident, human impact, or environmental impact, that is, a hydraulic fluid that is flame retardant, biodegradable, and biosafe. .

[0005]

The present invention is based on a base consisting of 30 to 90% by weight of propylene glycol, 0 to 50% by weight of glycerin and 10 to 60% by weight of water, and a saturated fatty acid having 8 to 14 carbon atoms. The present invention relates to a hydraulic fluid composition containing 0.1 to 2% by weight of a salt, which is excellent in flame retardancy, biodegradability and safety.

Generally, if importance is attached to flame retardancy, it is desired to mix water as a base. However, water alone is poor in lubricity and metal corrosion resistance and is not suitable as a hydraulic working fluid. In addition, the lubricants and anticorrosives that are commonly added to water glycol-based hydraulic fluids were selected with an emphasis on industrial properties, and there are problems with odor, safety, and biodegradability when applied to the above applications. It is common that there is.

The fluid of the present invention is based on a mixture of propylene glycol (PG) / glycerin, which is highly safe and biodegradable, with 10 to 60% of water for imparting flame retardancy. Further, the problem of imparting lubricity and anticorrosiveness has been solved by incorporating a saturated fatty acid salt having 8 to 14 carbon atoms. Examples of fatty acids include capric acid, caprylic acid, myristic acid, and lauric acid, and salts include potassium,
Sodium, triethane amine salt, etc. are mentioned.

In the present invention, the preferred range of each component of the base is 50 to 90% by weight of propylene glycol, 10 to 30% by weight of glycerin, and 10 to 40% by weight of water.

The hydraulic fluid of the present invention can be manufactured by a conventional method. That is, the additives are added to a predetermined amount of the base and mixed by stirring. The mixing can be carried out in a conventional mixing tank equipped with a stirrer and is usually carried out at 30 to 50 ° C.

[0010]

EXAMPLES Examples and comparative examples will be described below. Examples 1 to 3 Hydraulic fluids having the formulations (parts by weight) shown in Table 1 were prepared.

[0011]

[Table 1]

Test Example 1 The fire safety, safety (toxicity, skin irritation), and environmental resistance (biodegradability, detergency) of the hydraulic fluids of Examples 1 to 3 were evaluated by comparison with commercially available hydraulic fluids. Table 2 shows the results. Evaluation method: Flash point: JIS K 2265 (Petroleum product flash point test method) Biodegradability: Determined from the ratio of BOD value and theoretical TOD according to JIS K 0102 (Factory wastewater test method) (water-soluble liquid).

[0013]

[Table 2] A: R & O hydraulic fluid Hydol 32X B: Water glycol fluid Hydol HAW C: Fatty acid ester oil Quintol Brick 822

The hydraulic fluid is used as a hydraulically driven fluid for a long period of time, and acts as a lubricant for sliding parts of a hydraulic pump / hydraulic valve during this period, and with various materials (metal materials, rubber, etc.) used in a hydraulic system. The suitability of is also necessary. Therefore, a compatibility test with materials and a pump durability test were performed.

Test Example 2 Rubber material immersion test Test method: In accordance with JIS K 6301, immersion temperature 60 ° C.
Immersion was carried out for 670 hours. Results: Table 3 shows the volume change rate. Good compatibility with hydraulic rubber.

[0016]

[Table 3]

Test Example 3 A piston pump durability test was carried out for Examples 1 and 2. Test pump: manufactured by Yuken Industry Co., Ltd., piston pump A10
-FR-01 Test valve: Yuken Kogyo Co., Ltd., BT-06 Test condition: Rotation speed 1800 rpm, Discharge pressure 7 MPa,
Discharge rate 19 L / min, liquid temperature 40 ° C., time 2000 hours Result: No deterioration in pump volume efficiency, almost no wear or discoloration of pump parts was observed. Moreover, the change in the properties of the hydraulic fluid was slight, and no foreign matter was deposited or the filter was not clogged when the pump was disassembled, confirming the performance and stability of the hydraulic fluid.

Test Example 4 A home / welfare device, which is one of the fields to which the present invention is applied, comprises a compact hydraulic source, a compact hydraulic cylinder, a control valve, etc., which are compactly used. Under the following conditions, a simulated answer was constructed and a system test was conducted.

Test liquid Hydraulic fluid test circuit of Example 2 Hydraulic source: Gear pump 1 liter / min, relief valve 6M
Pa setting, motor AC100V-90W. Hydraulic cylinder: Piston diameter φ30, rod diameter φ18,
Stroke 200 mm Solenoid switching valve: Yuken Industry Co., Ltd., DSG-01-3C2 Switching frequency: 200,000 times (cylinder reciprocation) Endurance time: 1000 hours Saturation temperature: 40 ° C Test circuit and operating cycle: Fig. 1, Fig. 2 As a result, it was confirmed that the set pressure and flow rate change little and there is no liquid leakage from the system to the outside, and it can be used sufficiently in the intended application field.

Safety test (toxicity test) Test name: Subcutaneous hyperemia in continuous transdermal administration of hydraulic fluid to mouse Specimen: hydraulic fluid of Example 2 Test animals: mouse, Mus musculus, dd-AKN male, Twenty animals in each dilution group with a body weight of 21 to 24 g Test method: The sample was not diluted and 0.1 ml was applied as it was on the dorsal epidermis of the mouse once daily. After 8 days, each mouse was killed with carbon dioxide gas, and immediately after that, autopsy was performed for the presence or absence of hyperemia under the skin to which the sample was applied. For subcutaneous hyperemia, a hyperemia index (%) was obtained. This is a deadly hyperemic mouse (++)
Was set as 2 points and the hyperemic mouse (+) was set as 1 point, and it was calculated according to the following formula. Hyperemia index = {[total hyperemia score] / [number of test animals x
2]} × 100

[0021]

[Table 4]

[0022]

[Table 5]

[0023]

[Table 6]

Results and Discussion: As a result of applying this sample as a stock solution to the mice for 8 days, all the animals were not hyperemic. The detection power of skin irritation according to this test method is high, and the result is that a commercially available shampoo has a hydration index of 50% and olive oil has a hydration index of 20%. Therefore, when this test sample is used as a hydraulic fluid, there is no problem with skin irritation.

[0025]

EFFECTS OF THE INVENTION By using only safe and highly biodegradable components of the hydraulic fluid of the present invention, even if the hydraulic fluid leaks or touches the human body, it may cause a fire hazard, adversely affect the human body and the environment. It is easy to wash off with water, and has characteristics as a hydraulic working fluid. Therefore, the hydraulic fluid of the present invention is a flame-retardant, biodegradable, safety (toxic) aspect, without affecting human body and environment, household equipment of hydraulic drive system,
Useful for assistive devices.

[Brief description of drawings]

FIG. 1 is a system test circuit used in Test Example 4.

FIG. 2 is an operation cycle used in a system test of Test Example 4.

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[Procedure amendment]

[Submission date] November 8, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The fluid of the present invention is based on a mixture of propylene glycol (PG) / glycerin, which is highly safe and biodegradable, with 10 to 60% of water for imparting flame retardancy. Further, the problem of imparting lubricity and anticorrosiveness has been solved by incorporating a saturated fatty acid salt having 8 to 14 carbon atoms. Examples of fatty acids include capric acid, caprylic acid, myristic acid, and lauric acid, and salts include potassium,
Sodium, include Torieta Roh Ruamin salt.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

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Claims (2)

[Claims] 1. Propylene glycol 30 to 90% by weight, glycerin 0 to 50% by weight, water 10 to 60% by weight
Flame retardancy, biodegradability, which is obtained by adding 0.1 to 2% by weight of a salt of a saturated fatty acid having 8 to 14 carbon atoms to a base consisting of
Hydraulic fluid composition with excellent safety. 2. The hydraulic fluid composition according to claim 1, wherein a base consisting of 50 to 90% by weight of propylene glycol, 10 to 30% by weight of glycerin and 10 to 40% by weight of water is used.