JP2505223B2 - Complex emulsion hydraulic fluid - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic fluid used as a pressure medium of a hydraulic device, which is particularly flame retardant and excellent in lubricity and rust prevention. The present invention relates to an O / W / O complex emulsion hydraulic fluid.

(Prior Art) As a pressure medium of a hydraulic device, a mineral oil type hydraulic fluid has been generally used. It has excellent lubricity and rust resistance, but it is flammable, so it is not suitable for fields with fire risk such as die casting machines, casting machines, electric welding machines, heating furnace peripheral equipment, and hot rolling mills. Suitable, flame retardant hydraulic fluids are widely used for such applications.

As the flame-retardant hydraulic fluid, fatty acid ester, phosphate ester, water glycol, W / O emulsion, O / W emulsion and the like are generally used.

Of these, the fatty acid ester is semi-flame retardant and combustible. Phosphoric acid ester does not burn continuously and is flame-retardant and has excellent lubricity, but its rust resistance is poor. In addition, the high cost is disadvantageous in implementation. Water glycol, W / O emulsion, and O / W emulsion all contain a large amount of water and are nonflammable, and are excellent in this respect, but lubricity and rust preventive properties are mineral oil and fatty acid ester. Is inferior to.

(Problems to be Solved by the Invention) In the current state of the art, no hydraulic fluid that is flame-retardant and has excellent lubricity and rust prevention has been obtained. However, it is absolutely necessary to protect important machinery and equipment from fire and to keep personnel safe, and therefore, in the above-mentioned fields where there is a danger of fire and aircraft hydraulic systems that require a high degree of safety. Flame-retardant hydraulic fluid is used.

Therefore, the use of flame-retardant hydraulic fluid with better lubricity and rust prevention ensures safety from fire and also prevents wear, seizure and rust on sliding parts in the hydraulic system, Therefore, it is an object of the present invention to prevent a malfunction of the hydraulic device and a deterioration in performance thereof, and an object of the present invention is to provide such a hydraulic oil.

(Means for Solving Problems) In order to achieve the above-mentioned object, the inventors of the present invention have selected three types of hydraulic fluids, water glycol, W / O emulsion, and O / W emulsion, which have excellent flame retardancy. As a result of research focused on it, the first hydraulic oil hydraulic fluid was an aqueous solution of glycols such as ethylene glycol and propylene glycol, polyether polymer, and other additives, and lubricated with water containing around 40%. Since it does not contain long-chain hydrocarbon groups, which have a great effect on the anti-corrosion property and the anti-corrosion property, there are problems in lubricity and anti-corrosion property.

The third O / W emulsion is an oil-in-water emulsion of mineral oil or synthetic oil, which is a long chain hydrocarbon, and contains 90 to 95% water.
Content is low and the oil content is low, so that it cannot be said that the lubricity and rust prevention are good.

The second W / O emulsion is a water-in-oil emulsion in which water is dispersed and emulsified in mineral oil or synthetic oil.
Around 50% has a higher oil content than the O / W emulsion,
It is slightly superior in terms of lubricity and rust resistance, but inferior to mineral oil hydraulic fluid.

However, by further dispersing mineral oil or synthetic oil in the aqueous phase of the W / O emulsion to form a double-structured emulsion, that is, an O / W / O type composite emulsion, a large amount of water is contained. Nonetheless, surprisingly, we found that the lubricity was greatly improved, and we proceeded with further research. Surprisingly, if the water displacing agent was included in the oil phase of the innermost phase, the rust resistance was remarkably improved. Based on this knowledge, the present invention has been achieved.

Accordingly, the present invention provides an O / W in which the outermost phase comprises a lubricating oil containing a mineral oil and / or a synthetic oil as a main component, and the innermost phase comprises a lubricating oil containing a mineral oil and / or a synthetic oil as a main component and a water displacing agent. The present invention relates to a complex emulsion hydraulic fluid, which is an / O type complex emulsion.

(Operation) The oil used in the outermost phase and the innermost phase in the present invention is a lubricating oil containing a mineral oil and / or a synthetic oil as a main component.

Mineral oil is a refined mineral oil used as a lubricating oil.
The kinematic viscosity at 8.89 ° C is in the range of approximately 2 to 30 cSt. Suitable synthetic oils are synthetic hydrocarbon oils such as poly-alpha-olefin oils. Mineral oils and synthetic oils can be added with additives generally used for hydraulic oils, such as rust preventives, extreme pressure additives, oiliness improvers, metal deactivators, antioxidants and the like.

Mineral oils and synthetic oils such as poly-alpha-olefin oils have advantages and disadvantages such as low temperature fluidity in the latter and thermal decomposition stability in the former. Therefore, they may be used alone or in a mixture of both depending on use conditions. Is appropriate. Further, since the mineral oil and / or the synthetic oil of the outermost phase are involved in lubrication as a main component on the sliding surface inside the hydraulic device, it is needless to say that excellent lubricity is required. At the same time, in the range where the sealing property of the sliding surface can be maintained, it is preferable that the viscosity is as low as possible and the penetrability is excellent and it is possible to penetrate into the lubrication slit. The content of lubricating oil in the outermost phase is 89 to 40% by weight based on the total emulsion, which is the most effective range. If it is less than 40% by weight, the contents of the inner phase and the innermost phase are too large and the stability is poor. On the contrary, if the content exceeds 89% by weight, the contents of the inner phase and the innermost phase are too small, and these effects become poor. The internal phase contains water as a main component, is a source of flame retardancy of the hydraulic fluid of the present invention, and is a component that imparts cooling property. It is also preferable to include a vaporizable rust preventive such as dicyclohexylamine nitrite or benzotriazole in the inner phase for the purpose of improving rust preventive property. Water content in the internal phase is 10-50% by weight based on the total emulsion
Is a range in which the effect is large, and if it is less than 10% by weight, flame retardancy and cooling properties are poor, and if it exceeds 50% by weight, stability becomes poor. The lubricating oil in the innermost phase is a component that has the effect of significantly enhancing the lubricity due to its presence. Further, the innermost phase lubricating oil contains a water displacing agent, whereby the rust preventive property is remarkably improved. Although such an effect was newly found as a result of research, the reason for this has not been confirmed, but is generally considered as follows.

In the O / W / O type composite emulsion of the present invention, there is a lubricating oil in the outermost phase, water is in the inner phase, and there is a lubricating oil dispersed in the inner phase and containing a water displacing agent in the innermost phase. So the innermost phase is doubly protected. Moreover, since the outermost phase is lubricating oil and is strong against mechanical shock and thermal shock, it can exist relatively stably even if it is subjected to high pressure and strong shear in the hydraulic system. However, in the lubricated part where the sliding surface is in an extreme condition where it is closer to seizure than boundary friction, the innermost phase interface is also destroyed, and the lubricating oil inside is released and participates in lubrication to ensure normal operation. It is considered to have a function of returning to a lubricated state. Also, if the two interfaces of O / W and W / O of the composite emulsion are destroyed, water will also contact the inner surface of the device such as the sliding surface, so if the inner surface metal is wetted with water for a long period of time, it will naturally occur. A rust accident occurs. In such a case, a mechanism is conceivable in which the water displacing agent contained in the innermost phase replaces water on the wet surface with oil to cover the metal surface with a lubricating oil film to prevent rusting. It is preferable that the innermost phase contains a rust preventive together with the water displacing agent. As the rust preventive agent used for this purpose, an oil-soluble rust preventive agent such as a dioleyl phosphate EO 1 mol adduct is suitable. As shown in FIG. 1, the water displacing agent used in the present invention has the following formula when oil (liquid paraffin) 1 added with it is in contact with water 2 on the surface of metal 3 and is in a quasi-equilibrium state. Defined substitution energy D _WO
Is negative.

D _WO = γ _so −γ _sw = γ _WO cos θ where γ _so , γ _sw , and γ _WO are the surface tensions between metal / oil, metal / water, and water / oil, and θ is the receding contact angle. Measure from the metal surface to which water is attached. Specifically, the presence or absence of water displacement of the water displacing agent can be determined by the following test method.

The surface of mild steel plate SPCC 80 × 60 × 1 mm is polished with # 240 polishing cloth, washed with warm petroleum benzine, degreased and dried.

0.15 cc (5 drops) of 0.01% fluorescein distilled water solution was dropped on the center of the surface, and then 1 cm from the outer circumference of the water drop.
On the distant surface, also 0%, 1% and 5% of the water displacement agent
0.15 cc of liquid paraffin solution is added dropwise. Then, the oil droplets of the liquid paraffin solution gradually spread over time,
If it has a water-displacing property, it penetrates under the water droplets, and the water droplets are lifted up, and after 1 minute, the water droplets are completely separated from the surface of the steel sheet and floated on the oil to be moved. When this state is reached, it is determined that there is water substitution. If the oil droplets do not have a water-replacing property, the water droplets remain attached to the steel sheet and do not move, and even if the surroundings are bitten by oil, they will not float and move. In this state, it is determined that there is no water substitution. Judging by this test method,
Fatty acids such as 9,10-dihydroxystearic acid, didodecyl sebacate, esters such as sorbitan monopalmitate, alkyl phosphites such as dioctyl phosphite, alkyl phosphates such as distearyl hydroxyphosphate, beef tallow trimethylenediamine, palm trimethylene. An N-alkyltrimethylene diamine such as diamine-oleate or a fatty acid salt of the same amine is water displacing agent and is a water displacing agent. As the rust preventive agent used in combination with the water displacement agent, 1 mole of dioleyl phosphate EO adduct, trade name CHIRESLITE A-2 (Kirest Chemical Co., Ltd.)
Manufactured) and the like. The appropriate range of the content of the water displacing agent is 0.1 to 5% by weight with respect to the innermost phase lubricating oil.
If it is less than 5% by weight, the effect of water replacement is poor, and therefore the rust preventive property of the emulsion is insufficient.
W emulsion becomes unstable. When a rust preventive agent is used, its content range is preferably 0.1 to 5% by weight, and it is appropriate that the total amount of the water displacing agent and the rust preventive agent does not exceed 5% by weight. If it is less than 0.1% by weight, the rust preventive effect is poor, and if the total amount of the rust preventive alone or the water displacing agent exceeds 5% by weight, the O / W emuljoin in the inner phase becomes unstable.

In addition, the content of the lubricating oil in the innermost phase is 1 to 10% by weight based on the total emulsion, which is the range in which the effect is large.
If it is less than 10% by weight, lubricity is poor, and if it exceeds 10% by weight, stability is poor.

A hydrophilic surfactant is used to disperse the innermost phase in water of the inner phase. A lipophilic surfactant is used to further disperse the O / W emulsion of the innermost phase-inner phase dispersion in the oil of the outer phase. As the hydrophilic surfactant, polyoxyethylene sorbitan monolaurate EO adduct such as 20 mol of polyhydric alcohol ester EO, higher alcohol EO adduct such as polyoxyethylene oleyl ether EO 16 mol, naphthene poly (alkylene tetraalkoxyborane), etc. Examples thereof include boron compounds, and examples of the lipophilic surfactant include polyhydric alcohol esters such as sorbitan oleate and tetraglycerin-condensed ricinoleate.

O / W / O by a known method from the above-mentioned outermost phase, inner phase, each substance of the innermost phase, hydrophilic surfactant, and lipophilic surfactant
Complex emulsions can be produced.

 An example of the manufacturing method is as follows.

Adopting a two-step emulsification production method, first of all, as a first step, a hydrophilic surfactant is dissolved in water as an internal phase substance, and a water displacing agent and a rust preventive agent are added to oil in this solution and uniformly dissolved and dispersed. The innermost phase substance thus prepared is added and emulsified by an emulsification dispersion device such as a homomixer to produce an O / W emulsion. Then second
Separately as a step, the lipophilic surfactant is dissolved in the oil of the outermost phase substance, the O / W emulsion prepared in the first step is added to this solution, and the mixture is emulsified by an emulsification dispersion device such as a homomixer to obtain O / W / Produces O complex emulsion. In addition to the homomixer, examples of the emulsification / dispersion apparatus that can be used in the present production method include a turbine-type emulsifier, a spiral pin mixer, a high-speed shear mixer, a media-type disperser, and a high-pressure emulsifier.

(Example) Table 1 shows the compositions (wt%) of Examples 1 to 8 and Comparative Examples 1 to 6, the properties of the products, and the effects.

The examples and comparative samples (O / W / O composite emulsion) were produced by the method described above.

Explaining Example 1, 30.0 g of water was placed in a container, 0.05 g of benzotriazole and 2.0 g of EO of ethylene oxide adduct of naphthenic acid EO (20 g of activator A) were added and stirred to dissolve the solution in a separate container. 40 ℃ viscosity, 46cS
t) 0.15 g of tallow trimethylenediamine [(trade name Duomin T) manufactured by Lion Akzo Co., Ltd. (water displacing agent A)] was added to 3.0 g of (mineral oil A), and dissolved oil was added to the mixture. Co., Ltd., Model 3) was processed at 10,000 rpm for 3 minutes to emulsify and disperse to obtain an O / W emulsion. In a separate container, take 60.8 g of naphthenic mineral oil (viscosity at 40 ° C, 22 cSt) (mineral oil B), add 4.0 g of sorbitan monooleate (activator C), stir and dissolve, and add the O / W emulsion to it. Using the above homomixer, the mixture was treated at 10,000 rpm for 3 minutes and emulsified and dispersed to obtain an O / W / O emulsion.

Similarly, the O / W / O emulsions of Examples 2 to 8 and Comparative Examples 1 to 3 were produced according to the compositions shown in Table 1.

Comparative Examples 1 to 3 do not contain a water displacing agent, and Comparative Examples 2 and 3 have an excessively small amount of mineral oil in the innermost phase and an excessively small amount of mineral oil. Comparative Examples 4 to 6 are all commercially available hydraulic fluids, 4 is a W / O type emulsion, 5
Is an O / W emulsion, and 6 is a mineral oil hydraulic oil.

The samples of each example were tested for the items shown in Table 1 to confirm their properties and effects. The test method and criteria are as follows.

A. Appearance A sample of 100 cc was sampled in a 150 cc capacity glass cylindrical container and the state was visually observed.

B. Stability 100 cc of a sample is placed in a 150 cc capacity glass cylinder and
The emulsion was allowed to stand at 70 ° C. for 7 days and then at 50 ° C. for 3 days, and changes in the emulsion state were visually observed. The judgment criteria are shown by the following symbols.

◯: Not separated Δ: Emulsion slightly separated ×: Emulsion completely separated C. Viscosity The viscosity was measured by the JIS K2283 kinematic viscosity of petroleum products and the viscosity test method.

D. Four-ball load-bearing performance In accordance with JIS K2519 Lubricating oil load-bearing performance test method, the load-bearing performance is improved by the method of gradually applying a load of 0.5 kg / cm ² per minute at 200 rpm with a Soda-type four-ball friction tester. It was measured.

E. Flash Point The flash point was measured according to JIS K2265 Crude oil and petroleum product flash point test method (Cleveland open type).

F. Copper plate corrosion test In accordance with JIS K2513 petroleum product copper plate corrosion test method, 50 ℃ × 24
The test was conducted for a certain period of time, and then the discolored state of the copper plate was visually observed. The judgment criteria are as follows.

1: Slightly discolored 2: Moderately discolored H. Steel plate rust preventive test JIS K2246 rust preventive oil, JIS G3141 steel plate (1 x 60 x 80 mm) is ground with No. 240 polishing cloth according to the wet test method, and post-warm petroleum naphtha Wash with warm anhydrous alcohol, and dry.

Then, soak it in the sample solution for 60 seconds, remove it from the solution, and then
Leave in air at room temperature for 24 hours. Then the steel plate is 49 ± 1
The film was placed in a wet box adjusted to a temperature of 95 ° C and a humidity of 95% or more, left for 24 hours, then taken out, and the state of rust on the steel sheet was observed. The criteria for judgment are as follows, and the percentages of rusted areas are shown.

A: 0% B: 1-10% C: 11-25% D: 20-50% I. Vane pump wear resistance test The vane pump was continuously operated under the following test conditions and then disassembled, and the wear amount of the vane and cam ring (mg) Was measured.

(Test conditions) (1) Pump HVP-L26RG (manufactured by Hokko Industry Co., Ltd.) (2) Discharge rate 26 / min (3) Discharge pressure 40kg / cm ² (4) Test time 96 hours (5) Liquid temperature 40 ± 5 ℃ (6) Liquid volume 100 (Effects of the Invention) As shown in Table 1, the O / W / O type composite hydraulic oil of the present invention is non-flammable, and the commercially available mineral oil hydraulic oil is flammable. For example, the present invention has a remarkable difference, and the commercially available O / W type and W / O type emulsion hydraulic fluids are nonflammable, but have lubricity (four-ball load bearing performance and vane pump wear resistance test) and rust prevention ( By comparing the steel plate anticorrosion test), it was confirmed that the present invention was significantly superior, and the object of the present invention was completely achieved here.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the relationship between the surface tension between each phase, the contact angle, and the water displacement action of oil when water-oil-metal is in contact and in a quasi-equilibrium state. 1 ... Oil, 2 ... Water 3 ... Metal

Claims (1)

(57) [Claims] 1. An outermost phase comprises a lubricating oil containing a mineral oil and / or a synthetic oil as a main component, and an innermost phase comprising a lubricating oil containing a mineral oil and / or a synthetic oil as a main component and a water displacing agent.
A compound emulsion hydraulic fluid, which is an O / W / O type compound emulsion.