JP2888747B2 - Flame retardant hydraulic fluid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant hydraulic fluid used for rolling mills, die-casting machines, etc. in the fields of iron and steel, non-ferrous metals, and hydraulic equipment, etc. in the field of construction. The present invention relates to a flame-retardant hydraulic oil which is excellent in stability and oxidation stability, does not cause a pinhole fire at a use site, and does not cause environmental pollution.

[0002]

2. Description of the Related Art In general, the properties required for a flame-retardant hydraulic fluid include, for example, an appropriate viscosity-temperature characteristic in terms of pressure and power transmission, and an appropriate property in terms of reducing pressure and power loss. It has excellent viscosity, excellent heat stability, oxidation stability and lubricity in terms of life, excellent emulsifying properties in view of the possibility of water contamination, and used in places where there is a risk of fire. Therefore, it is required to have characteristics such as a high flash point and no continuous combustion even in the event of ignition. Conventionally, such flame-retardant hydraulic fluids include emulsion type, water-glycol type,
Phosphate ester type or fatty acid ester type are used. However, emulsion-based and water-glycol-based hydraulic fluids have problems in heat stability, oxidation stability, lubricity or waste liquid treatment properties, and phosphate-based hydraulic fluids have viscosity-temperature characteristics. There are problems such as characteristics, hydrolysis resistance, deterioration of the sealing material, peeling of the coating, and waste liquid treatment. On the other hand, fatty acid ester-based hydraulic fluids do not have the above-mentioned problem and are widely used, but have a problem that their fire resistance and flame retardancy are insufficient. Various studies have been made to solve such problems in the fatty acid ester type hydraulic fluid. For example, Japanese Patent Application Laid-Open Nos.
JP-A Nos. 226096, 63-125598, JP-A-2-214795, and JP-A-3-21697 disclose techniques relating to fatty acid ester-based flame-retardant oils.

[0003]

However, all of the publications disclosed in these publications only specify flame retardancy at the flash point. In other words, the most problematic of flame-retardant hydraulic fluids is disasters caused by pinhole fires. Specifically, even if hydraulic fluid squirts from pinholes, it is difficult to ignite. Even if a single ignition occurs, if the fire source is removed, the combustion will not continue. Such a problem cannot be dealt with simply by defining the flash point. We have:
Focusing on the above-mentioned continuous burning properties, a high-pressure spray combustion test was conducted on various flame-retardant oils, and the conventional fatty acid ester-based flame-retardant oils which were said to have flame retardancy (especially,
Fatty acid esters using only oleic acid)
It was found that there was no satisfactory flame retardancy. Therefore,
As a result of intensive studies to develop a fatty acid ester-based flammable hydraulic oil with excellent thermal stability, oxidative stability and fluidity without continuous flammability, specific polyols, oleic acid and isostearic acid were obtained. It has also been found that the desired flame-retardant hydraulic oil can be obtained by adding a fatty acid ester obtained by reacting oleic acid, isostearic acid and other monocarboxylic acids at a specific ratio. The present invention has been completed based on such findings.

[0004]

That is, the present invention provides:
(A) neopentyl glycol, 2,2-dimethyl-3-
At least one polyol selected from hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropionate, glycerin and trimethylolpropane;
(B) a carboxylic acid composed of 15 to 85 mol% of oleic acid in all carboxylic acids and 15 to 85 mol% of isostearic acid in all carboxylic acids, or the carboxylic acid further contains 85 mol% or less of carbon atoms in all carboxylic acids A reaction product with a carboxylic acid containing 6 to 22 monocarboxylic acids (excluding oleic acid and isostearic acid), having a kinematic viscosity at 40 ° C of 40 to 80 cSt and a flash point of 290 ° C or more. An object of the present invention is to provide a flame-retardant hydraulic oil characterized by containing a hydraulic oil base oil containing a synthetic ester as a main component.

Hereinafter, the present invention will be described in more detail. First, in the flame-retardant hydraulic oil of the present invention, a hydraulic oil base oil containing a fatty acid ester as a main component is used.
In the present invention, as this fatty acid ester, a synthetic ester obtained by reacting the polyol of the component (A) with the oleic acid and isostearic acid of the component (B), or the polyol of the component (A) and the polyol of the component (B) Oleic acid, isostearic acid and monocarboxylic acids having 6 to 22 carbon atoms (excluding oleic acid and isostearic acid)
And a synthetic ester obtained by the reaction with Here, the polyol of the component (A) subjected to the synthetic ester formation reaction is neopentyl glycol, 2,2-dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropionate. It is at least one polyol selected from catenate, glycerin and trimethylolpropane. Each of these polyols may be used alone, or two or more of them may be used in combination.

On the other hand, the carboxylic acid of component (B) to be subjected to the synthetic ester formation reaction contains oleic acid and isostearic acid as essential components, and more preferably has 6 to 6 carbon atoms excluding oleic acid and isostearic acid. It is a carboxylic acid containing 22 monocarboxylic acids. In the esterification reaction of the carboxylic acid of the component (B) with the polyol of the component (A), oleic acid is blended in an amount of 15 to 85 mol% of all carboxylic acids and isostearic acid in an amount of 15 to 85 mol% of all carboxylic acids. When a monocarboxylic acid having 6 to 22 carbon atoms is used, it is used in an amount of 85 mol% or less, preferably 70 mol% or less. When the proportion of oleic acid is less than 15 mol%, the fluidity becomes poor, and when it exceeds 85 mol%, the flame retardancy becomes insufficient, which is not preferable. If the proportion of isostearic acid is less than 15 mol%, the flame retardancy becomes insufficient, and if it exceeds 85 mol%, the fluidity becomes poor, which is not preferable. Here, the monocarboxylic acid having 6 to 22 carbon atoms is not particularly limited. For example, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid , Myristic acid, pentadecanoic acid, palmitic acid,
Linear saturated fatty acids such as heptadecanoic acid, stearic acid, nonadecanoic acid, arachinic acid, behenic acid, undecenoic acid,
Linear unsaturated fatty acids such as elaidic acid, setreic acid, erucic acid, and brassic acid, isomyristic acid, isopalmitic acid, 2,2-dimethylbutanoic acid, 2,2-dimethylpentanoic acid, 2,2-dimethyloctanoic acid , 2-ethyl-2,
3,3-trimethylbutanoic acid, 2,2,3,4-tetramethylpentanoic acid, 2,5,5-trimethyl-2-t-butylhexanoic acid, 2,3,3-trimethyl-2-ethylbutanoic acid, 2,3
-Dimethyl-2-isopropylbutanoic acid, 3,5,5-trimethylhexanoic acid, and branched saturated fatty acids such as 2-ethylhexanoic acid. These monocarboxylic acids may be used alone or in combination of two or more.

[0007] The hydraulic oil base oil of the flame-retardant hydraulic oil of the present invention produces the above-mentioned polyol (A) and carboxylic acid (B) by a usual esterification reaction or transesterification reaction. It has a synthetic ester as a main component. In the esterification reaction or transesterification reaction of the polyol (A) and the carboxylic acid (B), the desired viscosity is adjusted by adjusting the charging ratio of the components (A) and (B). So that the flash point is 290 ° C or higher,
It is desirable to sufficiently cut light components. And when using the obtained synthetic ester as a hydraulic oil base oil,
The reaction product may be used as it is, or each reaction product may be blended and used so as to obtain a desired viscosity.

In the present invention, the synthetic ester used as a hydraulic oil base oil has a kinematic viscosity at a temperature of 40 ° C. of 40 to 80 cSt, preferably 45 to 65 cSt. If the viscosity is too high, the fluidity will be poor and the efficiency of the device will be poor. On the other hand, if the viscosity is too low, the operating oil tends to become mist when ejected, and to burn easily. The flash point is preferably 290 ° C. or higher. If the flash point is lower than 290 ° C., ignition becomes easy. The iodine value which is a measure of oxidation stability is preferably 65 or less. If the iodine value exceeds 65, the olefin content will increase, the oxidation life will be shortened, and combustion will be more likely.

The flame-retardant hydraulic oil of the present invention contains a hydraulic oil base oil containing the synthetic ester thus obtained as a main component, and further contains a high molecular compound having a number average molecular weight of 10,000 to 400,000. It is preferred to contain. Such polymer compounds include polyolefins, polyacrylates,
Polymethacrylates, polyalkylene glycols, polyalkylene glycol alkyl ethers, styrene-olefin copolymers, styrene-maleic ester copolymers, polyesters, and the like, in particular, polymethacrylate-based polymers or styrene-maleic ester copolymers It is preferably used. The above-mentioned polymer compound is added for the purpose of further reducing the mist of the base oil which has become difficult to form a mist. From such a viewpoint, its molecular weight is from 10,000 to 400,000 in number average molecular weight.
It is preferably 0. When the molecular weight is smaller than this, the above-mentioned effects are hardly expected, and when it is larger than this, the effect is deteriorated by shearing during use, and the effect is weakened, which further lowers the viscosity, which is not preferable. In the present invention, the above-mentioned polymer compound is preferably contained in the hydraulic fluid in an amount of 0.01 to 2.0% by weight. If the content is less than this range, the effect of the present invention is small, and if it is too large, the possibility of shear deterioration increases, which is not preferable.

[0010] The flame-retardant hydraulic oil of the present invention may further contain, if necessary, an antioxidant, an extreme pressure agent, a rust inhibitor, a defoamer, a demulsifier, etc., which are usually used as lubricating oil additives. Can be blended. As the antioxidant used here, for example, 2,6-di-t-butyl-4-methylphenol, 4,4′-methylenebis (2,6-di-t-butyl-4
Phenolic antioxidants such as -methylphenol), N
-Phenyl-α-naphthylamine, N-phenyl-β-
Amine antioxidants such as naphthylamine, phenothiazine, monooctyldiphenylamine or sulfur antioxidants such as alkyl disulfide and benzothiazole;
Zinc dialkyldithiophosphate and the like. Also,
Examples of the extreme pressure agent include zinc dialkyldithiophosphate, dialkyl polysulfide, triaryl phosphate, and trialkyl phosphate.
Examples of the rust preventive include alkenyl succinic acid, sorbitan monooleate, pentaerythritol monooleate, and amine phosphate. Further, examples of the antifoaming agent include dimethylpolysiloxane and diethylsilicate. Other demulsifiers include, for example, polyoxyalkylene glycol, polyoxyalkylene alkyl ether,
Examples thereof include polyoxyalkylene alkylamides and polyoxyalkylene fatty acid esters. The flame-retardant hydraulic oil of the present invention obtained as described above preferably has a biodegradability of 67% or more in a biodegradability test based on the CEC method.

The flame-retardant hydraulic oil of the present invention thus obtained contains a hydraulic oil base oil mainly composed of a synthetic ester formed by the reaction between the polyol (A) and the carboxylic acid (B). By doing so, it is excellent in flame retardancy, thermal stability and oxidative stability, and has no fear of pinhole fire. Therefore, the flame-retardant hydraulic oil can be suitably used for various hydraulic devices, construction machines, injection molding machines, machine tools, hydraulic drive robots, and the like. It can also be used as engine oil, gear oil and other industrial lubricants. In addition, since it has biodegradability, it can be used as a suitable lubricating oil from the viewpoint of environmental protection.

[0012]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Example 1 A five-liter four-necked flask was equipped with a stirrer, a thermometer, an argon blowing tube and a Dean-Stark water separator equipped with a condenser. In the above flask, 603 g (4.5 mol) of trimethylolpropane and 2,82 oleic acid were added.
2 g (10 mol) (polymethyltriol
Molar ratio to lopan 2.22) and isostearic acid
999 g (3.5 mol) (trimethylol which is a polyol
(0.78) , and the mixture was heated with a mantle heater under an argon stream to carry out an esterification reaction. When the internal temperature reached 160 ° C. (about 1 hour), the distillation of water started. The temperature was gradually increased and 240 ml of water was trapped in about 3 hours. At this time,
The internal temperature was 240 ° C. Further, in order to complete the reaction, the temperature was raised to 260 ° C., and the mixture was heated and stirred for 3 hours.
After that, the water separator was replaced with a distillation head,
The light components were distilled off under reduced pressure (2 mmHg) for 3 hours. The obtained fatty acid ester was 4092 g.

Examples 2 to 5 and Comparative Examples 1 to 4 Examples 2 to 5 and Comparative Examples 1 to 4 were carried out in the same manner as in Example 1 except that the components in the esterification reaction were changed as shown in Table 1. Comparative Examples 1 to 4 were carried out to obtain fatty acid esters. For each of the fatty acid esters obtained in Examples 1 to 5 and Comparative Examples 1 to 3, measurement of various physical properties, high-pressure spray combustion test and biodegradability test were performed as quality evaluation. Table 1 shows the results.

[0014]

[Table 1]

[0015]

[Table 2]

The symbols in the table are as follows. TMP: trimethylolpropane ESG: 2,2-dimethyl-3-hydroxypropyl-2 ',
2'-Dimethyl-3'-hydroxypropionate NPG: neopentyl glycol glyc: glycerin From Table 1, looking at the continuous burning time by the high pressure spray combustion test, Examples 1 to 5 are all very short and difficult. It turns out that it is excellent in flammability. On the other hand, in Comparative Examples 1 to 4, all were determined to have "continuous flammability", and it was found that sufficient flame retardancy could not be obtained simply by increasing the flash point. In addition, as a result of conducting a biodegradability test by the CEC method,
The fatty acid esters obtained in Examples 1 to 5 all had a biodegradation rate of 99% or more.

The measurement of various physical properties and the high pressure spray combustion test were performed in accordance with the following. 1) Kinematic viscosity It was measured according to JIS K-2283. 2) Oxidation stability The oxidation life was measured at a test temperature of 150 ° C in accordance with the rotating cylinder type oxidation stability test specified in Section 3.3 of JIS K-2514. In this oxidation stability test, except for Comparative Example 2, a sample oil containing 1% by weight of N-phenyl-α-naphthylamine was used as an additive. 3) Iodine value Measured according to JIS K-0070. 4) Flash point Measured with a Cleveland open-type (COC) tester according to JIS K-2274. 5) High pressure spray combustion test The sample oil sprayed by high pressure was ignited by a burner,
After pre-combustion for 2 seconds, the burner was removed from the fire, and the subsequent burning time was measured and used as an index of flame retardancy. In addition, about the thing which continued burning for 30 seconds or more, the test was discontinued at that time, and it was judged as "there is continuous burning". Test conditions Spray pressure: 70 kg / cm ² G (nitrogen pressurization) Sample oil temperature: 60 ° C. Nozzle: Monarch 60 ° PL 2.25 (hollow cone type) Between nozzle burners: 10 cm Pre-combustion time: 10 seconds Autoclave capacity: 1 liter 6) Biodegradability test The test was performed by the CEC method in accordance with CEC-L-33-T-82.

Examples 6 to 12 The fatty acid esters obtained in Examples 1, 2 and 3
A high-pressure spray combustion test was performed in the same manner as in Example 1 for each of the polymers to which the high molecular compounds shown in the table were added. The results are shown in Table 2.

[0019]

[Table 3]

[0020]

[Table 4]

As is apparent from Table 2, the addition of the high molecular compound to the fatty acid ester base oil significantly reduced the continuous burning time.

[0022]

As described above, the flame-retardant hydraulic oil of the present invention is excellent in flame retardancy, heat stability and oxidation stability, and does not cause a pinhole fire. Therefore, the flame-retardant hydraulic fluid of the present invention is a hydraulic fluid for a high-output hydraulic device, for example,
It is suitably used for various hydraulic devices, construction machines, injection molding machines, machine tools, hydraulic drive robots and the like. It can also be used as engine oil, gear oil and other industrial lubricants without any problem. Also, because it has biodegradability,
It can be used as a suitable lubricating oil also from the viewpoint of environmental protection.

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification code FI C10N 20:00 20:02 30:00 30:08 30:10 40:08 (56) References JP-A-63-125598 (JP) , A) JP-A-55-18467 (JP, A) JP-A-61-287987 (JP, A) JP-A-54-64264 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) C10M 105/38 C10M 109/02 C10M 145/14 C10M 145/16 C10N 40:08

Claims (10)

(57) [Claims] (A) Neopentyl glycol, 2,2-
At least one polyol selected from dimethyl-3-hydroxypropyl-2 ′, 2′-dimethyl-3′-hydroxypropionate, glycerin and trimethylolpropane, and (B) 15 to 85 mol% of all carboxylic acids A reaction product of oleic acid and a carboxylic acid comprising 15-85 mol% of isostearic acid in the total carboxylic acid, the synthetic ester having a kinematic viscosity at 40 ° C. of 40-80 cSt and a flash point of 290 ° C. or more. A flame-retardant hydraulic oil comprising a hydraulic oil base oil as a main component. 2. The carboxylic acid as the component (B) further comprises a monocarboxylic acid having 6 to 22 carbon atoms (excluding oleic acid and isostearic acid) of 85 mol% or less of the total carboxylic acid. The flame-retardant hydraulic oil according to claim 1. 3. The flame-retardant hydraulic oil according to claim 1, wherein the iodine value is 65 or less. 4. Further, the number average molecular weight is from 10,000 to 400,000.
2. The flame-retardant hydraulic oil according to claim 1, which contains 0.01 to 2.0% by weight of a high molecular weight compound. 5. The flame-retardant hydraulic oil according to claim 4, wherein the polymer compound is selected from a polymethacrylate polymer and a styrene-maleic acid ester copolymer. 6. The flame-retardant hydraulic oil according to claim 1, wherein a biodegradation rate in a biodegradability test based on the CEC method is 67% or more. 7. The flame-retardant hydraulic oil according to claim 2, wherein a biodegradation rate in a biodegradability test based on the CEC method is 67% or more. 8. The flame-retardant hydraulic oil according to claim 3, wherein a biodegradation rate in a biodegradability test based on the CEC method is 67% or more. 9. The flame-retardant hydraulic oil according to claim 4, wherein a biodegradation rate in a biodegradability test based on the CEC method is 67% or more. 10. The biodegradation rate in a biodegradability test based on the CEC method is 67% or more.
The flame-retardant hydraulic fluid described.