JPS6240398B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to hydraulic fluids, particularly mineral oil hydraulic fluids. In hydraulic systems that use mineral oil or certain other fluids as the hydraulic fluid, the presence of water causes various problems. This water can result from condensation, insufficient drying of the system before filling, or its secondary diffusion through old seals or flexible tubing. In either case, even if only a small amount of water is present (eg, on the order of 0.5%), the vapor lock temperature of the liquid will drop to the boiling point of water. This can lead to serious defects, in particular the brake system or the central hydraulic system containing the brake system being in a dangerous state. The present invention provides a novel composition suitable as a hydraulic fluid. That is, the composition of the present invention comprises: (a) a lubricating oil, preferably at a dose of 20 to 80% (wt%, hereinafter the same) based on the weight of the total composition; (b) a general formula [In the formula, (i) R ¹ , R ² and R ³ are the same or different and each is an aryl, an aralkyl, a straight or branched chain alkyl, or an alicyclic group (having 4 to 20 carbon atoms) ), or the formula −(R ⁴ O) − _o R ⁵
(In the formula, R ⁴ is the same or different and each is ethylene, propylene or butylene, R ⁵ is alkyl (1 to 18 carbon atoms, preferably 1
~4) or aryl, n is 1~
an integer of 10, more preferably 2 to 4); (ii) R ¹ and R ² are the same or different as defined above; R ³ is a general formula

[expression] or

[Formula] (In the formula, R ¹ and R ² are the same as above, R ⁶ is a group represented by alkylene (having 4 to 20 carbon atoms) or the formula -R ⁴ -(OR ⁴ )- _o (R ⁴ and n is the same as above) or (iii) R ¹ is the same as above, R ² and R ³ are combined and the formula

An oil-soluble boric acid ester or a mixture thereof represented by [Formula] (R ¹ is the same as above); (c) an oil-insoluble hydrolysis product of the boric acid ester; The total number of carbon atoms to prevent precipitation and precipitation is 5.
~200 amines and (d) formula [In the formula, R ⁷ is hydrogen or 1 to 4 carbon atoms]
alkyl, preferably methyl, having
R ⁸ , R ⁹ and R ¹⁰ are the same or different (preferably the same), and each represents straight-chain or branched alkyl (having 4 to 20 carbon atoms), aryl,
alkaryl, aralkyl or formula -(R ¹¹ -O
) - _n R ¹² (wherein each R ¹¹ is the same or different and is ethylene or propylene, R ¹² is alkyl (having 1 to 20 carbon atoms), aryl, alkaryl or aralkyl, m is 2 to 10 means an integer)] Consists of an oil-soluble orthoester represented by the following. The boric acid esters used in the compositions of the invention need to be oil-soluble, and in the case of boric acid trialkyl esters, oil-solubility is defined as linear alcohols having up to 12 carbon atoms or branched alcohols having up to 24 carbon atoms. Oil solubility can be imparted by selecting esters obtained from chain alcohols. In the case of di- and polyoxyalkylene glycol ether-derived borate esters, those derived from di- and polyoxyethylene glycol ethers are generally insoluble and at least one terminal ether group is sufficient to solubilize the ester. shall be. Alternatively, oil solubility of this latter type of ester can be imparted by attaching polyoxypropylene or polymeric polyoxyalkylene groups to the molecule. Examples of particularly useful boric acid esters include boric acid tris(dipropylene glycol monomethyl ether) ester, boric acid tris(ethylene glycol monobutyl ether) ester, boric acid tris(triethylene glycol monobutyl ether) ester, boric acid tris(tripropylene glycol monomethyl ether) ester, ) ester, boric acid tri-n-decyl ester, boric acid tri(isotridecyl) ester, boric acid tri(2-ethylhexyl) ester, and boric acid tri(3,3-dimethylbutyl) ester. The amine used in this invention needs to be of fairly low vapor pressure to provide a vapor lock temperature of 120°C or higher. The amine is also selected according to the borate ester used. A simple test to determine whether an amine is suitable for preventing precipitation of oil-insoluble hydrolysis products of borate esters is to dissolve the amine and borate ester in the lubricating oil of choice (same as in the final hydraulic fluid). ), sealed in a transparent glass ampoule with 0.5% water, heated at 100° C. for 24 hours, and cooled. In this so-called ampoule test, this combination is satisfactory if the resulting solution is clear. Many amines have been found suitable, including primary, secondary and tertiary amines, particularly those having a total number of carbon atoms from 5 to 200. Particularly useful amines for a wide range of borate esters are the amines better known under the trade names Primene 81R and Primene JMT (see Japanese Patent Publication No. 38-26870), which contain two methyl atoms on the α-carbon atom. A commercially available primary amine having a branched tertiary alkyl group of 5 to 19 carbon atoms. Other useful amines are polyisobutenyl succinimides derived from phenols, di- or polyamines in which the amine and formaldehyde have been previously alkylated with di- or polyisobutylene. The amounts of components b, c and d can be varied. However, based on the total weight of the composition, 1
~20%, preferably 5-10% boric acid ester,
5-30%, preferably 10-20% orthoester and 1-20%, preferably 1-10% amine are used. In the compositions of the invention, the ratio of orthoester to borate ester can be varied;
For example, the weight ratio can be 10:1 to 1:10, but the preferred weight ratio is 5:1 to 2: more orthoester than the commonly used borate ester.
It is 1. The addition of orthoesters can reduce the effects of water in the hydraulic fluid resulting from the absorption of loose water from the atmosphere due to the hygroscopic effect of boric acid esters or from the extraction of loose water from the rubber components in the target hydraulic system. This is to neutralize the The ratio of boric acid ester to amine depends on the nature of both components used, but is preferably from 5:1 to 1:1 by weight. In the compositions of the present invention, the lubricating oil used as the base oil is preferably a mineral oil, but synthetic hydrocarbon oils, synthetic carboxylic acid esters or mixtures thereof, siloxanes or phosphate esters or known synthetic lubricating oils may also be used. Can be done. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Tris(tridecyl) orthoformate ester 10% Tris(dipropylene glycol monomethyl ether) borate ester 10% Primeene JMT 5% Mineral oil 75% This composition meets the requirements of DTD585 specifications. Enclosed in a glass ampoule with 0.5% water,
The Gilpin vapor lock temperature after heating at 100°C for 24 hours was 177°C. The Gilpin Vapor Lock Test is used to evaluate the operating performance of motor vehicle brake systems as affected by the water content of the hydraulic fluid.
braking systems as affected by fluid water
Society of Automobile Engineers (SAE) document 710253 entitled “Content)”
This was done using the Gilpin apparatus and method described.
Gilpin Vapor Lock Temperature (VLT) is 3ml
The temperature was set at which bubbles were generated. Example 2 Tris(tridecyl) orthoformate ester 20% Tris(dipropylene glycol monomethyl ether) borate ester 5% Primeene JMT 5% Mineral oil 70% This composition satisfies the conditions of the DTD585 specification and was prepared using Gilpine (3 ml). ) The wet vapor lock temperature was 203°C. Example 3 Tris(tridecyl) orthoformate ester 20% Tris(dipropylene glycol monomethyl ether) borate ester 5% Primeene JMT 3% Mineral oil 72% This composition satisfies the conditions of the DTD585 specification and was prepared using Gilpine (3 ml). ) The wet vapor lock temperature was 206°C. Example 4 Tris(tridecyl) orthoformate ester 20% Tris(dipropylene glycol monomethyl ether) borate ester 5% Tris(tridecyl) borate ester 2% Primeene JMT 3% Mineral oil 70% This composition met the requirements of DTD585 specifications. The Gilpin (3 ml) wet vapor lock temperature was 205.5°C. Examples 5-24 Additionally, compositions containing different orthoesters of orthoesters and borate esters were formulated. Each composition contains primeene as the amine component.
JMT was used, and naphthenic mineral oil having the following physical properties was used as the base oil. Viscosity: 130cS (-40℃), 3.5cS (100〓) and 1.31cS (210〓), Fluidity: <-70〓, Boiling point:
248℃, flash point (sealed): 208℃, aniline point: 76
A sample of each composition was prepared at 100 °C with (i) 0.5% water.
and (ii) subjected to a humidity test as described in the FMVSS113 specification, but for an extended period of 5 days and without reference oil at 80% relative humidity and a temperature of 22°C. After that, it was subjected to Gilpin (3 ml) vapor lock test. In addition, a nitrile rubber piece of 2.54 cm ² and 2 mm thick was added to 50 ml of sample oil at 120°C.
The rubber expansivity of the sample oil with respect to nitrile rubber was determined by soaking it for a day and measuring the increase in its capacity. Their compositions and test results are shown in Table 1.

【table】

【table】

[Table] The abbreviations and commercially available products in Table 1 are as follows. DPM: dipropylene glycol monomethyl ether (Dowanol DPM in Example No. 10 is the trade name of dipropylene glycol monomethyl ether), TPM: tripropylene glycol monomethyl ether, PPG: polypropylene glycol,
Primeene 81R and Primeene JMT (trade name): Empyran KB2 (trade name), a commercially available primary amine with a branched alkyl group of 5 to 19 carbon atoms, with two methyl groups on the α-carbon: From the commercially available C12-14 diethylene glycol monoether mixture, the examples in Table 1 above, and the vapor lock test results, the hydraulic fluid of the present invention maintains a high vapor lock temperature even in the presence of water. I understand that. Further, the rubber expansion test results show that the hydraulic fluid of the present invention can be formulated as a hydraulic fluid with rubber expansion properties suitable for commercially available hydraulic systems.

Claims (1)

[Scope of Claims] 1 (a) a lubricating oil selected from the group consisting of mineral oils, synthetic hydrocarbon oils, synthetic carboxylic acid esters, siloxanes and phosphoric acid esters (b) 1 to 20% by weight based on the total weight of the composition general formula for [wherein (i) R ¹ , R ² and R ³ are the same or different and each is a straight-chain or branched alkyl group having 4 to 20 carbon atoms, an alicyclic group, an aryl or an aralkyl group, or a group of the formula -(R ⁴ O) - _o R ⁵ (wherein R ⁴ are the same or different and each is ethylene, propylene or butylene, R ⁵ is alkyl or aryl having 1 to 18 carbon atoms, n is 1 to 10 (ii) R ¹ and R ² are the same or different and are the same as above, R ³ is a group represented by the general formula [Formula] or [Formula] (wherein R ¹ and R ² is the same as above, R ⁶ means alkylene having 4 to 20 carbon atoms) or a group represented by the formula -R ⁴ -(OR ⁴ )- _o (wherein R ⁴ and n are the same as above) or (iii) R ¹ is the same as above, R ² and R ³ are combined to form a group represented by the formula [Formula] (wherein R ¹ is the same as above) oil-soluble boric acid esters or mixtures thereof (c) 1 to 20% by weight, based on the total weight of the composition, of primary and secondary esters having a total number of carbon atoms of 5 to 200; (d) 5 to 30% by weight, based on the total weight of the composition, of the general formula [In the formula, R ⁷ is hydrogen or 1 to 4 carbon atoms]
R ⁸ , R ⁹ and R ¹⁰ are the same or different and are each straight-chain or branched alkyl, aryl, alkaryl or aralkyl having 4 to 20 carbon atoms or of the formula -(R ¹¹ -
O) _-n R ¹² (wherein each R ¹¹ is the same or different and each is ethylene or propylene, R ¹² is alkyl, aryl, alkaryl or aralkyl having 1 to 20 carbon atoms, m is 2 to
(means an integer of 10) ] An oil-soluble orthoester represented by A hydraulic fluid composition characterized in that the ratio is 5:1 to 2:1.