JPH0379699A - Improved-lubricity silicone-based fluid composition and improvement of lubricity of silicone-based fluid - Google Patents

Abstract

PURPOSE:To obtain the subject composition having an improved friction property and an abrasion-prevention effect and useful as a torque-transmission fluid by blending a silicone-based fluid with a phosphate (phosphite). CONSTITUTION:With (A) 100 pts.wt. silicone-based fluid (preferable example; dialkylpolyorganosiloxane) preferably containing an inactivator for metals, (B) 0.1-3.0 pts.wt. phosphate and/or phosphite is blended to obtain the objective composition. The resultant composition is excellent in wide viscosity-temperature characteristics, inflamability, evaporation loss, shear stability, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lubrication performance-improving silicone-based fluid composition and a method for improving the lubricity performance of a silicone-based fluid. More particularly, the present invention relates to silicone-based fluids and methods for improving the frictional and anti-wear properties of silicone-based fluids.

(Prior Art) Silicone fluids, such as organopolysiloxanes, especially dialkylpolysiloxanes, have low temperature fluidity, viscosity-temperature properties, thermal stability, oxidation stability, shear stability, chemical stability, electrical properties, etc. Conventionally, because of its excellent
It is used in insulating oil, hydraulic oil, mold release agent, and torque transmission fluid for fluid couplings, etc., but it generally has the disadvantage of poor lubrication performance, such as copper-to-steel and copper-to-steel. It is known that during transmission, gelation occurs due to shear, friction, and heat generated between the two members of the joint, making torque transmission impossible. Therefore, its usable range as a lubricating oil is limited.

(Problems to be Solved by the Invention) As previously mentioned, silicone-based fluids have excellent properties such as viscosity and temperature characteristics, but in order to be used widely and practically as a lubricating oil, it is necessary to improve the friction properties. There is a need to improve lubrication performance such as and anti-wear properties.

Conventionally, methods for improving the lubrication performance of silicone-based fluids can be roughly divided into two methods: chemically modifying the silicone-based fluid itself and optimizing it by adding additives to the silicone-based fluid.
As for the former, various attempts have been made to modify the chemical structure of silicone-based fluids.

As for the latter, it has been proposed, for example, to improve the lubrication performance by adding a sulfur compound, such as di-tert-nonyl polysulfide, to a silicone fluid (U.S. Pat. No. 3,809,079). In this case, 1 part to 1 part of the polysulfide is added to the silicone fluid.
It is disclosed that by adding the IO part, sufficient lubrication performance can be exhibited under a load of 240 kg in the Shell type four-ball wear test.

However, as mentioned above, as a torque transmission fluid,
These conventional techniques cannot be said to be sufficiently suitable for eliminating deterioration caused by gelation during high-speed rotation and considering various uses such as fan couplings, viscous dampers, and liquid springs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a silicone-based fluid composition with improved lubrication performance in order to solve the above-mentioned problems, and to provide a method for improving lubrication performance, particularly frictional properties and anti-wear properties.

(Means for Solving the Problems) Briefly, the present invention provides a silicone-based fluid with improved lubrication performance, and a silicone-based fluid that improves friction properties and wear by adding a specific lubricating oil additive such as an anti-wear agent to the silicone-based fluid. The present invention relates to a method for improving prevention properties.

The first invention relates to a silicone-based fluid composition comprising a silicone-based fluid and at least one component selected from the group of phosphate esters and phosphite esters as described below, and the second invention relates to a silicone-based fluid composition comprising: The present invention relates to a method for improving frictional properties and anti-wear properties by adding at least one component selected from the group of phosphate esters and phosphite esters to a silicone fluid.

Each component used in the present invention will be explained in detail below.

The types of silicone fluid used in the present invention include 1
) organosilanes, 2) silicate esters, and 3) organopolysiloxanes, which are represented by the following general formula.

1) Organosilane-3i-R 2) Silicate ester R R R 3) Organopolysiloxane In the above general formula, R is a linear or branched chain such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, isoamyl, etc. represents an alkyl group, and may have intermediate or different formulas. Further, n (average degree of polymerization) is in the range of to-100.

Among the above-mentioned organopolysiloxanes, those having a phenyl group or a long chain alkyl group of C@ or more are not preferable because the viscosity-temperature characteristics deteriorate, and those having an alkyl group of C4 or less are preferable. A particularly preferred organopolysiloxane is dimethylpolysiloxane.

Silicone fluid has the following characteristics compared to mineral oil.

(a) Very good viscosity-temperature characteristics; for example, mineral oil has a high viscosity index of about 120, while silicone oil has a viscosity index of 400 or more.

Therefore, unlike mineral oil, there is no need to use a polymer-based viscosity index improver, and the shear stability is extremely excellent.

(b) It has excellent low-temperature fluidity, with a pour point of -50°C or lower.

(c) It has excellent heat and oxidation stability, and does not easily generate sludge even when used for a long time.

(d) It has a surface tension of about 21XIO'N/ca and wets metal surfaces and rubber surfaces more easily than mineral oil (27-29Xlσ5N/cI11).

The ability of the silicone-based fluid to dissolve or decompose additives can be further improved by adding an ester-based fluid. Ester fluids that can be used include:
There are (a) diester-based ones, (b) monoester-based ones, and (c) polyol ester-based ones. The diester fluid is obtained by condensation of an aliphatic dibasic acid having 4 to 9 carbon atoms and an alcohol having 4 to 8 carbon atoms.

Preferred dibasic acids are glutaric acid, adipic acid, azelaic acid, sebacic acid, etc., and preferred alcohols are amyl alcohol, isoamyl alcohol, n-hexanol, 2-ethylbutanol, n-octatool, 2-ethylhexanol, etc. . Diesters can be prepared by selecting from the group of dibasic acids and alcohols mentioned above. Among them, adipate and sebacate are preferred.

(b) Monoester fluid: A monoester fluid is obtained by condensation of an aliphatic basic acid having 12 to 18 carbon atoms and an alcohol having 1 to 4 carbon atoms.

Examples of the aliphatic basic acids include lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, with lauric acid and oleic acid being preferred.

Examples of the alcohol include methanol, ethanol, propatool, isopropatool, butanol, isobutanol, and isopropatool is preferred.

Specific examples of monoester fluids used in the present invention include methyl laurate and isopropyl myristate.

(c) Polyol ester fluid: This fluid is obtained by condensation of a polyol and an aliphatic basic acid, and includes the following fluids.

(1) Trimethylolpropane ester fluid nitrimethylolpropane or trimethylolethane and carbon number 4
to 12 esters obtained by condensation with aliphatic basic acids are used.

The above-mentioned fatty acids include butyric acid, chirasonic acid, caproic acid, caprylic acid, lauric acid, etc., and preferably caproic acid and caprylic acid.

()I) Pentaerythritol ester fluid: This is obtained by condensation of pentaerythritol and the aliphatic basic acid having 4 to 12 carbon atoms used in (1) above.

When the ester fluid is added, the blending ratio (volume ratio) is 5% to 70%, especially in the range of 5% to 50%, relative to the mixed fluid with the silicone fluid. Ru.

In the present invention, as described above, the antiwear agent added to improve the friction and wear resistance properties of the silicone fluid is at least one component selected from the group of phosphoric acid esters and phosphite esters. .

This type of additive will be explained below.

(a) Phosphate esters are used especially to improve initial low friction properties and anti-wear properties.

(b) Phosphite is used especially to ensure low friction properties over a long period of time.

Examples of the phosphoric acid compound include those represented by the following general formula.

0=P(ORI)(01?z)(OR1), 0-P
(011) (ORI) (OR2).

0-P(Ol1)2 (ORI), P(ORI)
(OR2)(Olh), P(Ol1)(ORI)(
OR2), P(Off)z (ORI).

Specifically, (1) oleyl acid phosphate (this is OH C+sHi, a mixture of OP-〇 and OH P-O, / C+sI(350
sHi, O)2POH), etc. are used.

The amount of the phosphoric acid compound used is 0.1% to 3.0% by weight based on the silicone fluid mentioned above from the viewpoint of its effectiveness.
Weight%.

Furthermore, the following additives can be used.

(1) Metal deactivator: When a bearing made of a composite material of plastic, copper, lead, etc. is used in a manner in which the silicone-based fluid comes into contact with metal, the copper or lead in the composite material is It is effective to include a metal deactivator in order to prevent elution into the fluid.

When copper, lead, zinc, etc. in the composite material elutes into the silicone fluid, it not only deteriorates the silicone fluid, but also weakens the composite material itself. This type of metal deactivator component includes thiadiazole type represented by the following general formula,
0 for silicone fluids, such as triazole-based fluids.
．． It is sufficient to mix Ol to 0.5% by weight.

Kuthiadiazole type> [In the formula, R is n- or l5o having 1 to 8 carbon atoms
-Alkyl group] triazole type [wherein R is n- or l5o having 1 to 8 carbon atoms]
-Alkyl group] (2> Ashless dispersant: The silicone fluid can be blended with an ashless dispersant, for example, an ashless dispersant mainly composed of polyalkenylsuccinimide and/or its derivatives. Prevents agglomeration and precipitation of acid compounds from silicone fluids,
It is used to exhibit stable friction and anti-wear properties over a long period of time.

The succinimide-based ashless dispersant described above is represented by the general formula below.

The ashless dispersant containing succinimide and/or its derivative as a main component is used in an amount of 0.05 to 1% by weight based on the silicone fluid from the viewpoint of effectiveness.

(3) Others: It goes without saying that in addition to the above-mentioned components, detergents and dispersants commonly used in this technical field can be used.

This type of detergent and dispersant includes metal sulfonates, metal phosphonates, metal phenates (the metal component is Mg
, Ca, 13o, Na, etc.).

In addition, for example, 4,4-methylbis-
Antioxidant IL agents such as 2,6-di-t-butylphenol and phenyl-α-naphthylamine are used. This ranges from 0.05% to 1.0% by weight based on the silicone fluid. oi=
% may be added.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

<Examples 1 and 2/Comparative Examples 1 and 2> The components shown in Table 1 below were used for the organopolysiloxanes shown in the same table. The diester was used to improve the dispersibility of the additive components in the organopolysiloxane.

Next, various evaluation items shown in Table 1 were tested.

The results are also shown in Table 1.

The shell four-ball wear scar diameter was evaluated by rotating the shell four-ball tester for 30 minutes under the conditions of a load of 40 kg, a sample oil temperature of 70° C., and a speed of 1800 rpm.

In addition, the friction coefficient was measured using a Bauden friction tester by applying sample oil to a test piece made from a nitrile rubber sheet, and applying a chrome steel test pin to the test piece under the conditions of a load fi 2 kg and a sliding speed of 0.3 + I 1 m/min. It was calculated from the frictional force obtained by sliding.

For comparison, the composition and evaluation results when no phosphate ester was added are also listed in Table 1.

As shown in Table 1, the friction properties and anti-wear properties, that is, the evaluation results of the friction coefficient and the four-ball wear scar diameter of the shell with the addition of phosphate ester, are more significant than those without the addition of phosphate ester. I got a great effect. Furthermore, it can be seen that it has excellent viscosity-temperature characteristics ranging from low-temperature side to high-temperature side, and is comprehensively superior in properties such as flammability, evaporation loss, and shear stability (viscosity reduction rate).

(The following is a blank space) [Effects of the Invention] According to the present invention, by adding a limited amount of a phosphate ester or a phosphite to a silicone fluid, the frictional properties and anti-wear properties of the silicone fluid are significantly improved. can do. In addition, it has excellent viscosity-temperature characteristics at high and low temperatures, as well as flammability, evaporation loss,
It also has excellent properties such as shear stability (viscosity reduction rate).

Claims (1)

[Claims] 1) A silicone-based fluid comprising a silicone-based fluid and an effective amount of at least one component selected from the group of phosphate esters and phosphite esters, and having improved frictional and anti-wear properties. Fluid composition. 2) The silicone fluid composition according to claim 1, wherein the silicone fluid is a dialkyl polyorganosiloxane. 3) The silicone-based fluid composition of claim 1, which comprises adding a metal deactivator to the silicone-based fluid. 4) A method of improving the frictional properties and anti-wear properties of a silicone-based fluid by adding at least one component selected from the group of phosphate esters and phosphite esters to the silicone-based fluid. 5) The method according to claim 4, wherein the silicone fluid is a dialkyl polyorganosiloxane. 6) A method according to claim 4, which comprises adding a metal deactivator.