JPH0459896A - Composition for fluid coupling - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in inhibition of thermal decomposition or gelation and durability by adding a stabilizer and an anti-wear agent to a base oil composed of a organopolysiloxane. CONSTITUTION:An objective composition obtained by using (A) an organopolysiloxane represented by the formula [R is 1-18C (halogenated) hydrocarbon: (n) is integer of 1-2000] as a base oil and adding (B) (i) 0.001-5wt.% (preferably 0.01-2wt.%) stabilizer such as dimethyl-sec.-butylamine or 2,6-tert.- butyl-alpha-dimethylamino-p-cresol and (ii) 0.01-5wt.% (preferably 0.1-3wt.%) anti- wear agent such as a triarylphosphate or a triarylphosphorothionate thereto.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to durable fluid coupling compositions.

[Conventional technology]

Fluid couplings include viscous couplings and fan clutches (fan couplings), etc. A viscous coupling has multiple inner plates arranged so that they can move toward the drive shaft and spacers that maintain constant spacing. It is constructed by alternately combining multiple outer plates fixed to the driven side and housing them in a housing, which is then filled with viscous fluid for torque transmission. A shearing force, that is, a shearing torque is generated in the plate group due to the difference in the rotational speed between the two sides, and the torque is transmitted to the driven shaft.

In addition, the fan coupling type clutch is attached to the tip of the pump shaft, and the grooves on the disk surface on the pump shaft side and the grooves on the wheel surface on the fan side are engaged, forming a so-called labyrinth between them. The disc has a structure in which it rotates while being immersed in organopolysiloxane oil within the body.The disc rotates as the pump rotates, and the characteristics of the organopolysiloxane oil transmit rotational power to the wheel side, which rotates the fan. It is possible to limit the maximum rotation of the fan used for cooling the radiator without increasing the rotation speed above a certain level.

In recent years, organopolysiloxane oils such as dimethylpolysiloxane and methylphenylpolysiloxane containing phenyl groups have been used as hydraulic fluids for hydraulic systems and fluid couplings, and those with a high viscosity index (Vl) are generally used. However, it is difficult to maintain stable torque transmission ability over a long period of time under severe usage conditions such as high temperatures. This is due to the low stability of organopolysiloxane oil, especially at high temperatures. Therefore, there is an urgent need to improve the stability of fluid coupling compositions containing organopolysiloxane oil as a main component.

Conventionally, antioxidants such as iron octanoate, phenylamine derivatives, and ferrocene derivatives have been added to organopolysiloxane oil in order to prevent oxidation and gelation of this type of fluid coupling composition. Although a certain gelation prevention effect can be obtained under high heat, continuous use in actual fluid couplings actually causes the problem of increased viscosity.

C Problems to be Solved by the Invention] An object of the present invention is to provide a stable composition for a fluid coupling that is excellent in preventing thermal decomposition and gelation.

[Means to solve the problem]

Therefore, the fluid coupling composition of the present invention is characterized in that a storage stabilizer and an anti-wear agent are added to the fluid coupling composition containing organopolysiloxane as a base oil.

Further, the composition for a fluid coupling of the present invention is characterized in that a storage stabilizer, an anti-wear agent, and an antioxidant are added to the composition for a fluid coupling using an organopolysiloxane as a base oil.

The organopolysiloxane has the formula (wherein R represents the same or different optionally halogenated hydrocarbon group having 1 to 18 carbon atoms, and n is an integer from 1 to 2000). This is shown in .

As R, methyl group, ethyl group, n-propyl group, i
-propyl group, n-butyl group, i-butyl group, t-butyl n-pentyl group, neopentyl group, hexyl group,
Alkyl groups such as heptyl group, octyl□ group, decyl group, and octadecyl group, aryl group such as phenyl group and naphthyl group, benzyl group, 1-phenylethyl 12
-7 Aralkyl group such as 22-ethyl group, 0-1m~
Araryl groups, such as p-diphenyl groups.

m-1p-chlorophenyl□ group, 0-1m-1p-promphenyl group, 3.3.3-)lifluorobrobyl group,
1. 1. 1. 3. 3. 3-Hexafluoro-
halogenated hydrocarbon groups such as 2-propyl, heptafluoroisopropyl and heptafluoro-n-propyl. In particular, as the group R, fluorinated hydrocarbon groups having 1 to 8 carbon atoms excluding aliphatic unsaturated groups are advantageous, and methyl groups and phenyl groups are also advantageous, and methylpolysiloxanes and phenylpolysiloxanes are also preferable. Mixtures may also be used.

The present invention is characterized in that a storage stabilizer and an anti-wear agent are added to a composition for a fluid coupling using an organopolysiloxane as a base oil, or an antioxidant is further added to the storage stabilizer and an anti-wear agent. That is.

The storage stabilizer added to the fluid coupling composition of the present invention will be explained.

□ Storage □ Stabilizers include aliphatic tertiary amines such as dimethyl-se-dibutylamine methylethyl-n-butylamine, 2,6-di-t-butyl-α dimethylaminovalacresol, and p-aminophenol. These storage stabilizers may be used alone, but a synergistic effect can be obtained when two or more of them are used in combination. 0.001-5% by weight based on polysiloxane
, preferably 0.01 to 2% by weight.

Next, the anti-wear agent added to the fluid coupling composition of the present invention will be explained.

As a phosphorus-based wear inhibitor, the general formula is as follows:
Compounds containing at least one of (2) are effective. In the following formula, R may be hydrogen, an alkyl group, an aryl group, or a benzyl group, and may be the same or different.

R/ R-0/ R-8/ (R)*N/ 2-o/ Specific compounds are shown below.

Examples of the compound represented by the above structural formula (■) include triaryl phosphate, such as benzyl diphenyl phosphate, allyl diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, ethyl diphenyl phosphate, tributyl phosphate, Dibutyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate, diethylphenyl phenyl phosphate, propylphenyl diphenyl phosphate, dipropylphenyl phenyl phosphate, triethylphenyl phosphate ,
Tripropylphenyl phosphate, butylphenyl diphenyl phosphate, dibutylphenyl phenyl phosphate, tributylphenyl phosphate,
There are phosphoric acid esters of propylphenyl phenyl phosphate mixture, butylphenyl phenyl phosphate) fi INF, and acidic phosphoric esters such as lauryl acid phosphate, stearyl acid phosphate, and di-2-ethylhexyl phosphate.

Examples of the compound represented by the structural formula (2) include di-n-butylhexyl 7-year-old sulfonate.

As a compound represented by the structural formula 〇, n-butyl-n-
Examples include dioctylphosbuinate.

Examples of the compound represented by the structural formula (2) include triarylphosphorothionate, such as triphenylphosphorothionate and alkyldiarylphosphorothionate.

Examples of the compound represented by the structural formula (2) include triisopropyl phosphite and diisopropyl phosphite.

Compounds represented by the structural formula [phase] include trilauryl thiophosphite and the like.

Examples of the compound represented by the structural formula (2) include hexamethylphosphoric triamide.

Examples of the compound represented by the structural formula [phase] include dibutylphosphoramidate.

Examples of the compound represented by the structural formula (2) include thioperoxydiphosphoric acid tetra-2-ethylhexyl ester.

Among the compounds represented by the structural formula (2), there are compounds in which R is an octyl group.

Among these, compounds having the structure of triaryl phosphate or triaryl phosphorothionate have remarkable effects in terms of thermal stability.

The proportion of the phosphorus anti-wear agent used is 0.01% to 5% by weight, preferably 0.1% by weight based on the organopolysiloxane.
It is preferable to use it in an amount of 3% to 3% by weight.

In addition, as sulfur-based wear inhibitors, diphenyl sulfide,
Sulfides such as diphenyl disulfide, di-n-butyl sulfide, di-n-butyl disulfide, di-tert-dodecyl disulfide, di-tert-dodecyl trisulfide, and sulfurized oils and fats such as sulfurized palm oil and sulfurized dipentene. , thiocarbonates such as xanthic disulfide, and zinc thiophosphate wear inhibitors such as primary alkylzinc thiophosphate, secondary alkylzinc thiophosphate, alkyl-
Zinc thiophosphate anti-wear agents such as zinc allylthiophosphate and zinc allylthiophosphate can be used.

The proportion of the sulfur-based anti-wear agent and the zinc thiophosphate-based anti-wear agent used is preferably 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on the organopolysiloxane.

These anti-wear agents may be used alone or in combination of two or more (i.e., combinations of phosphorus-based agents, combinations of sulfur-based agents, combinations of zinc thiophosphate agents, and even combinations of phosphorus-based agents and sulfur-based agents). By using it in combination with other systems such as), the synergistic effect can reduce viscosity changes, torque changes, and the amount of wear debris. The usage ratio of these mixed anti-wear agents is 0.01% by weight based on the organopolysiloxane.
~5% by weight, preferably 0.1% to 3% by weight.

Next, the antioxidant added to the fluid coupling composition of the present invention will be explained.

Examples of antioxidants include dioctyldiphenylamine, phenyl-α-naphthylamine, alkyldiphenylamine, N-nitrosodiphenylamine, phenothiazine, N,N'-dinaphthyl-p-fuynylenediamine, acridine, N-methylphenothiazine, N-ethyl Phenothiazine, dipyridylamine, diphenylamine, phenolamine, 2,6-di-t-butyl-α-
Amine antioxidants such as dimethylaminovalacresol, 2.6-di-t-butylparacresol, 4.4°
-methylenebis(2,6-di-t-butylphenol)
, phenolic antioxidants such as 2,6-di-t-butylphenol, organic iron salts such as iron octoate, ferrocene, iron naphtonite, organic cerium salts such as cerium naphtonite and cerium toluate, siliconium octoate, etc. It is preferable to use organometallic compound antioxidants such as organosiliconium salts. Further, the above antioxidants may be used alone, but they can also be used in combination of two or more to produce a synergistic effect.

The usage ratio of the above antioxidant is 0.001 to 5% by weight, preferably 0.01 to 5% by weight based on the organopolysiloxane.
It is recommended to use 2% by weight.

[Function] In conventional compositions for fluid couplings, from the viewpoint of preventing thickening effect due to thermal deterioration accompanying use under high heat,
Improvements have been made mainly by improving antioxidants. However, when a fluid coupling composition containing an antioxidant is applied to an actual fluid coupling, viscosity still increases.

The present inventors considered that the cause could not be solved simply by improving the effect of antioxidants, and as a result of examining the cause,
We have discovered that metal contact between materials in fluid couplings has an extremely large effect.

In other words, it is thought that the newly formed surface of the metal generated by this metal contact acts as a catalyst for the deterioration of the organopolysiloxane and acts on the deterioration of the fluid coupling composition. This phenomenon can be prevented by adding storage stabilizers, anti-wear agents, or even antioxidants as additives, which eliminates the thickening phenomenon of organopolysiloxane oils and also reduces torque changes. It can be said that

The present invention will be explained below with reference to Examples.

[Example 1] Dimethyl silicone (viscosity 50,000"/8% 25°C
), tricresyl phosphate (A) and 26-di-t-butyl-α-dimethylaminovalacresol (B)
) and were added in varying amounts as shown in the table below, and the prepared fluid coupling composition was heated at 25°C with a filling degree of 85% by volume in a viscous coupling having 111 disks. It was filled with. The viscous coupling with a rotational difference of 25 rpm was kept in a chamber kept at a constant temperature of 150° C. and operated for 200 hours.

The results of measuring changes in viscosity and torque after the test are shown in the table below.

A composition for a fluid coupling was prepared by adding the phosphate and amine in varying amounts as shown in the table below, and the same procedure as in Example 1 was carried out. The results of the performance test are also shown in the table below.Measurements were stopped before 200 hours due to a sudden increase in torque. When using a stabilizer alone, there are many changes in viscosity and torque, but
It can be seen that both viscosity change and torque change can be suppressed by combining phosphates and amines.

[Example 2] In place of tricresyl phosphate in Example 1, triphenyl phosphorothionate was used.As seen from this table, compared to the case of using phosphorothionates alone, storage stabilizers were used. It can be seen that by combining these, viscosity changes and torque changes can be suppressed to a low level.

[Example 3] Instead of tricresyl phosphate in Example 1, tricresyl phosphoric acid (A) and triphenyl phosphorothionate (C) were used in a weight ratio of 1=1. A fluid coupling composition was prepared by adding the total amount of amines and the amount of amines as shown in the table below, and a performance test was conducted in the same manner as in Example 1. The results are shown in the table below. .

Therefore, the composition for fluid couplings can be made to have less viscosity reduction and less torque change.

In addition, phosphates, phosphthalothionates,
Furthermore, by using a storage stabilizer at the same time, a more excellent fluid coupling composition can be obtained.

Applicant Toen Co., Ltd. Agent Patent Attorney (1) Nobuhiko, (7 others) As shown in this table, by combining phosphates and phosphthalothionates and adding them together with amines, It can be seen that viscosity changes and torque changes can be kept low.

[Effects of the Invention] The fluid coupling composition of the present invention does not cause deterioration of the organopolysiloxane base oil by adding a storage stabilizer, an anti-wear agent, or an antioxidant to the organopolysiloxane base oil. There is no 40:08

Claims (2)

[Claims] (1) A fluid coupling composition comprising an organopolysiloxane as a base oil, to which a storage stabilizer and an anti-wear agent are added. (2) A fluid coupling composition comprising an organopolysiloxane as a base oil, to which a storage stabilizer, an anti-wear agent, and an antioxidant are added.