JPH0688026A - Organopolysiloxane composition for viscous fluid coupling - Google Patents

Abstract

PURPOSE:To provide an organopolysiloxane composition for viscous fluid coupling which scarcely undergoes viscosity rise or fall under the conditions of high temperature and high shear, scarcely undergoes a torque change, and can withstand service for a long time. CONSTITUTION:The composition comprises 100 pts.wt. fluid organopolysiloxane of the general formula: R<1>aR<2>bSiO@{9146/28}4-(a+b)]/2 (wherein R<1> is alkyl; R<2> is aryl; a+b=1.95-2.05; and b/(a+b)=0.05-0.30) and 0.01-5 pts.wt. compound of the general formula (wherein R<3>s are the same or different alkyl groups) or its polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organopolysiloxane composition for viscous fluid couplings, and more particularly to an organopolysiloxane composition for viscous fluid couplings which has little increase in viscosity and decrease in viscosity under high temperature and high shear and is stable for a long time. It relates to a siloxane composition.

[0002]

2. Description of the Related Art Conventionally, as a fluid used for a viscous fluid coupling, it has a proper viscosity, a high flash point, is stable against oxidation and thermal decomposition, and has a small temperature dependence of viscosity. Organopolysiloxane fluids are commonly used because of the properties required. However, due to severe shearing and heat generation due to friction generated in the fluid coupling, the organopolysiloxane fluid alone has a drawback in that viscosity increase or gelation or the like occurs after a certain period of time and the function as the fluid coupling is lost. . Therefore, a method of adding various antioxidants to the organopolysiloxane fluid and blending them to prevent their deterioration is being studied. For example, JP-B-55-18457 and JP-B-63-
In JP 19538, a dimethylpolysiloxane composition having a low viscosity increase under high temperature conditions can be obtained by adding and blending dimethylpolysiloxane having a low degree of polymerization modified with an aromatic amine compound to a dimethylpolysiloxane fluid. It is disclosed.

[0003]

However, the dimethylpolysiloxane compositions obtained by these methods all have a low polymerization degree of dimethylpolysiloxane modified with an aromatic amine compound under high temperature and high shearing force. A rearrangement reaction occurs with the dimethylpolysiloxane fluid of the base oil,
The viscosity of the dimethylpolysiloxane fluid itself decreases. Therefore, when using this as a viscous fluid coupling,
There is a drawback that the torque transmission rate is reduced and the function as a fluid coupling is lost. In addition, there is a drawback in that the production of a low-polymerization degree dimethylpolysiloxane modified with an aromatic amine compound requires a complicated procedure, resulting in a high cost. The present inventors have arrived at the present invention as a result of extensive studies to solve the above-mentioned drawbacks. That is, an object of the present invention is to provide an organopolysiloxane composition for viscous fluids, which has little increase in viscosity and decrease in viscosity under high temperature and high shear, has almost no torque fluctuation, and can withstand long-term use. .

[0004]

Means for Solving the Problem and Its Action The above-mentioned object is (A) the general formula R ¹ _a R ² _b SiO _{[4- (a + b)] / 2} (wherein R ¹ is an alkyl group, R ² is an aryl group, a + b = 1.
95-2.05, b / (a + b) = 0.05-0.30. ) Organopolysiloxane fluid 10
0 parts by weight and (B) general formula

[Chemical 2] (In the formula, R ³ is the same or different alkyl groups.) Or its polymer 0.01 to 5
The present invention relates to an organopolysiloxane composition for viscous fluid couplings, which is characterized by comprising parts by weight.

To explain this, it is used in the present invention.
The organopolysiloxane as the component (A) is the main ingredient of the composition of the present invention, and in the above formula, R ¹ is an alkyl group exemplified by a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group and the like. And of these, a methyl group is preferable. R ² is an aryl group exemplified by a phenyl group and a tolyl group, and among them, a phenyl group is preferable. a + b is a number of 1.7 to 2.3. b / (a + b)
Indicates the amount of aryl groups with respect to all organic groups.
If this value becomes large, the temperature-viscosity coefficient becomes large, and the decrease in viscosity at high temperature becomes significant, which impedes torque transmission. Further, if this value is small, a sufficient effect of improving heat resistance is not recognized and the dissolving ability of the component (B) is also lowered. Therefore, it is preferably in the range of 0.05 to 0.30, more preferably 0.10 to 0.30. It is a number of 0.15. Examples of such a diorganopolysiloxane include a dimethylsiloxane / methylphenylsiloxane copolymer capped with trimethylsiloxy groups at both ends, a dimethylsiloxane / diphenylsiloxane copolymer with trimethylsiloxy groups blocked at both ends, and a dimethylsiloxane with dimethylphenylsiloxy groups blocked at both ends. -Methylphenylsiloxane copolymer, dimethylphenylsiloxy group-capped dimethylsiloxane-diphenylsiloxane at both ends, and the like are exemplified. Although the viscosity of this component is not particularly limited, it is 100 to 1,000,000 at 25 ° C.
Those within the range of centistokes are preferable from the viewpoint of torque transmission, and more preferably 500 to 500,00.
It is within the range of 0 centistokes. In the composition of this component, the component (A) as described above may be used alone, or may be used as a mixture of two or more kinds having different viscosities, or two or more kinds having different chemical structures. You may use it as a mixture of.

The component (B) used in the present invention is a component characterizing the present invention, and has the general formula

[Chemical 3] (In the formula, R ³ is an alkyl group exemplified by a methyl group, an ethyl group, a propyl group, an isopropyl group, an octyl group and a nonyl group, and these R ³ may be the same or different from each other.). It is the compound shown or its polymer. A typical example of such a compound is quinoline,
There are 1,2-dihydro-2,2,4-trimethyl-, homopolymers. The addition amount of this component is 0.01 to 5 parts by weight based on 100 parts by weight of the component (A). This is because when the compounding amount is less than 0.01 part by weight, the action and effect due to the addition of this component are not recognized, and when it exceeds 5 parts by weight, the solubility of this component in the component (A) becomes poor. It may be difficult to obtain a uniform organopolysiloxane composition.

The composition of the present invention can be easily produced by uniformly mixing the predetermined amounts of the above-mentioned components (A) and (B) under heating. In this case, since the component (B) is usually solid, it is advantageous to mix the component (B) under a temperature condition at which the component (B) is melted or higher. The heating temperature at this time is generally 6
It is in the range of 0 to 130 ° C, preferably 90 to 130 ° C. Further, in this mixing, a part of the component (A) and the component (B) may be uniformly mixed in advance and then the remaining component (A) may be mixed.

[0008]

EXAMPLES The present invention will now be described in detail with reference to Examples.
In the examples, “part” means “part by weight”, viscosity is measured at 25 ° C., and “cs” is centistokes.

[0009]

Example 1 100 parts of a dimethylsiloxy-diphenylsiloxane copolymer having a viscosity of 4000 cs and having trimethylsiloxy groups at both ends blocked (diphenylsiloxane unit content: 15 mol%) was added to the formula.

[Chemical 4] Low polymer of compound shown by [Quinoline, 1,2-dihydro-
2,2,4-trimethyl-, homopolymer; Softening point 65-110
0.5 ° C., degree of polymerization 2-4], and under a nitrogen atmosphere,
The mixture was stirred at 100 ° C. for 5 minutes and uniformly mixed to prepare an organopolysiloxane composition for viscous fluid coupling. 30 g of this organopolysiloxane composition for viscous fluid coupling
It was taken in a 0 ml beaker and left in a hot air circulation oven at 280 ° C., and the change with time of its viscosity was measured (Test 1). In addition, 80 g of these compositions were injected into a fluid coupling device, and continuous operation was performed at an ambient temperature of 280 ° C./3000 rpm to measure the gelling time of the organopolysiloxane for viscous fluid coupling (Test 2). These results are shown in Table 1 below as Test 1 and Test 2, respectively. In Table 1, the maximum viscosity decrease rate is the viscosity change rate when the maximum decrease in viscosity during the test is reached, and the maximum viscosity decrease time is the time until the viscosity becomes the minimum, and The conversion time is the time until the viscosity rises and the fluidity is lost.

[0010]

[Example 2] 0.5 part of the reddish brown powder used in Example 1 was added to 100 parts of a dimethylsiloxy-diphenylsiloxane copolymer having a viscosity of 10,000 cs and having trimethylsiloxy groups at both ends blocked (diphenylsiloxane unit content: 10 mol%). Then, the mixture was stirred and mixed at 100 ° C. for 5 minutes in a nitrogen atmosphere to prepare an organopolysiloxane composition for a viscous fluid coupling. The characteristics of this composition were measured in the same manner as in Example 1, and the results are shown in Table 1.

[0011]

Example 3 0.5 part of the reddish brown powder used in Example 1 was added to 100 parts of a dimethylsiloxy-diphenylsiloxane copolymer having a viscosity of 10,000 cs and having trimethylsiloxy groups blocked at both ends (diphenylsiloxane unit content: 15 mol%). Then, the mixture was stirred and mixed at 100 ° C. for 5 minutes in a nitrogen atmosphere to prepare an organopolysiloxane composition for a viscous fluid coupling. The characteristics of this composition were measured in the same manner as in Example 1, and the results are shown in Table 1.

[Table 1]

[0012]

EFFECTS OF THE INVENTION The organopolysiloxane composition for viscous fluid couplings of the present invention comprises the components (A) and (B), and since it contains the special compound (B), it has a high temperature. In addition, there is little increase in viscosity and decrease in viscosity under high shear, and there is almost no torque fluctuation, and it can withstand long-term use.

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Claims (1)

[Claims] 1. (A) General formula R ¹ _a R ² _b SiO _{[4- (a + b)] / 2}
(In the formula, R ¹ is an alkyl group, R ² is an aryl group, and a + b =
1.95 to 2.05, b / (a + b) = 0.05 to 0.30
Is. ) Organopolysiloxane fluid 1 represented by
And 100 parts by weight of (B) general formula: (In the formula, R ³ is the same or different alkyl groups.) Or its polymer 0.01 to 5
An organopolysiloxane composition for viscous fluid couplings, characterized in that it is composed of parts by weight.