JPH0737628B2 - Silicone working fluid - Google Patents

Description

Detailed Description of the Invention

(Field of Industrial Application) The present invention relates to a silicone working fluid, particularly to a silicone working fluid used for a fan clutch and a viscous damper for transportation equipment or various industrial equipment. (Prior art and its problems) Silicone working fluids based on dimethyl silicone oil or methylphenyl silicone oil have less viscosity decrease due to temperature rise than other mineral oils and synthetic oils, and also have excellent heat resistance. Therefore, it is mainly used for transportation equipment, such as fan clutches, viscous couplings, vibration absorbing viscous dampers, etc. There are many reports especially for fan clutches (Japanese Patent Publication No. 55-18457, 6).
1-21591, 63-28960, JP-A-57-195196, 6
2-283194). However, since they use dimethyl silicone oil or methylphenyl silicone oil as the base oil, they have poor boundary lubricity (Plastic Materials Course).

[9], “Silicon resin”, pp. 55-58, Nikkan Kogyo Shimbun), metal wear powder generated during operation mixes into the working fluid, resulting in unstable output performance and internal friction heat. There is a problem in that the heat of the silicone working fluid is accelerated due to the high temperature due to the large amount. It has been reported that a sulfur-containing compound is added to a silicone oil to improve the drawback of the boundary lubricity (JP-A-64-65195). In this report, trifluoropropylmethyl silicone oil is proposed as a base oil as an example of silicone oil. It is already known that this trifluoropropylmethyl silicone oil has excellent boundary lubricity, and it is used as a lubricating oil or a grease base oil for precision machines. However, the viscosity change of this trifluoropropylmethyl silicone oil with temperature is larger than that of dimethyl silicone oil, and therefore, when working fluids using these as base oils are used at low temperatures, the output becomes too large, and when used at high temperatures. Then, the output becomes too small and stable output performance cannot be obtained. (Means for Solving Problems) The present invention is directed to a specific trifluoropropylmethylsiloxane-dimethylsiloxane copolymer (which may hereinafter be simply referred to as a fluorine-containing copolymer) and an aromatic amino group-containing organopolysiloxane. The above problem is solved by combining and in a specific amount ratio. That is, the silicone working fluid of the present invention has the formula (A): A trifluoropropylmethylsiloxane unit represented by the formula: A dimethylsiloxane unit represented by the following general composition formula [I], In the formula, a and b are 1.95 ≦ a + b ≦ 2.20 and 0.
A number satisfying 01 ≦ b / (a + b) ≦ 0.3, 100 parts by weight of a trifluoropropylmethylsiloxane-dimethylsiloxane copolymer having a viscosity at 25 ° C. of 1 to 1,000,000 centistokes represented by: ) The following general composition formula [II] or [III], Or Where R ¹ is A monovalent aromatic amino group selected from, R ² is a monovalent saturated hydrocarbon group or a phenyl group, n is 1 to 50, p is 0 to 47, q is 1 to 10 and p + q is 1 to
An aromatic amino group-containing organopolysiloxane represented by
0.01 to 5 parts by weight. (A) Trifluoropropylmethylsiloxane-dimethylsiloxane copolymer The trifluoropropylmethylsiloxane-dimethylsiloxane copolymer used as the base oil in the present invention has the above-mentioned general composition formula, that is, It is represented by. Here, a and b are numbers satisfying 1.95 ≦ a + b ≦ 2.20, and b / (a + b) is 0.01 to 0.3, preferably 0.05 to 0.20.
Must be within the range. This b / (a + b) is
It is an index showing the content of trifluoropropyl group in the copolymer, and when this value is smaller than 0.01, the obtained silicone working fluid has insufficient lubricity,
On the other hand, when it is larger than 0.3, the change in viscosity with respect to temperature change becomes large, and it becomes difficult to maintain a stable output. Further, this fluorine-containing copolymer has a temperature of 25 ° C. in order to form an effective lubricating film and effectively disperse other components described later.
Viscosity at 100 to 1 million cSt, preferably 100 to 100,000 cSt
Must be in St range. (B) Aromatic Amino Group-Containing Organopolysiloxane In the present invention, an aromatic compound represented by the above general composition formula [II] or [III] is used in combination with the above-mentioned trifluoropropylmethylsiloxane-dimethylsiloxane copolymer. Amino group-containing organopolysiloxanes are used. This organopolysiloxane imparts heat resistance to the silicone working fluid. Particularly in the aromatic amino group-containing organopolysiloxane represented by the general composition formula [II] or [III],
If the n value is larger than 50, it is necessary to increase the compounding amount for obtaining the desired heat resistance improving effect, and it may not be practical as an additive. Therefore, the n value should be in the range of 1 to 50. Is good. Furthermore, p value is larger than 47 and p + q
Since it is necessary to increase the blending amount even when is larger than 48, it is desirable that the p value is in the range of 0 to 47 and p + q is in the range of 1 to 48. Further, when the q value is larger than 10, This organopolysiloxane has a reduced solubility in the above-mentioned trifluoropropylmethylsiloxane-dimethylsiloxane copolymer, so that it is 1-10%.
It is required to be in the range of. Incidentally, this organopolysiloxane containing an aromatic amino group is already known and, for example, In the presence of a hydrochloric acid scavenger such as pyridine, triethylamine, picoline, etc., an aminophenol and a chlorinated alkylpolysiloxane are subjected to a condensation reaction in a toluene solvent, and the hydrochloride is removed, followed by heating and stripping under reduced pressure. Can be obtained by In the present invention, the preferred examples of the aromatic amino group-containing organopolysiloxane represented by the general formula [II] are as follows. Further, the following can be illustrated as preferable examples of the aromatic amino group-containing organopolysiloxane represented by the general formula [III]. Such an organopolysiloxane is the above-mentioned trifluoropropylmethylsiloxane-dimethylsiloxane copolymer.
It is used in a proportion of 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, per 100 parts by weight. That is, when the amount used is less than 0.01 parts by weight, the heat resistance of the resulting silicone working fluid becomes unsatisfactory, and even when it is used in excess of 5 parts by weight, a significant heat resistance improving effect is obtained. Not only is it economically disadvantageous. Lubricity improver In order to further improve the lubricity of the silicone working fluid, molybdenum disulfide, benzyl disulfide,
Although various known lubricity improvers such as tricresyl phosphate can be blended, in the present invention, zinc dialkyldithiophosphate is particularly preferable because it does not adversely affect the heat resistance of the obtained silicone working fluid. Can be suitably mixed. This zinc dialkyldithiophosphate is used in an amount of 10 parts by weight or less, preferably 0.1 to 10 parts by weight, and most preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the base oil trifluoropropylmethylsiloxane-dimethylsiloxane copolymer. It is preferable to add and blend them in a quantity ratio. Here, if the blending amount is more than 10 parts by weight, it becomes difficult to dissolve or stably disperse in the obtained silicone working fluid, and if it is less than 0.1 part by weight, the lubricity imparting effect is insufficient. As the zinc dialkyldithiophosphate, since the solubility or dispersibility in the base oil trifluoropropylmethylsiloxane-dimethylsiloxane copolymer is good, the alkyl group is a linear or branched hexyl group,
Particularly preferred are long-chain alkyl groups having 6 or more carbon atoms such as a heptyl group, an octyl group, a decyl group, a dodecyl group, and a tetradecyl group. The invention is illustrated by the following example. (Examples) In the following examples, "parts" in the examples indicate "parts by weight", and the viscosity unit is centistokes (cSt). The physical property test was performed by the following methods. Heat resistance test 25 g of the silicone working fluid was sampled in a clean 100 ml hard glass beaker and left in a hot air circulating constant temperature bath at 200 ° C. for 240 hours to measure the change in viscosity. Lubrication test Using a reciprocating friction tester (manufactured by Kyowa Giken), a friction test was performed according to the following conditions, and the dynamic friction coefficient and the weight loss of the movable test piece after 10 minutes were measured. Fixed test piece: S45C carbon steel, diameter 8mm, length 65mm Movable test piece: S45C carbon steel, 15mm × 15mm × 65mm Load: 11.3Kg Stroke speed: 200 reciprocations / minute Stroke width: 50mm The base oil, trifluoro Propylmethylsiloxane-
The following were used as the dimethylsiloxane copolymer and the aromatic amino group-containing organopolysiloxane of the additive. (A) Trifluoropropylmethylsiloxane-dimethylsiloxane copolymer The following three types of trifluoropropylmethylsiloxane-
A dimethyl siloxane copolymer was used. All of these copolymers are of the terminal trimethylsiloxy group blocking type. A1: b / (a + b) = 0.15, b = 0.30 Viscosity (25 ℃) 4820cSt A2: b / (a + b) = 0.20, b = 0.40 Viscosity (25 ℃) 11500cSt A3: b / (a + b) = 0.05, b = 0.10 Viscosity (25 ℃) 10200cSt A4: b / (a + b) = 0.35, b = 0.70 Viscosity (25 ℃) 4550cSt (B) Organopolysiloxane containing aromatic amino groups The following two organopolysiloxanes containing aromatic amino groups It was used. [Example 1] to [Example 7] As shown in the table, 100 parts by weight of various terminal trimethylsiloxy group-blocked trifluoropropylmethylsiloxane-dimethylsiloxane copolymers were mixed with various aromatic amino group-containing organopolys. Siloxane and optionally di-2-
A silicone working fluid to which zinc ethylhexyldithiophosphate was added and blended was prepared and tested. The test results obtained were all excellent in heat resistance, viscosity-temperature characteristics, and lubricity. [Comparative Example 1] Silicone operation obtained in the same composition except that the terminal trimethylsiloxy group-blocked trifluoropropylmethylsiloxane-dimethylsiloxane copolymer A1 in Example 1 was replaced with a terminal trimethylsiloxy group-blocked dimethylpolysiloxane. When the fluid was tested, it showed excellent heat resistance and viscosity-temperature characteristics, but extremely low lubricity. [Comparative Example 2] A terminal trimethylsiloxy group-blocked trifluoropropylmethylsiloxane-dimethylsiloxane copolymer of Example 2
A silicone working fluid obtained with the same composition except that A1 was replaced with trifluoropropylmethylpolysiloxane blocked with a trimethylsiloxy group at the end was tested and found to have excellent lubricity but poor heat resistance and viscosity-temperature characteristics. there were. [Comparative Example 3] When a silicone working fluid obtained in the same composition except that the aromatic amino group-containing organopolysiloxane in Example 1 was removed was subjected to a heat resistance test, gelation occurred,
It had extremely low heat resistance. [Comparative Example 4] A silicone working fluid obtained in the same formulation except that trifluoropropylmethylsiloxane-dimethylsiloxane copolymer A1 having a terminal trimethylsiloxy group blocked in Example 1 was replaced with A4 was tested. Although it had excellent heat resistance and lubricity, it had poor viscosity-temperature characteristics. The measurement results of the above Examples and Comparative Examples are also shown in Table 1. (Effect of the Invention) According to the present invention, the low-temperature viscosity characteristics and heat resistance of the trifluoropropylmethylsiloxane-dimethylsiloxane copolymer could be significantly improved without impairing the excellent lubricity. INDUSTRIAL APPLICABILITY The silicone working fluid of the present invention has excellent lubricity, heat resistance and low temperature viscosity characteristics stably for a long period of time, and is effectively used for fan clutches, viscous dampers, etc. for various transportation equipment or various industrial equipment. It The silicone working fluid may be used alone or in combination with conventionally known dimethyl silicone oil, methylphenyl silicone oil or various synthetic oils.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C10N 20:02 30:02 30:08 40:08 (72) Inventor Takahiro Goi Annaka City, Gunma Prefecture 2-13-1 Isobe Shin-Etsu Kagaku Kogyo Co., Ltd. Silicon Silicon Electronic Materials Research Laboratory (56) References JP-A-60-106891 (JP, A) JP-A 1-95195 (JP, A) JP-A 1-65195 (JP, A)

Claims (1)

[Claims] 1. Formula (A): A trifluoropropylmethylsiloxane unit represented by the formula: A dimethylsiloxane unit represented by In the formula, a and b are 1.95 ≦ a + b ≦ 2.20 and 0.
A number satisfying 01 ≦ b / (a + b) ≦ 0.3, 100 parts by weight of a trifluoropropylmethylsiloxane-dimethylsiloxane copolymer having a viscosity at 25 ° C. of 1 to 1,000,000 centistokes represented by: ) The following general composition formula, Or Where R ¹ is A monovalent aromatic amino group selected from, R ² is a monovalent saturated hydrocarbon group or a phenyl group, n is 1 to 50, p is 0 to 47, q is 1 to 10 and p + q is 1 to An aromatic amino group-containing organopolysiloxane represented by
A silicone working fluid consisting of 0.01 to 5 parts by weight.