Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
  • C10M107/50—Lubricating compositions characterised by the base-material being a macromolecular compound containing silicon
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2229/00—Organic macromolecular compounds containing atoms of elements not provided for in groups C10M2205/00, C10M2209/00, C10M2213/00, C10M2217/00, C10M2221/00 or C10M2225/00 as ingredients in lubricant compositions
  • C10M2229/04—Siloxanes with specific structure
  • C10M2229/041—Siloxanes with specific structure containing aliphatic substituents
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
  • C10N2020/01—Physico-chemical properties
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/08—Hydraulic fluids, e.g. brake-fluids

Definitions

• Glycol ether base agents are typical examples of convention hydraulic oils used in automotive brake and clutch systems.
• the drawbacks of a glycol ether base hydraulic oil include the significant decline in both the boiling point and the temperature at which vapor lock occurs when the hydraulic fluid contains water either absorbed from the environment or introduced by accident.
• a large number of hydraulic oils with a silicone oil principal agent or base have been proposed to date.
• dimethylsilicone oils have been recognized as a hydraulic fluid and in particular as an automotive brake fluid because they exhibit a relatively insignificant variation in viscosity over a wide range of temperatures, a low solidification temperature and a high boiling point.
• the present invention relates to a hydraulic fluid comprising a methylpolysiloxane oil containing siloxane units of general formula (CH 3 ) a SiO (4-a)/2 where a is 1, 2, or 3 wherein said methylpolysiloxane oil has a specific gravity of 1.02 or greater at 25°C.
• the present invention also relates to a process of transmitting power from one place to another via a hydraulic fluid medium where the hydraulic fluid medium comprises a methylpolysiloxane oil containing siloxane units of general formula (CH 3 ) a SiO (4-a)/2 where a is 1, 2, or 3 wherein said methylpolysiloxane oil has a specific gravity of 1.02 or greater at 25°C.
• the methylpolysiloxane oil of the present invention may be constituted of a single unit or of a combination of two or all three units from among CH 3 SiO 3/2 , (CH 3 ) 2 SiO and (CH 3 ) 3 SiO 1/2 siloxane units. However, it must exhibit a specific gravity of * 1.02 at 25°C and be an oil at room temperature. Under these restrictions, the following four combinations are practical: CH 3 SiO 3/2 units, alone; CH 3 SiO 3/2 units and (CH3)2SiO units; CH 3 SiO 3/2 units and (CH 3 ) 3 SiO 1/2 units; CH 3 SiO 3/2 units, (CH 3 ) 2 SiO units and (CH 3 ) 3 SiO 1/2 units.
• methylpolysiloxane oils of this invention may be readily produced by methods well known in the art.
• these methylpotysiloxanes may be produced by the homo-hydrolytic or co-hydrolytic polycondensation of methylpolysiloxanes or methylalkoxysilanes.
• Preferred methylchlorosilanes include methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane.
• Preferred methylalkoxysilanes include the methylmethoxysilanes and the methylethoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, and trimethylethoxysilane.
• This oil is a satisfactory hydraulic oil and in particular a satisfactory brake fluid because it exhibits an insignificant change in viscosity over a wide temperature range, a low solidification temperature, a high boiling point, as well as chemical stability.
• Trimethylchlorosilane (220 g, 2.0 moles), dimethyldichlorosilane (4,515 g, 35.0 moles), methyltrichlorosilane (1.944 g, 13.0 moles) and toluene (2,000 g) were charged to a 10 L three-necked flask equipped with stirrer, addition funnel and reflux condenser. Water (810 g, 45 moles) was added dropwise over 3 hours with stirring temperatures of * 50 P C. The vigorous evolution of hydrogen chloride was observed. After addition of the water, the mixture was heated to 60°C and then reacted for 1 hour. The reaction solution was combined with 2 L of water, stirred and then allowed to stand and the aqueous layer was subsequently removed.
• This washing procedure was conducted three times in order to remove residual hydrochloride from the methylpolysiloxane-containing layer.
• the methylpolysiloxane containing layer was then heated in order to remove water azeotropically with toluene. Toluene was removed by raising the temperature to 150°C.
• the resulting methylpolysiloxane had a viscosity of 12.6 cSt and a specific gravity of 0.991.
• This methylpolysiloxane was combined with 30 g of acid clay and stirred at 120°C for 5 hours. The generation of water by polycondensation of silanol group bonds in the methylpolysiloxane was observed.
• the reaction solution was combined with 50 g diatomaceous earth as a filter aid and then filtered under increased pressure. The filtrate was subjected to reduced pressure to remove low-boiling compounds. Finally, volatiles were removed at a temperature of 240°C under a reduced pressure of 10mm Hg.
• the product methylpolysiloxane oil (referred to hereafter as A) was colorless and transparent with a viscosity of 56 cSt and a specific gravity of 1.026. Component analysis by Si 29- NMR spectroscopy indicated that this methylpolysiloxane oil contained 4 mol percent of (CH 3 ) 3 SiO 1/2 units, 71 mol percent of (CH 3 ) 2 SiO units, and 25 mol percent of CH 3 SiO 3/2 units.
• the methylpolysiloxane (A) had a 1.7 9 Me/Si ratio.
• a co-hydrolytic polycondensation of methyltrichlorosilane (790 g, 5.3 moles), dimethyldichlorosilane (682 g, 5.3 moles) and trimethylchlorosilane (2,170 g, 20 moles) was prepared by a method identical to that used for methylpolysiloxane oil (A) to produce methylpolysiloxane oil (B) with a viscosity of 744 cSt and a specific gravity of 1.084.
• methylpolysiloxane oil (B) contained 10 mol percent of (CH 3 ) 3 SiO 1/2 units, 45 mol percent of (CH 3 ) 2 SiO units, and 45 mole percent of CH 3 SiO 3/2 units and that methylpolysiloxane oil (C) contained 80 mol percent (CH 3 ) 2 SiO units and 20 mol percent of CH 3 SiO 3/2 units.
• the CH 3 /Si ratios for methylpolysiloxane oils (B) and (C) was 1.65 and 1.80, respectively.
• dimethylsilicone oil (D) was prepared by the same procedure described above.
• the dimethylsiloxane oil (D) consisted of (CH 3 ) 3 SiO 1/2 units (4 mol percent) and (CH 3 ) 2 SiO units (96 mol percent).
• the dimethylsiloxane oil (D) had a Me/5i ratio of 204, a specific gravity of 0.96, and a viscosity of 50 cSt.
• methylpolysiloxane oils (A), (B) and (C) and the dimethylsiloxane oil (D) was separately combined with 5 weight percent distilled water, agitated by shaking for 10 minutes and allowed to stand for 30 minutes in order to examine the water-oil separation.
• the water and siloxane oil underwent complete separation with the water forming the upper layer.
• the dimethylsiloxane oil (D) separation was observed with water forming the lower level.
• Methylpolysiloxane oil (A) was examined at low temperatures for water resistance according to a test method for automotive brake fluids Japanese Industrial Standard (JIS) K2233.
• JIS Japanese Industrial Standard
• One hundred milliliters of methylpolysiloxane oil (A) was placed in a centrifuge tube to which was added 3.5 ml of distilled water. After shaking for 10 minutes the sample was allowed to settle for 5 minutes at which time the sample was cooled to -40°C. The sample remained at -40°C for 120 hours. After completion of the test the methylpolysiloxane oil (A) was found to have remained transparent. The water, which was totally located above the siloxane oil (A), was frozen. The test tube was then turned upside down.
• test method JIS K2233 requires that such an air bubble reach the surface of the test brake fluid in a time of less than 10 seconds.
• a similar test was performed on dimethylsiloxane (D). After completion of this test a part of the water was found to have solified within the siloxane oil (D) and remain suspended therein and a part of the solified water had settled out.
• the metal corrosiveness and styrene butadiene rubber (SBR) swell of methylpolysiloxane oil (A) and dimethylsilicone oil (D) were also evaluated by the methods of JIS K2233. Each oil was combined with tributyl phosphate (5 weight percent) as a rubber shrinkage inhibitor before testing. Metal corrosiveness was determined using a clean panel (80 x 13 mn) of the appropriate metal. The metal panel was placed in the siloxane oil at 100°C for 120 hours and any changes in weight were noted. The rubber swell was determined by immersing the SBR cup at either 70 or 120°C for 70 hours.-The cup was washed with ethanol and the physical properties determined. The results are reported in Tables 1 and 2. As compared with dimethylsilicone oil (D), methylpolysiloxane oil (A) satisfied the properties of an automotive brake fluid in every measured respect.
• SBR styrene butadiene rubber

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Silicon Polymers (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=15520895

Family Applications (1)

Country Status (2)

Cited By (4)

Family Cites Families (2)

• 1982
  • 1982-08-31 JP JP57151547A patent/JPS5941394A/ja active Pending
• 1983
  • 1983-08-31 EP EP83108576A patent/EP0102088A3/fr not_active Withdrawn

Also Published As

Similar Documents

Legal Events