CA1103652A

CA1103652A - Oxysilane functional fluids

Info

Publication number: CA1103652A
Application number: CA306,086A
Authority: CA
Inventors: Colin J. Harrington; Herbert F. Askew; Terry J.P. Bridgwater
Original assignee: Castrol Ltd
Current assignee: Castrol Ltd
Priority date: 1977-06-24
Filing date: 1978-06-23
Publication date: 1981-06-23
Also published as: JPS6051517B2; GB1595701A; SE7807146L; DE2827741A1; BE868422A; AU524142B2; IT1097273B; AU3741678A; IT7824927A0; ZA783614B; FR2395308A1; JPS5417386A; FR2395308B1; SE425608B

Abstract

CANADA

ABSTRACT OF THE DISCLOSURE
"FUNCTIONAL FLUIDS "
A functional fluid having particular application as hydraulic fluid, refrigerant oil, electrical oil or heat transfer fluid comprises a major amount of a hydrocarbon oil and a minor amount of an oxysilane compound having the general formula:- wherein:-Rl is alkyl, alkenyl, aryl, alkaryl, aralkyl oralicyclic; R2 and R3 are each independently a group as defined for Rl or a group of the formula - (oR5) - oR6;
R4 is a group cf the formula - (OR )n - OR or a group of the formula:-

Description

11t3~5Z

This invention relates to functional fluids and in particular to functional fluids based on hydrocarbon oils.
The performance of functional fluids based on hydro-carbon oils is often found in practice to be impaired by the presence of water, this problem being particularly acute when such fluids are used as hydraulic fluids e.g.
in aviation or automob-les, or as electrical or refrigerant oils. In hydraulic fluids for example, water may be present as the result of condensation or inadequate drving of the 10 hydraulic system prior to filling or subsequently, by entry through worn seals and it has been found that the effective vapour lock temperature (VLT) of the fluid can be reduced to the boiling point of water even by the presence of Jery minor amounts of water, e.g. of the order of 0. 5-Q . This 15 constitutes a serious deficiency with particularly dangerous consequences in those systems which are brake systems or central hydraulic systems including brake systems.
F~rthermore, in electrical oils the presence of free water increases conductivity and thus promotes electrical discharge 20 and in refrigerant oils water may ~eparate out as ice crvstals.
We have now found that certain silicon compounds are useful as water scavengers in functional fluids based on hydrocarbon oils and may thus alleviate the problems outlined above as previously encountered in the use of 25 such fluids~

According to the present invention there is provided a functional fluid comprising a major amount of a hydrocarbon oil and a minor amount of an oxysilane compound having the general formula:-Rl~ R3 wherein:-(i) Rl is alkyl, preferably containing from 1 to 20,more preferably 1 to 4, carbon atoms; alkenyl, preferably containing from 2 to 20 carbon atoms; aryl, preferably phenyl; alkaryl or aralkyl, preferably containing from 7 to 20 carbon atoms; or alicyclic, preferably containing from 6 to 20 carbon atoms;
(ii) R and R are each independently a group as defined for R or a group of the formula ~ ( oR5 )n ~ oR6 ;
(iii~ R is a group of the formuIa - (OR5)n - OR
or a group of the formula Rl - R7 - Si - R2 wherein R , R and R are independently as defined above;
(iv) R is alkylene, prefera~ly containing from 1 to 15, more preferably 1 to 4, carbon atoms, especially ethylene, propylene o~ butylene; and each R may be the same as or diferent from any other group R ;
- (v) R is alkyl, preferably containing from 1 to 20, more preferably 4 to 18, especially 6 to 15, carbon atoms;
alkenyl, preferably containing from 2 to 20 carbon atoms;
aryl, preferably phenyl; alkaryl or aralkyl, preferably containing from 7 to 20 carbon atoms; or alicyclic, preferably containing from 6 to 20 carbon atoms; and each R may be the same as or different from any other group R6;
(vi) n is zero or an integer, preferably zero or an integer of from 1 to 30, more preferably 1 to 10, particularly 1 to 4; and each n may be the same as or different from any other n; and (vii) R i~ a d rect linkage or a group of the 15 formula - ( oR5 ~tn - wherein R5 and n are independently as defined above, provided that when R is a direct linkage at least one group R or R is a grou~ of the formula -- (oR5 )-- oR6 .
The water scavenginq action of the oxysilane compounds 20 defined above has been found to be improved in the pres2nce of an amine and functional fluids in accordance with the invention which additionally comprise as an optional constituent a small amount, e.g. from 0.5 to 20%, more particularly from 1 to 10%, by weight of an amine are 25 accordingly preferred. Many amines have been found to be s~

suitable, including primary, secondary and tertiary amines, especially those containing a total of at least 5 carbon atoms. Amines which have been found to be particularly B useful include Primene 81 R and Primene JMT which are 5 commercially available primary amines with two methyl groups on the alpha carbon atom.
Other amines which may be useful are Mannich bases formed by condensation of an amine and formaldehyde with a phenol previously alkylated with di- or polyisobutylene;
10 polyisobutenylsuccinimides derived from di- or polyamines;
or amides derived from di- or polyalkylene polyamines and polyisobutenyl substituted monocarboxylic acids.
The amount of oxysilane compound employed in the functional fluids of the invention may vary over a wide 15 range, e.g. from 0.1% to 50% by weight based on the total weight of the fluid.
More particularly, the amount will depend on several factors such as:-(a) the nature of the fluid base-stock;
(b3 the normal use of the functional fluid;
(c) the physical properties required of the finished functional fluid; and (d) the amount of ~7ater likely to be encountered by the fluid in its final use.

~ I f~t~tlf/~' In hydraulic fluids for instance the oxysilane compound would normally be employed in an amount of from 1 to 35%, preferably from 10 to 20~, by weight. On the other hand, in refrigerant oils, electrical oils and heat transfer fluids the preferred amounts of oxysilane compound would generally be somewhat lower e.g. from 0.1 to 5.0% by weight.
The oxysilane compounds employed in the fluids of the present invention may be readily prepared from 10 chlorosilanes by reaction with appropriate hydroxy compounds us~ng well known techniques. A detailed description of such preparative methods is to be found in J. Amer. Chem.
Soc. 80, 1733 (Wright et al) and 68, 70 (Peppard et al).
The hydrocarbon oil used as base-stock in the 15 functional fluids of the invention is preferably a mineral oil, whether derived from crude oil or synthesised from hydrocarbons. Specific examples of such oils are hydrorefined mineral oils and alkylated benzenes.
The functional fuilds of the invention may optionally 20 comprise, e.g. in an amount from 0.1 to 30%, preferably 0.5 to 20%, by weight based on the total weight of the fluid, one or more silane derivatives having the general formula:~
R
R8 _ Si - R10 II
l Rll i~a)3652 wherein:
(a) R8 is a group of the formula R - (OR )m~ OR
(b) each of R9 and R10 is independently alkyl, preferably containing from 1 to 18 carbon atoms, more preferably methyl; alkenyl, preferably containing from

2 to 18 carbon atoms; aryl, preferably phenyl; alkaryl, preferably alkyl substituted phenyl in which the alkyl substituent contains from 1 to 12 carbon atoms; or aralkyl, preferably benzyl; a group of the formula - OR ; or a group of the formula Rl - (oR13)m - ORl -;
(c) R is a group of the formula R12 - (oR13) or a group of the formula:-R - Si - (oR13) oR17 and each R may be the same as or different from any other group Rll;
(d) R12 is alkyl, preferably containing from 1 to 18 carbon atoms; alkenyl, preferably containing from 2 to 18 carbon atoms; aryl, preferably phenyl; alkaryl, prefera~ly alkyl s~bstituted phenyl in which the alkyl substituent contains from 1 to 12 carbon atoms; or aralkyl,preferably benzyl; and each R12 may be the same as or different from any other grsup R
- (e) R13 is an alkylene grcup, preferably containing 1~Lt)36S2 from 1 to 15, more preferably 1 to 4, carbon atoms, especially ethylene or propylene; and each Rl may be the same as or different from any other group R13;
(f) R14 is an alkylene group, preferably containing from 1 to 15, more pareferably 1 to 6, carbon atoms; and each R14 may be the same as or different from any other group R
(gj m is zero or an integer, preferably zero or an integer of from 1 to 4; and each m may be the same as or 10 different from any other m;
(h) each of R 5 and R 6 is independently alkyl, preferably containing from 1 to 18 carbon atoms, more preferably methyl; alkenyl, preferably cor.taining from 2 to 18 carbon atoms; aryl, preferably phenyl; alkaryl, 15 preferably alkyl substituted phenyl in which the alkyl substituent contains from 1 to 12 carbon atoms; o : aralkyl, preferably benzyl; a group of the formula -oR17;
or a group of the formula R - (OR 3)m ~ ORl -; and (i) R 7 is a group of the formula R - (OR )m ~
20 and each R may be the same as or different from any other group R17 The above defined silane derivatives of Formula II
are more fully d~scribed in our U.K. Patent Application No. 48009/75 (e~uivalent to German Offenlegungsschrift 26 S2 71~) to which reference ~ay be ~ade for further )3~Z

details.
It will be understood that the functional fluids of - the present invention may contain small amounts e.~. 0.05 to 20%, par~icularly 0.1 to 2%, by weight of additives conventionally employed in such fluids.
In a further aspect of the present invention there is pro~ided a hydraulic system for transmitting power by hydraulic means which system contains as the hydraulic fluid, a functional fluid as hereinbefore described.
In yet another aspect of the present invention there is provided a method of operating a hydraulic system which comprises introducing into the hydraulic system as the hydraulic fluid a functional fluid as hereinbefore described and transmitting power by applying pressure to 15 the hydraulic fluid.
The invention will now be illustrated by the following Examples:-Examples 1 to 21 Functicnal fluids in accordance with the invention 20 were formulated and subjected to the followin~ tests:-(a) Kinematic viscosities at -40~C, in centistokes (cS!, were measured in the manner set forth in the current SAE J1703 specification;
(b) Rubber swell properties with res~ect to 25 nitrile (HN S7~ and urethane (HU723) rubbers were determined in the manner set forth in the BS 903 il~3~5Z

specification by measuring the increase in volume of 2.54 cm.
square, 2 mm. thick rubber specimens after immersion in the test fluid at 70~C for 3 days.
(c) Vapour lock temperatures were determined by the Gilpin Vapour Lock Test as specified in SAE Paper 710 253 entitled "Operating ~erformance of Motor Vehicle Braking Systems as affected by Fluid Water Content", the Gilpin vapour lock temperature (VLT) being taken to correspond with the appearance of 3 ml of vapour. This test was 10 performed upon fluids which had previously been subjected to a Humidity Test at a relative humidity (RH) of 80% and a temperature of about 23C substantially as described in the FMVSS 116 DOT 3/4 specification but extended to a 5 day period and without a reference fluid.
Details of the oxysilane compounds and propor,ions thereof in the fluids and of the results obtained in the above tests are given in Table l.
In each case the fluid also contained 2~ Primene JMT, a commercially available tertiary alkyl primary amine 20 containing approximately 18 carbon atoms.
The hydrocarbon oil constituting the balance of the fluid was in each case a naphthenic mineral oil having the following characteristics:

10 .

~)3~52 Viscosity:- 130 cS at -40F; 3.5 cS at 100F; and 1.31 cS at 210~F.
Pour Point:~ ~- 70F.
Boiling Point:- 248CC.
Flash Point (closed):- 208C.
Aniline Point:- 76~C.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A functional fluid comprising a major amountof a hydrocarbon oil and a minor amount of an oxysilane compound having the general formula:-I
wherein:-(i) R1 is alkyl, alkenyl, aryl, alkaryl, aralkyl or alicyclic;
(ii) R4 and R3 are each independently a group as defined for R1 or a group cf the formula -( OR5)n - OR6 ;
(iii)R is a group of the formula - (OR5)n - OR6 or a group of the formula:- wherein R1, R2 and R3 are independently as defined above;
(iv) R5 is alkylene; and each R5 may be the same as or different from any other group R5;
(v) R6 is alkyl, alkenyl, aryl, alkaryl, aralkyl or alicyclic; and each R6 may be the same as or different from any other group R6 ;
(vi) n is zero or an integer; and each n may be the 15.

same as or different from any other n; and (vii) R7 is a direct linkage or a group of the formula -( OR5 )n O - wherein R5 and n are independently as defined above, provided that when R7 is a direct linkage at least one group R2 or R3 is a group of the formula -( OR5)n- OR6.

2. A fluid according to elaim 1 wherein Rl and R6 are alkyl containing from 1 to 20 carbon atoms, alkenyl eontaining from 2 to 20 carbon atoms, phenyl, alkaryl or aralkyl containing from 7 to 20 carbon atoms or alicyclic containing from 6 to 20 carbon atoms; R5 is alkylene containing from 1 to 15 carbon atoms; and n is zero or an integer of from 1 to 30.

3. A fluid according to claim 2 wherein R1 is alkyl containing from 1 to 4 carbon atoms.

4. A fluid according to claim 2 wherein R5 is alkylene containing from 1 to 4 carbon atoms.

S, A fluid aceording to any one of claims 2 to 4 wherein R6 is alkyl containing from 6 to 15 carbon atoms.

16.

16.

6. A fluid according to any one of claims 2 to 4 wherein n is zero or an integer of from 1 to 10.

7. A fluid according to claim 1 wherein the oxysilane is selected from:-(i) compounds of the formula (RO)3 - Si - CH3 wherein R is 2-octyl, tridecyl or CH3 - ;

(ii) compounds of the formula (R0) 2-Si- (CH3) 2 wherein R is n-octyl, tridecyl, phenyl or CH3 2 ;

(iii)the compound having the formula (iv) the compound having the formula (v) compounds of the formula (RO) - Si - (CH3) 3 wherein R is 2-ethylhexyl, tridecyl, phenyl or CH3 -;

17.

(vi) the compound having the formula (vii) the compound having the formula ;

(viii) the compound having the formula ; and (ix) compounds of the formula R1 Si(OR)3 wherein R1 is phenyl and R is 2-ethylhexyl, R1 is ethyl and R is 2-methylcyclohexyl, R1 is ethyl and R is benzyl, R1 is vinyl and R is butyl triglycol or R1 is 2,4,4-trimethylpentyl and R is C4H9OCH2CH2-.

8. A fluid according to claim 1 which additionally comprises from 0.5 to 20% by weight of an amine.

9. A fluid according to claim 8 wherein the amine is a primary, secondary or tertiary amine containing at least 5 carbon atoms.

10. A fluid according to claim 1 wherein the hydrocarbon oil is a mineral oil.

18.

11. A fluid according to claim 1 which additionally comprises one or more silane derivatives having the general formula:- II

wherein:
(a) R8 is a group of the formula R12 - (OR13)m- OR14-;
(b) each of R9 and R10 is independently alkyl, alkenyl, aryl, alkaryl, aralkyl, a group of the formula -OR11 or a group of the formula R12 - (oR13)M - oR14 - ;
(c) R11 is a group of the formula R12 - (OR )m-or a group of the formula:- and each R may be the same as or different from anyother group Rll (d) R12 is alkyl, alkenyl, Aryl, alkaryl or aralkyl;
and each R12 may be the same as or different from any other group R12;
(e) R13 is an alkylene group; and each R13 may be The sæme as or different from any other group R13 ;

19.

(f) R14 is an alkylene group; and each R14 may be the same as or different from any other group R14;
(g) m is zero or an integer; and each m may be the same as or different from any other m;
(h) each of R15 and R16 is independently alkyl, alkenyl, aryl, alkaryl, aralkyl, a group of the formula -OR17 or a group of the formula R12 - (OR13)m - OR14 -;
and (i) R17 is a group of the formula R12 - (oR13)m -and each R17 may be the same as or different from any other group R17.

12. A fluid according to claim 11 wherein each of R9 and R10 is independently alkyl containing from 1 to 18 carbon atoms, alkenyl containing from 2 to 18 carbon atoms, pheNyl, alkyl substituted phenyl in which the alkyl suBstituent contains from 1 to 12 carbon atoms, benzyl, a group of the formula -OR11 or a group of the formula R12 - (OR13)m -OR14 -; R12 is alkyl containing from 1 to 18 carbon atoms, alkenyl containing from 2 to 18 carbon atoms, phenyl, alkyl substituted phenyl in which the alkyl substituent contains from 1 to 12 carbon atoms or benzyl;
R13 is an alkylene group containing from 1 to 15 carbon atoms; R14is an alkylene group containing from 1 to 15 carBon atoms; m is zero or an integer of from 1 to 4; and 20.

each of R15 and R16 is independently alkyl containing from 1 to 18 carbon atoms, alkenyl containing from 2 to 18 carbon atoms, phenyl, alkyl substituted phenyl in which the alkyl substituent contains from 1 to 12 carbon atoms, benzyl, a group of the formula -OR17 or a group of the formula R12 (OR13) - ORl4 -.

13. A fluid according to claim 11 or claim 12 wherein the silane derivative of formula II is present in an amount of from 0.5 to 20% by weight, based on the total weight of the fluid.

14. A fluid according to claim 1 wherein oxysilane compound of formula I is present in an amount of from 1 to 35%
by weight based on the total weight of the fluid.

15. A fluid according to claim 1 wherein oxysilane compound of formula I is present in an amount of from 0.1 to 5.0% by weight.

16. A fluid according to claim 1 which additionally comprises one or more additives conventionally employed in hydraulic fluids, refrigerant oils, electrical oils or heat transfer fluids.

21.