Note: Descriptions are shown in the official language in which they were submitted.
r, D. ~a!~r 2~229~
- FE~ ~
Tel.4701 /p~ o,z. 4410
H~LS AXTIENGESELLSCHAFT
- PATENTABTEILUNG -
Hydraulic fluids
The invention relates to flame resi~tant hydraulic fluids
S which are ecologically saf~ and have lubricating
propertie~.
Hydraulic ~luid~ based in particular on mineral oils are
in common u~e. However, in mining, for safety reason~,
flame resistant hydraulic-fluids are neces~ary and these
are used in a large number of applications, for example
in coal cuttins machines, tunnelling ma~hines, turbo
couplings and hydraulic prop~. However, even outside the
mining industry, flame resi~tant fluid~ are preferred
wherever disa~trou3 fires could be cau~ed by the e~cape
of combustible media from the closed hydraulic sy~tem.
The current flame resistant hydraulic fluid~ are in
particular aqueous sy3tems, either oil-in-water emul~ions
(HFA) or glycol-polyglycoI-wat2r mixtures (~FC). The
chief disadvantage of the o/w emul~ions i8 that they are
metastable ~y~tems which can become critical in par-
ticular owing to temperature variation~ and electrolyte~
(D~-A-3,508,946). Where thickened ~ystem~ are concerned,
such a~ are reguir~d to avoid le2kage 108~e8 from the
seal~ in pump8 and valve~ and to form lubr~cattng films
be~ween solid surface~ in fric~lonal contact, the
po1ymers used u3ually have little ~hear stability, if
any.
.
HFC fluid~ ba~ed on monoglycol~, oli~oglycol8 or poly~ly-
col~ have, in addition to ~ub3tantial flam~ resi~tance,
~0 the advantage of being physiologically harmles~ and
ecologically acceptable (P. Lehringer, ~rd~l un~ ~ohle-
Erdga~-Petrochemie 41, 230 (198B)3, which i8 particularly
advanta~eous in mobile application. where leakage~ of
hydraulic fluid often ~eep i~to the 80il- These syst~ms
' . , ~ ''`
', ' ,
2~2~
- 2 - o.Z. 4410
are al~o considered to be substantially Rhear-stable,
which however can be viewed a~ a critici~m ~ince u~ually
particularly those polymers making the greatest contribu-
tion to the overall vi8c08ity of the fluid which are most
liable to shear damage owing to their chemical stxucture.
A further disadvantage of the current HFC fluids i~ that
the pxoportion of active ingredient must be very high 80
that a minimum vi8c06ity i8 retained even a~ Romewhat
elevated temperature~. Water content~ < 50% are quite
typical h~re (C. Rasp, Tribologie Schmierungstechn. 35,
185 (1988)). Moreover, the additive packages ~or produ-
cing good lubricating and anti-wear action~ are ve~y
comple~ in these fluids.
The ob~ect i8 therefore to provide flame resistant,
ecologically safe hydraulic fluids which have an adequate
vi8c08ity and a ~ood lubricating action at low concentra-
tion3 of active ingredient.
This ob~ect i3 achieved by aqueous hydraulic fluids which
are ba~ed on an aqueous surfactant solution.
The invention accordingly provides aqueou~ hydraulic
f luids which are characterized in that they contain 5
30% by wei~ht of alkylpolyglyco~ide, 0 to 20% by w~ight
of ~urfactant additive~, 0 - 10% by weight of non-
~urfactallt additive~ and water 1;o 100% by weight, the
proportion o~ act$ve ingredient being at mo~t 40% by
weight .
Surpri~ingly, it ha~ been found that alkylpoly~lyco~ides
have, both alone at relatively l~w concentrations and
el~e in the presence of other surfactants, a particular-
ly high vi8co~ity levQl coupled with a very good lubri-
cating action.
Alkylpolyglycoside~
The alkylpolyglycoside~ ussd according to the inv~ntion
~2~
~ 23443-436
3 - ~.Z. 4~10
conform to the general formula (I)
R-0-Z~, (I)
in which R represents a linear or branched, saturated or
un~aturated alkyl radical having 8 to 20, preferably 3 to
18, carbon atom~ and Z~ rapresent~ an o1igoglyco~ide
radical with on av~ra~ n = 1 to ~0, preferab1y 1 t~ 5,
hexose unit~ or pento~e unit~ or mix~ure~ ~hereof.
ThQ alkyloligo~lyco8id~ u8~d accord~nq to the invent~on
can be pr~pared who11y or pa.rtly baRed on renewable raw
materL~I 18, by Xno~im proces~ . For ~x~mple d~extrc~83 i~
reac ~d ~n th~ pre~ence of an acidic cataly~t with
n-butanol to form butylo11goglyco~ide mixtures which are
convertad ~ith long-ohain ~lcoho1s, li~ewise i~ the
presence o~ ~n acidlc c~t~ly~t, to form tho desired
~lkyloli~oglyco6ide mixturas. ~e formula of the products
can vary within certain lim~ ts . The alkyl radical ~ i~
determined by the choice of long-chain alcohol. It i~
advan~ageou~ on econo~ic ground~ to u~e ~ndu~trially
acce~sible surfactant alcohol~ having 8 to 2Q carbon
atom~, ~or example oxo ~lcohols, Zieqler alcohols and
natural a1cohols fro~ the hydrog~nation of fa~ty acid~
and fatty acid derivativos.
The oligoqlyco~yl radical Z~ i~ detormined on tha on~ hand
by the ~eleatlon of the carbohydrate and on the other
hand by the re~ulatio~ o~ the average degree of
oligo~erization n, ~or example accordin~ to ~-A-
1,943,689~ In principle, lt i~ po~ible to ¢onvert known
: poly~accharides, ollgo~acc~aride~ and ~ono~acch~rid~ ~or
exa~ple ~tarch, maltodextr~n, dextrose, galactoae,
mannose, xylo~e and ~o on into alkyloligoglyco3ides.
Parti~ul~r prefere~ce i~ given to the indu~tr~ally
~ccea~ible c~rbohydra~e- ~tnrch, mal~odextrln ~nd dex-
troD0. S~nce the industrially relevant alky1polygly-
co~ida-~ynthe~es are not reyio-3electlve or ~toreo-
selective the alkylpolyglycosldes are always ~ ures ofol~go~era which in turn ar~ m~xtures of different i~ome-
ric atructuxe~. Pyrano~e and furano~e ~tructures are
~2~
4 _ o.z. 4410
present side by side, with ~- and ~-~lycosidic linkages.
Even the linkage po~itions differ between pair~ of
saccharide radical3.
Depending on the method of synthesis, the alkylpolyglyco-
sides may also contain associated substances such as
resi~ual alcohol~, monosaccharides, oligosaccharide~ and
oligoalkylpolyglycosidesO
Suractant additi~e~
~he 1~me resistant hydraulic fluids according to the
invent~on can moreover contain up to 20~ by weight of
~urfactant additives which are selected from the follow-
ing compound~ or are composed of mixtures of these
compound~:
a3 Alkylbenzene~ulphonate~ordialkylbenzenesulphonate6
of the fonmula (II)
~(R1)C~H3SO3M (II~
in which R denotes a branched or unbranched alXyl
radical having 8 to 20 carbon atom~, Rl denotea
hydrogen or a branched or unbranched alkyl radical
having 1 to lO carbon a~om~, where the total number
of carbon atom~ in R and R1 i8 at le~st 8, preferab-
ly 10 to 18, and ~ denotes Na, R, ammonium or alkyl-
amm~nium.
b) Alkane~ulphonates and/or olefin~ulphonates of the
formul~ (III)
R''SO3M' (III)
in which R'' denotes a saturated or unsaturated, branched
or unbranched alkyl radical havinq 8 to 20 carbon atoms
and M' denotes Nat R, ammonium or alkylammonium.
c) Pe~roleumaulphonate~
d~ Fatty alcohol derivatives or alkylphenol derivatives
of the following foxm~la (IV3:
~22~
,
5 - O.Z. 4410
[R' ' ' (C~H4~lO(R~ ' ' 'O)y3zU~I ~ ' (IV~
in which R' ' ' denotes a saturated, branched or
unbranched alkyl .radical having 6 to 20 ~ preferably
8 to 16, carbon atoms, x = O or 1, R'''' denote~ C2H"
or C3H6~ y i5 0 S;O 15, Z iB 1 or 2, U denote~ SO3,
CH2COO, CHCOO~ ~v is 0 or 1 and ~' ' denote~ H, ~a, R,
a~noni~lm or alkyl a~anoniura.
e) Other ~urfactant additi~re~s are carbo~sylic acid~ with
~elati~ely long, branched ~r ~nbran~::he~, saturat~d
or un~aturated hydrocarSon chains and alsc~ par~ial
e~ters of pho~phoric acid in particular those of
alcohc>ls or of fatty alcohol ethoxylate3 or of
allcylphenol ethoxylate~. The latter can be prepared
~y reacting the relevant alcohol~ or oxyethylat~s
with phosphoric acids, pho~phoru~ oxides or phosphs~-
rus halides.
Finally, cationic ~urfactant~ ~uch as quaternary ammonium
compound also have advantaqeou effects as additive~ to
alkylpolyglyco~ides in aqueou hydraulic fluid~, for
example a pronounced improvement in the lubricating
propertie~ .
Non-surfactant additives
Suitable non-~urfac:tant additive~ in the hydraulic fluid3
~ ~ accordLng to the invention are amines or alkanolamine~
used as pH regula~orB or corros~oA inhibitor~; sodium
molybdate, ~oric acid aminoe~ters, ben20triazole or
toluenetriazole likewi~e a~ corrosion inhibitors;
morpholine or ~-methylmorpholine a~ vapour pha~e inhi-
bitor~ cone antifoam~ or other antifoams; glycol
and/or glycol ether~ or urea as solubility promoter~ and
optionally water ~olubla polymers for ad~u~ting the
temperature profile of the vi~co~ity and also
pre~ervative~.
Be~ides water a~ the aolvent, the hydraulic fluid accor-
- 6 - o.z ?'~
ding to the invention iB based on alkylpolyglycoaides, a
toxicologically harmle~ class of surfactan~s having
excellent biodegradability (95 to 97~ by weight coupled
unit test, DOC). 3 to 30% by weight, preferably 5 to 25%
by weight, of alkylpolyglycoside are present in the
fluids according ~-o khe invention and the total concen~
tration of active ingredient~ is at mo3t 40~ by weight,
preferably 35~ ~y weight.
~he hydraulic fluid~ according to the invention are
u~ually clear in the temperature range between 5 and
80DC, or may be ~lightly opale~cant in the presence of
silicon~ antifoams. The fluids are usually rendered
weakly alkaline.
The following example~ are intended to describe the
fluid3 and trade marks signify the following typ~s of
compound:
MARLON^ A i6 the ~odium salt of a linear C10-C~3-
alkylbenzene~ulphonic acid (Huls AG)
MARLON~PS is the aodium ~alt of a C~3-Cl~-paraffin-
sulphonic acid (HU1B AG)
Polymekon 730 i~ a silicone antifoa~ (Goldschmldt AG)
~.
A 15% by w~ight ~olution of Cl2-C13-alkylpolyglycoside
~av~ra~e DP 1.7, determined via lH-NMR) i8 prepared 1n
deionized watsr. The vi~co~ity behaviour of the solu~ion
(rotational vi~co~eter~ Haake RV 20, M 5, 50C, ~hear
rate rang2 30-300 ~ec~~) i8 newtonian and the visco~ity i~
about 150 mPa.~. Repeated ultra~ound bombardment
(Telsonic USG 1000, 20 kHz) for periods of 10 minutes did
not ~lter the vi~co~ity and confirm~ the expected shear
~tability of the 8y8tem. The clarification temperature of
the ~olution i0 10C. The solution undergoes no optical
change with increasing temperature (up to 80). The wear
characteristics (lubricating action) of the solution were
~C~S3~
- 7 - O.Z. 4~10
investigated using the Reichert fric~ional wear balance
(weight 108s of the test rolls after a frictional path of
100 m under a load of 1500 g). The average of 3 test runs
was 6.6 ~ 0.5 mg at a specific ~urface pre3sure of
2400 N/cm2. No foa~ing was ob~erved during the wear
mea~urement. Comparati~e wear tests with deionized water
on the one hand and ~cubasol Hydro~h~rm~ 36 ~glycol-based
hydraulic fluid) on the other hand gave, under the same
conditions, weight losses of 66 and 6.9 mg. Comparison of
~e results demonstrate~ that even a 15% by weight
solution of the alkylpolyglycoside ha~ not only an
adequate viscosity le~el ~ut also pronounced lubricating
properties.
Example 2
A 15% by weight solution of N-C12-C18-N,N,N-trimethyl-
ammoni~m chloride in deionized water ha~ a low viscosity
(about 1 ~Pa.s) at 50C and its anti-wear effect, deter-
mined as in Example 1, is only moderate with a weight
10s8 figure of 34.5 mg. HoweYer, if half of the
quaterna~y ammonium compound i8 replaced by Cl2-Cl3-alkyl-
polyglycoside (average DP 1.7~, a pronoun~ed lubricati~g
action re~ults, with a weight loss of 10.9 ~ 0.6 mg,
while he viscosity remains almost uncha~ged and the
clarification temperature increases from +2C to +5C.
~xampl0_~
A 10~ by weight solution of C1~-Cl~-alkylpolyglycoside
(aver~ge DP about 1.3) in deionized water ha~ newtonian
flow behaviour and a viscosity of 70 mPa.~ at 50C. The
investigation of the wear behaviour carried out as in
~xample 1 gave a weight lo~ of the test piece of 15 mg.
~xamples 4 to 13 [~ables)
The relev~nt examples demonstrate the effectivenes~ of
the mixture~ according to the invention wi~h regard to
the viscosity level and antiwwear properties. The ultra-
- 8 - O.z. ~410
sound bombar~ment carried out with the solutions
corresponding to Example 4 and 10 (2 exposures of 10
minute~ with the viscosity being determined after each
exposure) demonstrates complete shear stability of the
structures producing elevated viscosity. Examples 11 and
12 demonstrate the effectiveness of the mixtures accord-
ing to the invention in waters of different hardne~se~
(calcium hardness).
2~2~
_ g _ O.Z. ~410
Table 1
Example No. 4 5 6 7 8
Composition
(~ by weight)
, _ _ _ _
Cl2cl3-Alkylpoly- - 8.5 10 7 16
glyco~ide (average DP 1.7)
CloCl~Alkylpoly- 12.5 - - -
glyco~ide (average DP 1.3~
MARLOM A - 8.5 - 7 -
MARLON PS- 12.5 - 10
Triisopropylammonium _ 4 _ _ 4
oleate
Partial e~ter of pho~- _ _ - 4 -
phoric acid wi~h ethoxy-
lated nonylphenol having
7 mol of ethylene
oxide/mol
Polymekon 730 0.15 - - _ _
Isopropanola~ine 3 3 3 3 3
Et~ylane glycol ~ 15
_ _ . .
Vi3c08ity 5~C (c5t) 20 47 4 57 2~
Clarification tempera- _ 3 5 5 3
ture (~C)
pH 8.1 8.6 9.7 8.5 ~2
: Frictional wear4.5 3.7 2.6 2.1 59
testl) (mg~
Foam (DIN 53 902) _ _ *2~
1~ Average from 3 test runs with a friction~l path of
100 m and a surface pressure between 3000 and 5000
N/c3n2
2) The ~a~e test in the pre~encQ of 0.15~ by weight of
Polymekon 730 gives no foam.
`` 2~2~
- 10 - o.z. 4~10
Table 2
Example No- 9 1~ ll2) 123'13
Composition
(~ by weight)
, __ _ _
Cl2C,3-AlkYlPlY- _ 8 13 13 25
glycosid~ (a~erage DP 1.7
Clocl4-Alkylp~ly- 7 _ _ _ _
glyco6ide (average DP 1.3
MARLON A 7 8 - _ _
MARLON PS - - 13 13
Trii~opropylammvnium _ _ _ _ _
oleate Paxtial e~ter of 4 4 _ _ _
pho phoric acid with
eth~xylated nonyl
phanol having
7 mol of ethylene oxide/
mol
Polymekon~ 730 - - 0.15 0.15
Isopropanolamine 3 3 3 3 3
Ethylene glycol - 15 _ _ _
Vi6co~ity 50~C (cSt) 51 21 32 34 71
Clari~ication tempera- 1 5 - - 6
ture (C)
P~ .1 ~.7 8.0 8.1 9
Fxic~ional woar ~8 1.4 2.2 2.3
te~t" (mg)
Foam (DIN 53 902~ _ _ _ _ _
Average from 3 te~t run~ with a frictional path of
100 m and a surface pres~ure between 3000 and 5000
N/cm2
2~ Water with 20 degrees of German hardnes~
3) Water with 50 degrees sf German hardne~.
