DE2244083A1 - PHOSPHATE-BASED HYDRAULIC LIQUIDS PROTECTED AGAINST OXIDATION - Google Patents

Description

ORrINQ. HANS H. PONTANI Patent attorney Kleinoslheim near Asthaffenborg Hirschpfad 3 - Tel. 06027/325

6. 2244093

Stauffer Chemical Company, Dobbs Perry, New York 10522 / USA

Hydraulic '' protected against gradation ! Phosphate-based liquids

The present invention relates to functional fluids with superior protection against oxidation; In particular, the present invention relates to functional "liquids." who use phosphate esters or amides as raw materials, incorporating a combination of a hydrogen phosphate ester and a hindered phenol.

It has been found that the oxidative stability of liquids based on phosphate esters and amides unexpectedly can be improved by including a synergistic combination of a hydrogen phosphate in this and a hindered phenol.

Those suitable for use in the present invention The basic substances of functional fluids are those Esters and amides of an acid of phosphorus represented by the general structural formula

It

R- (Ι) _α -Ρ - OC ₁ ) OH ₂ -

- 2 -

are characterized, viobei Y oxygen, sulfur and E --- IT, Y, oxygen, sulfur and R ^ -ii, Yp is oxygen, sulfur and Re-N, R, R ₁ , R ₂ , E ,, R ^ and R ₁ - denote alkyl, aryl, substituted alkyl and substituted aryl and can be the same with regard to the other radicals. or be different? a, b and c are integers with the value 0 to 1 and the sum of a + b + c is 1 to 3.

Typical examples of alkyl radicals are: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-amyl, isoamyl, 2-methylbutyl, 2,2-dimethylpropyl, 1-methyl-butyl, diethylmethyl, 1,2-dimethyl-propyl, tert-amyl, n-hexyl, 1-methylamyl, 1-ethyl-butyl, 1,2,2-trimethyl-propyl, 3,3-dimethyl-butyl, l, l, 2-'J} rimethyl-propyl, 2-methyl-amyl, 1,1-dimethyl-butyl, 1-ethyl-2-methylpropyl, 1,3-dimethyl-butyl, isohexyl, 3-methylamyl, 1,2-dintibhyl-butyl, 1-methyl-1-ethyl-propyl, 2-ethyl-butyl, n-heptyl, 1,1,2,3-tetramethyl-propyl, 1,2-Mmethyl-ethyl-propyl, 1,1,2-trimethyl-butyl, 1-isopropyl-2-methylpropyl, l-methyl-2-ethyl-butyl, 1,1-diethyl-propyl, 2-methyl-hexyl, 1,1-dimethyl-amyl, 1-isopropyl-butyl, l-ethyl-3-methyl-butyl, 1,4-dimethyl-amyl, isoheptyl, 1-methyl-l-ethyl-butyl, l-ethyl-2-methyl-butyl, 1-methylhexyl, 1-pi'opyl-butyl ^ n-octyl, 1-methyl-heptyl, 1,1-diethy, l-2-methyl-propyl, 1,1,3,3-tetramethyl-butyl, 1,1-di- -butyl, 1,1-dimethyl-hexyl, 1-methyl-1-ethyl-amyl,

"bad 309812/0866

1-Kethyl-1-propyl-butyl, 2-ethyl-hexyl, 6-methyl-heptyl (1-cooctyl), n-1 ^{:. r} onyl, 1-methyl-octyl, 1-ethyl-heptyl, 1, l ~ Drmetliyl-heptyl, 1-ethyl-l-jn? opyl-butyl, 1,1-diethyl-3-taethyl-butyl, diisobutyl-methyl, 3.5 ₅ 5- ^r toitflethyl-hexyl, ~ j , S-dimethyl-heptyl, ii-decyl, 1-propyl-heptyl, 1,1-diethylhe :: yl, l _} l ~ dipropylbutyl., 2-isopropyl-5-diethyl-'he3iyl and ΰη -, -G-, o-alkylgxuppeii. Also included are aralkyl groups, such as bensyl, α- or β-phenylethyl, α-α-l-dimethylbeijüyl uria and the like. Cyclohexyl, cyclohexyl and the like are also included.

• Typical examples of substituted alkyl radicals the Hai ο geiialky Ir adikal, which by the structure form el

: iedergepebeii? ierden, '.-. ^r obei Hai halogen means, Ii ". • nni.jer? or is equal to 2 n + 1, η can be a fourth from O to Io ^Ί .ΐ and IL- and 3U hydrogen, halogen or JkI-" xylraa.ilir .le? - ■ a can. Population are radicals in which "IaI fluorine is and includes those that are given by the fol-foi.Tüeln :: iede:":

S ₆

,1,

309812/0856

^! 6th

«6

= 6

30Ö812 / 0856 " ⁵ -

■ ^H 6 O ₂ H ₇ O CH ₂ -CF ₂ GF ₂ G-

-, O GH ₁ CF ₂ CF ₂ G-

O ₀ H _n -OOH ₀ OF ₀ OF ₀ OB ^ O-

C ₇ H ₀ OGH ₀ CF ₀ OF ₀ OF ₀ C- / 2 H 2 2

O GH ₂ CF ₂ OF ₂

O ₅ II ₁₁

° 6 ^Η 13

0 _Ζμ Η ₉ 00Ή (ΟΪ ₂ ) ₄ 0-

CL

OJP ₅ (C ₈ H ₁₇ ) C-

(CIV,) _{/ f} C- U ₃ H ₇ OUIL ₁ (OF ₂ ) _{/ μ} Ο

b (-j

ι ι

«6 ι

Cf ₅ Cf ₂ (O ₃ H ₇ ) O- Cf .CF ₂ (C ₄ II ₉ ) 0-

H- it.

6th b

1 1

308812 / 0Θ56

¹ V b

^H 6 %

1 t

GF - ^ (CF, J ₂ (G ₂ H _n ) G- -CF ₃ (GF ₂ ) ^ C ₃ H ₇ ) C-

b 6

t I

; .CT- (Of Jj) ₂

CF ₃ (GF _£ ) ₂ (G ₈ H ₁₇ ) G- CF ₅ (CF ₂ J ₅ (G ₂ H ₅ ) C-

CF, (CF _p ) - (G ₄ Ho) C-

^il 6 · "ο

I .1.

309812/0856

^E 6

^H 6

= 6

OT ₃ (CF ₂ VC ₂ H ₅ ) C- CT ₃ (CP ₂ ) ^ (O ₃ H ₇ ) O-

^E 6 ^H 6

₅ (CFg) ₅ (C ₅ H ₁₁ ) C- CF ₃ (CF ₂ ) ^ (C ₆ H ₁₅ ) C-

309812/0856

\ ■ '■ "■ ' - ■■■%

) C- CF _x (CF ₀ ) C- (CQH _{n π} ) C-

CF ₃ G (O ₂ H ₅ ) ₂ -

uobei Eg and H ₁ -, which have the meaning described above *.

The halogenated alkyl radicals can be primary, secondary or be tertiary .. - ■ "-" ■

Other suitable fluorine containing radicals include fluorinated alkoxyalkyl radicals, especially those by the the following formulas:

^Η 6

R ₇

■ ■ _ 10 -

309 812 / 08B6

H _n

B ₇

C ₂ H ₅ OCU ₂

H.. b ι

¹ V

J ₆ H ₁ ^ OGH ₁ GF ₂ GP ₂ C- G ₂ H ₅ OGH ₀ CF ,, CF ₀ CF ₂ Ο

ι ι

H ₉ R-

^Ά 6 ^Η 6

ι ι

G ₇ H ^ OCH ₀ CF ₀ CF ₀ CF ₀ C- 0,, FUOGiI ₀ GF, GF ₀ CF ₀ C-

J / ε. d. cL cL . y cddc

^{± X} 6 ^{± X} 6

I I

JL-, ι w \ yj.j. _o \ ^ jL- _o v / j; _o wJc _O 0— Ο ^ -ϋτ -UOU ₀ OJJ - L / ΰ , -. Gi! _o 0—

2 2 2 2 6 I9 d ei 2 £:

I I

^H 6 ^H 6

I I

OCH _o (GF ₂ ), G-

^£ Ϊ09812 / 0856

^7th - 1:

"where H ^ and Ii-, have the meaning previously described.

It is also within the scope of this invention that Hydrogen and fluorine in the haloalkyl radicals described above by other halogens, such as chlorine or bromine, can be replaced. ·

Typical examples of aryl and substituted aryl radicals are: phenyl, alkoxylated phenyl, by iilower alkyl radicals substituted phenyl, phenyl, cresyl and xylyl, which is phenyl or substituted phenyl partial or complete hydrogen present. was replaced by a halogen, o-, m- and p-'Jrifluormethylphenyl, o-, m- and p-2,2,2-trifluoroethylphenyl, o-, m- and p-3,3,3-Ii'ifluorpropylphenyl and o-, m- and p-4,4-, 4-'-hrifluorobutylphenyl. Are exemplary too Isopropylphenyl, butylphenyl, α-alkylbenzylphenyl and α, α-dialkylbeiizylphenyl, e.g. α-methylbenzylphenyl, α, α-dimethylbenzylphenyl. . .

The preferred bases for the present Invention are: 'Ir-ialkylphosphate, in which the alkyl group Has -4 to 20 carbon atoms; Triaryl phosphates, in which the aryl group is phenyl, cresyl, xylyl, isopropylphenyl and / or a-methylbenzyl; mixed alkyl aryl phosphates, i.e. aryl dialkyl phosphates and alkyl-diaryl-phosphates, in which the alkyl groups have 4 to 8 carbon atoms and the

308812/0858 -12

Aryl groups phenyl, cresyl, xylyl, isopropylphenyl and α-methylbenzylphenyl. The most preferred Phosphates for the present invention are: ö? Ri butyl phosphate, Trihexyl phosphate, tri- (n-butyl) phosphate, tri- (2-ethylhexyl) phosphate, Tridecyl phosphate, tricresyl phosphate, üirixylyl phosphate, cresyl phenyl phosphate, xylyl cresyl phosphate, XyIyI-phenylphosphate, isopropylphenylphenylphosphate, α-methylbenzyl phenyl phosphate, diisopropyl phenyl phenyl phosphate, Biphenyl-phenylphosphates and their mixtures.

The mixed aryl esters mentioned above are also said to be the Complex mixtures of the phosphates comprise the aforementioned particular aryl groups in various ratios contain. Isopropylphenyl-phenylphosphate is said to be • the reaction product of phosphorus oxychloride and a Mixture of phenol and isopropylphenol, the phenols being used in any weight ratio, lock in. This product is a mixture of triphenyl phosphate, Triisopropyl phenyl phosphate, phenyl bis (isopropylphenyl) phosphate and isopropylphenyl diphenyl phosphate.

The antioxidant of the present invention contains a hydrogen phosphate ester or its amine salt. Of the The term "phosphate ester" as used herein is intended to include the dialkyl hydrogen phosphates and the alkyl dihydrogen phosphates and their amine salts. These connections correspond

309812/0856

13.-

the general formula

-H ₈ O - P

OA

-OA-,

where Hn is an alkyl group with 1 to 20 carbon atoms, A is hydrogen, an alkyl group having 1 to 20 carbon atoms, a heterocyclic amine or an amine cation of general! formula. "- ,."

I.
I.

H-

is, in which H ¹ , R "and R ^{111 are the} same or different and represent a CV to Cp _O -alkyl radical, an aryl radical or hydrogen and A ^{1 is} A or a C- to C2Q-alkyl group. These compounds belong - to the state of the art and are commercially available as mixtures of the alkyl dihydrogen phosphates and the dialkyl hydrogen phosphates or their salts. Examples of these substances are the following: dodecyl hydrogen phosphate, methyl isostearyl hydrogen phosphate, tridecyl dihydrogen phosphate, p-gresyl isostearyl hydrogen phosphate, their amine salts, their mixtures and the like.

309812/0866

A preferred one for use in the present invention Alkyl hydrogen phosphate is a mixture of the acidic Dodecyl phosphate sold under the trademark "'OJuHEOLELfH" by the E.I. du Pont de Uemours, Inc., Wilmington, DeIaware, is put on the market. This alkyl hydrogen phosphate mixture has the properties listed in Table I:

Table I.

Specific gravity (15.6 ⁰ G) 0.98

kg / 1 (pounds / gallon) at 15.6 ⁰ O 0.98 (8.1?)

Color, ASTM 11.0

Acid number, (mg KOH / g) 270.

Phosphorus, weight percent 10.1

Sulfur, wt .- # 0.0 Viscosity:

SUS cST 580 81 64 11.6

Temperature ( ⁰ C) ( ⁰ P)

37.8 (10U)

98.9 (210)

Viscosity index 150

Pour Point ⁰ G ( ⁰ F) below -17.8 (below 0)

Freezing Point, ⁰ G ( ⁰ F) 11.7 (55)

Flash Point ⁰ C ( ⁰ F)

(Cleveland tester) IbO t '^ 20)

Fire Point ⁰ C ( ⁰ F)

(Cleveland tester) 182 (56ο)

Curing temperature ⁰ C ( ⁰ F) 179.4 over 55)

- 1'' -

309812/0858 bad original

The other essential ingredient in the antioxidant of the present invention is a hindered phenol. The term ^{liier; l} it prevented phenol ".soll diejenigen- substituted phenols denote the least eil" fine ο alkyl group having up to 8 carbon atoms on the Pheuylr-ing in adjacent positions to HydrojLylgruppe having -.- ".Obgleich any of the known antioxidants to - Based on hindered phenols can be used in the context of the present invention, it has proven to be particularly advantageous to use a bisphenol which is hindered _{via an alkylene group L .cbuiidenes.} The expression "hindered biophenol bonded via an alkylene group" is intended to be compounds of the general formula

denote, in which H ₀ and E-, ~ are identical or different and are branched-chain alkyl groups with 3 to 8 carbon atoms, H -, -, and E-, ~, - are the same or different and stand for hydrogen or alkyl groups with 1 to 8 carbon atoms. Each of the hydroxyl groups is in the position of at least one of the branched-chain alkyl groups. As stated above, these compounds belong to the state of the art ". Of the preferred,.

Hindered bisphenols bound via an alkylene group

309812/0866 ^ _om , _m _ _

Those in which R -, -, and R, p are hydrogen, ie hindered bisphenols bonded via a methylene group, and those in which Bq and R-jQ are alkyl groups with 3 to 5 are particularly suitable for the present invention Carbon atoms are. These connections can be represented by the following examples:

4,4'-methylene-bis- (2,6-di-tert-butylphenol), 4.4 ^l -methylene-bis- (2,6-di-tert-amylphenol), 4.4 ^l -methylene -bis- (2,6-di-isopropylphenol), 2,2-methylene-bis- (3-tert.-butyl-6-isopropylphenol), 4,4'-methylene-bis- (3-tert.- butyl-6-isopropylphenol), 2,2'-methylene-bis- (3,4-di-tert-butylphenol)

and their mixtures.

The antioxidant combination of the present invention is used in an amount sufficient to stabilize the basic substance against oxidative degradation. In most cases the amount of hindered phenol is from about 0.1 to about 11% by weight based on the matrix and preferably from about 0.5 to about 2 %. The Hydrogenphosphatester or the amine salt is present in amounts of from about 0.005 to about 3 wt .-%, - © rzugsweise from about 0.01 to about 0.1% _t percentage of the basic substance present. Of course, for the purpose of iCransport

- 17 - ■■

309812/0866

■ and storage, a concentrate of the basic substance and the antioxidant combination can be produced, which can then be diluted with additional basic substance before use in order to adjust the concentration of the antioxidant combination to the desired range. For example, a base substance concentrate with 10% by weight of a hindered bisphenol bound by an alkylene group and 0.5 % hydrogen phosphate ester or amine salt can be prepared and later diluted with 9 parts base substance per part concentrate to reduce the antioxidant concentration to 1% or .05% decrease. .

The liquids of the present invention can additionally contain known additives, such as ash-free dispersants of the alkoxylated alkylphenol type, metal inactivators such as benzotriazole and Ν, Ν'-disalicylidene-1,2-dipropane diamine, antifoams such as methylsilicone and the like. The liquids also contain of the present invention normally viscosity index (VI) improvers in an amount up to about 10% by weight. Any VT are improver compatible with the basic substance of the present invention, i @ t _f * used. It has been found that it is most advantageous to use the polymers and copolymers of the 0 to Coq-alkyl esters of acrylic and methacrylic acid with a molecular weight of about 5,000 to about 50,000% in the context of the present invention,

309812/0016

The fluids of the present invention can find a variety of uses, e.g., in compressors, hydraulic lifts, elevators, in aircraft hydraulic systems, in braking systems, oxygen ovens, in equipment for shell casting, in leveling devices, power steering devices, in mining equipment and the like and as lubricants for steam turbines.

The invention is illustrated, but not limited, by the following examples.

example 1

A basic substance based xylyl-cresyl phosphate, in which the xylyl and Oresylgruppen approximately in a weight ratio of 4: 1 are present and a viscosity of approximately 220 Saybolt Universal Seconds at 37.8 ⁰ C was treated with 1.0 % By weight 4,4'-methylene-bis- (2,6-di-tert-butylphenol) blended (liquid A). A second portion of the same basic substance is blended as above and also contains 0.05% by weight of a commercially available mixture of dodecyl hydrogen phosphates which is sold under the trademark "OHTHOLEUM" 162 by E, I. du Pont de Nemours, (liquid B). The two liquids described above, along with the phosphate-based basic substance alone, are tested according to the modified oxidation stability test Fed. Test Method Std. No, 791a, Method 5508.4, and the ASTM D665-60 corrosion test

- 19 -

909812/0856

checked. The results of these tests are shown in Table II contain. ''

Tabel!! .

( Viscosity at 57, S ⁰ G (SUS) Jrund- liquid liquid
substance AB. 400 237; 240 Acid number (mg KOH / g) 226. 77- . 0.14 0.31 0.11 9.8 Resistance to oxidation
72 h, 175 C, air flow: 5 l / h ■ ' -0.054
-0.016
-0.085
-0.185
-0.762 302 27O Viscosity according to the
Exam (SUS) 27 / 13. Increase in viscosity 2.7 4.0 2.8. Acid it counts after the
test 0.069 -0.023
-0.016
-0.100
-0.138
-0.569 -0.054
-0.062
-0.069
-0.123
+0.400 Angi ^ iff on metal specimens
(g loss)
Mg
- ' Stole
Al
Ag
Cu satisfied
putting Resistance to hydrolysis;
93.3 0.48 hours • 3.3 10.4 Acidity of the water
layer (mg KGH) 0.008 0.15 ρ
Eupfer loss (mg / cm) satisfied- satisfied-
representing denstei
lend Appearance of the copper:

The results contained in Table II clearly show the superior oxidation resistance of liquids according to the present invention. The rise in

- 20 -

308812/0856

Oxidation resistance of liquid B to liquid Ά is without a doubt surprising because hydrogen phosphates so far / have not been used as antioxidants for any Liquids, much less so for the phosphate-based liquids according to the present invention, recognized. These results are also unexpected because phosphate-based fluids contain a A similar content of hydrogen phosphate alone did not show any significant increase in the resistance to oxidation.

Example 2

Liquid 0 is made like liquid B with the Exception that 0.01% by weight OBTHOLEUM is used. This liquid is tested twice in the same manner as in Example 1. The results are in Table III compiled:

T a b e 1 1 e III

Percent change in viscosity test Acid number before test (mg KOH / g) Acid number after test (mg KOH / g) '

Change in metal weight (mg / cm)

Mg

Steel Al Ag Cu

liquid Verse «4tfr. Vers.-No. 19.5 18.2 0.06 0.06 2.77 3.25 -0.054-
-0.04-6
-0.023
-0.085
-0.315 -0.038
-0.023
-0.031
-0.100
-0.177

309812/0856

From Table IH it can be seen that even a decrease the amount of hydrogen phosphate to one fifth of the amount used in liquid B, a substantial one; Increases the resistance to oxidation.

Example 3

An 'Oreyl- ^ lyl-phenylphosphat, in which the Ore sy 1-, Xy IyI- and phenyl groups are contained approximately in a weight ratio of 4: 1: with a viscosity of 150 SUS at 57.8 ⁰ O is with 1 wt. % 4,4'-methylene-bis- (2,6-di-tert-butyl- 'phenol) and 0.05% by weight ^{I (} OEa "HOLEUM" 162). This liquid has a remarkably higher resistance to oxidation than the matrix alone and passes the rust test, ASTM D .895, in both distilled water and synthetic seawater.

309812/0850

Claims (8)

Κ. · ■ ·· ■ .224 * 0.83 Claims
1.) A functional fluid consisting of a) a basic substance based on a phosphate of the general formula O
H - (Y) ₃ - P - (X ₁ ) _o - where Y is oxygen. Sulfur and E -, - H, X _{1 acid} substance, sulfur and H ₄ J _- -N ₇ Xg oxygen, sulfur and Ej - N is, E, E-,, E ₀ , E _x , E ,. and R ₁ - alkyl, aryl, y x I. c. O H- P substituted alkyl and substituted aryl, and a, b and c are numbers with the value 0 to 1, so that their sum a + b + c is 1 to 3 and b) an oxidizing agent combination of about 0.005 to about 3 % by weight, based on the total liquid, of a hycixogen phosphate ester or its amine salt with the general formula wherein Eg is an alkyl group having 1 to 20 carbon atoms is, A for vase fabric, an alkyl group mib 1 to 20 carbon atoms or an amine cation of 309812/0856 E "
ι where H ^1:, E "and E '''is hydrogen or an alkyl radical and A ^{1 is} A or an allyl group having 1 to 20 carbon atoms and about 0.1 to about 11% by weight, based on the total liquid, of a hindered phenol. 2.) Liquid according to claim 1, characterized in that the hindered phenol has an alkylene group bound bisphenol of the general formula where Eq and EJ are ₀ branched chain. Are alkyl groups having 3 to 8 carbon atoms, and E ₁₁ and E ₁ O are hydrogen or alkyl groups having 1 to 8 carbon atoms. 3.) Liquid'nach claim 2, characterized in that Ε, -, and E ₁ P is hydrogen. OBlGiNAL INSPECTED 309812/0856 4 ·.) Liquid according to claim 2, characterized in that the hindered * bound via an alkylene group
Bisphenol 4,4 · -Methylene-bis- (2,6-di-terb.-butylphenol)
is. 5.) Liquid according to claim 1, characterized in that that the hydrogen phosphate ester is a mixture of the dodecyl hydrogen phosphates. 6.) Liquid according to claim 1, characterized in that R, R-, and Rp phenyl, oresyl, xylyl, isopropylphenyl, Are biphenylyl and α-methylbenzylphenyl. 7.) Liquid according to claim 6, characterized in that the hydrogen phosphate is a mixture of the dodecyl hydrogen phosphates and the hindered phenol
4,4'-methylene-bis- (2,6-di-tert-butylphenol). 8.) A functional fluid in the form of a mixture consisting of a) a or basic substance based on a phosphate of the general formula H - (ϊ) _β - P 309812 / 0F5B tr where X is oxygen, sulfur and R ^ -N, T ₁ acid-- substance, sulfur and R ^ -N, Y ₂ oxygen., sulfur and Ec-N, R, R ₁ , R ₂ , R 1, R ^ and R _{5 are} alkyl, aryl, substituted alkyl and substituted aryl, and a, b and c are numbers from 0 to 1 so that their Sum a + b + c is 1 to 3, and b) a portion of an oxidation stabilizer consisting of • an antioxidant combination of a hydrogen phosphate ester and a hindered phenol is composed. ; . 309812/0856