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Patentedv Dec. 24,]946
'
2,413,170
UNITED STATES
PATENT oFFrcE
2,413,170
LIQUID STABLE AT LOW TEMPERATURES
Frank M. Clark, Pitts?eld, Mass, assignor to Gen
eral Electric Company, a corporation of New
York
No Drawing. Application April 1, 1943,
Serial No. 481,462
4 Claims.
1
(Cl. 252-65)
2
,
The present invention comprises liquid compo
sitions which are suitable for uses in ?elds in
which extraordinarily low temperatures areen
countered, as, for example, in hydraulic and elec
for an inde?nite period to such extreme cold as
-40° C. or even lower.
The mineral oil addition may be chosen ina I
tric apparatus whichis exposed to temperatures . s
as low as —40° C., or even lower during use or
shipment.
~
'
wide range of viscosities say from 50 to 2000 sec-7
onds Saybolt at 100° F. However, even solid ma
terials as hereinafter shown may be added to ,pre-V
vent crystal formation with time.
It is required that liquids in such apparatus
In place of mineral oil any one or a mixture ‘of
must not only have congealing temperatures so
the following crystallization-inhibiting materials
low that there is no likelihood of solidi?cation, 10 may be substituted, including not only hydrocar
but such liquids usually should have low viscosity
bons, but also other organic or carbo-hydrogen
compounds. The following materials, which are
used in a non-halogenated state, are illustrative:
which is retained at low temperatures. It is also
highly desirable that such low congealing liquids
should not form crystalline components which
diphenyl, diphenyl oxide, pinene, benzene, tolu
would clog hydraulic apparatus and would cause 15 ene, isopropyl benzene, wood rosin, hexane, cy
breakdown of electrical apparatus.
clohexane, dimethyl naphthalene, N-butyl alcoIn many respects liquid compositions made up
hol, isoamyl alcohol.
"
"
‘f‘
of a mixture of unlike chlorinated components
A ‘second composition adapted to remain liquid
are well suited to withstand excessively low tem
at excessively low temperatures is the following,
peratures without congelation.
in which chlorinated diphenyl is not present:
If the chlorine
content of such compositions is suf?ciently high
they are non-in?ammable. It is found, however,
that upon prolonged exposure to low tempera
tures solid crystalline components form in other
wise liquid compositions.
Ingredients
Parts by
weight
25 Pentachlor ethyl benzene ____________________________ _.
I have discovered that the formation of crys
tals at excessively low temperatures in such com
37. 2
38. 0
-
Crystal inhibitor ____________________________________ _ _
positions is inhibited or wholly prevented by the
24. 8
Tetrachlor ethyl benzene ____________________________ _Trichlor ben 1mm
1 -7
presence of a minor content of unhalogenated
Although both the above examples illustrative
carbo-hydrogen compounds, that is less than ten
percent by weight. Although larger additions
of such crystal inhibitors are not precluded sub
stantially larger additions will impart inflam
mability to a composition. Preferably the
amount of carbo-hydrogen compound should be
of my invention comprise ethyl benzene com
pounds, it should be understood that the advan
tages accruing from the present invention are
not limited to such compounds. Retention of
liquidity at extremely low temperatures also is
obtained in compositions comprising other chlo
rinated compounds, such as chlorinated toluene
within a range of one to seven percent, and usu
ally approximately one percent.
My invention will be illustrated by the follow
and chlorinated isopropyl benzene. While my in
vention is not restricted to halogenated alkylated
ated benzene compounds which have been halo 40 aromatic compounds its advantages in this class
of compositions is most marked. Fluorine and
genated.
.
other halogens may be used in place of chlorine.
A composition comprising the following com
In the dielectric ?eld, as in electric capacitors,
ponents has a congelation temperature of about
ing examples of compositions containing alkyl
—56° 0., when tested in a normal manner. When
. compositions embodying my invention have been
exposed to —40° C. for a protracted period, vary 45 found to be particularly advantageous in high
frequency circuits- For example,‘ a dielectric
ing from a day to a Week, crystals are slowly
composition, such as above described containing
formed. The behavior of such compositions re
trichlor benzene, tetra and pentachlor ethyl ben
sembles that of supercooled liquids.
zene, and pentachlor diphenyl, the amount of
mineral oil being about one percent, has the fol
Ingredients
1:33:11?’ 50 lowing dielectric constant and power factor in a
range of operating temperatures at 1000 kilocy
Trlchlorbenzene ____________________ -.
35
Tetrachlor ethyl benzene-
34. 2
Pentachlor eth lbenzene.
22.8
Penmhlm ‘111) ‘W1 ----------- --
8-0 55
When about one to seven parts by weight of a
.
.
.
.
crystal inhibitor, such, for example, as mineral
oil is added then slow crystallization no longer
Occurs even though the compositions are exposed 60
C165’
Temp.,°0.
DleLconst.
Power factor
4-05
0. 05s
3.93
.040
3_75
3-65
_025
~021
2,413,170
What I claim as new and desire to secure by
Letters Patent of the United States is:
1. A low viscosity liquid composition of matter
which is capable of remaining liquid at about
—40° C. for protracted periods without the for
mation therein of crystals, which composition
consists principally of (1) a mixture of chlori
higher than about ten kilocycles. At low com
nated ethyl benzenes and (2) mineral oil con
mercial frequencies (e. g. 60 cycles) the power
stituting from about one to seven percent by
factor normally rises as the temperature rises.
The power factor is low over a wide range of 10 weight of said composition.
2. A low viscosity liquid composition of matter
frequency as indicated by the following vtable,
which is capable of remaining liquid at about
the power factor being indicated in percent.
It is noteworthy that thepower factor falls
with a rise of temperature of the composition.
The dielectric constant falls only to an insigni?
cant extent. This characteristic of the described
compositions is not peculiar to the particular fre
quency here given. It is obtained at frequencies
~40“ C. for periods at least as long as one week
without the formation therein of crystals, said
Frequency in kilocycles
15 composition consisting principally of (1) tetra
- 'l‘emp.,°0.
140
400
550
650
800
chlor'ethyl benzene, pentachlor ethyl benzene
1000
25 ________________________ -- 0.020 0.026 0.033 0.037 0.044
100 _______________________ _- .075 .033 .031 .035 .035
and trichlorbenzene and (2) mineral oil con
stituting from about one ‘to seven percent by
0.058
.021
20
The characteristics at 1000
second illustrative composition
nated diphenyl is absent) are
following table. The amount
kilocycles of the
(in which chlori
indicated by the
of mineral’ oil in
this instance was one percent.
Diel.
Temp" 0 0‘
const.
25
50
7*‘.
l
-
100 __________________________________________ ..
,
Power
factor
4.14
3.98
0. 040
.022
3.23
.020
a. 71
.019
weight of said composition.
3. A low viscosity liquid composition of matter
which is capable of remaining liquid at about
—40° C. for a time as.long as one week without
the formation therein of crystals, said composi
tion consisting of (1) tetrachlor ethyl benzene,
25 pentachlor ethyl benzene and trichlorbenzene
and (2) about 1% of mineral oil by weight.
4. A low viscosity liquid composition of matter
which is capable of remaining liquid at ‘about
—40° C. for as long as one week without the
30 formation therein of crystals, said composition
It should be noted that the power factor de
consisting of the following ‘ingredients in sub
stantially the proportions indicated 'by weight
Parts
Trichlorbenzene _____- ____ _. ______________ __
35
Pentachlor diphenyl __________ __~__.__l_.._l____._
8
Mineral
1
creases and at 100° 0., is slightly less than one 35 Tetrachlor ethyl benzene _______ _‘__..__.__V___ 34
half its value at 725° C.
Pentachlor ethyl benzene _____ __'.____>_ _____ __ 22
Power capacitors constructed to be operable at
high e?iciency and with a low power factor and
containing halogenated compounds of low vis
cosity will be described in another patent appli 40
cation Serial No. 486,047, ?led May ‘7, 1943.
oill ______ -1 ____ __‘____‘ ___________ __
M. CLARK.
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