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Patented Sept. 10, 1946
2,407,59
STATES err
a
2,407,589
AQUEOUS ALKALINE REACG CLEANING
BATH HAVING REDUCED FOG CHAR
ACTERISTICS
Henry Earl , Tremain and Leslie R. ‘Bacon,
Wyandotte, Mich., assignors to Wyandotte
Chemical corporationpwyandotte, Mich., a cor
por‘ation of Michigan
No Drawing. Application February 3,1944,
'
~
Serial No. 520,960
5Claims.
(01.252-156)
2
This invention relates to'the suppression of '
foaming in aqueous alkaline solutions, and more
particularly to the suppression of foaming in im
pure alkaline washing solutions upon agitation by
the addition thereto of small amounts of certain
organic materials.
.
suppression under any given circumstances.
Larger quantities are of value only as they serve
to maintain a reserve against depletion by chemi- -
cal reaction, evaporation, mechanicaI carry-out
‘ by adherence to surfaces of moving machine parts
,
or containers traversing the foam inhibited liquid,
Due to the introduction of the hydraulic'type
splashing or other causes. Accordingly, it is gen
erally very advisable that a working reserve in ex
cess of said‘minimum be provided and adequately
bottle washer, the problem ‘of foaming of the al
kaline solution used is more often encountered. v,
This foaming di?iculty is attributable to the tre 10 maintained, the reserve commonly being greater
mendous agitation produced. .Whenever foam
with increased temperatures to provide against
over?ows and is lost down the' sewer, this loss in
increased losses by evaporation and chemical re
creases the necessary _alkali make-up and thus
action‘.
the cost of bottle washing, quite aside from a
'
The
I
'
alkaline constitution has considerable
variety of other- inconveniences and dangers. 15 bearing on the foaming behavior, and is espe
Because this type bottle washer is of considerable
cially marked in the case of alkali phosphates. A
importance and the materials known to the prior
concentration of 1.6 to,2.3% P205, by analysis, in
art have not been entirely satisfactory, the ?nd
the caustic frequently is suf?cient to cause exces
ing ,of an additive functioning‘ e?iciently as a
sive foaming. Little decay of the foam occurs‘ in
foam suppressor has remained a problem. How 20 several minutes of quiescence after the formation.
ever, the tendency to foam ‘of alkali solutions is
The presence of large proportions of soda ash or
not restricted to any particular mechanical or
small amounts of sodium sulfate and -silicates in
hydraulic system, but exists wherever foreign
caustic alkali is responsible for somewhat similar
matter such as proteins, fats, soaps and surface
foaming behavior.
\
active agents in general are present and there is 25 The object of the invention is to provide a
opportunity for air or other gases to be entrapped.
new type of anti-foamer additive for an aqueous
Furthermore, the quantity of foam formed in
solution containing alkaline compounds to allay
creases the longer such solutions are in use be
cause increased amount of foam promoters are
foaming or to ‘hold in check and suppress the
tendency to foam, or to change the character of
accumulated from the dirty or used objects. The 30 foam being formed into a less stable type. It is
tendency to foam is in?uenced by conditions
also an object of this invention to provide aque
other than the amount of agitation and quantity
ous alkaline baths containing anti-foamer, which
of foaming promoters present. In general an in
foam to a much lesser extent under operating crease in the temperature increases the dl?iculty .
- conditions than said bathswithout these addi
of suppressing foam; and an- increase in alkali 35 tives. It is, furthermore. an object to clean glass
concentration assists in suppression of foam or
ware or dishes. metallic and other objects by con
froth. Likewise‘an increase of suppressor con¢
tacting them with an aqueous alkali solution con
centration increases, without exception, the effec.
needed to e?ect-complete suppression.
taining foam suppressing additives to offset the
tiveness of foam abatement, up to the minimum
More or less de?nite minimum quantities of
foam suppressing agents are required to effect
presence of colloidal ~or other‘ extraneous mate
40
rials tending to produce foams upon agitation.
'More particularly, it is an object to employ the
anti-foamers described herein in machines such
2,407,589
as mechanical dish washers, bottle washers or
Corporation), wheat flour (commercial brand),
metal parts washers to control objectionable
.foam'ing behavior arising from the presence of
contaminations .derived from the objects con
Nacconol N. R. (wetting agent understood to be
keryl benzene sodium sulfonate), and an alkali
tacted by the alkaline wash water.
oleate soap.
I
Three standard foaming solutions were pre
pared by mixing‘ the following materials and re
?uxing at boiling temperature for one hour:
.
Other objects of the invention in part will b
obvious and in part will appear hereinafter.
It has been proposed to prevent foaming by
‘adding such, materials as octyl alcohol (0. A.
16,1254), caprylic alcohol (0. ‘A. 12,1058), oleyl 10
and other high alcohols and mineral oils to Pre
vent the foaming of various types of solutions.
Evaporated milk _____________ "grams"
Foamite ____________ _;___.'._....__do__.._
1.603
5.480
Flour ________ __, _____________ __do____
4.820
Nacconol N. R. ‘-s ____________ -_do-____
0.045
There are disadvantages to using these materials
in alkali solutions. The simple alcohols are
changed chemically by the alkaline medium and
are consequently e?ective for only a, relatively
Oleate soap ___________________ _..do____
0.069
Caustic soda __________________ .._do____ 24.0
Water _________________________ __ml__ 800.0
short life only. Not only is there a lesser con
centration of the initial alcohols, but the products
of the chemical reaction promote foaming. Min.
tions and treated as follows:
I
Portion 1—diluted to 800 ml.
Portion 2-—16 grams of ‘caustic soda added and
This mixture was divided into three equal por
. eral oils ‘are objectionable in the beverage‘ or food 20
industries because of dimcult rinsibility and the
"
diluted. to 800 m1.
'
'
Portion 3--32 grams of caustic soda added and
diluted‘to 800 ml.
odor and taste left upon bottles or other wares.
Furthermore, these compounds are in part vola
tile and their eifect is only temporary.
The three solutions then comprise respectively,
We have found'that an ideal foam inhibitor 25 approximately 1, 3 and 5% (all percentages here
should possess the following necessary quali?ca
in stated being by weight unless otherwise stated)
tions, but these alone are not sumcient:
solutions of the caustic alkali, each containing a‘
total of 0.5% of the mixed foaming components.
(1) Insolubility or ‘very low solubility in the
foaming solution, 1. e. form a recognized I These foaming systems differ only in concentra
30 tion of alkali.
separate phase
(2) Liquidity at temperature employed
(3) Non-reactivity in the'washing medium and
-
' Tests
non-destructibility to an ineffectual mate
The various materials tested for foam suppres
sion properties were made up for use as 20% solu
rial or a positive foamer
tions in acetone.
‘
-
.
50 ml. portions of each alkali solution were
It should have good spreading and rinsing prop
erties under the conditions of use. Furthermore,
from the practical standpoint of the food and
introduced ‘into 125 ml. Pyrex Erlenmeyer flasks.
The properties quantities of foam inhibitors were
added, the ?asks stoppered and placed in a forced
draft air oven. At the end of 24, 48 and '72 hours
beverage industries, it should - be non-odorous,
non-toxic and communicate no repulsive taste via 40
the ?asks were removed in conveniently sized
the cleansed wares to food products.
groups, agitated andfoam observations made at
Applicants have found as a result of much ex
the end of 10 seconds and 5 minutes after shak- '
perimentation and testing that di-tertiary-amyl
phenoxyethanol, p-tertiary-amylphenoxyethanol
and diamyl phenol which are thus characterized,
possess exceptional foam inhibiting power for
aqueous alkaline solutions even when used in very
small quantities. They are each particularly
ing. The observations were recorded in terms‘ of
6 “Excellent,” “Good,” “Fair,” "Poor" and “Bad.”
"Poor" de?nes the foaming tendencies of portion
2 supra in a 3% pure caustic solution. ‘.‘Bad’.’
applies to any system foaming to a greater extent
adapted vfor hydraulic type bottle washing,
wherein excessive foaming from contaminated
alkali wash water is usually encountered. Of
these three materials the preferred is di-tertiary- I
amylphenoxyethanoL. However, applicants have
found that when a 50-50 by weight mixture of
trioctyl phosphate , with
di-tertiary-amylphe
noxyethanol was employed, the inhibiting action
was about one-third less effective than with the
use of the latter alone as the anti-foamer. These
aforesaid compounds are effective when employed
in conjunction with either tetradecanol or tri
octyl phosphate, which latter compounds are
known foam inhibitors.
In determining the ‘efficiency and behavior of .1
these inhibitors under various operating condi
tions. several materials consideredas represent 65
ative of contaminants to be found in actual com
mercial alkaline'wash liquids were selected as
foam promoters. Sodium hydroxide, sodium car
bonate and tetrasodium pyrophosphate are rep
resentative alkaline chemical compounds em
ployed in such commercial alkaline washing solu
tions. As representative contaminants there
were Selected evaporated milk (commercial
brand), Foamite (a natural vegetable product
manufactured by American-LaFrance Foamite
than standard foamer A. “Fair'’ represents the
degree where the foaming is no more than half
that of the standard. “Good” represents the de
gree of foaming, wherein the surface of the so
lution is only' partly covered with foam. "Excel
lent” signi?es that all foam is inhibited or in
stantly destroyed.
A large number of known anti-foaming mate
rials were examined, but did not qualify under
conditions of the above test within 24 hours at
140° F. Only those materials were retained for
consideration which rated "good" or "excellent"
on this test.
Among the materials so dismissed
were iso-amyl phthalate, tributyl phosphate,
n-amyl alcohol, benzyl alcohol, heptadecanol,
resorcinol, benzyl chloride, butyl Cellosolve lau
rate,‘ butyl Cellosolve palmitate, dibutyl phthal
ate, diphenyl phosphate, tricresyl phosphate, tri
phen'yl phosphate, diphenyl and diamylnaphtha
lene. - \iTetradecanol, i. e. 7-ethyl-, 2-methyl
undecanol-,
4 - ditertiary - amylphenoxyethanol
and trioctyl phosphate survived the test.
The following examples in Table -I are set out
as illustrations of the present invention. How
ever, they are not presented with the intention
of limiting the scope of the invention, since many
variations may be made.
2,407,589
Table L-Comparison of foam inhibitors ‘on 8%
solutions of alkali (72% NaOH,28% NaaC‘Os)
with 0.5% addition of mixed loamcra at 160‘ 1-‘.
Percent loam inhibitor added to solution
Hum hem
site:
ioem
inhibitor
Foam inhibitor
“Mm”
0.00
‘0.01
0.025
- one
Foam
deoa
period . y
Foam
deca
period y
Foam
decay
period
Foam
decor
period
10sec. 5min. 10sec. 6min. 10sec. 5min. 10sec. 5min.
24
N
m___________________ .-
g
24
48
None ................... ..
72
Lmmmmmlo11 """" "
'r
mm“
P
PP
P
P
BI
B
B
P
,B
‘IF 0 mon 2!!
.
P
it72
2*
1 ........... _-
4s
‘
a
i’P
i‘
.
...... ..
i5P
i5
i3P
i
iP
- .1:
.
.
iP '
i‘
.
iP
i
a.
a
.1;
a
5
4s IIIIIIIIIIIIIIII
F
o r’
F
o
r
G
“118ml --------------- -—
72
F
F .
F
F
F
o
Trioctylphosph ate ..... ._
48
ii
F
a
P
i
F
a
G
a
E
m'mmmylphen?y'
24
72
l P-Poor.
h
P
______________ ._
' B-Bad.
l F-Fair.
‘ G-Good.
6 E-Excellent.
z;
i
1
Under the conditions represented by the fore
Various combinations of the foam inhibitors
going table it is seen that the carbonated alkali 30 forming applicants’ invention described herein
presents a more dimcult foam control problem
can be employed with each other. Also these
than a caustic soda solution of equal ‘concentra
_foam inhibitors are well suited to be employed in
tion by weight. Where a light, mineral oil was
association with one or more of the previously added to the carbonated alkali, after 24 hours or
known
foam inhibitors. By such combinations
longer, there resulted an unsatisfactory inhibi
an inhibitor composition can be offered having
tion under all conditions, although some bene?t 35 activity over a wide range of operating. condi
over the entirely uninhibited condition. Tetra
tions and over a ions period of time. Also if ac
decanol shows improved results over mineral oil,
quainted in. advance of concentration of alkali
especially at the higher concentrations, but the
or alkaline salts in the solutions to be treated, or
effect is transient. Trioctyl phosphate at this
temperature is generally more e?’ective > than 40 of the nature of the‘ foaming constituents, those
inhibitors or combination of inhibitors most ei~
tetradecanol after 48 and 72 hours, but slower in
fective for speci?c conditions can ‘be recom
' anti-foaming action than di-tertiary-amylphen
oxyethanol at the same lower concentrations.
This latter material shows a more comprehen
mended.
'
i
For a low alkali range, for example up to 1%,
45 an inhibitor composed of 50% tetradecanol and
sive pattern of general eifectiveness under varied
50% di-tertiary-amylphenoxyethanol has proven
conditions of use.
to be very effective. For high temperatures and
a stronger alkali concentration, for example
This same-more general pattern of effective
ness is further shown by the examples of Table II
3-5%,
a mixture of trioctyl phosphate and di-‘
in which an alkali of different composition is 50
tertiary-amylphenoxy-ethanol is excellent. For
employed over a considerable temperature range.
low temperature operation, a mixture of equal
Table H.-Comparison of foam inhibitors on 1%
solutions of alkali (95% NaOH+5% tetrasodi
um pi/rophosphate) using 0.5% addition of
mixed joamers and 0.025% foam inhibitor
,
120° F.
140° F.
160° F.
Foam decay,
period
Foam decay
period
Foam decay
period
Hours held
Foam inhibitor
after loam
inhibitor
addition
10 sec.
24
None ............ ..
Light mineral oil..
B1
B
10 sec.
B
6 min.
Pl
10 sec.
ii min.
B
B
48
B
P
B -
B
B
B
72
24
P
B
P
B
P 1
P
P
- P
B
B
P
P
48
72
24
Tetredecanol .... .-
6 min.
B
B
B
B
P
P
Fi
B
B
P
P
F
P
B
P
P
B
P
48
B
/ B
P
P
P
P
72
B
B
B
B
P
P
Trioctyl phosphate
24
48
G4
IF
Di-tertiary-amylphenom-ethanol.
72
24
48
72
G
P
P
F
IB-Bad.
IP-Poor.
iF-Falr.
Ei
G
P
P
P
P
P
P
F
P
E
P
P
F
P
F
F
F
P
F
F
F
P
P
F
F
P
F
F
F
‘Ci-Good.
lE--Exo,ellcnt.
2,407,589
.
parts of trioctyl phosphate, di-tertiary-amyl
phenoxyethanol, and tetradecanol is very satis
factory.
-
8
and dish washing of about 0.05%, on the basis
of weight of the washing solution is suf'iicient,
There are various specific applications of the
invention other than treating washing solutions,
Laboratory tests under dynamic conditions
have shown the marked ef?ciency of di-tertiary 5 such as the reduction or elimination of foaming
in coating solutions for paper ?nishes, in beater
amylphenoxyethanol by itself and‘ in combina
operations for paper making, in glue manufac
tion with other materials. To conduct these tests
ture and sugar boiling; in each of these, ma
an apparatus was constructed employing a 10
terials
of decided alkaline reaction are employed.
gal. steel drum as a container for‘, a foaming so
lution, a positive pressure pump for withdrawing 10 These foam inhibitors can also be used in alka
line anti-freeze mixture, in alkaline liquors un
solution from the liquid phase near the bottom
dergoing distillation, in boiler waters, in soap liq
and delivering same via a number of Jets into
nor; for treating fabrics, in wet method dust col
milk bottles inverted overthe solution reservoir.
lectors, and as a safety control against boiling
Foaming constituents were employed in the same
of kettles used in soap manufacture.
ratios as hitherto described, but at ?ve fold con 15 over
The above described foam inhibitors function
centrations, 'i. e. 10 liters of foaming solutions
in the various types of aqueous alkaline solutions.
. contained 300 g. of caustic soda, 33.4 g. evap
They are operative in strongly alkaline mediums
orated milk, 113.7 g. “Foamite," 100.4-g. ?our,
in which caustic alkalies may be present and in
0.935 g. "Nacconol NR" and 1.465 g. sodium ole
ate. 10v ml. of the anti-foamer was employed 20 weakly alkaline solutions. They are of most
(0.1% approximately). Foam was allowed tode- .
V velop close to the point of over?owing the con
tainer prior to addition of the anti-foamer.
- Under these circumstances a 60-50 mixture of
di-tertiary-amylphenoxyethanol
and
utility probably in the ?eld of alkaline detergents,
especially those containing caustic alkali.
-
The above description and speci?c examples
are to be construed as illustrative only and not
limiting the scope of the invention. Any
trioctyl 25_ as
modi?cations or variations therefrom which con
phosphate suppressed or caused complete decay
-'
form to the invention are intended to be included
of the standing foam within about one to four
in the scope of the claims.
minutes operation of the system at 20 lb. pump
We claim:
pressure and 140° F. solution temperature. This
1. An aqueous alkaline solution having reduced
addition effectively suppressed foam for about 80 foaming'characteristics
containing in addition to
hours
of
continuous
operation,
failing
111/2
water, a soluble alkaline agent, and a constitu
rather abruptly within about 15 minutes after
ent tending to produce foam, admixed with a
the ?rst foam appeared. A check run failed in
minimum
of .01% by weight of at least one foam
11 hours and 55 minutes. Two runs using
selected from the group consisting of
straight di-tertiary-amylphenoxyethanol failed 35 inhibitor
di - tertiary - amylphenoxyethanol, p-tertiary
at 17 and 17% hours respectively. Trioctyl
phosphate, therefore, depreciated the perform
ance of di-tertiary-amylphenoxyethanol alone.
P-tertiary-amylphenoxyethanol under similar
conditions failed at 2% hours, but lo‘ml. addi
tion of the same inhibitor extended foam sup
pression for several fold this period.
Tests conducted under practical milk bottle
amylphenoxyethanol and diamyl phenol.
_2. An aqueous alkaline~reacting cleaning bath
having reduced foaming characteristics contain
40 ing in addition to water, caustic alkali and at ‘
least one constituent tending to produce foam,
» admixed with a minimum of .01% by weight of at
' least- one foam inhibitor selected from the group
consisting of di-tertiary-amylphenoxyethanol,
‘ washing conditions have shown that as little as
45 p-tertiary-amylphenoxyethanol and diamyl phe
nol.
phenoxyethanol and trioctyl phosphate added at
3. An aqueous alkaline-reacting solution hav
intervals of 1 to 11/4 hours to 625 gal. of a 315%
ing reduced foaming characteristics containing
caustic test solution of a 72% NaOH-28%
in addition to water, a soluble alkaline com
NaaCOs bottle washing alkali in 13 gr. hardness
water and operating at ll5-l35° F. and 15-18 lb. 50 pound and a constituent tending to produce foam,
20 cc. of the 50-50 mixture of di-tertiary-amyl
admixed with a foam inhibitor composition com
pump pressure were sufilcient to deal with an
prising a mixture of di-tertiary-amylphenoxy
ethanol and trioctyl phosphate, each of said last
extremely dimcult foaming problem.
In another plant also using a “soaker-hydro"
type machine and a very difficult alkali from the
. named ingredients being present in the amount
to 1/2 of the entire mixture.
foam suppression viewpoint (adding one part of 55 of 4.$4; An
aqueous alkaline-reacting solution hav
an alkali polyphosphate to 6-7 parts of a 95%
ing reduced foaming characteristics containing
caustic-5% tetrasodium pyrophosphate solution 1‘ in addition to water, a soluble alkaline compound
held at 3% caustic test and 140° F.), excellent
and a constituent tending to produce foam, ad
foam suppression resulted from the addition of 60 mixed
with a foam inhibitor composition com
1 pint of the same 50-50 mixture to about 350
prising
a mixture of equal parts of (ii-tertiary
gal. of washing solution. Foam suppression was
amylphenoxyethanol and trioctyl phosphate.
immediate and complete and no adverse results
were noted on washing or rinsing performance.
This addition was effective for more than 30
hours of operation.
The amount of foam inhibitor to be used in
5. An aqueous alkaline-reacting solution hav
ing reduced foaming characteristics containing
65 in addition to water, a soluble alkaline com
any particular assignment cannot be de?nitely
stated because of the variation of such factors
as surface tension of the solution, the area ex
posed, the temperature, or the violence of agi 70
tation. In general, an amount of anti-foamer
for aqueous alkaline cleansing solutions for bottle
pound and a constituent tending to produce
foam, admixed with a foam inhibitor composition
the major ingredient of which is di-tertiary
amylphenoxyethanol.
HENRY EARL TREMAIN.
LESLIE R. BACON.
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