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Claims  |
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What is claimed is:
1. A water in oil emulsion defoamer composition comprising:
(a) from about 0.5 to about 10 percent by weight of quick-chilled amide,
which is a reaction product of a polyamide having at least one alkylene
group of 2 to 10 carbon atoms and a fatty acid of from 6 to 18 carbon
atoms,
(b) from about 0.3 to about 10 percent by weight of hydrophobic silica
(c) from about 0.5 to about 5 percent by weight of polymer selected from
the group consisting of copolymer of vinyl acetate and fumaric acid
esterified with tallow alcohol, copolymer of vinyl acetate with maleic
acid esters, copolymer of vinyl acetate with ethylene, copolymer of vinyl
acetate with propylene, copolymer of vinyl acetate with butylene, methyl
glucoside alkoxylated with four moles of propylene oxide, glycerine
alkoxylated with fifteen moles of ethylene oxide and forty-five moles of
propylene oxide, butanol alkoxylated with thirty moles of propylene oxide,
copolymer of lauryl methacrylate and vinyl pyrrolidone, methacrylate
copolymer dissolved in refined oil, blown hydrogenated soya oil, blown
vegetable oil, blown castor oil, soya alkyd, phenol modified coumarone
indene resin, glycerol ester of gum rosin, glycerine ester of
polyvinylpyrrolidone, lauric acid, palmitic acid, stearic acid, linseed
oil, castor oil, lard and tallow,
(d) from about 0.5 to about 5 percent by weight of emulsifier selected from
the group consisting of nonionic, anionic acid cationic surfactants,
(e) from about 15 to about 65 percent by weight of oil,
(f) from about 20 to about 60 percent by weight of water,
(g) from about 0 to about 3 percent by weight of silicone surfactant,
(h) from about 0 to about 0.5 percent by weight of formaldehyde solution
and
(i) from about 0 to about 0.5 percent by weight of silicone oil.
2. The defoamer composition of claim 1 wherein the amide is the reaction
produce of a polyamine selected from the group consisting of ethylene
diamine, butylene diamine, diethylene triamine, triethylene tetramine,
hexamethylene diamine, decamethylene diamine, hydroxyethyl ethylene
diamine, and 1:3-diamino-2-propanol, and a fatty acid selected from the
group consisting of hexanoic acid, decanoic acid, lauric acid, palmitic
acid, oleic acid, stearic acid, ricinoleic acid, naphthenic acids, tall
oil acid, tallow fatty acid, and hydrogenated tallow fatty acid.
3. The defoamer composition of claim 1 wherein the oil is selected from the
group consisting of fuel oil, mineral seal oil, paraffinic oil, naphthenic
oil, cyclohexane, xylene, toluene and dodecane.
4. The defoamer composition of claim 1 wherein the amide is ethylene
bisstearamide, the polymer is polymethacrylate, and the emulsifier is
castor oil alkoxylated with fifteen moles of ethylene oxide.
5. The defoamer composition of claim 4 wherein there is present about 2.5
percent by weight of amide, about 1.5 percent by weight of silicone
surfactant, about 1.5 percent by weight of emulsifier, about 49.8 percent
by weight of water and about 0.1 percent by weight of formaldehyde
solution.
6. The defoamer composition of claim 1 wherein the amide is ethylene
bisstearamide, the polymer is copolymer of vinyl acetate and fumaric acid
esterified with tallow alcohol and the emulsifier is castor oil
alkoxylated with fifteen moles of ethylene oxide.
7. The defoamer composition of claim 1 wherein there is present about 2.5
percent by weight of amide, about 1.5 percent by weight of silicone
surfactant, about 1.5 percent by weight of emulsifier, about 49.8 percent
by weight of water and about 0.1 percent by weight of formaldehyde
solution.
8. The defoamer composition of claim 1 wherein the emulsifier is a nonionic
surfactant.
9. The defoamer composition of claim 1 wherein the polymer is a copolymer
of alkyl methacrylate and vinyl pyrrolidone.
10. The defoamer composition of claim 1 wherein the emulsifier is a
nonionic surfactant and the polymer is a copolymer of alkyl methacrylate
and vinyl pyrrolidone.
11. The process for preparing the water in oil emulsion defoamer
composition of claim 1 comprising:
(A) mixing
(a) from about 0.5 to about 10 percent by weight of an amide which is the
reaction product of a polyamine containing at least one alkylene group
having from two to ten carbon atoms and a fatty acid having from six to
eighteen carbon atoms,
(b) from about 0.5 to about 5.0 percent by weight of a polymer,
(c) from about 1 to about 10 percent by weight of an oil, and
(d) from about 0 to about 3 percent by weight of a silicone surfactant to
obtain a mixture of the amide and the polymer in the oil and the
surfactant;
(B) melting the mixture from step (A) by heating to a temperature not lower
than the melting point of the highest melting ingredient and not higher
than the flash point or point of decomposition of the least stable
ingredient, whichever is lower;
(C) maintaining the melt at the temperature of step (B) after a clear,
uniform melt has been obtained for a sufficient period to destroy any
sub-visual crystalline nuclei of the amide remaining therein;
(D) quick-chilling the melt by
(a) rapidly charging the same into a cooling oil present in an amount and
at a temperature sufficient to hold the temperature of the cooling oil
below the softening point of the amide after the melt is added thereto,
and which is being continually agitated, thus forming an agglomerate which
remains suspended therein, and cooling the agglomerate suspension of a
quick-chilled amide to room temperature, or
(b) rapidly charging the same onto a cold, heat conductive surface
accompanied by vigorous stirring and spreading of the melt over the
surface thus forming an agglomerate, scraping the agglomerate off the
surface and charging it into a tank containing a cooling oil at room
temperature, thus forming an agglomerate suspension of a quick-chilled
amide;
(E) charging separately to the agitated suspension of amide from step (D)
(a) from about 10 to about 60 percent by weight of oil,
(b) from about 3 to about 70 percent by weight of hydrophobic silica in oil
having from about 10 to about 15 percent by weight of silica,
(c) from about 0.5 to about 5 percent by weight of an emulsifier,
(d) from about 20 to about 60 percent by weight of water, and
(e) from about 0 to about 0.5 percent by weight of formaldehyde to obtain a
suspension;
(F) mixing the suspension from step (E) to obtain an emulsion, and
(G) homogenizing the emulsion from step (F) to obtain a defoamer
composition and then adding from 0 to about 0.5 percent by weight of
silicone oil to the homogenized defoamer composition.
12. The defoamer composition produced by the process of claim 11.
13. The process of defoaming an aqueous system comprising adding a foam
controlling amount of the defoamer composition of claim 1 to the aqueous
system.
14. The method of defoaming brown stock washer liquor in papermaking
comprising adding a foam controlling amount of the defoamer composition of
claim 1 to the liquor.
15. The method of foam prevention in a water based protective coating
comprising adding a foam controlling amount of the defoamer composition of
claim 1 to the coating. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to water based defoamer compositions and their use
in defoaming aqueous systems containing foam producing solids.
2. Description of the Prior Art
U.S. Pat. No. 2,715,614--Snook, issued Aug. 16, 1955 describes a defoamer
composition for paper machines which is a white semi-fluid aqueous
emulsion containing a paraffin hydrocarbon having at least 12 carbon
atoms, a partial ester of a polyhydric alcohol and a fatty acid having 14
to 22 carbon atoms, an ester of a monohydric alcohol having less than 9
carbon atoms and a fatty acid having 14 to 22 carbon atoms, an ester of a
polyethylene glycol having a molecular weight of from about 200 to about
4000 and a fatty acid having from 14 to 22 carbon atoms and water.
U.S. Pat. No. 2,843,551--Leonard et al, issued July 15, 1958 describe a
defoamer composition for latex paint which is a cream colored paste
containing a paraffin hydrocarbon, an ester of a polyethylene glycol
having a molecular weight greater than 400 and a fatty acid having from 12
to 22 carbon atoms, an aliphatic carboxylic acid having from 6 to 22
carbon atoms and a hydrocarbon soluble organopolysiloxane having from 1 to
3 alkyl radicals per silicon atom and water.
U.S. Pat. No. 3,652,453--MacDonnell, issued Mar. 28, 1972 describes a water
based defoamer composition containing quick-chilled amide, polymer,
emulsifier, oil and water.
U.S. Pat. No. 4,032,473--Berg et al, issued June 28, 1977 describe a water
based defoamer composition containing a water insoluble mineral
hydrocarbon, solid fatty acid diamide, hydrophobic silica particles and a
nonionic emulsifier which is a stearyl alcohol ethoxylate. The composition
is homogenized to obtain a stable pumpable emulsion having the appearance
and consistency of heavy cream.
SUMMARY OF THE INVENTION
Water based defoamer compositions are prepared containing from about 0.5 to
about 10% by weight of quick-chilled amide, about 0.3 to about 10% by
weight of hydrophobic silica, about 0.5 to about 5% by weight of polymer,
about 0.5 to about 5% by weight of emulsifier, about 15 to about 65% by
weight of oil and about 20 to about 60% by weight of water. Optionally,
these defoamer compositions may contain from about 0 to about 3% of
silicone surfactant, about 0 to about 0.5% by weight of aqueous
formaldehyde solution as a preservative and about 0 to about 0.5% by
weight of silicone oil. These water based defoamer compositions contain
less oil than commercial oil based products. Foam controlling amounts of
water based defoamer compositions are added to aqueous systems containing
from producing solids to control or prevent foaming. These water based
compositions are useful in defoaming in kraft brown stock washers and
latex paints.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Water based defoamer compositions may be prepared using the indicated
percentage by weight ranges of ingredients shown in the table.
______________________________________
Indicated
percentage by weight
______________________________________
quick-chilled amide 0.5-10
hydrophobic silica 0.3-10
polymer 0.5-5
emulsifier 0.5-5
oil 15-65
water 20-60
silicone surfactant 0-3
formaldehyde solution 0-0.5
silicone oil 0-0.5
______________________________________
Properties of each ingredient are described in detail below.
Quick-chilled solid amides useful in this invention may be prepared by
reaction of a polyamine containing at least one alkylene group having from
two to ten carbon atoms and a fatty acid having from six to eighteen
carbon atoms. Generally, the polyamine and fatty acids are reacted
together in stoichiometrically equivalent amounts. For example, the amide
can be obtained by reaction of a polyamine with a fatty acid or mixture of
fatty acids such as hexanoic, decanoic, lauric, palmitic, oleic and
stearic acids, hydroxy acids such as ricinoleic acid or naphthenic acids
obtained as by-products in the refining of petroleum. Natural mixtures of
fatty acids such as tall oil acids, tallow fatty acids and the like can be
used. Suitable amines include ethylene diamine, butylene diamine,
diethylene triamine, triethylene tetramine, hexamethylene diamine,
decamethylene diamine, hydroxyethyl ethylene diamine,
1,3-diamine-2-propanol and the like.
An amide useful herein is hydrogenated tallow diamide of ethylene diamine.
It was prepared by charging 95.7 parts by weight of bleached-hydrogenated
tallow fatty acids into a stainless steel reactor equipped with condenser,
water trap and agitator. The entire process including charging of
reactants and cooling of the reaction product is carried out under a
nitrogen atmosphere. The acids are then heated to about 165.degree. C. to
about 175.degree. C. and 10.1 parts by weight of ethylene diamine is
added. After the diamine is added, the reaction mixture is heated with
agitation to about 170.degree. C. to about 185.degree. C. The mixture is
reacted at about 180.degree. C. to about 185.degree. C. until the acid
value is less than 5 and the alkalinity less than 0.6% by weight. The
resulting reaction product of ethylene diamine and tallow fatty acid is
then cooled to room temperature and used in the "Quick-Chilling" Process
described below. If desired, the cooled reaction product can be ground to
obtain the amide in the form of a very fine powder. One or a mixture of
amides can be used if desired.
The "Quick-Chilling" Process used herein is essentially the same as that
described in U.S. Pat. Nos. 3,652,453--MacDonnell, issued Mar. 28, 1972
and 3,677,963--Lichtman et al, issued July 18, 1972, which descriptions
are hereby incorporated by reference. In the quick-chilling process used
in this invention the amide is combined with other ingredients such as the
polymer, silicone surfactant and oil in the melt. The quick-chilling
process consists of heating the amide and the other ingredients to the
above its melting point, maintaining the amide in a molten state for at
least 15 minutes, and then rapidly quick-chilling the amide by: (a) adding
a colder liquid such as oil or water; (b) rapidly dropping the melt into
colder liquid; or (c) applying the melt to a cold surface and adding the
resulting coagulate to the liquid. Optionally, the amide may be mixed with
some of the liquid before heating, in which case the mixture should be
heated to a temperature where the amide is fully dissolved and then
maintained at that temperature for at least 15 minutes. It is important in
either case that the amide be heated long enough for any crystalline
nuclei to be destroyed, so that the amide may more readily assume the
desired new crystalline structure formed by the quick-chilling process.
The term "colder" is defined as room temperature (22.degree. C.) or below.
Hydrophobic silica useful herein may be prepared from any of the well-known
forms of silica such as: (1) silica aerogel, a colloidal silica prepared
by displacing the water from a silica hydrogel by a low-boiling,
water-miscible, organic liquid, heating in an autoclave or the like above
the critical temperature of the liquid, and then venting the autoclave,
(2) fume silica, a colloidal silica obtained by burning silicon
tetrachloride and collecting the resulting silica smoke, (3) precipitated
silica prepared by destabilization of a water-soluble silica under
conditions which do not permit the formation of a gel structure, but
rather cause the flocculation of silica particles into coherent aggregates
such as by the addition of sodium ions to a sodium silicate solution; as
well as aluminum silicate, copper silicate, magnesium silicate, zinc
silicate, and the like. Almost any grade and particle size of silica is
useful although finer particles are preferred. Hydrophilic inorganic
particles which might be expected to be silica substitutes such as calcium
hydroxide, magnesium hydroxide and calcium carbonate were found not to be
useful.
Any suitable method may be employed for treating the normally hydrophilic
silica to render it hydrophobic. One method which has proved very
satisfactory involves spraying the silica with silicone oil and heating at
elevated temperature, i.e., from about 250.degree. C. to about 350.degree.
C., for about 1/2 to about 2 hours. The amount of silicone oil utilized
may vary from about 5% to about 100% by weight based on the weight of the
silica. However, amounts from about 7 to about 25% will usually be
satisfactory and are preferred.
The silicone oil can be a polysiloxane oil such as an alkyl, aryl,
alicyclic or aralkyl siloxane or polysiloxane having a viscosity of from
about 10 to about 3000 centistokes at 25.degree. C. Preferred silicone
oils include alkyl polysiloxanes having viscosities of from about 40 to
about 100 centistokes at 25.degree. C. These alkyl polysiloxanes include
dimethyl polysiloxane, diethyl polysiloxane, dipropyl polysiloxane, methyl
ethyl polysiloxane, dioctyl polysiloxane, dihexyl polysiloxane, methyl
propyl polysiloxane, dibutyl polysiloxane, didodecyl polysiloxane, methyl
phenyl polysiloxane or the like.
The finely divided silica may also be rendered hydrophobic by treatment
with vapors of an organo-silicon halide or mixture of organo-silicon
halides. Examples of suitable organo-silicon halides are given in U.S.
Pat. Nos. 2,306,222 and 2,412,470 and include alkyl (methyl), aryl
(phenyl), alkaryl (tolyl) and aralkyl (phenyl methyl) silicon halides. The
treatment may be carried out by agitating the finely divided material in a
closed container in the presence of vapors of the treating material, e.g.,
dimethyl dichlorosilane. The amount of treating material and length of
treatment will depend upon the surface area of the inorganic material and
nature of the organo-silicon halide employed. In general, it will be
satisfactory to use from about 5 to about 30% by weight of treating agent
based on the weight of silica and a time of treatment from about 1/2 hour
to about 2 hours.
Still another method of rendering the silica hydrophobic is by dispersing
it in silicone oil, i.e., in a concentration from about 2-10% and heating
the dispersion to about 250.degree.-300.degree. C. for about an hour more
or less. The hydrophobic silica may then be extracted by centrifuging the
mixture after dilution with hexane or a similar type of solvent and drying
the resulting solid.
The hydrophobic silica utilized will desirably have an average particle
size less than about 10 microns and preferably less than about 5 microns.
Most preferred is an average particle size from about 0.02 micron to about
1 micron. Where particle size of the silica is measured in terms of Oil
Absorption Value, 125 g of oil absorbed per 100 g of silica is the minimum
useful value and 170 or higher value is preferred. The hydrophobic silica
is dispersed in oil to obtain a dispersion of from about 10 to about 15%
by weight silica which is added as a component C ingredient.
Polymers useful herein include vinyl acetate copolymerized with
ethylenically unsaturated comonomers which are copolymerizable therewith
such as maleic and fumaric acid esters, ethylene, propylene and butylene;
polyalkylene oxide adducts such as methyl glucoside propoxylated with 4
moles of propylene oxide; glycerine alkoxylated with 15 moles of ethylene
oxide and 45 moles of propylene oxide; butanol propoxylated with 30 moles
of propylene oxide; the copolymer of lauryl methacrylate and vinyl
pyrrolidone; methacrylate copolymers dissolved in solvent-refined (100 SUS
at 38.degree. C.) neutral oil; and phenol modified coumaroneindene resins.
These materials can be used alone or in admixture with each other.
One oil soluble polymer which is preferred is a copolymer of vinyl acetate
and fumaric acid esterified with a tallow alcohol. Such an oil soluble
polymer is available from Exxon Chemical Co. in the form of a mineral oil
solution thereof under the trademark "Paratone 440" which consists of
about 25 parts by weight of said copolymer in 75 parts by weight of a
liquid hydrocarbon. This product has the following properties:
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Viscosity at 98.9.degree. C., cs
1300
Flash Point, COC, .degree. C.
182
Color, ASTM 40
Specific Gravity at 15.6.degree. C.
0.92
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Another preferred oil soluble polymer is a copolymer of styrene and a
polyester. Such an oil soluble polymer is available from The Lubrizol
Corporation in the form of a paraffin oil solution thereof under the
trademark "Lubrizol 3702" consists of about 30 parts by weight of said
copolymer in 70 parts by weight of liquid hydrocarbon. This product has
the following properties:
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Viscosity at 98.9.degree. C., SUS
3800
Viscosity at 98.9.degree. C., cSt
815
Specific Gravity 15.6.degree. C.
0.905
______________________________________
Still another preferred oil soluble polymer is a copolymer of alkyl
methacrylate and N-vinyl pyrrolidone. Such an oil soluble polymer is
available from Rohm and Haas Company in the form of a neutral oil solution
thereof under the trademark "Acryloid 966" which consists of about 30
parts by weight of said copolymer in 70 parts by weight of liquid
hydrocarbon. This product has the following properties:
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Viscosity at 98.9.degree. C., SUS
3730
Viscosity at 98.9.degree. C., cSt
800
Flash Point, COC,.degree. C.
192.5
Color, ASTM 3
Specific Gravity at 15.6.degree. C.
0.899
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The emulsifier may be a nonionic, anionic or cationic surfactant. Useful
nonionic surfactants include castor oil plus 15 EO (one mole of castor oil
condensed with 15 moles of ethylene oxide), nonylphenol plus 1.5 EO,
hexadecylphenol+5 EO or the Pluronics. Suitable ethylene oxide condensates
may be prepared by condensing ethylene oxide with any organic compound
having a reactive hydrogen and a hydrophobic moiety containing at least 10
carbon atoms. Useful condensates include ethoxylated alkylphenols,
aliphatic alcohols, fatty acids, amines, esters or amides of fatty acids
having at least 10 carbon atoms in the hydrophobic moiety or
polyoxypropylene glycol. Ethylene oxide condensates are well known and are
used extensively as nonionic surfactants. Additional details on other
useful nonionic surfactants as well as suitable anionic and cationic
surfactants may be found in U.S. Pat. No. 4,021,365--Sinka and Lichtman
issued May 3, 1977, whose teachings are incorporated by reference herein.
The oil used in the defoamer composition may be any liquid aliphatic,
alicyclic, aromatic hydrocarbon. The hydrocarbon should be liquid at room
temperature and atmospheric pressure, have a viscosity of from about 30 to
about 400 SUS (Saybolt Universal Seconds at 100.degree. F.), a minimum
boiling point of at least 150.degree. F. and an average from about 6 to 25
carbon atoms. Suitable hydrocarbons include hexane, heptane, octane,
dodecane, mineral seal oil, stoddard solvent, petroleum naphtha, benzene,
toluene, xylene, paraffinic mineral oil, naphthenic mineral oil and their
mixtures. When the oil is used in quick-chilling of the amide, the oil
must have a minimum boiling point equal to the melting point of the amide.
Triglycerides such as soya oil, rapeseed oil, etc. and fatty alcohols, Oxo
bottoms and the like may be used instead of oil in the composition.
The silicone surfactant may be a polysiloxane-polyalkylene oxide copolymer
such as silicone surfactant (a), a polydimethylsiloxane-polyalkylene oxide
copolymer having a cloud point of 23.degree. C. (1% solution in water).
The polysiloxane-polyalkylene oxide copolymer may be silicone surfactant
(b) having a cloud point of 36.degree. C. or silicone surfactant (c) which
is Union Carbide SAG5300 silicone antifoam having a cloud point of
38.degree. C. (1% solution in water). Other useful
polysiloxane-polyalkylene oxide copolymers include silicone surfactant (d)
having a cloud point of 43.degree. C. and silicone surfactant (e) having a
cloud point of 41.degree. C. (1% solution in water).
The formaldehyde solution used as a preservative may be a 37% aqueous
solution of formaldehyde or an alcoholic solution containing an equivalent
amount of formaldehyde. The term formaldehyde solution includes
formaldehyde in the form of 30 to 40% aqueous solutions, 30 to 55% alcohol
solution using alcohols such as methanol, butanol or isopropanol,
polymeric forms such as paraformaldehyde, trioxane or hexamethylene
tetraamine as well as chemical compounds such as acetals which will
liberate formaldehyde.
The silicone oil may be a polysiloxane oil such as an alkyl, aryl,
alicyclic or aralkyl siloxane or polysiloxane having a viscosity of from
about 10 to about 3000 centistokes at 25.degree. C. Preferred silicone
oils include alkyl polysiloxanes having viscosities of from about 40 to
about 1000 centistokes at 25.degree. C. These alkyl polysiloxanes include
dimethyl polysiloxane, diethyl polysiloxane, dipropyl polysiloxane, methyl
ethyl polysiloxane, dioctyl polysiloxane, dihexyl polysiloxane, methyl
propyl polysiloxane, dibutyl polysiloxane, diodecyl polysiloxane and the
like, each having a viscosity of from about 10 to about 3000 centistokes
at 25.degree. C.
Useful water based defoamer compositions which are invert emulsions may be
prepared with the above ingredients using the following procedure:
(A) mixing
(a) from about 0.5 to about 10.0 percent by weight of an amide which is the
reaction product of a polyamine containing at least one alkylene group
having from two to ten carbon atoms and a fatty acid having from six to
eighteen carbon atoms,
(b) from about 0.5 to about 5.0 percent by weight of a polymer,
(c) from about 1 to about 10 percent by weight of an oil, and
(d) from about 0 to about 3 percent by weight of a silicone surfactant to
obtain a mixture of the amide and the polymer in the oil and the
surfactant;
(B) melting the mixture from step (A) by heating to a temperature not lower
than the melting point of the highest melting ingredient and not higher
than the flash point or point of decomposition of the least stable
ingredient, whichever is lower;
(C) maintaining the melt at the temperature of step (B) after a clear,
uniform melt has been obtained for a sufficient period to destroy any
sub-visual crystalline nuclei of the amide remaining therein;
(D) quick-chilling the melt by
(a) rapidly charging the same into a cooling oil present in an amount and
at a temperature sufficient to hold the temperature of the cooling oil
below the softening point of the amide after the melt is added thereto,
and which is being continually agitated, thus forming an agglomerate which
remains suspended therein, and cooling the agglomerate suspension of a
quick-chilled amide to room temperature, or
(b) rapidly charging the same onto a cold, heat conductive surface
accompanied by vigorous stirring and spreading of the melt over the
surface thus forming an agglomerate, scraping the agglomerate off the
surface and charging it into a tank containing a cooling oil at room
temperature, thus forming an agglomerate suspension of a quick-chilled
amide;
(E) charging separately to the agitated suspension of amide from step (D)
(a) from about 10 to about 60 percent by weight of oil,
(b) from about 3 to about 70 percent by weight of hydrophobic silica in oil
having from about 10 to about 15 percent by weight of silica,
(c) from about 0.5 to about 5 percent by weight of an emulsifier,
(d) from about 20 to about 60 percent by weight of water, and
(e) from about 0 to about 0.5 percent by weight of formaldehyde
to obtain a suspension;
(F) mixing the suspension from step (E) to obtain an emulsion, and
(G) homogenizing the emulsion from step (F) to obtain a defoamer
composition and then adding from 0 to about 0.5 percent by weight of
silicone oil to the homogenized defoamer composition.
The viscosity range of the defoamer compositions in this invention is 200
to 4,000 cs, with the preferred range being 500 to 2000 cs.
The following test method may be used to determine effectiveness of the
defoamer composition in reduction of and prevention of foam in brown stock
washer liquor. Commercial brown stock washer liquor was used in the test
described below.
The defoamer compositions of this invention are also useful in the
reduction of existing foam (knock-down) and prevention of foam formation
(hold-down) which occurs in brown stock washer liquor during the pulping
process. When used for this purpose, from about 0.003 to about 0.5 parts
by weight of defoamer solids are added to the pulp, per 100 parts by
weight of dry pulp.
The following apparatus and test method was used in determining the
effectiveness of various compositions in knocking down and holding down
foam in brown stock washer liquor. The apparatus and method could,
however, be used for testing any liquid which forms a foam upon agitation
and/or heating.
A 1000 cc tall form beaker is used as the primary container for the liquid
to be tested. A curved glass outlet fused onto the base of the beaker is
connected with a rubber hose to a centrifugal pump. The pump is used to
circulate continuously the test liquid from the beaker into the pump and
back into the beaker. Pumping is carried out at a rate so that the test
liquid in the beaker is agitated by the reentering test liquid to such an
extent that foam forms. The pumping rate is about two gallons per minute.
Test liquid enters the beaker at a point about 6 centimeters about the
surface of the liquid in the beaker and strikes the surface of the liquid
in the beaker at an angle of 90.degree..
In carrying out the testing of the defoamer compositions, 500 cc of freshly
obtained concentrated brown stock washer liquor is charged at about
75.degree. C. into the beaker. This liquid, when quiescent, fills the
beaker to a level of about 8.3 centimeters from the bottom. This level is
marked and labeled the 0 line. In the test for hold-down, 0.1 cc of
defoamer composition is added to the 500 cc of test liquid in the beaker.
The pump and stop watch are started simultaneously. Height of the foam
about the 0 line is measured at 15 second intervals for the first minute,
then at 30 second intervals, and recorded. In the test for knock-down, the
liquor is agitated and heated prior to the addition of any defoamer
composition. After a foam has built up to 8 centimeters, 0.1 cc of the
defoamer composition to be tested is added and the data is recorded as
above.
Test results using the above method are shown in Table II.
These tests demonstrate that the compositions of this invention are
effective defoamers compared to existing commercial oil based defoamers
containing quick-chilled amides.
The apparatus and method described above may also be used to evaluate the
defoamer composition in any liquid which forms foam during agitation
and/or heating.
Other aqueous systems which may be defoamed with these invert defoamer
compositions include kraft screen room bleach plant applications, pulp and
paper mill effluents, animal glues, other adhesives, latex, starches,
other resinous systems, water base paints and the like.
For a fuller understanding of the nature and advantages of this invention,
reference may be made to the following examples. These examples are given
merely to illustrate the invention and are not to be construed in a
limiting sense. All quantities, proportions and percentages are by weight
and all references to temperature are .degree.C. unless otherwise
indicated.
EXAMPLE I
A defoamer composition was prepared using the indicated quantities (% by
weight) of ingredients shown under Components A, B and C for Example I in
Table I.
The Component A ingredients were charged to a kettle, heated to 150.degree.
C. to melt and mixed until uniform. The uniform molten Component A mixture
was heated for 15 minutes at 145.degree. C. and dropped into the Component
B ingredient which had been previously cooled to 25.degree.
C..+-.2.degree. C. to form a quick-chilled amide as described in U.S. Pat.
No. 4,021,365--Sinka and Lichtman, issued May 3, 1977. Components A and B
were blended for 15 to 30 minutes and temperature of the quick-chilled
amide mixture was adjusted to below 50.degree. C.
The ingredients shown in Component C in Example I in the Table were then
added to the agitated Component A and B mixture. Paraffinic oil,
paraffinic/napthenic oil, 14% hydrophobic silica by weight in oil and
castor oil plus 15 EO condensate ingredients were added separately to the
agitated Component A and B mixture. The water ingredient was then heated
to 25.degree..+-.3.degree. C. and added slowly to the mixture to obtain an
emulsion which was mixed until uniform. A total weight of 0.1% by weight
aqueous formaldehyde solution was then added to the emulsion as a
preservative and the emulsion mixed until homogeneous.
The homogeneous emulsion was homogenized in a Manton-Gaulin homogenizer at
1250.+-.50 psi at 25.degree. C..+-.3.degree. C. and agitated for 15
minutes. Then 0.1% by weight of silicone oil was added and the mixture
stirred for an additional 15 minutes to finish the defoamer composition.
EXAMPLES II-XI
Defoamer compositions were prepared using the indicated quantities (% by
weight) of ingredients shown for Components A, B and C under Examples II
through XI in Table I following the procedure given in Example I.
EXAMPLE XII
Emulsion defoamer compositions prepared in Examples I through XI were
evaluated as defoamers for brown stock washer liquor using the procedure
described in the specification. Results of these tests are shown in Table
II as well as comparative tests with a commercial oil based product
containing quick-chilled amides.
TABLE I
__________________________________________________________________________
DEFOAMER COMPOSITIONS (% by wt)
Component
Ingredient 1 II III
IV V VI VII
VIII
IX X XI
__________________________________________________________________________
A paraffinic oil
2.0
2.5
2.5
2.5
2.0
2.0
2.0
2.0
2.0
2.0
2.0
A ethylene bisstearamide
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
A polymethacrylate in oil
3.0 1.0
3.0
3.0
3.0
4.5
3.0
3.0
3.0
A silicone surfactant (a)
1.5
A silicone surfactant (b)
0.5
2.0 1.5
A silicone surfactant (c) 1.5
A silicone surfactant (d) 1.5
A silicone surfactant (e) 1.5
A butanol + 30 PO 1.5
A vinyl acetate/tallow
fumarate copolymer
2.0
2.0
2.0 1.5
B paraffinic oil
21.0
22.5
21.0
22.0
21.0
21.0
21.0
21.0
21.0
21.0
21.0
C paraffinic/naphthenic oil
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
5.0
C paraffinic oil
6.0
6.0
3.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
C hydrophobic silica in oil
8.0
8.0
11.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
C castor oil + 15 EO
1.0
1.5
1.2
1.5
1.0
1.0
1.0
1.0
1.0
1.0
1.0
C water 49.8
49.5
49.6
49.5
49.8
49.8
49.8
49.8
49.8
49.8
49.8
C formaldehyde solution
0.1 0.1 0.1
0.1
0.1
0.1
0.1
0.1
0.1
C silicone oil
0.1 0.1 0.1
0.1
0.1
0.1
0.1
0.1
0.1
__________________________________________________________________________
TABLE II
______________________________________
HOLD-DOWN EFFICACY TESTS
With Georgia Brown Stock Washer Liquor
Dosage 100 .mu.l (microliter)
Foam Level vs Time (Sec)
Defoamer Example
15 30 45 60 75 90 120 150 180
______________________________________
I 18 5 8 10 13 18 20 28 30
20 10 10 15 15 20 23 28 30
Coml. oil based
20 8 10 13 15 18 23 33 40
20 8 10 10 15 15 20 28 35
II 30 20 25 38 48 55 70 80
III 15 10 13 15 18 20 25 30 35
15 10 13 15 18 20 25 30 35
IV 20 18 25 35 45 55 70 80
V 20 8 8 10 15 18 23 30 35
18 8 8 10 15 18 23 30 35
VI 15 8 10 10 15 18 23 30 35
15 8 10 10 15 18 23 30 35
VII 10 5 10 10 15 18 23 30 35
10 5 8 10 13 15 23 30 35
VIII 10 5 8 10 13 15 20 28 30
10 5 8 10 13 15 20 28 30
IX 5 5 10 10 10 13 20 20 20
5 5 10 10 10 13 20 20 20
X 15 10 10 13 15 18 23 28 33
15 10 10 13 15 18 23 28 33
XI 10 5 5 8 10 10 13 15 20
13 8 10 10 10 10 13 15 20
______________________________________
EXAMPLE XIII
This example demonstrates use of the defoaming compositions of Examples I
and III as latex paint defoamers in the following Shaker Test.
Hold-down foam tests were conducted by adding 0.5% by weight of each
defoamer composition based on the weight of latex to Rhoplex AC-490 (Rohm
and Haas Company) acrylic latex. The defoamer composition was added to 125
cc of the latex weighed into a 250 cc can. Samples prepared with and
without defoamer composition were shaken on a Red Devil paint shaker for 5
minutes. Immediately after shaking, the density (wt/gal) of each sample
was determined. The decrease in density of each sample was compared with
the control to determine the amount of air entrapped and the following
results were obtained.
______________________________________
% Air
Entrapped
______________________________________
Blank (No Defoamer) 27.7
0.5% (by wt) of Example I
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