CA1040964A

CA1040964A - Foam control composition

Info

Publication number: CA1040964A
Application number: CA222,742A
Authority: CA
Inventors: Joseph W. Keil
Original assignee: Dow Corning Corp
Current assignee: Dow Silicones Corp
Priority date: 1974-09-03
Filing date: 1975-03-21
Publication date: 1978-10-24
Also published as: DE2518053A1; AR202610A1; JPS5435879B2; FR2283947A1; FR2283947B1; DE2518053B2; DE2518053C3; GB1505665A; BE832978A; JPS5128868A; AU7976475A; BR7504299A

Abstract

Abstract of the Disclosure A composition for controlling foam is disclosed which consists essentially of (1) a base oil of poly-oxypropylene polymers, polyoxypropylene-polyoxyethylene copolymers or siloxane glycol copolymers, (2) mineral oil, (3) silica or a siloxane resin composed of SiO2 and (CH3)3SiO1/2 units, and (4) a siloxane copolymer dispersing agent.

Description

104~3~?64 The use of mineral oil as an antifoamer or defoamer is well known. One of the problems in using mineral oil as a foam control agent has been the inability to introduce it into certain systems because of its incompatibility. Another problem has been keeping the mineral oil well dispersed throughout the medium in which foam is being controlled. It has been found in accordance with this invention, that the aforementioned problems can be substantially minimized with the composition of this invention.
Thus, in accordance with the present teachings a composition is provided which consists essentially of (1) 65 to 98.4 percent by weight of a base oil selected from the group consisting of polyoxypropylene polymers and polyoxypropylene~polyoxyethylene copolymers ~-having molecular weights in the range of 500 to 6000, and ` siloxane glycol copolymers having the general formulae (a) RaSi[(OsiMe2)n(osiMeG)bosiMe2G]4-a~
(b) RaSi¦(OSiMe2)n(OsiMeG)cosiMe3]4-at (c) GMe2Si(OSiMe2)n(OSiMeG)bOSiMe2G, and ~ -: .~ - -.
(d) Me3Si(OSiMe2)n(OSiMeG)cOSiMe3 in which formulae R is a hydrocarbon radical free of aliphatic unsaturation and contains from 1 to 10 carbon atoms, -Me is a methyl radical, -'. G is a radical of the structure -D(OR')mA --wherein D is an alkylene radical contain-ing from 1 to 30 carbon atoms, R'is an alkylene radical containing from

2 to 10 carbon atoms, and jf 30 A is a capping group, a ha~ a valwe of 0 or 1, n has a value of at least 1, ~` B~
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'` l~g~964 b has a value of 0 to 50, and . c has a value of 1 to 50, (2) 1 to 20 percent by weight of mineral oil,

(3) 0.5 to 5 percent by weight of a material selected from the group consisting of silica and a resin : composed of SiO2 and (CH3)3SiOl/2 units in which resin in the ratio of the SiO2 units to the (CH3)3Siol/2 units is in the range of 1:0.4 to 1:1.2, and `

(4) 0.1 to 10 percent by weight of a dispersing agent which maintains (2) dispersed in (1) and which is a siloxane copolymer selected from the group consisting of (i) copolymers consisting essentially of SiO2 units, (cH3)3siol/2 units and Q(CH3)2Siol/2 ~` units wherèin Q is a polyoxypropylene ~ polymer or a polyoxypropylene-polyoxyethylene .~ copolymer radical having a molecular weight ~ in the range of 500 to 6000, Q being attached :~ to the silicon atom via a silicon-carbon bond, .
, the ratio of the SiO2 units to the total 3 3 1/2 and Q(CH3)2SiOl/2 units being in the range of 1:0.4 to 1:1.2, and 3 (ii) copolymers which are the reaction products derived from heating a mixture of a siloxane copolymer consisting essentially .
;i 2 un t nd (CH3)3sil/2 units in ~; which the ratio of SiO2 units to the . (CH3)3SiOl/2 units is in the range of ~` 1:0.4 to 1:1.2, and a hydroxylated -.
. polyoxypropylene polymer or a hydroxylated ~ 30 polyoxypropylene-polyoxyethylene copolymer j having molecular weights in the range of ~ 500 to 6000.
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` ` 1~64 The first component of the composition is a base oil which can be a polyoxypropylene polymer or a polyoxypropylene-polyoxyethylene copolymer. These polymers are commercially available from many sources and are characterized as polymers of [CH2CH(CH3)O] units or such units copolymerized with (CH2CH2O) units. The polymers may be terminated with methyl, ethyl or propyl groups, for example, or they may be terminated with hydroxyl groups.
The terminal groups are not known to be critical for the purposes of this invention. It is noted, however, that the commercially available products commonly are hydroxyl terminated and are referred to by those skilled in the art by the misnomers "polypropylene glycols" or "polypropylene-polyethylene glycols" regardless of whether they are monols, diols, triols or polyols. It has been found that such polymers having molecular weights in the range of 500 to -6000 are useful in the composition of this invention.
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~)4~64 The base oil can also be a siloxane glycol copolymer havin~ the general formulae (a) ~aSi[(OSiMe2)n(OSiMeG)bOSiMeqG]4 a' (b) RaSi[(OSiMe2)n(OSiMeG)cOSiMe3]4 a' (c) GMe 2 Si ( OSiMe 2 ) n(OSiMeG)bOSiMe~G, and (d) ~le 3 Si ( OSiMe 2 ) n(OSiMeG)cOSiMe 3 in ~hich I`ornlulae R is a hydrocarbon radical free of aliphatic unsaturation and contains from 1 to 10 carbon atoms, Me is a methyl radical, G is a radical of the structure -D(ORI)mA wherein D is an alkylene radical containing from 1 to 30 carbon atoms, R' is an alkylene `~ ra~ical containing from 2 to 10 carbon atoms, m has a value of at least 1, and A is a capping group, a has ` a value of 0 or 1, n has a value of at least 1, b has a value of 0 to 50, and c has a value of 1 to 50.
In the above formulae, R can be any hydrocarbon radical free of aliphatic unsaturation which contains ~ from 1 to 10 carbon atoms such as a methyl, ethyl, propyl, :~
t, isopropyl, butyl, hexyl, decyl, phenyl, tolyl, benzyl, xylyl, methylcyclohexyl, cyclohexyl, cyclopentyl, ~ phenylpropyl or a ~-phenylethyl radical.
-~ Speclfic examples of alkylene radical D which links the ~lycol portion of G to the silicon atom are the methylene, ethylene, propylene, isopropylene, butylene, octylene, decylene, octadecylene and the myricylene radlcals. Pre~erably, D contalns from 1 to 18 carbon atoms. - ~-R' in the above formula is any alkylene radical containing from 2 to 10 carbon atoms. Thus, R' can be ;
an ethylene, propylene, isopropylene, butylene, hexylene, ;

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7, 1()4(3~64 octylene or a decylene radical Most preferably, R' contains from 2 to 4 carbon atoms. It is noted that R' can be derived ~rom a single 1ycol or a comblnation of glycols. That is to say, for example, OR' can be ethylene oxide units, propylene oxide units or butylene oxlde units only, or OR' can be comblnations of such units.
The symbol m which defines the number Or 0~' units ln the glycol portlon of the molecule can have a value as low as 1 and can range up to 1000 or more.
~` 10 Generally, m will have an average value in the range of 10 to 100.
The glycol or polyoxyalkylene unlt is terminated or capped by the A group. The speclfic nature of this .;, .
group is not known to be critical for purposes of this invention. Thus, the ~lycol can be capped by a hydroxyl group (A is a hydrogen atom), by an ether group (A
is a monovalent hydrocarbon radical such as a methyl, ~ butyl, vinyl or pAenyl radical), by a carboxyl radical, J by the salt or ester of a carboxyl radical, by a carbonate -~
ester group, or by an isocyanate group.
The symbol n which defines the number of dlmethylsiloxane units in the molecules can have a value of at least 1 and can range up to 1500 or more.
It is believed that the number of dimethylsiloxane units in the molecule in relationship to the glycol containing G units æhould be at least 10:1 for the most satisfactory results to be obtained. The upper ratio of OSiMe2 units to G containing units can be 50:1 or more.
The siloxane glycol copolymers useful as base oils herein are well known commercially available .~ . ,. .
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~4~964 materials. For those unfamiliar wlth these compounds, attention is dlrected to U.S. Pats. 3,402,192; 3,518,288;
and 3,637,7~3 for illustrative descriptions of their preparations and other details.
The base oil can constitute from 65 to 98.4 percent by weight Or the composition. The base oil can be made up of a polyoxypropylene polymer per se, a polyoxypropylene-polyoxyethylene copolymer per se, a siloxane glycol copolymer per se, or a mixture of any of these. The partlcular base oll used will depend on the particular nature of the system ln which lt ls deslred to control the foam.
The second component of the composltion is mineral oll. Mlneral oll can constltute from 1 to 20 percent by welght of the composltion. The term " mlneral oll" as used herein includes its analogs such -as naphthenic mineral oil, paraffinic mineral oil~
~; white oil, and the like.
The thlrd component of the composltlon ls a sllica or a siloxane resin composed of S102 unlts and t 20 (CH9),SiOl/2 units. This component can make up from 0.5 to 5 percent by weight of the composition. Examples o~ suitable silicas include silica aerogels, precipitated silicas, silica xerogels, fume silicas, and treated silicas which have organosilyl groups on their surface. Such silicas are commercially available and well known to those skilled in the art as are other -silicas which can be employed herein. Generally speaklng, ~ -the ~ilica should be finely divided and preferably has~ ;
an average particle size of less than 10 mlcrons. ---.

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~Q~964 The siloxane resins composed of SiO2 units and (CH3)3SiO,/2 units are well known materlals whlch are commercially available. Those reslns which are useful in this inventlon have a ratlo of the Sl02 unlts to the (CH333SiO~/2 units in the ran~e of 1:0.4 to 1:1.2. These resins as prepared usually contain resldual hydroxyl groups (about 2 to 5 percent by welght). The residual hydroxyl groups can be reduced to practlcally nothing by well-known technlques such as ~OH bodying.
So far as ls known at thls time, all of these resins, regardless of the amount of residual hydroxyl groups, are useful in this invention~

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J, The fourth essentlal component o~ the composltlon of this lnventlon ls characterlzed as a " dlspersing . .
agent " for want of a better term. The function of thls ~¦ component ls to keep (2) dlspersed ln base oll (1).
Two types of siloxane copolymers have been found which `~ wlll serve this purpose. One of these copolymers conslsts essentially of siO2 unlts, (CH3),SiOl/2 unlts and Q(CH,)2SiOl/2 units wherein Q is a polyoxypropylene polymer or a polyoxypropylene-polyoxyethylene copolymer radical having molecular weights in the range of 500 to 6000, Q being attached to the sillcon atom via a silicon-carbon bond, and the ratio of the siO2 units to the total (CH3)~SiOl/2 and Q(CH3) 2sio~/2 units is ".- .':' ~- ln t~e range of 1:0.4 to 1:1.2. The other known operable copolymer ls the reaction product obtained by heating 1 a mixture o~ ~ slloxane copolymer consistlng essentially 1 f Sl02 units and (CH,),SiOl/2 units ln which the t 30 ratio o~ the siO2 unlts to the (CH3),SlOl/z units is .,~ ,. - ,.

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104(3~;4 ; in the rane of 1:0.4 to 1:1.2, and a hydroxyl containlng polyoxypropylene polymer or a hydroxyl containlng polyoxypropylene-polyoxyethylene copolymer having molecular weights in the ran~e of 500 to ~oOo.
The first copolymer is best prepared by cohydrolyzing and condensin~ a mixture of (CH3)3SlCl, H(CH~)~SiCl and SiCl 4 and then coupllng an allyloxy ended polyoxy-alkylene polymer thereto wlth the aid of a platinum catalyst. For those un~amlliar wltn thls preparatlon, attention is dlrected to U.S. Patent 3,511,7~8, particularly Examples 5 and 6, ror details.
` The second copolymer which is preferred ls made simply by heating a mixture of the two ingredlents $ ror about two hours at reflux, preferably ln the presence ; of a siloxane condensation catalyst such as potasslum -~ hydroxlde or tin octoate. In thls case, it is theorized ~-that the resldual hydroxyl groups on the sllicon atoms in the slloxane condense with the hydroxy groups of the polyoxyalkylene polymer to form a silicon-oxygen-carbon bond between the two reactants.
Component (4) as prepared generally contalns a solvent such as xylene or toluene. Thls component i . . . :
can be used as prepared or the solvent can be removed ~rom the product before incorporatlon lnto the composition. ~ -Either way no difrerence in performance ls known to -` -occur. If the solvent is not removed before adding this component, one less processing step is involved and the r~ nal product is more economically produced. The compositlon of thls lnvention can contain, therefore, ~rom 0 to 10 percent by weight of a solvent.
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104(~'9~;4 The composition of this invention is prepared by simply mixing the four CGmpOnentS together in the correct proportions. So far as is known at this time, there is no particular order in which the components should or need be mixed.
The amount of the con~position of this invention w}lich is employed will depend on the particular system in which foam is to be controlled and the extent to which the user wishes to control the foam. Thus, the amounts will vary depending on whether one is using the composition in an alkaline soap solution, evaporation of alkaline paper blac~ liquor, concentration of synthetlc rubber ` latices, stea~ distillation of styrene-butadiene emulsions, refining sugar, dyeing textiles, treatin~ sewa~e for . ~ . . . .
~`~ disposal, or the like. The compositions of this lnventlon can be used as any kind of foam control agents, i.e., as defoaming agents and/or antifoaming agents.
Defoaming agents are ~enerally considered as foam reducers whereas antifoamlng agents are generally considered as foam preventors. As noted, the instant compositions can serve in either or both capacities. ~-~
Now in order that those skilled in the art may better understand how the present invention can be practiced, the following examples are given by way o~ illustration and not by way of limitation. All parts and percents referred to herein are by weight, and all vlscositles measured at 25C., unless otherwise specified.
In the examples, the " antifoam pump test " -referred to is as descrlbed hereinafter unless otherwise speclfled. Thls test makes use of a motor drlven pump -`

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;4 (Eastern Industries Model B-l: style CZZ-71-ZV) which continually recirculates the foaming system. The foaming system is pumped into a stainless steel cylinder 7 inches high with a 5 inch diameter (2000 ml. capacity) where foam height is measured. A heating mantel is located at the bottom of the cylinder to control the temperature.
In this test, 1000 ml. of a 0.1% solution o polyoxyethylene sorbitan monooleate in water i5 placed in the pump test vessel. Lines are marked on the inside of the cylinder at levels of 1, 2 and 3 inches above the surface of the liquid.
The surfactant solution is heated in the pump test vessel to 66C., then a number of drops of the antifoam composition being tested is added, and then the mixture is heated to 88C. `
before turning the pump on. The length of time for the foam ~`
to reach a particular height is recorded. The pump is then shut off and the length of time for the foam to break ~e.g. when the liquid surface can be seen) is recorded.
Also, the sides of the cylinder wall are examined and the presence or absence of an antifoam deposit ~sometimes referred -to as an "oily" deposit) recorded. The presence of such a deposit indicates that such antifoams would cause objectionable spotting of textile goods.
Example 1 A series of tests were run using the antifoam pump test described above. The antifoam compositions ! used in this test are described below.
Composition A is a commercially available material consisting essentially of a polydimethylsiloxane fluid ~` treated silica in mineral oil. ~ --., -.

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la~ 4 Composition B consisted essentially of 100 parts commercially available mineral oil, 5 parts silica, 1.33 parts of a 50% xylene solution of a siloxane resin copolymer composed of SiO2 and (CH3)3SiO1~2 units~ the ratio of said units being in the range of 1:0.4 to 1:1.2, 0.67 part of a hydroxyl endblocked polydimethylsiloxane having a viscosity of about 65 cs., 1 part of a thickening agent, and 2 parts of a tall oil fatty acid.
Composition C consisted essentially of 10 parts of composition B plus 0.5 parts of a mineral oil -~
soluble nonionic surfactant. Composition C is self-emulsifying in water.
Composition D consisted essentially of a 30~
solution in water of a mixture of 40 parts of composition A, 60 parts of a polyoxypropylene-polyoxyethylene copolymer (about a 1:1 mole ratio) having a molecular weight of about 6280, and S parts of a siloxane copolymer which is the reaction product derived from heating at reflux a mixture of 25 parts of a siloxane consisting essentially of SiO2 and (CH3)3SiOl/2 units in which the ratio of the SiO2 to (CH3)3SiOl/2 units is in the range of 1:0.4 to 1:1.2, 75 parts of a hydroxylated polyoxyethylene-polyoxypropylene copolymer ~about a 1:1 mole ratio) having a molecular weight of about 2600, and 0.1 part of .
KOH catalyst. Composition D is self-emulsifying in water.

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~4~;4 Composition E consisted essentially of a 30%solution in water of a mixture of 70 parts of a poly-oxypropylene-polyoxyethylene copolymer ~about a 1:1 mole ratio) having a molecular weight of about 6280;
5 parts of a siloxane copolymer which is the reaction product derived from heating at reflux a mixture of 25 parts of a siloxane consisting essentially of SiO2 and (CH3)3SiOl/2 units in which the ratio of the SiO2 to ~CH3)3SiOl/2 units is in the range of 1:0.4 to 1:1.2, 75 parts of a hydroxylated polyoxyethylene-polypropylene copolymer (about a 1:1 mole ratio) having a molecular weight of about 2600, and 0.1 part of KOH catalyst;
and 30 parts of a composition prepared by heating at about 100C. for about 2 hours a mixture of 100 parts of mineral oil, 10 parts of silica, 2.67 parts of a 50% xylene solution of a copolymer composed of SiO2 and (CH3)3SiOl/2 units in --the range of 1:0.4 to 1:1.2, 0.33 parts of a hydroxyl endblocked polydimethylsiloxane fluid having a viscosity ~-` of about 65 cs., and 1 part of hexamethyldisilazane.
Composition E is self-emulsifying in water.
Composition F was a commercial dye assistant -consisting mainly of solvents and emulsifiers.
Composition G consisted essentially of 9.4 parts of composition F plus 0.6 part of a composition -prepared by heating at about 100C. for about 2 hours a ' ' , ' : '' A

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104~64 mixture of 100 parts of mineral oil (Security 39), 10 parts of silica (Quso G-30), 2.67 parts of a 50% xylene solution of a copolymer composed o.~ SiO2 and (CH3)3SiOl/2 units in the range of 1:0.4 to 1:1.2, 0.33 part of a hydroxyl endblocked polydimethylsiloxane fluld having a viscosity of about 65 cs., and 1 part of hexamethyldisilazane. ~.-Composition H consisted essentially of 8 parts :
of composition F plus 2 parts of composition E without the water.
- 10 The amounts of the above compositions employed and the results of the pump tes~ are set forth in Table I. .

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A composition which consists essentially of (1) 65 to 98.4 percent by weight of a base oil selected from the group consisting of polyoxypropylene polymers and polyoxypropylene-polyoxyethylene copolymers having molecular weights in the range of 500 to 6000, and siloxane glycol copolymers having the general formulae (a) RaSi[(OSiMe2)n(OSiMeG)bOSiMe2G]4-a, (b) RaSi[(OSiMe2)n(OSiMeG)cOSiMe3]4-a, (c) GMe2Si(OSiMe2)n(OSiMeG)bOSiMe2G, and (d) Me3Si(OSiMe2)n(OSiMeG)cOSiMe3 in which formulae R is a hydrocarbon radical free of aliphatic unsaturation and contains from 1 to 10 carbon atoms, Me is a methyl radical, G is a radical Or the structure -D(OR')mA wherein D is an alkylene radical containing from from 1 to 30 carbon atoms, R' is an alkylene radical containing from from 2 to 10 carbon atoms, and A is a capping group, a has a value of 0 or 1, n has a value of at least 1, b has a value of 0 to 50, and c has a value of 1 to 50, (2) 1 to 20 percent by weight of mineral oil, (3) 0.5 to 5 percent by weight of a material selected from the group consisting of silica and a resin composed of SiO2 and (CH3)3SiO1/2 units in which resin the ratio of the SiO2 units to the (CH3)3SiO1/2 units is in the range of 1:0.4 to 1:1.2, and (4) 0.1 to 10 percent by weight of a dispersing agent which maintains (2) dispersed in (1) and which is a siloxane copolymer selected from the group consisting of (i) copolymers consisting essentially of SiO2 units, (CH3)3SiOi/2 units and Q(CH3)2SiO1/2 units wherein Q is a polyoxypropylene polymer or a poly-oxypropylene-polyoxyethylene copolymer radical having a molecular weight in the range of 500 to 6000, Q being attached to the silicon atom via a silicon-carbon bond, the ratio of the SiO2 units to the total (CH3)3SiO1/2 and Q(CH3)2SiO1/2 units being in the range of 1:0.4 to 1:1.2, and (ii) copolymers which are the reaction products derived from heating a mixture of a siloxane copolymer consisting essentially of SiO2 units and (CH3)3SiO1/2 units in which the ratio of SiO2 units to the (CH3)3SiO1/2 units is in the range of 1:0.4 to 1:1.2, and a hydroxylated polyoxypropylene polymer or a hydroxylated polyoxypropylene-polyoxyethylene copolymer having molecular weights in the range of 500 to 6000.

2. A composition as defined in claim 1 wherein (1) is a polyoxypropylene polymer, (3) is a treated silica, and (4) is copolymer (ii).

3. A composition as defined in claim 2 which contains from 0 to 10 percent by weight of a solvent.

4. A composition as defined in claim 1 wherein (1) is a polyoxypropylene polymer (3) is a siloxane resin, and (4) is copolymer (ii).

5. A composition as defined in claim 4 which contains from 0 to 10 percent by weight of a solvent.

6. In a process of controlling foam which includes the addition of a foam control agent to the system in which the foaming is to be controlled, the improvement comprising using the composition of claim 1 as the foam control agent.

7. In a process of controlling foam which includes the addition of a foam control agent to the system in which the foaming is to be controlled, the improvement comprising using the composition of claim 2 as the foam control agent.

8. In a process of controlling foam which includes the addition of a foam control agent to the system in which the foaming is to be controlled, the improvement comprising using the composition of claim 4 as the foam control agent.