Title of Invention

METHOD FOR THE PRODUCTION OF DEFOAMER FORMULATIONS

Abstract Disclosed is a method for producing defoamer formulations using hydrophilic silicic acids. (i) In a first step ofsaid method, (A) 100 parts of at least one polyorganosiloxane composed of units of general formula Ra(R10)bSiO(4.a.b)/2 (I), wherein R and R1 have the meaning indicated in claim 1, a and b represent 0, 1, 2, or 3, respectively, the sum a+b being less than 3 provided that b does not equal 0 in 0.01 to 0.2 percent of all units of general formula (I) while b equals 0 in the remaining units of formula (I), are mixed with (B) 0.1 to 100 parts of at least one hydrophilic precipitated or pyrogenic silicic acid having a BET surface of 20 to 1000 m2/g, (C) 0 to 50 parts of a Silicon^ resin that essentially consists of units of general formula R3SiOi/2 and Si04/2, (D) 0 to 200 parts of a polyorganosiloxane composed of units of formula Ra,(R20)b,SiO(4.a-_b.)/2 (II), wherein R and R2 have the meaning indicated in claim 1, af and bf represent 0, 1, 2, or 3, respectively, the sum a'+b' being smaller than or equal to 3 provided that b1 is different from 0 in less than 0.01 percent or in more than 0.2 percent of all units of general formula (II) while b' equals 0 in the remaining units of formula (II), and, optionally, (E) 0 to 5.0 parts of an alkaline or acid catalyst, and, optionally, (F) 0 to 1000 parts of an organic silicon-free Compound, (ii) In a second step, said mixture is heated to a temperature ranging from 50 to 250°C, the heating process being carried out at least until the viscosity has a value that is less than 50 percent of the viscosity with which the mixture produced in the first step was provided before being heated.
Full Text

Method for the production of defoamer formulations
■« The invention relates to a method for the production of defoamer formulations using hydrophilic silica.
In numerous liquid Systems, more particularly aqueous Systems, which include surface-active Compounds as desired or eise unwanted constituents, it is possible for problems to occur as a result of foaming if these Systems are contacted more or less intensely with gaseous substances, such as during the introduction of gases into wastewaters, during intense stirring of liquids, during distillation, washing or coloring Operations or during dispensing Operations, for example,
This foam can be controlled by mechanical means or through the addition of defoamers. Siloxane-based defoamer formulations have proven particularly appropriate here.
Defoamer formulations based on siloxanes are produced, for example, in accordance with US 3383327 A by heating hydrophilic silica in polydimethylsiloxanes.
The production of defoamer formulations using polysiloxanes containing alkoxy or hydroxyl groups «M* IS likewise known. It involves, for example, using polysiloxanes which on average carry more than one alkoxy group per Silicon atom (DE 2903725) . This high concentration of functional groups, however, results in poor stability in the foaming media, leading in part to an action which rapidly subsides, This is desirable in those instances, for example, where the defoamer formulation is intended to act only during dispensing Operations, but is not to suppress the foam later on (US 4101443 A) . For the majority of applications, however, it tends to be a disadvantage.

P 163541 Bl describes a method for the production of efoamer formulations that react polysiloxanes having erminal hydroxyl groups with other siloxanes, under he action of catalysts, to form branched siloxanes. hese branched siloxanes are then heated together with ow molecular mass polysiloxanes (e.g., having a 'iscosity of 10-50 mm2/s) having two terminal hydroxyl iroups and with hydrophilic silica. The resultant iefoamer formulations have a very high viscosity, which .s a disadvantage for practical use.
Patterson, Robert E. (Colloids Surf., A; 74(1); 115-26; L993) likewise describes the production of defoamer Eormulations using hydrophilic silica and polydimethylsiloxanes containing terminal hydroxyl groups. A molar mass of this polysiloxane of 4000 to 18 000 g/mol is said to be optimum for the action in the black liquor produced during papermaking. As the skilled worker can easily calculate, this finding means that polydimethylsiloxanes in which 0.8-4 mol% of the siloxane units carry a silanol group are optimum in terms of defoamer activity.
Given that the activity of the defoamer formulations thus produced is deserving of improvement, it is often proposed that pretreated hydrophobicized silicas be used in place of the hydrophilic silica. According to US 3113930 A, Joint heating of the silica with the polydimethylsiloxane is advantageous even in processes using pretreated hydrophobicized silica. In the process of GB 1549884 Al the pretreated hydrophobic silica is added at the emulsifying stage; EP 23533 Bl selects the appropriate pretreated hydrophobic silica on the basis of the specified methanol wetability; US 4145308 A improves the incorporation of the pretreated hydrophobic silica by adding oleic acid.

According to DE 19504645 Cl, pretreated hydrophobic silica is added to formulations prepared by heating hydrophilic silica in polydimethylsiloxanes, for the purpose of achieving improved activity of the defoamer formulations thus produced.
In US 6656975 Bl, pretreated hydrophobic silicas are used so that the contact angle between the defoamer formulation, an encapsulant, and an organic carrier liquid is less than 13 0°, thereby facilitating encapsulation and production of defoamer dispersions.
The methods for the production of defoamer formulations that use pretreated hydrophobic silicas have the disadvantage that they are uneconomic by virtue of the high price of the pretreated hydrophobic silicas.
The defoamer formulations produced in accordance with the prior art have the disadvantage, moreover, that they do not always exhibit a sufficiently long-lasting activity in highly foaming, surfactant-rich Systems, or that on account of the high viscosity they are difficult to handle and in storage are not stable.
The object of the invention was therefore to provide an economic method for the production of defoamer formulations, producing defoamer formulations which do not have the abovementioned disadvantages, exhibit an improved activity, more particularly an improved long-term activity, in surfactant-rich, highly foaming media in particular, but which nevertheless are easy to handle, i.e., do not display high viscosities, and for which the viscosity during storage should not be subject to any significant alteration.
The invention provides a method for the production of
defoamer formulations using hydrophilic silicas that
involves
(i) in a first step mixing

(A) 100 parts of at least one polyorganosiloxane
composed of units of the general formula
Ra(R10)bSiO(4-a-b)/2 (I) ,
in which R can be identical or different and denotes hydrogen or a monovalent, substituted or unsubstituted, saturated or unsaturated hydrocarbon radical having 1 to 30 carbon atoms per radical,
R1 can be identical or different and denotes a hydrogen atom or a monovalent, substituted or unsubstituted, saturated or unsaturated hydrocarbon radical having 1 to 30, preferably 1-4, carbon atoms per radical, a is 0, 1, 2 or 3,
b is 0, 1, 2 or 3, preferably 0 or 1, the sum a + b being with the proviso that in 0.01% to 0.2% of all the units of the general formula (I) , preferably in 0,02% to 0.15% of all the units of the general formula (I), more preferably in 0.05% to 0.1% of all the units of the general formula (I), based in each case on the total number of units of formula (I), b is other than 0, preferably 1, while in the remaining units of the formula (I) b is 0, with
(B) 0.1 to 100 parts, preferably 1 to 15 parts, of at least one amorphous, hydrophilic, precipitated or fumed silica having a BET surface area of 20-1000 m2/g, preferably 50-800 m2/g, more preferably 80-500 m2/g,
(C) 0 to 50 parts, preferably 1 to 50 parts, of a silicone resin composed substantially of units of the general formula R3SiOi/2 and Si04/2/ R having the definition indicated above,

(D) 0 to 200 parts, preferably 1 to 200 parts, of a
polyorganosiloxane composed of units of the
formula

where R has the definition indicated for it above, R2 can be identical or dif ferent and denotes a hydrogen atom or a monovalent, substituted or unsubstituted, saturated or unsaturated hydrocarbon radical having 1 to 30, preferably 6 to 30, carbon atoms per radical, a' is 0, 1, 2 or 3,
b' is 0, 1, 2 or 3, preferably 0 or 1, the sum a' + b' being with the proviso that in less than 0.01% or in more than 0.2% of all the units of the general formula (II) , preferably in more than 1%, with particular preference in more than 5%, of all the units of the general formula (II) , based in each c'ase on the total number of units of the formula (II), b' is other than 0, preferably 1, while in the remaining units of the formula (II) b' is 0, and if desired
(E) 0-5.0 parts of an alkaline or acidic catalyst
and if desired
(F) 0-1000 parts of an organic Compound containing no
Silicon,
and
(ii) in a second step heating this mixture to a temperature of 50-250°C, heating being continued at least until the viscosity has a value of less than 50%, preferably less than 40%, more particularly less than 30% of the viscosity, as measured using a cone/plate viscometer at a temperature of 25°C and a shear rate of 1/s, of the mixture prepared in the first step prior to said heating.

The defoamer formulations produced by the method of the invention have the advantage of a significantly improved activity in tandem with low and virtually constant viscosity. As well as low viscosity, which is needed for the defoamer formulation to be easy to handle in further processing, such as during emulsification, for example, it is also important for the viscosity on storage not to undergo any significant alterations - in other words, that the defoamer formulation is stable in this respect as well. Preferably the viscosity on room-temperature storage alters by less than 25%, more preferably by less than 10%.
It was not possible to deduce from the prior art that a method for the production of defoamer formulations using hydrophilic silica would produce products having much better activity and also lower and more stable viscosity if that method were to be carried out using a polyorganosiloxane (A) which contains a low but defined fraction of siloxane units containing hydroxyl or alkoxy groups, the mixture of this polysiloxane and the hydrophilic silica being heated until the viscosity was less than 50%, preferably less than 40%, more particularly less than 3 0% of the viscosity, as measured using a cone/plate viscometer at a temperature of 25°C and a shear rate of l/s, prior to said heating.
Examples of radical R are alkyl radicals, such as the methyl, ethyl, n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl radical, hexyl radicals, such as the n-hexyl radical and 2-ethylhexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the n-octyl radical and isooctyl radicals, such as the 2,2,4-trimethylpentyl radical, nonyl radicals, such as the n-nonyl radical, decyl radicals, such as

the n-decyl radical, dodecyl radicals, such as the n-dodecyl radical, and octadecyl radicals, such as the n-octadecyl radical; cycloalkyl radicals, such as cyclopentyl, cyclohexyl, cycloheptyl, and methylcyclohexyl radicals; alkenyl radicals, such as the vinyl, 5-hexenyl, cyclohexenyl, 1-propenyl, allyl, 3-butenyl, and 4-pentenyl radical; alkynyl radicals, such as the ethynyl, propargyl, and 1-propynyl radical; aryl radicals, such as the phenyl, naphthyl, anthryl, and phenanthryl radical; alkaryl radicals, such as o-, m-, and p-tolyl radicals, xylyl radicals, and ethylphenyl radicals; and aralkyl radicals, such as the benzyl radical, the a- and the ß-phenylethyl radical.
Examples of substituted radicals R are haloalkyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2',2',2'-hexafluoroisopropyl radical, the heptafluoroisopropyl radical, and haloaryl radicals, such as the o-, m-, and p-chlorophenyl radical, and also substituted alkyl radicals, such as the cyanoethyl, glycidyloxypropyl, polyalkylene glycol propyl, aminopropyl, and aminoethylaminopropyl radicals.
Preferably more than 80 mol% of the radicals R are methyl groups.
Examples of radicals R1 are linear or branched alkyl radicals as indicated above for R.
Examples of radicals R2 are linear or branched alkyl radicals as indicated above for R.
Used preferably as polyorganosiloxanes (A) in the first step of the method are linear polydiorganosiloxanes which if desired may contain units of the formula RSi03/2 (R having the definition indicated for it above) and Si02. The polydiorganosiloxanes (A) preferably containtftej not more than 2% of RSi03/2 or Si04/2 units.

The sum a + b in the polyorganosiloxanes (A) composed of units of the formula (I) has a value on average of preferably 1.5 to 2.4, more preferably 1.8 to 2.3, with particular preference 1.9 to 2.1.
Examples of polyorganosiloxanes (A) are polyorganosiloxanes which are composed of the following units (percentages based on the total number of units in the polyorganosiloxanes (A)):
(Al) : 98.0% (CH3)2Si02/2
1.80% (CH3)3SiOi/2
0.2 0% HO(CH3)2SiOi/2 or OH (CH3) Si02/2
(A2) : 98.5% (CH3)2Si02/2
1.35% (CH3)3Si01/2
0.15% HO(CH3)2Si01/2 or OH (CH3) Si02/2
(A3): 99.2% (CH3)2Si02/2
0.70% (CH3)3Si01/2
0.1% CH30(CH3)2Si01/2 or CH30 (CH3) Si02/2
(A4) : 99.5% (CH3)2Si02/2
0.47% (CH3)3Si01/2
0.03% H0(CH3)2Si0i/2 or OH (CH3) Si02/2
(A5) : 99.63% (CH3)2Si02/2
0.22% (CH3)3SiOi/2
0.15% HO(CH3)2SiOi/2 or OH (CH3) Si02/2
(A6) : 99.17% (CH3) 2Si02/2
0.03% CH3Si03/2
0.72% (CH3)3SiOi/2
0.08% HO(CH3)2Si01/2 or OH (CH3) Si02/2
(A7) : 98.769% (CH3) 2Si02/2
0.03% CH3Si03/2
0.001% Si04/2

1.08% (CH3)3Si01/2
0.12% HO(CH3)2SiOi/2 or OH (CH3) Si02/2
(A8) : 99.80% (CH3)2Si02/2
0.01% CH3Si03/2
0.16% (CH3)3SiOi/2
0.04% HO(CH3)2SiOi/2 or OH (CH3) Si02/2
(A9) : 99.63% (CH3)2Si02/2
0.26% (CH3)3Si01/2
0.11% C2H50 (CH3) 2Si01/2/ C2H50 (CH3) Si02/2 ,
HO(CH3)2Si01/2 or OH (CH3) Si02/2
(A10) : 98.0% (CH3)2Si02/2
0.01% CH3Si03/2
1.85% (CH3)3Si01/2
0.15% C8H170(CH3)2SiOi/2 or OH (CH3) Si02/2
The polyorganosiloxanes (A) preferably have a viscosity of 10 to 1 000 000 mPa.s at 25°C/ more preferably 50 to 50 000 mPa.s at 25°C, with particular preference 100 to 20 000 mPa.s at 25°C.
The Si-bonded RxO groups in the polyorganosiloxanes (A) composed of units of the formula (I) are preferably hydroxyl groups or C^ alkoxy groups, such as C2H50 groups.
The polyorganosiloxanes (A) composed of units of the formula (I) contain these Si-bonded RxO groups preferably in amounts of 0.005 to 0.099 mol%, more preferably in amounts of 0.01 to 0.074 mol%, with particular preference in amounts of 0.02 to 0.05 mol%, based in each case on all of the silicon-bonded radicals R and R10.
The polyorganosiloxane (A) is preferably prepared in a
catalyzed polycondensation and/or equilibration
process, for which the catalyst used may be any of the

acidic or basic catalysts known for siloxanes. The
preparation of polyorganosiloxanes of this kind,
comprising units of the formula (I) , is known to the
skilled worker.
Silicas (B) used in the first step of the method are preferably hydrophilic amorphous silicas having a BET surface area of 20-1000 m2/g, preferably 50-800 m2/g7 more preferably 80-500 m2/g. These hydrophilic silicas may be fumed or precipitated silicas and they preferably have a particle size of less than 10 \xm and an agglomerate size of less than 100 |-im.
In combination with the silicas (B) it is possible to use silicone resins (C) . The silicone resins (C) are polysiloxanes of nonlinear construction which as well as R3SiOi/2 (M) and Si04/2 (Q) units may also contain units of the formula RSi03/2 (T) and R2Si02/2 (D) units. Preference is given to using resins which are composed of R3SiO!/2 (M) and Si04/2 (Q) units; these resins are also referred to as MQ resins. The molar ratio of M to Q units is situated preferably in the ränge from 0.5 to 2.0, more preferably in the ränge from 0.6 to 1.0. These silicone resins may further contain up to 10% by weight of free hydroxyl or alkoxy groups.
In one preferred version of the invention the defoamers contain 1-5 parts of silica (B) and 5-15 parts of MQ resins (C) per 100 parts of component A.
Used as component (D) are, for example, polydiorganosiloxanes having a viscosity of preferably 100 to 1 000 000 mPa-s at 25°C. These polydiorganosiloxanes may be branched, for example, as a result of the incorporation of RSi03/2 (R having the definition indicated for it above) or Si04/2 units. These branched or part-crosslinked siloxanes then have viscoelastic

properties. The polydiorganosiloxanes (D) preferably
not more than 2% of RSi03/2 or Si04/2 units.
In one preferred embodiment use is made as component (D) of 0.1 to 50 parts, with particular preference 1 to 25 parts, more particularly 2 to 15 parts of polyorganosiloxanes composed of units of the general formula (II) where R is a methyl radical, R2 is a linear and/or branched hydrocarbon radical having 6 to 30 carbon atoms, and in 1% to 10%, pref erably 5% to 10%, of all the units of the formula (II), based on the total number of units, b' is other than 0, being preferably 1, while in the remaining units of the formula (II) b' is 0. b' here pref erably adopts on average a value of 0.005 to 0.1, and the sum (a' + b') has on average a value of 1.9 to 2.1. Products of this kind are obtainable for example through alkali-catalyzed condensation of silanol-terminated polydimethylsiloxanes with a viscosity of preferably 50 to 50 000 mPa-s at 25°C and aliphatic alcoholics having more than 6 carbon atoms, such as isotridecyl alcohol, n-octanol, stearyl alcohol, 4-ethylhexadecanol or eicosanol.
Catalysts (E) can be added in the first step of the method. Examples of alkaline catalysts are alkali metal and alkaline earth metal hydroxides, such as NaOH, KOH, CsOH, LiOH, and Ca(OH)2. Examples of acidic catalysts are hydrochloric acid, sulfuric acid, and phosphorus nitride Chlorides.
As a further component (F) it is possible, in the first step of the method or eise later, to add preferably water-insoluble organic Compounds having a boiling point of greater than 100°C. Examples of such organic Compounds are mineral oils, natural oils, isoparaffins, polyisobutylenes, residues f rom the synthesis of alcohols by the oxo process, esters of low molecular

fiass synthetic carboxylic acids, fatty acid esters, :atty alcohols, ethers of low molecular mass alcohols, Dhthalates, esters of phosphoric acid, and waxes. The Drganic Compounds (F) are used preferably in amounts of 3 to 2 00 parts per 100 parts of polyorganosiloxanes (A) .
hs further components for the production of the defoamer formulations of the invention it is possible to add optionally modified polysiloxanes, which may be linear or branched and which carry at least one polyether moiety, in amounts of preferably 1 to 50 parts per 100 parts of component (A). Polyether-modified polysiloxanes of this kind are known and are described for example in EP 1076073 A.
The mixing of components (A) , (B) , (C) , (D) , and, if desired, further components, such as (E) and (F) , may take place discontinuously or continuously by means of simple stirring, kneading and/or eise using high shearing forces in colloid mills, dissolvers, or rotor-stator homogenizers, the mixing, such as stirring, and/or the homogenizing producing an energy input of preferably at least 0.1 kj/kg, with particular preference of 1 to 10 000 kJ/kg, more particularly of 5 to 1000 kJ/kg.
This mixing Operation may take place under reduced pressure in order to prevent the incorporation of air which is present in highly disperse fillers.
In the second step of the method the mixture is heated preferably at 100 to 200°C. The mixing and/or homogenizing may be continued at the heating stage. Heating may take place under inert gas (such as helium, argon or nitrogen) , under reduced pressure or eise in the presence of air.
As part of the method of the invention it is also possible for the mixing, for example, of components

(A) , (B) , (C) , and (D) and any further components to take place itself at an elevated temperature; in other words, for the first and second steps of the method to run wholly or partly simultaneously.
The mixture is preferably heated until the viscosity of the mixture has a value of less than 40%, in particular a value of 5% to 25%, of the viscosity the mixture produced in the first step had prior to said heating. The viscosity here is defined as the viscosity determined at a shear rate of 1/s using a cone/plate viscometer.
This reaction can be assisted by the addition of catalysts, such as KOH, or the addition of silanes or silazanes.
The defoamer formulations produced in accordance with the invention are notable for their high activity and for a viscosity which is constant on storage.
The defoamer formulation produced in accordance with the invention can be added to the foaming liquors directly, in Solution in suitable solvents, such as methyl ethyl ketone or tert-butanol, as a powder or as an emulsion.
The emulsifiers required for the preparation of the emulsions may be anionic, cationic or nonionic and are known to the skilled person for the preparation of stable silicone emulsions. It is preferred to use emulsifier mixtures, in which case there should be at least one nonionic emulsifier present, such as, for example, sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, ethoxylated fatty acids, ethoxylated linear or branched alcohols having 10 to 20 carbon atoms and/or glycerol esters. In addition it is possible to add Compounds known as thickeners, such as polyacrylic acid, polyacrylates, cellulose ethers such

as carboxymethylcellulose and hydroxyethylcellulose, natural gums such as xanthan gum and polyurethanes, and also preservatives and other typical additions known to the skilled worker.
Technologies for the preparation of silicone emulsions are known. Typically the preparation is accomplished by simply stirring together all of the ingredients and, where appropriate, subsequently homogenizing the mixture using rotor-stator homogenizers, colloid mills, jet dispersers or high-pressure homogenizers. The defoamer formulations produced in accordance with the invention can also be processed further into free-flowing powders. These powders are preferred in the context, for example, of use in powder laundry detergents. These defoamer powders contain, for example, 2-20% by weight of the defoamer formulations. Examples of carriers employed include zeolites, sodium sulfate, cellulose derivatives, urea, and sugars. Examples of further possible ingredients of the defoamer powders include waxes and organic polymers, of the kind described in EP 887097 A and EP 1060778 A, for example. These powders are produced by methods known to the skilled worker, such as spray drying or agglomerative granulation.
The defoamer formulations produced in accordance with the invention can be used wherever disruptive foam is to be suppressed. This is the case, for example, in nonaqueous Systems, such as in tar distillation or a petroleum processing. The defoamer formulations of the invention are suitable more particularly for Controlling foam in aqueous Surfactant Systems, an application in which they are distinguished from prior-art defoamer formulations by a higher and longer-lasting activity at low levels of addition. The defoamer formulations of the invention can be used for defoaming wastewaters, intensely agitated liquids, distillation, washing, coloring or finishing Operations

in household or industry, or chemical digestion or conversion Operations/ such as chemical syntheses, cellulose production or papermaking or petroleum processing (refining), for defoaming in fermentative Operations, in the preparation of dispersions, in the preparation or application of formulated products such as, for example, sprays, cosmetics or drugs or of foams which occur during dispensing Operations.
Working Examples
All of the parts indicated below (unless indicated otherwise) are based on weight. The viscosities relate to 25°C and a shear rate of l/s.
Tests of defoamer activity
1, Antifoam index AFI
In an apparatus in accordance with DE-A 2551260, 200 ml of a 4% strength by weight aqueous Solution of a sodium alkylsulfonate (Mersolat) containing 10 mg of the defoamer under investigation (in Solution in 10 times the amount of methyl ethyl ketone) were foamed for 1 minute using two counter rotating stirrers. Subsequently the collapse of the foam was recorded. The area of the plot of foam height versus time was used to calculate the antifoam index. The lower this index, the more effective the defoamer.
2. Stirring test
3 00 ml of a Solution containing 1% by weight of a defoamer-free alkaline washing powder were foamed for 5 minutes with a st irrer at a speed of 1000 revolutions/min. Subsequently 100 \xl of a 10% strength by weight Solution of the defoamer in methyl ethyl ketone were added and stirring was continued for

25 minutes more. Throughout the time the foam height was recorded.
As a measure of the activity, the average foam height relative to the foam height without defoamer was calculated after 2-3 min. The lower the resulting figure, the more active the defoamer.
In the examples below, % of units means the fraction of the corresponding siloxane units relative to the total number of all the siloxane units in the siloxane.
Example 1:
91 parts of a polydimethylsiloxane (A), which is composed of 99.2% of units of the formula (CH3) 2Si02/2 and 0.8% of units of the formula (CH3) 3SiOi/2, and in which 0.03% of all the units of the polydimethylsiloxane carry Si-modified ethoxy groups, 4.5 parts of hydrophilic fumed silica (B) having a BET surface area of 200 m2/g, and 4.5 parts of a polydimethylsiloxane (D) , which is composed of 92% of units of the formula (CH3) 2Si02/2 and 8% of units of the formula (CH3) 2 (OH) SiOi/2, are intimately mixed using a dissolver disc. This mixture had a viscosity of 200 000 mPas.
This mixture was then heated at 150°C for 4 hours, in
the course of which the viscosity had dropped to
30 100 mPas, i.e., 15% of the initial viscosity of the
mixture.
The stirring test (test 2) carried out with this
mixture gave a foam height of 30 (see Table 1) . The
defoamer is therefore very effective.
The defoamer formulation thus obtained was then tested
for its stability. The results of this test are
summarized in Table 1.

lomparative experiment Cl:
»1 parts of a polydimethylsiloxane, which is composed >f 99.2% of units of the formula (CH3)2Si02/2 and 0.8% of mits of the formula (CH3) 3SiOi/2, and in which there are 10 detectable radicals of the formula OR1 attached to :he Silicon, 4.5 parts of hydrophilic fumed silica (B) laving a BET surface area of 200 m2/g, and 4.5 parts of i polydimethylsiloxane (D) , which is composed of 92% of mits of the formula (CH3)2Si02/2 and 8% of units of the Eormula (CH3) 2 (OH) SiOi/2/ are intimately mixed using a iissolver disc. This mixture had a viscosity of 124 000 mPas.
This mixture was then heated at 150°C for 4 hours, in the course of which the viscosity had dropped to 70 000 mPas, i.e., 56% of the initial viscosity of the mixture.
The stirring test (test 2) carried out with the defoamer formulation thus produced gave a foam height of 75 (see Table 1) . The defoamer has a poor, inadequate action.
The defoamer formulation thus obtained was then tested for its stability. The results of this test are summarized in Table 1.
Example 2:
100 parts of a polydimethylsiloxane (A) , which is composed of 99.2% of units of the formula (CH3)2Si02/2 and 0.8% of units of the formula (CH3) 3SiOi/2/ and in which 0.08% of all the units of the polydimethylsiloxane carry hydroxyl groups attached to the Silicon (Si-OH), 5 parts of hydrophilic fumed silica (B) having a BET surface area of 200 m2/g, and 5 parts of a polydimethylsiloxane (D) , which is composed of 92% of units of the formula (CH3) 2Si02/2 and 8% of units of the formula (CH3) 2 (OH) SiOi/2, are intimately

üxed using a dissolver disc. This mixture had a
riscosity of 55 000 mPas.
This mixture was then heated at 150°C for 7 hours, in
:he course of which the viscosity had dropped to
5600 mPas, i.e., 10% of the initial viscosity of the
nixture.
rhe antifoam index AFI was ascertained. The results are
summarized in Table 1.
rhe defoamer formulation thus obtained was then tested
for its stability. The results of this test are
likewise summarized in Table 1.
Comparative experiment C2:
100 parts of a polydimethylsiloxane, which is composed of 99.2% of units of the formula (CH3)2Si02/2 and 0.8% of units of the formula (CH3) 3SiOi/2, and in which there are no detectable radicals of the formula OR1 attached to the Silicon, 5 parts of hydrophilic fumed silica (B) having a BET surface area of 2 00 m2/g, and 5 parts of a polydimethylsiloxane (D) # which is composed of 92% of units of the formula (CH3) 2Si02/2 and 8% of units of the formula (CH3) 2 (OH) SiOi/2, are intimately mixed using a dissolver disc. This mixture had a viscosity of 48 000 mPas.
This mixture was then heated at 150°C for 7 h, in the course of which the viscosity had dropped to 32 500 mPas, i.e., 68% of the initial viscosity of the mixture.
The antifoam index AFI was ascertained. The results are summarized in Table 1.
The defoamer formulation thus obtained was then tested for its stability. The results of this test are likewise summarized in Table 1.


It is clear that with the inventively produced defoamer of Example 2 the AFI is not even 50% of the AFI of the noninventive defoamer of Comparative experiment 2, meaning that it is twice as active. This is all the more surprising given the fact that component (D) in both cases introduces a high fraction of Si-bonded OH groups, so that the smaller amounts of SiOH from component (A) were surprising in their effect. The inventively produced defoamer of Example 1 as well is outstandingly active, as is apparent from the less than half as high foam height as compared with Comparative example 1 in the stirring test.
The stability of the inventively produced defoamers is outstanding. On storage, the viscosity alters by less than 10% from the viscosity after heating, whereas this alteration in viscosity is higher in the case of the noninventive, comparative examples.
Example 3
89.3 parts of a polydimethylsiloxane (A) , composed of 99.5% of (CH3)2SiO units and 0.5% of (CH3)3SiOi/2 units,

and in which 0.07% of all the units of the
polydimethylsiloxane carry hydroxyl groups (Si-OH),
5 parts of hydrophilic fumed silica (B) having a BET
surface area of 300 m2/g,
3 parts of a polydimethylsiloxane (D) having a terminal
C20 alkyl group,
2 parts of a silicone resin (C) composed substantially
of units of the general formula (R3SiO) 0.5 and Si02
units, and
0.7 part of a 20% strength methanolic KOH (E) are
intimately mixed using a dissolver diso. This mixture
had a viscosity of 188 000 mPas.
This mixture was then heated at 150°C for 4 hours, in
the course of which the viscosity had dropped to
27 200 mPas, i.e., 14% of the initial viscosity of the
mixture.
The defoamer formulation thus obtained was then tested
for the antifoam index AFI, the stirring test, and the
stability. The results of these tests are summarized in
Table 2.
Comparative experiment C3:
89.3 parts of a polydimethylsiloxane, composed of 99.5% of (CH3)2SiO units and 0.5% of (CH3)3SiOo.5 units, and in which there are no detectable radicals of the formula OR1 attached to the Silicon,
5 parts of hydrophilic fumed silica (B) having a BET surface area of 300 m2/g,
3 parts of a polydimethylsiloxane (D) having a terminal
C20 alkyl group,
2 parts of a silicone resin (C) composed substantially of units of the general formula (R3SiO)0.s and Si02 units, and
0.7 part of a 20% strength methanolic KOH (E) are intimately mixed using a dissolver disc. This mixture had a viscosity of 31 300 mPas.

Thi s mixture was then heated at 15 0 ° C for 4 hours, in the course of which the viscosity had dropped to 28 670 mPas, i.e., 92% of the initial viscosity of the mixture.
The defoamer formulation thus obtained was then tested for the antifoam index AFI, the stirring test, and the stability. The results of these tests are summarized in Table 2.
Example 4:
89.3 parts of a polydimethylsiloxane (A) , composed of
99.5% of (CH3)2SiO units and 0.5% of (CH3)3SiOi/2 units,
and in which 0.030% of all the units of the
polydimethylsiloxane carry hydroxyl groups (Si-OH),
5 parts of hydrophilic fumed silica (B) having a BET
surface area of 300 m2/g,
3 parts of a polydimethylsiloxane (D) having a terminal
C20 alkyl group,
2 parts of a silicone resin (C) composed substantially
of units of the general formula (R3SiO)0.5 and Si02
units, and
0.7 part of a 20% strength methanolic KOH (E) are
intimately mixed using a dissolver disc. This mixture
had a viscosity of 205 000 mPas.
This mixture was then heated at 150°C for 4 hours, in
the course of which the viscosity had dropped to
27 000 mPas, i.e., 13% of the initial viscosity of the
mixture.
The defoamer formulation thus obtained was then tested
for the antifoam index AFI, the stirring test, and the
stability. The results of these tests are summarized in
Table 2.

komparative experiment C4:
39.3 parts of a polydimethylsiloxane, composed of 100%
Df (CH3) 2SiO units, and in which 0.9% of all the units
of the polydimethylsiloxane contain hydroxyl groups
(Si-OH),
5 parts of hydrophilic fumed silica (B) having a BET
surface area of 300 m2/g,
3 parts of a polydimethylsiloxane (D) having a terminal
C20 alkyl group,
2 parts of a silicone resin (C) composed substantially
of units of the general formula (R3SiO)0.5 and Si02
units, and
0.7 part of a 2 0% strength methanolic KOH (E) are
intimately mixed using a dissolver disc. The mixture
obtained had a viscosity of 846 mPas.
This mixture was then heated at 150°C for 4 hours, in
the course of which the viscosity had dropped to
565 mPas, i.e. , 67% of the initial viscosity of the
mixture.
The defoamer formulation thus obtained was then tested
for the antifoam index AFI, the stirring test, and the
stability. The results of these tests are summarized in
Table 2.
The mixture is not stable on storage. As a result of
solid Sedimentation, it becomes inhomogeneous and hence
unusable.
Comparative experiment C5
89.3 parts of a mixture of the polydimethylsiloxanes used in comparative examples C3 and C4 - that is, polydimethylsiloxane composed of 99.5% of (CH3) 2SiO units and 0.5% of (CH3)3SiO0.5 units, and in which there are no detectable radicals of the formula OR1 attached to the Silicon, and polydimethylsiloxane composed of 100% of (CH3) 2SiO units and containing 0.9% of hydroxyl groups attached to the Silicon (Si-OH), the mixture

being adjusted such that 0.03% of all the units of the
polydimethylsiloxane of the mixture carry hydroxyl
groups attached to the Silicon (Si-OH),
5 parts of hydrophilic fumed silica (B) having a BET
surface area of 300 m2/g/
3 parts of a polydimethylsiloxane (D) having a terminal
C20 alkyl group,
2 parts of a silicone resin (C) composed substantially
of units of the general formula (R3SiO) 0.s and Si02
units, and
0.7 part of a 20% strength methanolic KOH (E) are
intimately mixed using a dissolver disc. This mixture
had a viscosity of 420 000 mPas.
This mixture was then heated at 150°C for 4 hours, in
the course of which the viscosity had dropped to
350 000 mPas, i.e., 83% of the initial viscosity of the
mixture.
The defoamer formulation thus obtained was then tested
for the antifoam index AFI, the stirring test, and the
stability. The results of these tests are summarized in
Table 2.
The mixture undergoes gelling on storage and is
therefore unusable.


The inventive defoamers (Table 2) not only are much more effective than the noninventive defoamers in terms of the AFI and the stirring test, but also have good stability, in contrast to the noninventive defoamers, which are unstable in viscosity or which form a solid Sediment or undergo gelling. The viscosity of the inventively produced defoamers alters by less than 10% over 3 months of storage at room temperature.

Example 5:
90 parts of a polydimethylsiloxane (A) , which is composed of 99.5% of (CH3) 2SiO units and 0.5% of (CH3)3SiOi/2 units and in which 0.050% of all the units of the polydimethylsiloxane carry hydroxyl groups (Si-OH),
5 parts of hydrophilic fumed silica (B) having a BET surface area of 400 m2/g,
5 parts of a Silicon resin (C) which is composed substantially of units of the general formula (R3SiO)0.5 and Si02 units are intimately mixed using a dissolver disc. This mixture was then heated at 150°C f or 4 hours. The defoamer formulation thus obtained had a viscosity of 5070 mPas (25°C) and was then tested for « the antifoam index AFI. The lower this index, the more active the defoamer (see "Antifoam index AFI", page 15, penultimate paragraph of the description). The results of this test are summarized in Table 3.
Comparative experiment C6:
90 parts of a polydimethylsiloxane, which is composed of 99.5% of (CH3)2SiO units and 0.5% of (CH3)3SiOi/2 units and in which there are no detectable radicals of the formula OR1 attached to the Silicon,
5 parts of hydrophilic fumed silica (B) having a BET surface area of 400 m2/g,
5 parts of a Silicon resin (C) which is composed substantially of units of the general formula (R3SiO)0.5 and Si02 units are intimately mixed using a dissolver disc. This mixture was then heated at 150°C for 4 hours. The defoamer formulation thus obtained had a viscosity of 4940 mPas (25°C) and was then tested for the antifoam index AFI. The results of this test are summarized in Table 3.


Clear from the comparison of example 5 with example C6 is the superior action of the inventive formulations (even without component (D)), since the AFI of example 5 is much lower than that of comparative experiment C6.






















Claims:
1. A method f or the production of def oamer formulations using hydrophilic silicas that involves (i) in a first step mixing
(A) 100 parts of at least one polyorganosiloxane
composed of units of the general formula

in which R can be identical or different and denotes hydrogen or a monovalent, substituted or unsubstituted, saturated or unsaturated hydrocarbon radical having 1 to 3 0 carbon atoms per radical,
R1 can be identical or different and denotes
a hydrogen atom or a monovalent, substituted
or unsubstituted, saturated or unsaturated
hydrocarbon radical having 1 to 3 0y\ per
radical, *QMW ojwtf*
a is 0, 1, 2 or 3, b is 0 or 1,
the sum a + b being with the proviso that in 0.01% to 0.2% of all the units of the general formula (I) , based on the total number of units of formula (I) , b is 1, while in the remaining units of the formula (I) b is 0, with
(B) 0.1 to 100 parts of at least one amorphous, hydrophilic, precipitated or fumed silica having a BET surface area of 20-1000 m2/g,
(C) 0 to 50 parts of a silicone resin composed substantially of units of the general formula R3SiO!/2 and Si04/2/ R having the definition indicated above,

(D) 0 to 200 parts of a polyorganosiloxane
composed of units of the formula
Ra' (R20)b where R has the definition indicated for it above,
R2 can be identical or different and denotes a hydrogen atom or a monovalent, substituted or unsubstituted, saturated or unsaturated hydrocarbon radical having 1 to 30>t per
radical, ' t&fttat ojftni^
a' is 0, 1, 2 or 3, b' is 0 or 1,
the sum a' + b' being with the proviso that in less than 0.01% or in more than 1% of all the units of the general formula (II), based on the total number of units of the formula (II), b' is 1, while in the remaining units of the formula (II) b' is 0, with the proviso that (A) and (B) are used alternatively in combination with (C) , in which case (C) is used in amounts of 1-50 parts, or in combination with (D) , in which case (D) is used in amounts of 1-2 00 parts,
or in combination with (C) and (D) , in which case (C) is used in amounts of 1-50 parts and (D) is used in amounts of 1-2 00 parts, and if desired
(E) 0-5.0 parts of an alkaline or acidic catalyst
and if desired
(F) 0-1000 parts of an organic Compound
containing no Silicon,
and
(ii) in a second step heating this mixture to a temperature of 50 to 250°C, heating being

continued at least until the viscosity has a value of less than 50% of the viscosity, as measured using a cone/plate viscometer at a temperature of 25°C and a shear rate of 1/s, of the mixture prepared in the first step prior to said heating.
2. The method of claim 2, characterized in that in 0.02% to 0.15% of all the units of the formula (I) , based on the total number of units of the formula (I) , b is 1, while in the remaining units of the formula (I) b is 0.
3. The method of claim 1 or 2, characterized in that the RxO groups in the polyorganosiloxanes (A) are hydroxyl groups.
4. The method of claim 1, 2 or 3, characterized in that the R20 groups in the polyorganosiloxanes (D) are Ci-30 alkoxy groups.
5. The method of any one of Claims 1 to 4, characterized in that 0.1 to 50 parts of polyorganosiloxane (D) are used per 100 parts of polyorganosiloxane (A) , and in the polyorganosiloxanes (D) R2 denotes a linear and/or branched hydrocarbon radical having 6 to 3 0 carbon atoms.
6. The method of any one of Claims 1 to 5, characterized in that water-insoluble organic Compounds having a boiling point of greater than 100°C are used as organic Compounds (F) containing no Silicon.
7. The use of defoamer formulations prepared according to any one of in Claims 1 to 6 for

preparing Solutions, powders, emulsions or dispersions having a defoaming action,
8. The use of defoamer formulations prepared according to any one of in Claims 1 to 7 for defoaming wastewaters, intensely agitated liquids, distillation, washing, coloring or finishing Operations in household or industry, or chemical digestion or conversion Operations, such as chemical syntheses, cellulose production or papermaking or petroleum processing (refining), for defoaming in fermentative Operations, in the preparation of dispersions, in the preparation or application of formulated products, such as sprays, cosmetics, drugs, paints or inks, or of foams which occur in the course of dispensing Operations.


Documents:

3605-chenp-2007 amended claims 08-06-2011.pdf

3605-CHENP-2007 AMENDED PAGES OF SPECIFICATION 31-01-2011.pdf

3605-CHENP-2007 AMENDED CLAIMS 31-01-2011.pdf

3605-CHENP-2007 CORRESPONDENCE OTHERS 08-06-2011.pdf

3605-chenp-2007 form-3 31-01-2011.pdf

3605-CHENP-2007 POWER OF ATTORNEY 31-01-2011.pdf

3605-CHENP-2007 EXAMINATION REPORT REPLY RECIEVED 31-01-2011.pdf

3605-CHENP-2007 CORRESPONDENCE OTHERS 07-07-2010.pdf

3605-chenp-2007-abstract.pdf

3605-chenp-2007-claims.pdf

3605-chenp-2007-correspondnece-others.pdf

3605-chenp-2007-description(complete).pdf

3605-chenp-2007-form 1.pdf

3605-chenp-2007-form 3.pdf

3605-chenp-2007-form 5.pdf

3605-chenp-2007-pct.pdf


Patent Number 248297
Indian Patent Application Number 3605/CHENP/2007
PG Journal Number 27/2011
Publication Date 08-Jul-2011
Grant Date 04-Jul-2011
Date of Filing 17-Aug-2007
Name of Patentee WACKER CHEMIE AG
Applicant Address Hanns-seidel-platz 4, 81737 München
Inventors:
# Inventor's Name Inventor's Address
1 SCHNEIDER, Otto Carl-bosch-strasse 6, 84489 Burghausen
2 BURGER, Willibald Elisabethstrasse 14, 84489 Burghausen
3 RAUTSCHEK, Holger Mühlenblick 1, 01612 Nünchritz
PCT International Classification Number C08L 83/04
PCT International Application Number PCT/EP2006/001155
PCT International Filing date 2006-02-09
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10 2005 007 313.1 2005-02-17 Germany