CA2135420A1 - Defoamer emulsion based on organofunctionally modified polysiloxanes - Google Patents
Defoamer emulsion based on organofunctionally modified polysiloxanesInfo
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- CA2135420A1 CA2135420A1 CA002135420A CA2135420A CA2135420A1 CA 2135420 A1 CA2135420 A1 CA 2135420A1 CA 002135420 A CA002135420 A CA 002135420A CA 2135420 A CA2135420 A CA 2135420A CA 2135420 A1 CA2135420 A1 CA 2135420A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
- C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D19/00—Degasification of liquids
- B01D19/02—Foam dispersion or prevention
- B01D19/04—Foam dispersion or prevention by addition of chemical substances
- B01D19/0404—Foam dispersion or prevention by addition of chemical substances characterised by the nature of the chemical substance
- B01D19/0409—Foam dispersion or prevention by addition of chemical substances characterised by the nature of the chemical substance compounds containing Si-atoms
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/10—Block- or graft-copolymers containing polysiloxane sequences
- C08L83/12—Block- or graft-copolymers containing polysiloxane sequences containing polyether sequences
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/42—Block-or graft-polymers containing polysiloxane sequences
- C08G77/46—Block-or graft-polymers containing polysiloxane sequences containing polyether sequences
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
- C08J2383/04—Polysiloxanes
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- Health & Medical Sciences (AREA)
- Dispersion Chemistry (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Toxicology (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Silicon Polymers (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
- Degasification And Air Bubble Elimination (AREA)
- Paints Or Removers (AREA)
Abstract
A defoamer emulsion, based on organofunctionally modified polysiloxanes, is obtained by mixing one or several more closely defined organofunctionally modified siloxanes and, optionally, finely divided silica, and emulsifying the mixture by means of a low-shear stirrer with water which contains a hydrophilic, organofunctionally modified polysiloxane.
Description
FIELD OF lNV~NllON
The invention relates to defoamer emulsions based on organofunctionally modified polysiloxanes. More particularly, the invention relates also to those emulsions which contain finely divided silica.
BACKGROUND INFORMATION AND PRIOR ART
The use of methylpolysiloxanes for defoaming liquids is one of the first areas in which these products were used. There exists a large number of publications and patents wherein the mode of action of the siloxanes is described, and advice is given for selecting suitable siloxanes and the forms in which they are prepared .
It was already recognized earlier that the use of mixtures of different polysiloxanes can be advantageous. For this purpose, a large number of different organofunctionally-modified polysiloxanes have also been developed. A typical organo-functional group, which modifies the properties of the polysil oxanes, is the polyether group with oxyethylene and/or oxypropylene units. In the course of further development, polysiloxanes, with combinations of polyether groups of different hydrophilicity, were used for the modification. Finely divided, mostly pyrogenic silica, which is optionally used in the hydrophobized form, is an important component of such defoamer emulsions based on polysiloxanes.
Y2-21438. -2-- ~I35420 From the large number of O~enlegungsschriften and patents relating to defoamers based on polysiloxanes, the following publications are cited as examples:
U.S. patent 3, 984, 347 relates to a preparation, which consists essentially of:
1. 50 to 98.9% by weight of a basic oil, which is a polyoxypropylene or a polyoxypropylene-polyoxyethylene polymer with a molecular weight of 500 to 6,000, or a siloxane glycol polyme-; of the general formulae (a) (RaSi (OSiMe2) n (OSiMeG)bOSiMe2G) 4-a~
(b) (RaSi (OSiMe2) n (OSiMeG) rOSiMe3) 4-a~
(c) GMe2Si(OSiMe~) n (OSiMeG)bOSiMe2G), (d) Me3Si(OSiMe2) n (OSiMeG)rOSiMe3 wherein R is a hydrocarbon with 1 to 10 carbon atoms, free of olefinic double bonds, Me is a methyl group, ~IY2-21438.
~13~
G is a group having the formula -D(OR')mA, in which D is an alkylene group wlth 1 to 30 carbon atoms and R' is an alkylene group-with 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 l, n has a value of at least 12, b has a value of 0 to 50, and c has a value of 1 to 50;
2. 1 to 40~ by weight of a defoamer, which is obtained essentially from 88 to 95 parts by weight of a liquid poly-dimethylsiloxane with a viscosity of at least 20 cSt at 25C, S to 10 parts b-y weight of silica and 0 to 20 parts by weight of a siloxane resin, which consists essentially of the units SiO2 and (CH3)3SiO1/2 in the ratio of 1 : 0.4 to 1 : 1.2;
and ~`~'2-21438.
- 21~5~20 3. 0.1 to 10~ by weight of a dispersant, which disperses component 2 in component 1 and is a siloxane copolymer, which either is i) a polydimethylpolysiloxane-polyether copolymer, in which the molecular weight of the polysiloxane is at least 2,000, and the polyoxypropylene polymer has a molecular weight of at least 800, or a polyoxyethylene-polyoxypropylene copolymer with a molecular weight of 1,500, the polyether being linked over an SiC bond to a silicon atom of; the siloxane, or ii) a polydimethylpolysiloxane-polyether polymer, which is obtained by heating a mixture of a methyl-hydrogenpolysiloxane having a molecular weight of at least 1,500, and a polyoxypropylene glycol having a molecular weight of at least 800, or a polyoxyethylene-polyoxypropylene glycol having a molecular weight of at least l,S00.
!~Y2-21438.
-~ ~13~420 The p~2blishea ~:uropean patent application 0 354 016 relates to a tex~ile detergent which contains raw detergents, builders and at least one material for controlling the foam,~ with the distinguishing feature that a dispersable preparation of a silicone defoamer is contained in the detergent and consists of a non-aqueous emulsion of a primary and a secondary defoamer, the primary defoaming ingredient being a mixture of:
a) a liquid or organopolysiloxane with at least one hydroxyl and hydrocarbon group, b) a silicone resin or a compound producing a silicone resin, c) a finely divided filler, and d) a catalyst for the reaction between a) and c), the secondary defoaming ingredient being a mixture of a liquid methylpolysiloxane, at least one nonionic silicone surfactant, a first organic dispersant and a second dispersant, based on a nonionic difunctional block copolymer with terminal primary hydroxyl groups.
-2143~. -6-~13542~
Finally, reference is made to the published European patent application 0 427 263, in which a silicone-based defoamer preparation is described, which contains (i) a polydiorgano-siloxane, (ii) silica, and (iii) 4 to 2500 parts by weight, based on 100 parts by weight of the sum of components (i) and (ii) of a modified silicone oil, the molecule of which has at least one functional organic group which is linked to a silicon atom, a~
well as at least one epoxy, amino, amide, carboxyl, alkoxyl or '.~ydroxyl group, and at least one optionally substituted polyoxyalkylene group which is linked to a silicon atom.
Even though these known defoamers can be iused advantageously to prevent or eliminate foam in aqueous systems, unfulfilled or inadequately fulfilled requirements, nevertheless, remaln .
One of these requirements is to prepare defoamer emulsions which are as concentrated and stable as possible and can be diluted by the user to the desired concentration, while .etaining the stability of the emulsions. This is possible with simple stirring equipment without requiring expensive stirring technology or special precautions. At the same time, the diluted emulsions must satisfy high stability requirements and should exhibit high stability particularly when subjected to temperature changes and to shaking. It is, therefore, an object of the invention to solve this technical problem.
~'Y2 21438.
~13~
OBJECT OF THE lN V l':N l lON
An object of the present invention is a defoamer emulsion based on organofunctionally modi~ed polysiloxanes.
SU~IARY OF THE lNV~;NllON
Such a defoamer can be obtained by mixing together (a~ O to 90 parts by weight of an organopolysiloxane of the general formula Rl-SiO- SiO- '-iO- SiRl CH3 CH3 a O CH3 CH3- i-CH3 b --1 c ~ hereinafter referred to as Formula I) in which Rl can be the same or di~erent in the average molecule and represents an alkyl group with 1 to 8 carbon atoms, or the -Z-(CnH2nO-)mR2 group, wherein R2 is a hydrogen group or an alkyl group with 1 to 8 carbon atoms, ~IYt-2 1 438 .
s~
- 2135~2~
Z is a divalent group having the formula -O-, -(CH2)p-O- or -CH2-CH(CH3)-CH2-O- with p = 2 or 3, n has an average numerical value of 2.7 to 4.0, m has an average numerical value of 5 to 130, a has an average numerical value of 4 to 1,500, b has an average numerical value of 0 to 100, and c has an average numerical value of 0 to 50;
(b) 0 to 90 parts by weight of an organopolysiloxane of the general ormula CH3 fH3 fH3 CH3 R3-Sio- SiO- SiO- iR3 CH3 CH3 d O CH3 CH3 - 51 _ CH3 e (referred hereinafter as Formula II) in which ~IY~-21438.
213$~20 R3 can be the same or di~erent in the average molecule and represents a hydroxyl group or alkoxy group with 1 to 4 carbon atoms, d has an average numerical value of 4 to 1,500, e has an average numerical value of O to 100, and f has an average numerical value of O to 50;
(c) O to 90 parts by weight of an organopolysiloxane of the general formula R5-o- [CXH2xO] -y -iO- ~CxH2xO] -Y Rs CH3 w (referred to hereinafter as Formula III) in which ~Y2-21438.
21~5A20 Rs can be the same or different in the average molecule and represents an alkyl group with 1 to 4 carbon atoms, with the proviso that at least 90~ of the Rs groups are methyl groups, x has an average numerical value of 2.6 to 3.0, y has an average numerical value of 8 to 80, w has an average numerical value of 7 to 50, and z has an average numerical value of 1.5 to 10, the sum of the components (a), (b) and (c) being not less than 10 parts by weight and not more than 90 parts by weight; and (d) O to 15 parts by weight of finely divided silica, and stirring this mixture into a mixture of (e) and (f) obtained from (e) 5 to 85 parts by weight of an organopolysiloxane of the general formula ~ ~ 2 ~t438 fH3 CH3 fH3 fH, R4-sio- SiO- SiO- SiR4 I
CH3 CH3 g O CH3 CH3 - S i - CH3 h (referred to hereinafter as Formula IV) in which R4 in the average molecule can be the same or di~erent and represents an alkyl group with 1 to 8 carbon atoms or the -Z-(CqH2qO-)rR2 group, wherein R2 and Z have the meanings already given, q has an average numerical value of 2.0 to 2.7, r has an average numerical value of 5 to 120, g has an average numerical value of 4 to 200, h has an average numerical value of 0 to 100, and j has an average numerical value of 0 to 50;
~'Y2-21438. -l2-213S~
and (f) 5 to 50 parts by weight of water with a low-shear stirrer and thus converting this mixture into a stock emulsion, which is diluted to the desired concentration subsequently or only immediately before it is used.
In Formula I, R1 preferably represents a methyl group or a polyether group, in which Z is -o- or -(CH2) 3-0- . In this case, the polyether group has the formula -(CH2)3-O-(CnH2nO-)mR2.
The average numerical value of n is 2.7 to 4.0, a nume~ical value of 2.7 to 3 being preferred. This average numerical value is obtained during the block-wise synthesis of the polyether or random addition reaction of corresponding amounts of ethylene oxide and propylene oxide. Optionally, higher alkylene oxides can also be used.
The average numerical value of m is 5 to 130. It indicates the average number of oxyalkylene units in the polyether group.
Preferably, m has an average numerical value of 6 to 50.
R2 is a hydrogen group or an alkyl group with 1 to 8 carbon atoms. Especially preferred is an alkyl group with 1 to 5 carbon atoms, particularly the butyl group. The subscripts a, b, and c preferably have the following values: a = 4 to 800, b = 0 to 50, c = 0 to 30.
-l3-~1~5~0 The secon~ polysiloxane component corresponds to the general Formula II. In this polysiloxane, R3 represents a hydroxyl group or a lower alkoxy group with 1 to 4 carbon atoms.
The hydroxyl group is preferred and the alkoxy group is to be regarded as a precursor, which can be converted into the hydroxyl group under hydrolysis conditions.
Admittedly, the values of d, e and f are to be regarded as independent of the subscripts a, b and c. However, they correspond to the given and preferred ranges but need not be identical in the two formulas.
The third polysiloxane component corresponds to the general Formula III. In this polysiloxane, Rs represents an alkyl group with 1 to 4 carbon atoms, however, with the proviso that at least 90~ of the Rs groups are methyl groups. The subscripts have the following average values:
x = 2.6 to 30, preferably 2.8 to 3.0;
y = 8 to 80, preferably 20 to 60;
w = 7 to 50, preferably 13 to 30;
and z = 1.5 to 0, preferably 1.5 to 5.
~iY2-21438.
~1~5~20 The polyslloxanes of Formulas I, II and III can be present in the inventive defoamer emulsion in amounts of, i~ each case, 0 to 90 parts by weight. However, the condition that the sum of the two polysiloxanes constitutes at least 10 parts by weight but does not ex-eed 90 parts by weight, must be fulfilled. For example, the following combinations (aside from other combinations) are possible:
Siloxane Type Parts by Weight Siloxane I 90 0 0 30 20 Siloxane II 0 90 0 30 45 Siloxane III 0 0 90 30 25 Component d is a finely divided silica which is customarily used in defoaming emulsions as an action-enhancing substance. In general, pyrogenically produced silica is used which can also be hydrophobized by treatment with silanes. Preferably, amounts of 0.2 to 5 parts by weight are used.
As polysiloxane e with the general Formula Iv, siloxanes are preferably ! used in which the R4 groups represent an alkyl group with 1 to 4 carbon atoms and/or groups having the formula -(CH2)3-O-(CqH2qO-)2H. In distinction from the polyether siloxanes of Formula I, the polyether group of the polyethersiloxanes 5 is more hydrophilic, that is, the average value of q, ranging from 2.0 to 2.7, is lower than that of the siloxanes I. This is brought about by a higher proportion of ethylene oxide in the synthe~is of the polyether. A range of 2.3 to 2.6 is particularly preferred.
~'Y2-21438.
-From the values of the subscripts g, h and j, it is evident that the polysiloxanes of Formula IV generally have a lower molecular weight than the polysiloxanes of Formula I. , The following average numerical values are preferred for the subscripts: g = 4 to 100, h = 0 to 20 and j = 0 to 25.
The inventive defoamer emulsion can be obtained by mixing together components (a) = siloxane I, (b) = siloxane II, (c) =
polysiloxane III and (d) silica and stirring into this mixture the components (e) = polysiloxane of Formula IV and (f) water by means of a low-shear stirrer.
A procedure is preferred in which the components (a), (b), (c) and (d), to begin with, are heated in the presence of an alkaline equilibrating catalyst for 0.5 to 10 hours at 50C to 200C. An alkaline equilibrating catalyst, preferably an e~ective amount, about 0.5 to 2 parts by weight, of an alcoholic solution of an alkali or ammonium hydroxide or carbonate, such as an ethanolic solution of potassium hydroxide, is used.
Preferably, the equilibration is carried out for 3 to 6 hours at 90C to 150C. It can be assumed that, during this reaction, there are also reactions between the polysiloxanes and reactive centers at the surface of the finely divided silica.
~IY2-21438.
-l6-- 2135~20 The mixture, so obtained, is now emulsified with the mixture of components (e) and (f) to form a stock emulsion. The latter can then be diluted to the desired concentration immediately or at a later time, if necessary, on the location where the defoamer is to be used. The concentration for use is generally 5 to 20~ by weight of dispersed phase.
Despite the low water content, the stock solution, which can be diluted pursuant to the invention, has a low viscosity and can be converted in any convenient manner, for example, simply by stirring-in water into the desired, dilute emulsion used for the defoaming.
The stability of the diluted emulsions can be increased even further by diluting the stock emulsion with water, which contains a stabilizer and/or thickener. Stabilizers and/or thickeners based on a carboxyl group-containing polyacrylate are particularly preferred. For this stabilization, the pH of the aqueous solution is adjusted to a value of about 7. Such stabilizers or thickeners are commercially available and described, for example, in the German O~enlegungsschrift 39 25 220 .
The stock emulsions, obtained pursuant to the invention, and the emulsions, diluted to the desired concentration, have the required stability when subjected to temperature changes and/or shaking as shown in the following Examples, it being understood that the Examples are provided by way of illustration and not by way of limitation.
~Y2-21438. -17-21~5~2~
A siloxane of Formula I (31 parts by weight, a = 80, c = 7, b = 0 and Rl = CH3- and -Z-(CnH2nO-)mR2 in the ratio of 2 : 7, wherein Z = -(CH2)p-O- with p = 3 and n = 2.9, m = 15, R2 = -H), are mixed with 5 parts by weight of a siloxane of Formula II
(d = 300, f = 0 and R3 = -OH) and treated with 2 parts by weight of a finely dispersed silica. After the addition of 0. 5 parts by weight of a 10~ methanolic solution of potassium hydroxide, the mixture, so obtained, is heated for 3 hours at 100C.
The heated product (37 parts by weight), is added'to a mixture of 30 parts by weight of a siloxane of Formula IV (g = 18, h = 6, j = 2 and R4 = -Z- (CqH2qO) rR2 with Z = -O-, R2 = C3H7-and q - 2.6, r = 40) and 33 parts by weight of water, and stirred with a low-shear stirrer.
A siloxane of Formula 1 (20 parts by weight, a = 18, b = 6, c = 2 and R1 = -Z(CnH2nO)m-R2 with R2 = C3H7- and n = 3, m = 33) is mixed with 20 parts by weight of a siloxane of formula III
(x = 3.0, y = 51, w = 15, z = 4). This mixture is added to a mixture of 20 parts by weight of siloxane of formula IV (g = 48, h = 0, j = 2 and R4 = -Z- (CqH2qO) rR2 with z = -(CH2)p-O-, p = 3, R2 = H- and q = 2.6, r = 40) and 40 parts by weight of water and stirrea together with little shear.
~'Y2-21438.
A siloxane of Formula III (60 parts by weight, x = 2.8, y = 20, w = 25 and z = 2) is stirred into a mixture of 25 parts by weight of a siloxane of Formula IV (g = 21, h = 7, j = 2 and R4 = -Z-(CqH2qO)rR2 with Z = -O-, R2 = C3H,- and q = 2.6, r = 40) and 15 parts by weight of water.
A siloxane of Formula II (38 parts by weight, d = 70, e = 10, f = 6, R3 = -OC2Hs) is mixed with 2 parts by weight of a finely dispersed silica. This mixture is stirred with little shear into a mixture of 30 parts by weight of a siloxane of Formula IV (g = 60, h = 0, j = 4 and R4 = -Z-(CqH2qO)rR2 with Z = -CH2-CH(CH3)CH2-O-, R2 = CH3-, q = 2.5 and r = 40), and 30 parts by weight of water.
A siloxane of Formula I (38 parts by weight, a = 500, c = 0 and Rl = CH3-) is mixed with 2 parts by weight of a finely dispersed silica and stirred with little shear into a mixture of 30 parts by weight of siloxane of Formula IV (g = 18, h = 6, j = 2 and R4 = -Z-(CqH2qO)rR2 with Z = -O-, R2 = C3H7- and q = 2.6, r = 40) and 30 parts by weight of water.
~Y2-21438.
-Water (80.1 parts by weight) is added to a stirred vessel and 2.5 parts by weight of a 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5) are added. 14.9 parts by weight of the emulsion of Example I are then added. This mixture is stirred with a multi-stage, impulse, counter-current agitator for 5 minutes at a peripheral speed of 3 m/s. After that, the pH of this emulsion is adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
Water (78.3 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
~IY2-21438.
213~420 Water (83.2 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 11.8 parts by weight of the emulsion of Example 3 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6% sodium hydroxide solution.
~XAMPLE 9 Water (80.1 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 14.9 parts by weight of the emulsion of Example 4 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6% sodium hydroxide solution.
~'Y2-21438. -21-2135~2~
Water (80.7 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 14.3 parts by weight of the emulsion of Example 5 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
Water (78.3 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a turbine with a peripheral speed of 5 m/s. The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
~Y2 21438. -2~- ;
213S4~D
EXAMPL~ 12 Water (78.3 parts by weight) is added to a stirred ve~sel, followed by 2.5 parts by weight of 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commerctally obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a dissolver disk at a peripheral speed of 7 m/s. The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6% sodium hydroxide solution.
Water (87.3 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a spatula. The pH
of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
a) Heat StabilitY
To determine the heat stability, the emulsions of Examples I to 13 were kept in a 250 mL glass bottle at 60C in an oven and evaluated every 8 hours. The time after which no destabilization of the emulsion is detectable, lS noted.
~IY2-21438.
~135~2û
b) Shakina Stabilitv The shaking stability was determined by filling 80 mL of the emulsion to be tested into 100 mL glass bottles and shaking them in a shaker with a shaking frequency of 240 per minute and a de~ection of 3 cm. The emulsion was checked hourly for destabilization. Emulsions with shaking stabilities of less than 2 hours could be harmed during transport. For this reason, longer shaking stabilities are desirable.
The heat stability of the emulsions of Examples I to 13 exceeded 150 hours.
The shaking stability of the emulsions of Examples I to 13 exceeded 8 hours.
The defoaming action of the emulsions of Example 7 and Examples 11 to 13, prepared with different peripheral speeds from the emulsion of Example 2, were checked in order to show that the defoaming is independent of the dilution method.
~Y2-21438. -24-213~120 TEST METHOD:
Dilexo AM 15 (a pure acrylate dispersion of the DEA
Company) is mixed with water in a ratio of 8 : 2 (dispersion I).
Dispersion I (100 g) is added to a 250 mL beaker and the temperature is adjusted to 20C. After that, 1~ of the defoamer emulsion to be tested is added. This mixture is stirred for 1 minute at 2,500 rpm with a turbine, the diameter of which is 4 cm and which is clamped in a stirrer in such a manner that it is 0.5 cm above the bottom of the beaker. Directly after the 3tirring, 50 mL of the stirred dispersion I is added to a tared 50 mL measuring cylinder and weighed. From the weight A~and density of the unstirred dispersion ~ (1.02 g/mL), the air, stirred in, can be calculated as a percentage by volume using the following equation:
~ by Volume of Air = 100 - 2A/aD
Defoamer A (g/50 mL)~ by Volume of Air Without 36.4 28.6 Example 7 46.4 g.o Example 11 46.5 8.8 Example 12 46.3 9.2 Example 13 46.7 8.4 NY2-21438.
The invention relates to defoamer emulsions based on organofunctionally modified polysiloxanes. More particularly, the invention relates also to those emulsions which contain finely divided silica.
BACKGROUND INFORMATION AND PRIOR ART
The use of methylpolysiloxanes for defoaming liquids is one of the first areas in which these products were used. There exists a large number of publications and patents wherein the mode of action of the siloxanes is described, and advice is given for selecting suitable siloxanes and the forms in which they are prepared .
It was already recognized earlier that the use of mixtures of different polysiloxanes can be advantageous. For this purpose, a large number of different organofunctionally-modified polysiloxanes have also been developed. A typical organo-functional group, which modifies the properties of the polysil oxanes, is the polyether group with oxyethylene and/or oxypropylene units. In the course of further development, polysiloxanes, with combinations of polyether groups of different hydrophilicity, were used for the modification. Finely divided, mostly pyrogenic silica, which is optionally used in the hydrophobized form, is an important component of such defoamer emulsions based on polysiloxanes.
Y2-21438. -2-- ~I35420 From the large number of O~enlegungsschriften and patents relating to defoamers based on polysiloxanes, the following publications are cited as examples:
U.S. patent 3, 984, 347 relates to a preparation, which consists essentially of:
1. 50 to 98.9% by weight of a basic oil, which is a polyoxypropylene or a polyoxypropylene-polyoxyethylene polymer with a molecular weight of 500 to 6,000, or a siloxane glycol polyme-; of the general formulae (a) (RaSi (OSiMe2) n (OSiMeG)bOSiMe2G) 4-a~
(b) (RaSi (OSiMe2) n (OSiMeG) rOSiMe3) 4-a~
(c) GMe2Si(OSiMe~) n (OSiMeG)bOSiMe2G), (d) Me3Si(OSiMe2) n (OSiMeG)rOSiMe3 wherein R is a hydrocarbon with 1 to 10 carbon atoms, free of olefinic double bonds, Me is a methyl group, ~IY2-21438.
~13~
G is a group having the formula -D(OR')mA, in which D is an alkylene group wlth 1 to 30 carbon atoms and R' is an alkylene group-with 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 l, n has a value of at least 12, b has a value of 0 to 50, and c has a value of 1 to 50;
2. 1 to 40~ by weight of a defoamer, which is obtained essentially from 88 to 95 parts by weight of a liquid poly-dimethylsiloxane with a viscosity of at least 20 cSt at 25C, S to 10 parts b-y weight of silica and 0 to 20 parts by weight of a siloxane resin, which consists essentially of the units SiO2 and (CH3)3SiO1/2 in the ratio of 1 : 0.4 to 1 : 1.2;
and ~`~'2-21438.
- 21~5~20 3. 0.1 to 10~ by weight of a dispersant, which disperses component 2 in component 1 and is a siloxane copolymer, which either is i) a polydimethylpolysiloxane-polyether copolymer, in which the molecular weight of the polysiloxane is at least 2,000, and the polyoxypropylene polymer has a molecular weight of at least 800, or a polyoxyethylene-polyoxypropylene copolymer with a molecular weight of 1,500, the polyether being linked over an SiC bond to a silicon atom of; the siloxane, or ii) a polydimethylpolysiloxane-polyether polymer, which is obtained by heating a mixture of a methyl-hydrogenpolysiloxane having a molecular weight of at least 1,500, and a polyoxypropylene glycol having a molecular weight of at least 800, or a polyoxyethylene-polyoxypropylene glycol having a molecular weight of at least l,S00.
!~Y2-21438.
-~ ~13~420 The p~2blishea ~:uropean patent application 0 354 016 relates to a tex~ile detergent which contains raw detergents, builders and at least one material for controlling the foam,~ with the distinguishing feature that a dispersable preparation of a silicone defoamer is contained in the detergent and consists of a non-aqueous emulsion of a primary and a secondary defoamer, the primary defoaming ingredient being a mixture of:
a) a liquid or organopolysiloxane with at least one hydroxyl and hydrocarbon group, b) a silicone resin or a compound producing a silicone resin, c) a finely divided filler, and d) a catalyst for the reaction between a) and c), the secondary defoaming ingredient being a mixture of a liquid methylpolysiloxane, at least one nonionic silicone surfactant, a first organic dispersant and a second dispersant, based on a nonionic difunctional block copolymer with terminal primary hydroxyl groups.
-2143~. -6-~13542~
Finally, reference is made to the published European patent application 0 427 263, in which a silicone-based defoamer preparation is described, which contains (i) a polydiorgano-siloxane, (ii) silica, and (iii) 4 to 2500 parts by weight, based on 100 parts by weight of the sum of components (i) and (ii) of a modified silicone oil, the molecule of which has at least one functional organic group which is linked to a silicon atom, a~
well as at least one epoxy, amino, amide, carboxyl, alkoxyl or '.~ydroxyl group, and at least one optionally substituted polyoxyalkylene group which is linked to a silicon atom.
Even though these known defoamers can be iused advantageously to prevent or eliminate foam in aqueous systems, unfulfilled or inadequately fulfilled requirements, nevertheless, remaln .
One of these requirements is to prepare defoamer emulsions which are as concentrated and stable as possible and can be diluted by the user to the desired concentration, while .etaining the stability of the emulsions. This is possible with simple stirring equipment without requiring expensive stirring technology or special precautions. At the same time, the diluted emulsions must satisfy high stability requirements and should exhibit high stability particularly when subjected to temperature changes and to shaking. It is, therefore, an object of the invention to solve this technical problem.
~'Y2 21438.
~13~
OBJECT OF THE lN V l':N l lON
An object of the present invention is a defoamer emulsion based on organofunctionally modi~ed polysiloxanes.
SU~IARY OF THE lNV~;NllON
Such a defoamer can be obtained by mixing together (a~ O to 90 parts by weight of an organopolysiloxane of the general formula Rl-SiO- SiO- '-iO- SiRl CH3 CH3 a O CH3 CH3- i-CH3 b --1 c ~ hereinafter referred to as Formula I) in which Rl can be the same or di~erent in the average molecule and represents an alkyl group with 1 to 8 carbon atoms, or the -Z-(CnH2nO-)mR2 group, wherein R2 is a hydrogen group or an alkyl group with 1 to 8 carbon atoms, ~IYt-2 1 438 .
s~
- 2135~2~
Z is a divalent group having the formula -O-, -(CH2)p-O- or -CH2-CH(CH3)-CH2-O- with p = 2 or 3, n has an average numerical value of 2.7 to 4.0, m has an average numerical value of 5 to 130, a has an average numerical value of 4 to 1,500, b has an average numerical value of 0 to 100, and c has an average numerical value of 0 to 50;
(b) 0 to 90 parts by weight of an organopolysiloxane of the general ormula CH3 fH3 fH3 CH3 R3-Sio- SiO- SiO- iR3 CH3 CH3 d O CH3 CH3 - 51 _ CH3 e (referred hereinafter as Formula II) in which ~IY~-21438.
213$~20 R3 can be the same or di~erent in the average molecule and represents a hydroxyl group or alkoxy group with 1 to 4 carbon atoms, d has an average numerical value of 4 to 1,500, e has an average numerical value of O to 100, and f has an average numerical value of O to 50;
(c) O to 90 parts by weight of an organopolysiloxane of the general formula R5-o- [CXH2xO] -y -iO- ~CxH2xO] -Y Rs CH3 w (referred to hereinafter as Formula III) in which ~Y2-21438.
21~5A20 Rs can be the same or different in the average molecule and represents an alkyl group with 1 to 4 carbon atoms, with the proviso that at least 90~ of the Rs groups are methyl groups, x has an average numerical value of 2.6 to 3.0, y has an average numerical value of 8 to 80, w has an average numerical value of 7 to 50, and z has an average numerical value of 1.5 to 10, the sum of the components (a), (b) and (c) being not less than 10 parts by weight and not more than 90 parts by weight; and (d) O to 15 parts by weight of finely divided silica, and stirring this mixture into a mixture of (e) and (f) obtained from (e) 5 to 85 parts by weight of an organopolysiloxane of the general formula ~ ~ 2 ~t438 fH3 CH3 fH3 fH, R4-sio- SiO- SiO- SiR4 I
CH3 CH3 g O CH3 CH3 - S i - CH3 h (referred to hereinafter as Formula IV) in which R4 in the average molecule can be the same or di~erent and represents an alkyl group with 1 to 8 carbon atoms or the -Z-(CqH2qO-)rR2 group, wherein R2 and Z have the meanings already given, q has an average numerical value of 2.0 to 2.7, r has an average numerical value of 5 to 120, g has an average numerical value of 4 to 200, h has an average numerical value of 0 to 100, and j has an average numerical value of 0 to 50;
~'Y2-21438. -l2-213S~
and (f) 5 to 50 parts by weight of water with a low-shear stirrer and thus converting this mixture into a stock emulsion, which is diluted to the desired concentration subsequently or only immediately before it is used.
In Formula I, R1 preferably represents a methyl group or a polyether group, in which Z is -o- or -(CH2) 3-0- . In this case, the polyether group has the formula -(CH2)3-O-(CnH2nO-)mR2.
The average numerical value of n is 2.7 to 4.0, a nume~ical value of 2.7 to 3 being preferred. This average numerical value is obtained during the block-wise synthesis of the polyether or random addition reaction of corresponding amounts of ethylene oxide and propylene oxide. Optionally, higher alkylene oxides can also be used.
The average numerical value of m is 5 to 130. It indicates the average number of oxyalkylene units in the polyether group.
Preferably, m has an average numerical value of 6 to 50.
R2 is a hydrogen group or an alkyl group with 1 to 8 carbon atoms. Especially preferred is an alkyl group with 1 to 5 carbon atoms, particularly the butyl group. The subscripts a, b, and c preferably have the following values: a = 4 to 800, b = 0 to 50, c = 0 to 30.
-l3-~1~5~0 The secon~ polysiloxane component corresponds to the general Formula II. In this polysiloxane, R3 represents a hydroxyl group or a lower alkoxy group with 1 to 4 carbon atoms.
The hydroxyl group is preferred and the alkoxy group is to be regarded as a precursor, which can be converted into the hydroxyl group under hydrolysis conditions.
Admittedly, the values of d, e and f are to be regarded as independent of the subscripts a, b and c. However, they correspond to the given and preferred ranges but need not be identical in the two formulas.
The third polysiloxane component corresponds to the general Formula III. In this polysiloxane, Rs represents an alkyl group with 1 to 4 carbon atoms, however, with the proviso that at least 90~ of the Rs groups are methyl groups. The subscripts have the following average values:
x = 2.6 to 30, preferably 2.8 to 3.0;
y = 8 to 80, preferably 20 to 60;
w = 7 to 50, preferably 13 to 30;
and z = 1.5 to 0, preferably 1.5 to 5.
~iY2-21438.
~1~5~20 The polyslloxanes of Formulas I, II and III can be present in the inventive defoamer emulsion in amounts of, i~ each case, 0 to 90 parts by weight. However, the condition that the sum of the two polysiloxanes constitutes at least 10 parts by weight but does not ex-eed 90 parts by weight, must be fulfilled. For example, the following combinations (aside from other combinations) are possible:
Siloxane Type Parts by Weight Siloxane I 90 0 0 30 20 Siloxane II 0 90 0 30 45 Siloxane III 0 0 90 30 25 Component d is a finely divided silica which is customarily used in defoaming emulsions as an action-enhancing substance. In general, pyrogenically produced silica is used which can also be hydrophobized by treatment with silanes. Preferably, amounts of 0.2 to 5 parts by weight are used.
As polysiloxane e with the general Formula Iv, siloxanes are preferably ! used in which the R4 groups represent an alkyl group with 1 to 4 carbon atoms and/or groups having the formula -(CH2)3-O-(CqH2qO-)2H. In distinction from the polyether siloxanes of Formula I, the polyether group of the polyethersiloxanes 5 is more hydrophilic, that is, the average value of q, ranging from 2.0 to 2.7, is lower than that of the siloxanes I. This is brought about by a higher proportion of ethylene oxide in the synthe~is of the polyether. A range of 2.3 to 2.6 is particularly preferred.
~'Y2-21438.
-From the values of the subscripts g, h and j, it is evident that the polysiloxanes of Formula IV generally have a lower molecular weight than the polysiloxanes of Formula I. , The following average numerical values are preferred for the subscripts: g = 4 to 100, h = 0 to 20 and j = 0 to 25.
The inventive defoamer emulsion can be obtained by mixing together components (a) = siloxane I, (b) = siloxane II, (c) =
polysiloxane III and (d) silica and stirring into this mixture the components (e) = polysiloxane of Formula IV and (f) water by means of a low-shear stirrer.
A procedure is preferred in which the components (a), (b), (c) and (d), to begin with, are heated in the presence of an alkaline equilibrating catalyst for 0.5 to 10 hours at 50C to 200C. An alkaline equilibrating catalyst, preferably an e~ective amount, about 0.5 to 2 parts by weight, of an alcoholic solution of an alkali or ammonium hydroxide or carbonate, such as an ethanolic solution of potassium hydroxide, is used.
Preferably, the equilibration is carried out for 3 to 6 hours at 90C to 150C. It can be assumed that, during this reaction, there are also reactions between the polysiloxanes and reactive centers at the surface of the finely divided silica.
~IY2-21438.
-l6-- 2135~20 The mixture, so obtained, is now emulsified with the mixture of components (e) and (f) to form a stock emulsion. The latter can then be diluted to the desired concentration immediately or at a later time, if necessary, on the location where the defoamer is to be used. The concentration for use is generally 5 to 20~ by weight of dispersed phase.
Despite the low water content, the stock solution, which can be diluted pursuant to the invention, has a low viscosity and can be converted in any convenient manner, for example, simply by stirring-in water into the desired, dilute emulsion used for the defoaming.
The stability of the diluted emulsions can be increased even further by diluting the stock emulsion with water, which contains a stabilizer and/or thickener. Stabilizers and/or thickeners based on a carboxyl group-containing polyacrylate are particularly preferred. For this stabilization, the pH of the aqueous solution is adjusted to a value of about 7. Such stabilizers or thickeners are commercially available and described, for example, in the German O~enlegungsschrift 39 25 220 .
The stock emulsions, obtained pursuant to the invention, and the emulsions, diluted to the desired concentration, have the required stability when subjected to temperature changes and/or shaking as shown in the following Examples, it being understood that the Examples are provided by way of illustration and not by way of limitation.
~Y2-21438. -17-21~5~2~
A siloxane of Formula I (31 parts by weight, a = 80, c = 7, b = 0 and Rl = CH3- and -Z-(CnH2nO-)mR2 in the ratio of 2 : 7, wherein Z = -(CH2)p-O- with p = 3 and n = 2.9, m = 15, R2 = -H), are mixed with 5 parts by weight of a siloxane of Formula II
(d = 300, f = 0 and R3 = -OH) and treated with 2 parts by weight of a finely dispersed silica. After the addition of 0. 5 parts by weight of a 10~ methanolic solution of potassium hydroxide, the mixture, so obtained, is heated for 3 hours at 100C.
The heated product (37 parts by weight), is added'to a mixture of 30 parts by weight of a siloxane of Formula IV (g = 18, h = 6, j = 2 and R4 = -Z- (CqH2qO) rR2 with Z = -O-, R2 = C3H7-and q - 2.6, r = 40) and 33 parts by weight of water, and stirred with a low-shear stirrer.
A siloxane of Formula 1 (20 parts by weight, a = 18, b = 6, c = 2 and R1 = -Z(CnH2nO)m-R2 with R2 = C3H7- and n = 3, m = 33) is mixed with 20 parts by weight of a siloxane of formula III
(x = 3.0, y = 51, w = 15, z = 4). This mixture is added to a mixture of 20 parts by weight of siloxane of formula IV (g = 48, h = 0, j = 2 and R4 = -Z- (CqH2qO) rR2 with z = -(CH2)p-O-, p = 3, R2 = H- and q = 2.6, r = 40) and 40 parts by weight of water and stirrea together with little shear.
~'Y2-21438.
A siloxane of Formula III (60 parts by weight, x = 2.8, y = 20, w = 25 and z = 2) is stirred into a mixture of 25 parts by weight of a siloxane of Formula IV (g = 21, h = 7, j = 2 and R4 = -Z-(CqH2qO)rR2 with Z = -O-, R2 = C3H,- and q = 2.6, r = 40) and 15 parts by weight of water.
A siloxane of Formula II (38 parts by weight, d = 70, e = 10, f = 6, R3 = -OC2Hs) is mixed with 2 parts by weight of a finely dispersed silica. This mixture is stirred with little shear into a mixture of 30 parts by weight of a siloxane of Formula IV (g = 60, h = 0, j = 4 and R4 = -Z-(CqH2qO)rR2 with Z = -CH2-CH(CH3)CH2-O-, R2 = CH3-, q = 2.5 and r = 40), and 30 parts by weight of water.
A siloxane of Formula I (38 parts by weight, a = 500, c = 0 and Rl = CH3-) is mixed with 2 parts by weight of a finely dispersed silica and stirred with little shear into a mixture of 30 parts by weight of siloxane of Formula IV (g = 18, h = 6, j = 2 and R4 = -Z-(CqH2qO)rR2 with Z = -O-, R2 = C3H7- and q = 2.6, r = 40) and 30 parts by weight of water.
~Y2-21438.
-Water (80.1 parts by weight) is added to a stirred vessel and 2.5 parts by weight of a 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5) are added. 14.9 parts by weight of the emulsion of Example I are then added. This mixture is stirred with a multi-stage, impulse, counter-current agitator for 5 minutes at a peripheral speed of 3 m/s. After that, the pH of this emulsion is adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
Water (78.3 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
~IY2-21438.
213~420 Water (83.2 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 11.8 parts by weight of the emulsion of Example 3 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6% sodium hydroxide solution.
~XAMPLE 9 Water (80.1 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 14.9 parts by weight of the emulsion of Example 4 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6% sodium hydroxide solution.
~'Y2-21438. -21-2135~2~
Water (80.7 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 14.3 parts by weight of the emulsion of Example 5 are added.
This mixture is now stirred for 5 minutes with a multi-stage, impulse, counter-current agitator at a peripheral speed of 3 m/s.
The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
Water (78.3 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a turbine with a peripheral speed of 5 m/s. The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
~Y2 21438. -2~- ;
213S4~D
EXAMPL~ 12 Water (78.3 parts by weight) is added to a stirred ve~sel, followed by 2.5 parts by weight of 30% dispersion of a thickener based on a polyacrylate containing carboxyl groups (commerctally obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a dissolver disk at a peripheral speed of 7 m/s. The pH of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6% sodium hydroxide solution.
Water (87.3 parts by weight) is added to a stirred vessel, followed by 2.5 parts by weight of 30~ dispersion of a thickener based on a polyacrylate containing carboxyl groups (commercially obtainable, for example, under the name of Acrysol RM-5). After that, 16.7 parts by weight of the emulsion of Example 2 are added.
This mixture is now stirred for 5 minutes with a spatula. The pH
of this emulsion is then adjusted to a value of 7 with 2.5 parts by weight of a 5.6~ sodium hydroxide solution.
a) Heat StabilitY
To determine the heat stability, the emulsions of Examples I to 13 were kept in a 250 mL glass bottle at 60C in an oven and evaluated every 8 hours. The time after which no destabilization of the emulsion is detectable, lS noted.
~IY2-21438.
~135~2û
b) Shakina Stabilitv The shaking stability was determined by filling 80 mL of the emulsion to be tested into 100 mL glass bottles and shaking them in a shaker with a shaking frequency of 240 per minute and a de~ection of 3 cm. The emulsion was checked hourly for destabilization. Emulsions with shaking stabilities of less than 2 hours could be harmed during transport. For this reason, longer shaking stabilities are desirable.
The heat stability of the emulsions of Examples I to 13 exceeded 150 hours.
The shaking stability of the emulsions of Examples I to 13 exceeded 8 hours.
The defoaming action of the emulsions of Example 7 and Examples 11 to 13, prepared with different peripheral speeds from the emulsion of Example 2, were checked in order to show that the defoaming is independent of the dilution method.
~Y2-21438. -24-213~120 TEST METHOD:
Dilexo AM 15 (a pure acrylate dispersion of the DEA
Company) is mixed with water in a ratio of 8 : 2 (dispersion I).
Dispersion I (100 g) is added to a 250 mL beaker and the temperature is adjusted to 20C. After that, 1~ of the defoamer emulsion to be tested is added. This mixture is stirred for 1 minute at 2,500 rpm with a turbine, the diameter of which is 4 cm and which is clamped in a stirrer in such a manner that it is 0.5 cm above the bottom of the beaker. Directly after the 3tirring, 50 mL of the stirred dispersion I is added to a tared 50 mL measuring cylinder and weighed. From the weight A~and density of the unstirred dispersion ~ (1.02 g/mL), the air, stirred in, can be calculated as a percentage by volume using the following equation:
~ by Volume of Air = 100 - 2A/aD
Defoamer A (g/50 mL)~ by Volume of Air Without 36.4 28.6 Example 7 46.4 g.o Example 11 46.5 8.8 Example 12 46.3 9.2 Example 13 46.7 8.4 NY2-21438.
Claims (4)
1. A defoamer emulsion based on organofunctionally modified polysiloxanes, obtained by mixing together (a) 0 to 90 parts by weight of an organopolysiloxane of the general formula in which R1 can be same or different in an average molecule and represents an alkyl group with 1 to 8 carbon atoms or -Z-(CnH2nO-)mR2 group, wherein R2 is a hydrogen group or an alkyl group with 1 to 8 carbon atoms, Z is a divalent group having the formula -O-, -(CH2)p-O- or -CH2-CH(CH3)-CH2-O- with p = 2 or 3, n has an average numerical value of 2.7 to 4.0, m has an average numerical value of 5 to 130, a has an average numerical value of 4 to 1,500, b has an average numerical value of 0 to 100, and c has an average numerical value of 0 to 50;
(b) 0 to 90 parts by weight of an organopolysiloxane of the general formula in which R3 can be same or different in an average molecule and represents a hydroxyl group or alkoxy group with 1 to 4 carbon atoms, d has an average numerical value of 4 to 1,500, e has an average numerical value of 0 to 100, and f has an average numerical value of 0 to 50;
(c) 0 to 90 parts by weight of an organopolysiloxane of the general formula in which R5 can be same or different in an average molecule and represents an alkyl group with 1 to 4 carbon atoms, with the proviso that at least 90% of the R5 groups are methyl groups, x has an average numerical value of 2.6 to 3.0, y has an average numerical value of 8 to 80, w has an average numerical value of 7 to 50, and z has an average numerical value of 1.5 to 10, the sum of the components (a), (b) and (c) being not less than 10 parts by weight and not more than 90 parts by weight;
and (d) 0 to 15 parts by weight of finely divided silica and stirring the mixture thus obtained into a second mixture obtained from (e) 5 to 85 parts by weight of an organopolysiloxane of the general formula in which R4 in an average molecule is same or different and represents an alkyl group with 1 to 8 carbon atoms or the -Z-(CqH2qO-)rR2 group, wherein R2 and Z have the meanings already given, q has an average numerical value of 2.0 to 2.7, r has an average numerical value of 5 to 120, g has an average numerical value of 4 to 200, h has an average numerical value of 0 to 100, j has an average numerical value of 0 to 50;
and (f) 5 to 50 parts by weight of water with a low-shear stirrer so as to obtain a stock emulsion, which is diluted before use.
(b) 0 to 90 parts by weight of an organopolysiloxane of the general formula in which R3 can be same or different in an average molecule and represents a hydroxyl group or alkoxy group with 1 to 4 carbon atoms, d has an average numerical value of 4 to 1,500, e has an average numerical value of 0 to 100, and f has an average numerical value of 0 to 50;
(c) 0 to 90 parts by weight of an organopolysiloxane of the general formula in which R5 can be same or different in an average molecule and represents an alkyl group with 1 to 4 carbon atoms, with the proviso that at least 90% of the R5 groups are methyl groups, x has an average numerical value of 2.6 to 3.0, y has an average numerical value of 8 to 80, w has an average numerical value of 7 to 50, and z has an average numerical value of 1.5 to 10, the sum of the components (a), (b) and (c) being not less than 10 parts by weight and not more than 90 parts by weight;
and (d) 0 to 15 parts by weight of finely divided silica and stirring the mixture thus obtained into a second mixture obtained from (e) 5 to 85 parts by weight of an organopolysiloxane of the general formula in which R4 in an average molecule is same or different and represents an alkyl group with 1 to 8 carbon atoms or the -Z-(CqH2qO-)rR2 group, wherein R2 and Z have the meanings already given, q has an average numerical value of 2.0 to 2.7, r has an average numerical value of 5 to 120, g has an average numerical value of 4 to 200, h has an average numerical value of 0 to 100, j has an average numerical value of 0 to 50;
and (f) 5 to 50 parts by weight of water with a low-shear stirrer so as to obtain a stock emulsion, which is diluted before use.
2. The emulsion of claim 1, obtainable by heating the components (a), (b), (c) and (d) in presence of an alkaline equilibration catalyst for 0.5 to 10 hours at 50°C to 200°C and then stirring components (e) and (f) into the mixture thus obtained.
3. The emulsion of claims 1 or 2, comprising that the water, used for the dilution to the desired concentration, contains a stabilizer.
4. The emulsion of claim 3, comprising that the stabilizer is a thickener, based on a polyacrylate-containing carboxyl groups, and further that the pH of the aqueous phase of the emulsion is adjusted to a value of about 7.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4343185A DE4343185C1 (en) | 1993-12-17 | 1993-12-17 | Defoamer emulsion based on organofunctionally modified polysiloxanes |
| DEP4343185.2-43 | 1993-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2135420A1 true CA2135420A1 (en) | 1995-06-18 |
Family
ID=6505342
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002135420A Abandoned CA2135420A1 (en) | 1993-12-17 | 1994-11-09 | Defoamer emulsion based on organofunctionally modified polysiloxanes |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0658361B1 (en) |
| JP (1) | JP2716667B2 (en) |
| CN (1) | CN1063765C (en) |
| AT (1) | ATE151306T1 (en) |
| AU (1) | AU678644B2 (en) |
| CA (1) | CA2135420A1 (en) |
| DE (2) | DE4343185C1 (en) |
| DK (1) | DK0658361T3 (en) |
| ES (1) | ES2100617T3 (en) |
| FI (1) | FI945935A (en) |
| GR (1) | GR3023956T3 (en) |
| NO (1) | NO943823L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220047969A1 (en) * | 2020-08-14 | 2022-02-17 | Evonik Operations Gmbh | Defoamer composition based on organofunctionally modified polysiloxanes |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1064268C (en) * | 1996-04-10 | 2001-04-11 | 财团法人工业技术研究院 | Composition of mixed silicon series defoaming agent |
| DE19623409C1 (en) | 1996-06-12 | 1998-02-12 | Bayer Ag | Defoamer mixtures, a process for their preparation and their use |
| GB2315757B (en) * | 1996-07-31 | 2000-03-29 | Gen Electric | Dilution stable antifoam emulsion concentrates |
| US5990181A (en) * | 1997-12-11 | 1999-11-23 | Witco Corporation | Aqueous foam quenching compositions |
| DE19922218A1 (en) * | 1999-05-14 | 2001-02-15 | Goldschmidt Ag Th | Use of water-insoluble poly (oxy-1,4-butanediyl) containing polyoxyalkylene-polysiloxane block copolymers for defoaming aqueous media |
| EP2087931A3 (en) * | 2008-02-05 | 2011-08-31 | Evonik Goldschmidt GmbH | Defoaming of ionic fluids |
| DE102012207484A1 (en) * | 2012-05-07 | 2013-11-07 | Wacker Chemie Ag | Defoamer formulations containing organopolysiloxanes |
| JP6179479B2 (en) * | 2014-08-05 | 2017-08-16 | 信越化学工業株式会社 | Oil compound for defoamer, method for producing the same, and defoamer composition |
| JP6197768B2 (en) * | 2014-09-03 | 2017-09-20 | 信越化学工業株式会社 | Oil compound for defoamer, method for producing the same, and defoamer composition |
| JP2023063105A (en) * | 2021-10-22 | 2023-05-09 | Ｅｎｅｏｓ株式会社 | Water-soluble processing oil composition and metal processing method |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE819399A (en) * | 1973-09-07 | 1974-12-16 | ANTI-FOAM | |
| US3984347A (en) * | 1974-12-19 | 1976-10-05 | Dow Corning Corporation | Foam control composition |
| US4395352A (en) * | 1978-06-29 | 1983-07-26 | Union Carbide Corporation | High efficiency antifoam compositions and process for reducing foaming |
| DE3011304A1 (en) * | 1980-03-24 | 1981-10-08 | Henkel KGaA, 4000 Düsseldorf | FOAM ABSORBERS AND THEIR USE IN SYNTHETIC RESIN, LACQUER AND COLOR DISPERSIONS |
| DE3627782A1 (en) * | 1986-08-16 | 1988-02-18 | Goldschmidt Ag Th | NEW ALKOXYSILOXANES, THE PRODUCTION AND USE THEREOF AS A VENTILATING AGENT FOR curable resins or plastisol |
| US5380464A (en) * | 1988-05-09 | 1995-01-10 | Dow Corning Corporation | Silicone foam control composition |
| US4983316A (en) * | 1988-08-04 | 1991-01-08 | Dow Corning Corporation | Dispersible silicone antifoam formulations |
| JPH0790128B2 (en) * | 1989-11-08 | 1995-10-04 | ダウコーニングアジア株式会社 | Silicone antifoam composition |
| JPH03157106A (en) * | 1989-11-16 | 1991-07-05 | Shin Etsu Chem Co Ltd | Antifoaming agent composite |
| DE3938109A1 (en) * | 1989-11-16 | 1991-05-23 | Goldschmidt Ag Th | AGENT FOR DEFOAMING AQUEOUS WASHING FLEETS |
| SE9301347A0 (en) * | 1992-04-27 | 1993-10-28 | Nikko Chemical Inst Inc | Anti-foaming composition of emulsion type and anti-foaming method using the same |
-
1993
- 1993-12-17 DE DE4343185A patent/DE4343185C1/en not_active Expired - Fee Related
-
1994
- 1994-10-10 NO NO943823A patent/NO943823L/en unknown
- 1994-11-09 CA CA002135420A patent/CA2135420A1/en not_active Abandoned
- 1994-12-03 AT AT94119090T patent/ATE151306T1/en not_active IP Right Cessation
- 1994-12-03 DK DK94119090.2T patent/DK0658361T3/en active
- 1994-12-03 EP EP94119090A patent/EP0658361B1/en not_active Expired - Lifetime
- 1994-12-03 DE DE59402369T patent/DE59402369D1/en not_active Expired - Lifetime
- 1994-12-03 ES ES94119090T patent/ES2100617T3/en not_active Expired - Lifetime
- 1994-12-16 JP JP6313682A patent/JP2716667B2/en not_active Expired - Fee Related
- 1994-12-16 FI FI945935A patent/FI945935A/en not_active Application Discontinuation
- 1994-12-17 CN CN94119007A patent/CN1063765C/en not_active Expired - Lifetime
- 1994-12-19 AU AU81534/94A patent/AU678644B2/en not_active Ceased
-
1997
- 1997-06-30 GR GR970401606T patent/GR3023956T3/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220047969A1 (en) * | 2020-08-14 | 2022-02-17 | Evonik Operations Gmbh | Defoamer composition based on organofunctionally modified polysiloxanes |
Also Published As
| Publication number | Publication date |
|---|---|
| AU8153494A (en) | 1995-06-22 |
| FI945935A0 (en) | 1994-12-16 |
| FI945935A (en) | 1995-06-18 |
| NO943823L (en) | 1995-06-19 |
| EP0658361B1 (en) | 1997-04-09 |
| AU678644B2 (en) | 1997-06-05 |
| DK0658361T3 (en) | 1997-10-20 |
| JPH07194904A (en) | 1995-08-01 |
| GR3023956T3 (en) | 1997-09-30 |
| DE59402369D1 (en) | 1997-05-15 |
| NO943823D0 (en) | 1994-10-10 |
| EP0658361A1 (en) | 1995-06-21 |
| CN1063765C (en) | 2001-03-28 |
| DE4343185C1 (en) | 1994-11-17 |
| JP2716667B2 (en) | 1998-02-18 |
| ATE151306T1 (en) | 1997-04-15 |
| ES2100617T3 (en) | 1997-06-16 |
| CN1112586A (en) | 1995-11-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |