JP2020073266A - Silicone defoaming agent composition, and silicone defoaming agent composition manufacturing method - Google Patents

Abstract

To provide a silicone defoaming agent composition which can assure dispersibility of a defoaming agent in a foaming liquid, and can assure defoaming persistence by exhibiting defoaming property from both sides of suppressing and breaking bubbles in a deforming agent of such a type that has been previously added to a given defoaming liquid.SOLUTION: A silicone defoaming agent composition of such a type that has been previously added to a defoaming liquid thereby defoaming. This silicone defoaming agent composition contains composite particle group of oil and silica containing silicone as an essential component, and any composite particle in the composite particle group extends to an inner surface of an envelope which constitutes foams formed by a foaming liquid. Thus, a zeta potential distribution width of the composite particle group is set according to the foaming liquid so that foam suppression and foam breaking are possible.SELECTED DRAWING: None

Description

The present invention relates to a silicone defoamer composition having a set zeta potential distribution width, which has excellent defoaming properties for various types of foams, and a method for producing the same. It is about.

Defoamers are widely used in processes involving foaming in the chemical industry, food industry, petroleum industry, yarn manufacturing industry, textile industry, pharmaceutical industry, and the like.
Silicones have a low surface tension and therefore have the potential to eliminate bubbles. Further, since it is known that silica has an effect of defoaming, a defoaming agent using both silicone and silica is widely used. There are seven types of silicone antifoaming agents: oil, compound, solution, emulsion, self-emulsifying, powder, and solid. The compound is sometimes referred to as an oil compound in the defoaming industry, but in the present invention, a mixture of an oil component containing silica oil as an essential component and silica, and a part of which is bonded by a chemical reaction are referred to as a compound. ..

The defoaming agent is roughly classified into two types: a type that is added to the foaming liquid in advance and a type that is applied from the outside after the foaming liquid foams. Of these, the type that is added to the foaming liquid in advance is the mainstream of the defoaming agent. Furthermore, there are two types of this type. One of them is to lower the interfacial tension of the foaming liquid by dissolving polyether modified silicone etc. in the foaming liquid in advance or by adding mineral oil etc. to the foaming liquid and forming an oil film on the liquid surface. Then, the foam is suppressed, that is, the foam is prevented from rising, or the foaming method is suppressed as much as possible. In this case, it is necessary to use a large amount of antifoaming agent. In addition, the quality of the foaming liquid is changed by a large amount of antifoaming agent, and the environmental load of drainage becomes large. The other type is a type in which the composite particles of silicone and silica are added to the foaming liquid in advance in order to cause the interfacial tension lowering function of silicone and the foam-breaking effect of silica, which causes foaming. In some cases, the action of foam breaking is exhibited. It is also believed to have a foam-suppressing effect, but its effect has not been fully confirmed. In the case of this type, the amount used as an antifoaming agent is small, and the quality of the foaming liquid does not change so much, so it is the most common type of antifoaming agent. On the other hand, in the type in which the antifoaming agent is applied from the outside to the foaming liquid which has already foamed, the antifoaming agent is administered by a method such as spraying. In this case, the bubbles are broken by either the physical action or the action of lowering the interfacial tension. In this case, although it may be effective for temporary foam breakage, it often has no defoaming persistence and no foam suppressing effect.

Therefore, antifoaming agents are most predominantly of the type of composite particles that have been added to the foaming liquid beforehand, and they exhibit defoaming mainly by the action of defoaming.
In order to function as an antifoaming agent, the composite particles must exist in the vicinity of the foam film, and the emulsion type is the most effective for dramatically improving the dispersibility in water. Most of the silicone defoamers are used. Further, it is often used as a compound in a solid state so that it can be immediately dispersed in a foaming liquid.

The defoaming performance of antifoaming agents often differs greatly depending on the foaming liquid, and even if it shows excellent defoaming performance for certain foaming liquids, it does not defoam other foaming liquids. Performance was sometimes insufficient. Therefore, conventional defoamers have designed antifoam compositions only by the rules of thumb in individual defoaming cases. Further, in developing an antifoaming agent for each foaming liquid, it was necessary to obtain the foaming liquid each time. Further, at the defoaming agent development site, the experience value of the engineer and trial and error of the experiment are largely involved, and thus the prolongation of the development period and the enlargement of human economic loss may be a problem. Even with the same antifoam composition, the defoaming performance often varies due to subtle differences in manufacturing methods, conditions, batches, etc. Frequently, the desired performance as an antifoaming agent is not exhibited. Was.
In the case of a silicone antifoaming agent, which is a type that is added in advance to the foaming liquid, which is the mainstream, and which consists of composite particles of silicone and silica, foaming occurs because the foaming effect is not sufficient, although it also has the effect of suppressing foaming. Break the bubbles. Because of this, trial and error to obtain stable defoaming performance is difficult.
In order to improve these problems, it is necessary to establish a method for theoretically and quantitatively designing, evaluating, and producing an antifoaming agent that exhibits a wide and stable defoaming property against various types of foams. ing. Further, there is a demand for an antifoaming agent that exhibits wide and stable defoaming properties against various types of foams.

On the other hand, for example, in Non-Patent Document 1, there is a direction in which the interface free energy change (E) when the defoaming agent enters the foam film and the interface free energy change (S) when it expands decrease. The so-called Ross theory has been proposed, in which when taken positively, bubble breaking occurs when both are negative.
However, E and S> 0 are judgments as to whether the arrangement in which the defoaming agent penetrates into the foam film and the arrangement in which the defoaming agent expands on the foam film are preferred as the equilibrium state, and on what time scale it occurs. Gives no predictions about. Therefore, even if it is designed so as to satisfy the conditions of the Ross theory, it takes a long time to invade and expand, and a defoaming agent that cannot be used as an actual defoaming agent can be produced. Furthermore, when selecting any particular raw material from among essentially the same raw materials, since they all have the same interfacial tension and surface tension, the Ross theory alone cannot provide a guideline for selection. is there.

In addition, Non-Patent Document 2 proposes a pinhole effect in which hydrophobic powder particles are destabilized by adsorbing a surfactant that stabilizes a foam film to destabilize the foam. The pinhole effect is a theory pointed out in many silica-containing silicone defoamers. Further, it is empirically believed that in many defoaming agents using silica, a so-called needle effect, in which the tip portion of silica is physically broken, is caused.
However, there is no discussion as to what requirements are required for hydrophobic powder particles such as silica to reach the foam film or exist in the vicinity thereof. That is, unless the conditions under which the pinhole effect or needle effect appears effectively are clarified, it is not possible to find a relationship with the practical defoaming performance.

Further, Non-Patent Document 3 presents a mechanism in which an antifoaming agent breaks through both surfaces of a foam film to form a bridge structure, and then both surfaces are short-circuited by water repelling to break the foam. Furthermore, Non-Patent Document 4 presents a mechanism in which the bridge structure is stretched inward of the foam film, and the defoaming agent portion becomes thin so that the foam becomes unstable and breaks. In these models, formation of a bridge structure by an antifoaming agent is recognized as the first step toward foam breaking.
However, it is not useful for designing an antifoaming agent, because the design factor that accelerates the formation of the bridge structure for various foams is not clear.

Further, in Non-Patent Document 5, an electric double layer made of adsorbed molecules on the surface of a foam film, such as a surfactant, functions to keep the thickness of the foam film above a certain level, and the adsorbed molecules are replaced with an antifoaming agent. It is argued that by doing so, breaking the stabilization mechanism due to the repulsion of the electric double layer facilitates bubble breakage.
However, in the case of using an antifoaming agent, the foaming usually occurs when the foam film is 1 μm or more, but the repulsion by the electric double layer between the inner walls of the two foam films does not appear until the foam film is thinned to about 20 nm. It is known and suggested that the electric double layer repulsion does not need to be taken into consideration in antifoam design.

From the above, the most predominant type of antifoaming agent that is added in advance to the foaming liquid and is composed of composite particles of silicone and silica, such as the silicone antifoaming agent composition described in Patent Document 1, , The above-mentioned defoaming theory alone is a concrete and quantitative index in terms of composition and manufacturing as a silicone defoaming agent composition for obtaining a constant defoaming performance for each manufacturing formulation and manufacturing batch. Can't get
Therefore, in the development of this type of antifoaming agent, it is necessary to obtain the target foaming liquid and find the optimal conditions by trial and error for the composition based on experience and the manufacturing method. The reproducibility of the defoaming performance of was not sufficient. The control method is qualitative visual recognition, and a control method based on a quantitative index has not been found.

The applicant of the present application discloses in Patent Document 2 that an aqueous dispersion in which lower-order aggregates of an inorganic particle group form high-order aggregates by non-chemical bonding and are dispersed in water, such as fumed silica particles. , And in the oil-in-water type Pickering emulsion in which oil is added based on such an aqueous dispersion, while mentioning the variation in the state between the composite particles, the zeta potential was measured to evaluate the stability and uniformity of the aqueous dispersion. However, it can be used as an index of stability and uniformity. However, this indicates that the narrower the zeta potential distribution width is, the better the stability and uniformity are, and no influence on the defoaming performance is shown. Further, the emulsion having a stable emulsion does not necessarily have a narrow zeta potential distribution width.
Further, the zeta potential is sometimes used for the purpose of improving the fiber treatment and the stability of the coating film. However, they were for the purpose of promoting the adsorption of substances.
As described above, there has never been an index for evaluating the defoaming performance of an antifoaming agent using the zeta potential, and there has not been a prior art suggesting this.

As described above, conventional silicone defoaming agents that defoam by adding in advance are universal defoaming agents that do not depend on the type of silicone component or silica used, or the type of foaming liquid. Since there was no index to measure the performance, the defoaming performance was constant for each manufacturing formulation and manufacturing batch, and there was no method for expressing it with good reproducibility, eliminating many trial and error in composition and process. I couldn't.
In addition, regarding the control of initial defoaming property and defoaming durability, the control of defoaming performance and dispersion stability, and the control of defoaming and defoaming, no index or method existed so far.

J. Phys. Chem. , 54 (3), 429 (1950) Ind. Eng. Chem. Fundam. , 16 (4), 472 (1977) Int. J. Mineral Process. , 9, 1 (1982) Langmuir, 15 (24), 8514 (1999) Oil Chemistry, 42 (10), 762 (1993)

Special table 2008-529778 gazette Japanese Patent No. 6344878

The present invention has been made in view of the above circumstances, and in a type of antifoaming agent added in advance to a given foaming liquid, while ensuring the dispersibility of the antifoaming agent in the foaming liquid. It is an object of the present invention to provide a silicone defoaming agent composition capable of ensuring defoaming durability by exhibiting defoaming properties from both sides of foam suppression and foam breaking.
The present invention has been made in view of the above circumstances, and in a method for producing an antifoaming agent of a type that is added in advance to a given foaming liquid, the dispersibility of the antifoaming agent in the foaming liquid is improved. A method of stably and reproducibly producing a silicone defoaming agent composition capable of ensuring defoaming persistence by ensuring defoaming properties from both sides of foam suppression and foam breaking The purpose is to provide.

Therefore, none of the prior art has disclosed a silicone antifoam composition that solves the above problems, and a method for producing the same.

As a result of intensive studies to achieve the above object, the inventors have found that the distribution width of the zeta potential of the composite particles of the silicone defoaming agent composition is equal to or greater than the threshold value set according to the foaming liquid. It has been found that the silicone antifoam composition has excellent antifoam performance for various types of foam.

The silicone antifoam composition of the present invention is a type of silicone antifoam composition that defoams by being added to a foaming liquid in advance, which comprises an oil component containing silica as an essential component and silica. The composite particles include a composite particle group, and any of the composite particles in the composite particle group reach the inner surface of the envelope film forming the foam formed by the foaming liquid, so that the foam can be suppressed and broken. The silicone defoamer composition is characterized in that the distribution width of the zeta potential of the group is set according to the foaming liquid.
The method for producing the silicone antifoam composition of the present invention is a method for producing a silicone antifoam composition of the type in which it is defoamed by adding it to the foaming liquid in advance. According to the step of selecting the type and / or amount of each of the oil component and the silica component, and the selected oil component and the silica component are mixed, and a silicone containing a composite particle group of the oil component and silica containing silicone as an essential component. The step of preparing an antifoam composition, the step of sampling the produced silicone antifoam composition and measuring the distribution width of the zeta potential of the composite particle group, and the surrounding that constitutes the foam formed by the foaming liquid. By extending to the inner surface of the membrane, the distribution width of the measured zeta potential becomes equal to or larger than a threshold value set according to the foaming liquid so that the foam can be suppressed and broken. The method for producing a silicone antifoam composition is characterized by repeating the adjusting step and the measuring step.

Action of the invention

The silicone defoamer composition of the present invention is a composite antifoaming agent in terms of defoaming persistence in an antifoaming agent of the type previously added to a given foaming liquid, because of the dispersibility of the composite particle group of the defoaming agent. While it is preferable that the distribution width of the zeta potential of the particle group is narrow, the condition of the foam to be defoamed changes depending on the type of foaming liquid and the transient state from the start of foam formation to the completion of foam formation. At the time of starting, by ensuring the dispersibility of the composite particle group in the foaming liquid, it is easy to create a situation in which one of the composite particles of the composite particle group exists inside the foam, and The composite particles depending on the foaming liquid so that it is possible to depress from both sides of the inner surface of the envelope film of the foam film by suppressing the interfacial tension of the foam film and the bubble breaking by the pinhole effect or needle effect. Regarding the zeta potential of the group, One in which a constant.
In addition, the foam suppression means a defoaming action in which the action of the composite particles in the foaming liquid is not formed or is difficult to occur mainly due to the decrease in the interfacial tension of the inner surface of the bubble. It means that no bubbles are generated at all, or that it is difficult to generate new bubbles in a situation where bubbles have already been generated. Further, the bubble breaking means a defoaming action in which the action of breaking the bubbles by the composite particles is dominant with respect to the already generated bubbles, mainly by the pinhole effect or the needle effect.
Further, the defoaming property and the defoaming performance have a broad meaning including both foam suppression and foam breaking. And, good defoaming performance means that each of the initial defoaming property and the defoaming durability is at least at or above the level acceptable at the defoaming site, unless otherwise specified.
The method for producing the silicone antifoam composition of the present invention relates to a method for producing an antifoaming agent of a type that is added in advance to a given foaming liquid, depending on the type of foaming liquid. A step of selecting the type and / or amount of each silica component, and mixing the selected oil component and silica component to prepare a silicone antifoam composition containing a composite particle group of oil and silica containing silicone as an essential component By sampling the silicone defoaming agent composition produced, the step of measuring the distribution width of the zeta potential of the composite particle group, and by reaching the inner surface of the envelope film forming the foam formed by the foaming liquid, Ensures dispersibility of the defoamer in the foaming liquid by setting the measured zeta potential distribution width to a value that is greater than or equal to the threshold value set for the foaming liquid so that foam suppression and foam breaking are possible. And foam Defoaming performance is what makes it possible to stably reproduce well demonstrated in accordance with the.
In addition, until the distribution width of the measured zeta potential becomes equal to or more than the threshold value set according to the foaming liquid, by repeating the selecting step and / or the adjusting step, and the measuring step, depending on the foaming liquid. The burden of trial and error for producing an antifoaming agent having the required performance is reduced.

The details of the silicone antifoam composition and the method for producing the same of the present invention will be described below.
In addition, in the case of the present invention, both of the case where the compound is added to the foaming liquid for defoaming and the case where the compound is emulsified and then added to the foaming liquid for defoaming are targeted. Modes for carrying out the invention for both cases will be described below.

The silicone antifoam composition of the present invention is a compound composed of an oil containing silica as an essential component and silica, or an emulsion of the compound. In the case of a compound, it is added directly to the foaming liquid, or as an aqueous dispersion, and then added. In the case of an emulsion, it is added to the foaming liquid as it is, or it is diluted with water as appropriate and then added.
Silicone is an organopolysiloxane having an average composition formula represented by the general formula (1). The chemical structure may be linear or branched, but needs to be oily.
R ¹ _a SiO 2 _{(4-a) / 2} (1)
In the formula (1), R ¹ may be the same or different in the molecule, and may be a substituted or unsubstituted saturated or unsaturated monovalent hydrocarbon group having 1 to 25 carbon atoms, a substituted or unsubstituted It is an aromatic group having 6 to 30 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, or a hydrogen atom group.

The above organic groups are specifically methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, neopentyl group, hexyl group, 2-ethylhexyl group, heptyl group, Alkyl groups such as octyl group, nonyl group, decyl group, dodecyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group; aryl groups such as phenyl group, tolyl group, xylyl group, biphenyl group, naphthyl group; benzyl, phenylethyl group, phenylpropyl group, an aralkyl group such as a methyl benzyl _{group; -CH 2 -CH 2 -CH 2 -N} 2, -CH 2 -CH 2 -CH 2 -NH (CH 3), - CH _{2 -CH 2 -CH 2 -N (CH} 3) 2, -CH 2 -CH 2 -NH-CH 2 -CH 2 -NH 2, - _{H 2 -CH 2 -CH 2 -NH (} CH 3), - CH 2 -CH 2 -CH 2 -NH-CH 2 -CH 2 -NH 2, -CH 2 -CH 2 -CH 2 -NH-CH 2 _{-CH 2 -N (CH 3) 2} , -CH 2 -CH 2 -CH 2 -NH-CH 2 -CH 2 -NH (CH 2 CH 3), - CH 2 -CH 2 -CH 2 -NH-CH _{2 -CH 2 -N (CH 2 CH} 3) 2, -CH 2 -CH 2 -CH 2 -NH-CH 2 -CH 2 -NH nitrogen-containing hydrocarbon group represented by _{(cyclo-C 6 H 11)} A part or all of hydrogen atoms in the hydrocarbon group is substituted with a halogen atom, a cyano group or the like, a 2-bromoethyl group, a 3,3,3-trifluoropropyl group, a 3-chloropropyl group, Chlorophenyl group, dibromophen Group, tetra-chlorophenyl group, difluorophenyl group, beta-cyanoethyl group, .gamma.-cyanopropyl group, and substituted hydrocarbon groups such as beta-cyanopropyl group. Particularly preferred organic groups are methyl _{groups, -CH 2 -CH 2 -CH 2 -NH} -CH 2 -CH 2 -NH 2 group, a phenyl group.

a is a numerical value related to the order of the siloxane bond, and if a is 2.0, it represents a straight-chain organopolysiloxane. a is a positive number of 1.9 ≦ a ≦ 2.2, preferably 1.95 ≦ a ≦ 2.15. When a is less than 1.9, the viscosity of the organopolysiloxane is too low, so that the silicone component and the silica component tend to separate in the foaming liquid, resulting in poor defoaming durability and exceeding 2.2. Since the action of lowering the interfacial tension of the foam film is not sufficient, the initial defoaming property is poor and it is not suitable.
The organopolysiloxane may be either a single component or a mixture of two or more components.

The viscosity of the organopolysiloxane at 25 ° C. is preferably 1 to 2,000,000 mPa · s. It is more preferably 1 to 100,000 mPa · s, and particularly preferably 1 to 50000 mPa · s. If it is less than 1 mPa · s or more than 2,000,000 mPa · s, the compound cannot be stably dispersed in the foaming liquid, and the emulsion is difficult to emulsify and a stable emulsion cannot be obtained.
The structure of this organopolysiloxane may be any as long as it is within the above-mentioned conditions, but from the viewpoint of easy availability, economical efficiency, and chemical stability, it is 80 mol% or more of the total R ^1. It is particularly preferable that 90% mol% or more is a methyl group.

Although silicone is an essential component as the oil component used in the silicone antifoam composition of the present invention, a mixture of silicone with an organic oil may be used. Any type of fluid may be used as long as it is fluid and compatible with silicone. Examples are various mineral oils, synthetic oils, vegetable oils and the like. Select the most suitable oil type according to the field of use of the foaming liquid. For example, in the field of food, use of vegetable oil, which has little effect on the human body, etc. The type of organic oil may be one type, or two or more types may be used in combination.
The ratio of silicone and organic oil used is not limited, but the ratio of silicone is preferably 50% by mass or more. This is because if it is less than 50% by mass, the effect of lowering the interfacial tension by silicone cannot be sufficiently obtained.

Silica is an essential component in the silicone antifoam composition of the present invention. Since it is necessary to disperse in the foaming liquid as composite particles together with an oil containing silicone as an essential component, silica needs to be in the form of particles.
The silica particles are particles of silicon dioxide produced by a synthetic method, and do not include mineral silica such as diatomaceous earth and crystalline quartz. Examples of the silicon dioxide produced by the synthetic method include fine powder by a dry method such as fumed silica, calcined silica, and fused silica, and precipitated silica or colloidal silica by a wet method. These are known to those skilled in the art. Among these, it is preferable to use calcined silica, precipitated silica or colloidal silica. These can be used alone or in combination of two or more. The silica particles used in the present invention may be hydrophilic silica in which the silanol groups on the surface remain, or hydrophobic silica in which the silanol groups on the surface are silylated. Hydrophobic silica is produced by a known method in which hydrophilic silica is treated with halogenated organosilicon such as methyltrichlorosilane or alkoxysilanes such as dimethyldialkoxysilane, silazane, and low molecular weight methylpolysiloxane. You can
The silica particles should be particulate rather than lumpy. Further, it may be in a state of primary aggregates in which primary particles are aggregated, or in a state of secondary aggregates in which primary aggregates are further aggregated.

The present invention is a type that is added to a foaming liquid in advance, and a compound consisting of an oil component having silica as an essential component and silica, or an emulsion thereof is used as a defoaming agent, and a good defoaming agent is used. As an index showing performance, the zeta potential of composite particles composed of oil and silica produced by the silicone antifoam composition of the present invention will be taken up.
The zeta potential is a potential on a liquid surface (sliding surface) that moves together with a dispersion in a liquid, and is generally used as an index of a charge state of the dispersion. For example, when two dispersion particles have zeta electrons with the same sign and a sufficiently large absolute value, electrostatic repulsion avoids collision and thus does not aggregate. In recent years, attempts have been made to extend the concept of zeta potential to plates and fibers. For example, when a metal plate as a non-treatment agent and a dispersion have opposite signs or the same sign but have a small absolute value. , The dispersion is easily adsorbed on the non-treatment agent.
The zeta potential has been used as an index showing the dispersion stability of silica in an aqueous dispersion of silica to some extent. It has been considered that the narrower the zeta potential distribution width of the aqueous dispersion, the better the dispersion stability. The narrow distribution width of the zeta potential means that many silica particles having the same sign and similar potential are present, and it is considered that the dispersion stability is good because the silica particles are less likely to aggregate.
As described above, conventionally, the zeta potential has been used as an index of particle stability and aggregability in an aqueous dispersion of particles, whereas in the present invention, it is also used as an index of defoaming performance by composite particles. It was a surprising discovery that it could be used.

The mechanism of defoaming when the composite particle group of the silicone defoamer composition of the present invention exists at the interface of the foam film can be explained by Ross theory and the like. That is, defoaming is achieved by lowering the interfacial tension of the foam film by silicone and the pinhole effect or needle effect by silica particles. However, the requirement for the composite particles of the silicone antifoaming agent to approach the interface of the foam film has not been clarified.

When the composite particle group of the silicone antifoam composition of the present invention is dispersed in water or a foaming liquid, the surface of the composite particle has various electric potentials determined by the difference in its composition and / or morphology. Is generating. Including the difference in the sign, there is a variation in the electric potential within one composite particle and between the composite particles. In addition, the situation changes from time to time. In different composite particles, points where electric potentials having different signs exist are attracted to each other. Between points having the same sign, there may be a repulsion, but there may be a case where the points are close to each other. Particles are constantly moving due to convection and Brownian motion, and even though the inside of particles is highly viscous, they are in the category of fluid, so the chemical structure is always moving.Therefore, the distribution of potentials inside and between composite particles is Always in flux. Therefore, in the composite particles, the attracting portion and the distant portion are mixed and are constantly changing.
Therefore, when the composite particle group of the silicone antifoam composition of the present invention is dispersed in water or a foaming liquid, while ensuring stability as the composite particle group, any of the composite particles In, it can be said that it has a channel which can be electrically approached to another composite particle or another substance.

On the other hand, the electric potential at the inner interface of each foam particle in the foaming liquid is completely nonuniform at each location. Further, in a transitional state from the start of foam formation from the foaming liquid to the completion of foam formation, the distribution of the electric potential at each place changes with time. In such a state, in order for the composite particles of the silicone defoaming agent composition of the present invention to effectively exhibit the defoaming action, the dispersibility of the composite particle group in the foaming liquid is ensured at the start of foam formation. This makes it easier to create a situation in which any of the composite particles of the composite particle group is present inside the foam, and the composite of the silicone antifoam composition is formed on the inner surface of the envelope film forming the foam formed by the foaming liquid. The particles need to be spread.

  There is a possibility that there may be points that can approach each other by the action of electric potential between the composite particle group of the silicone antifoam composition of the present invention and the envelope film forming the foam formed by the foaming liquid. If the relationship between the potential of the channel of any of the composite particles in the composite particle group and the potential of somewhere on the inner surface of the envelope that constitutes the bubble is optimized, the composite particles will extend to the inner surface of the envelope. The silicone can be defoamed by lowering the interfacial tension of the foam film and / or by the pinhole effect or needle effect of the silica particles. Therefore, on the side of the composite particles of the silicone defoaming agent composition, the probability that the defoaming action is exhibited is high because of the variety of potential channels for such optimization.

The above relationship is discussed below from the viewpoint of zeta potential. That is, the conditions for the zeta potential of the inner surface of the envelope film of bubbles change depending on the type of foaming liquid and the transient state from the start of foam formation to the completion of foam formation.
It has been found in the present invention that it is effective to widen the distribution width of the zeta potential of the composite particles of the silicone defoaming agent composition in order to enhance the defoaming effect in such a situation. This is because, while the condition of the inner surface of the bubble surrounding film varies and the condition of the surface of the composite particles also varies, the optimum point where the defoaming effect is exerted appears somewhere among the variations.
Since the sign and distribution of the potential on the inner surface of the foam differ depending on the type of foaming liquid to be defoamed and the status of the foam, it is recommended to use composite particles with the most suitable zeta potential or zeta potential distribution. Although the defoaming effect should be the highest, the present invention has found that the defoaming effect is enhanced by the wide distribution of the zeta potential of the composite particles, regardless of the situation. However, in order to enhance the predetermined defoaming effect for a given foaming liquid, it is preferable that the lower limit threshold value of the zeta potential of the composite particles be individually and specifically set.

There is a possibility that not only the distribution width of the zeta potential of the composite particles of the silicone defoaming agent composition but also the shape and peak height of the distribution have an influence on the defoaming performance, but it is not known at present. At present, it is estimated that it is effective to define the widths of the 10% point and the 90% point as the distribution width when the both ends of the peak of the zeta potential distribution peak are 0% and 100%, respectively. is doing. It is regarded as the width of the zeta potential distribution that is sufficient for the existence of channels for defoaming that exceeds a certain probability.
Further, when the peak of the zeta potential distribution is divided into two or more, it is presumed that it is not suitable as a target of the zeta potential distribution width treated in the present invention. It is estimated that the effect of the zeta potential distribution width on the defoaming performance is more relevant when the number of peaks is one. However, when a peak has a shoulder, it is defined as one peak.

The higher the distribution width of the zeta potential of the composite particles of the silicone defoamer composition, the lower the dispersion stability in the foaming liquid. In the present invention, the dispersion stability of the composite particles in the foaming liquid can be secured by setting a certain upper limit value for the distribution width of the zeta potential.
In the conventional antifoaming agent for composite particles of silicone and silica, which was previously put in the foaming liquid, the dispersion stability was not always sufficient, or the dispersion stability often varied depending on the production recipe or batch. .. On the other hand, since the composite particle group of the silicone antifoam composition of the present invention has secured dispersion stability, in addition to the foam breaking property, the foam suppressing property can be sufficiently exhibited and can be stably exhibited. In this way, since both the foam suppressing property and the foam breaking property can be exhibited, it is possible to exhibit both the initial defoaming property and the defoaming sustainability.
However, since the dispersion stability of the defoaming agent is more important than that of the type that is added from the outside of the foaming liquid, the defoaming durability is more characteristic than the initial defoaming property.

  In understanding the zeta potential of the composite particles of the silicone antifoam composition of the present invention, in the case of the compound form, it is dispersed in water using a surfactant or the like as appropriate, and in the case of the emulsion form, the water content is appropriately changed. Measure by diluting with. In both cases, the zeta potential is measured by imitating the state in which the composite particles are dispersed in the foaming liquid.

The distribution width of the zeta potential of the composite particles of the silicone antifoam composition is determined by the compositional / morphological nonuniformity within and / or between the particles of the composite particles. As the compositional non-uniformity and the morphological non-uniformity increase, the distribution width of the zeta potential of the composite particles becomes wider. The larger the compositional non-uniformity and the morphological non-uniformity, the wider the distribution width of the zeta potential.

A specific method for increasing compositional non-uniformity and morphological non-uniformity in order to widen the distribution width of the zeta potential of the composite particles will be described below.
In the silicone defoaming agent composition, not only the oil content but also the composite particles using silica, that is, the use of silica particles broadens the distribution width of the zeta potential. In addition, the oil content containing silicone as a main component, and the variety of silica types and variations in morphology broaden the distribution range of the zeta potential.
The following are specific methods for increasing compositional non-uniformity.
The more types of silica particles used, the greater the compositional non-uniformity and the wider the zeta potential distribution range. The more types of silicone components used, the greater the compositional non-uniformity and the wider the zeta potential distribution. When an organic oil is used in combination as the oil component in addition to the silicone component, the compositional nonuniformity becomes large and the distribution width of the zeta potential becomes wide. Furthermore, the more types of organic oils, the greater the compositional non-uniformity and the wider the zeta potential distribution range.

The following are specific methods for increasing the morphological nonuniformity. The larger the mass ratio of the silica particles to the oil content, the larger the morphological nonuniformity within one composite particle and between the composite particles, and the wider the zeta potential distribution width. The more kinds of silica particles are used, the larger the morphological nonuniformity within one composite particle and between the composite particles, and the wider the zeta potential distribution width becomes.
When the silicone antifoam composition is in the emulsion form, the smaller the shear rate during the emulsion production, the larger the morphological nonuniformity within one composite particle and between the composite particles, and the wider the zeta potential distribution range becomes. ..

When the composite particles of the silicone defoaming agent composition are dispersed in the foaming liquid in advance, the desired initial defoaming property is obtained by setting the distribution width of the zeta potential according to the foaming liquid. It More specifically, the distribution width of the zeta potential should be equal to or greater than the threshold value set according to the type of foaming liquid, the type and concentration of dissolved substances such as ionic substances, and the state of liquid properties and foam properties. It is done by The composition is set so that the distribution width of the zeta potential is equal to or more than a predetermined threshold value, and the production conditions and the like are optimized to make the morphology nonuniformity of the composite particles into a desired state.
If the silicone antifoam composition is in emulsion form, a step to check the zeta potential distribution width is provided in the manufacturing process, and if it does not reach the prescribed threshold value, rework is performed to optimize shear rate and other process elements. The target initial defoaming property can be reliably obtained by repeating the check and the rework until the zeta potential distribution width becomes equal to or more than the predetermined threshold.

Until now, in industry, it was better that the distribution width of the zeta potential was wider, and there was no idea of controlling it.
Controlling the width of the zeta potential distribution is not limited to the antifoaming agent, but the antifoaming agent is most effective because the electric potential of the foam film is not uniform and it is particularly effective for transient situations. It is suitable.

On the other hand, as the defoaming durability, it is necessary to maintain the stability and dispersibility of the composite particles of the silicone defoaming agent, and also to cope with the change of the potential on the inner surface of the foam film with the change of time. For that purpose, it is necessary that the composite particles have various surface potentials, that is, the zeta potential distribution width is wide. That is, since the distribution width of the zeta potential is wide, the defoaming performance can be obtained by reusing the composite particles once deviated from the defoaming performance. Therefore, the wide range of the zeta potential distribution of the silicone defoaming agent improves both the initial defoaming performance and the defoaming sustaining performance.

The wide distribution of the zeta potential of the dispersed particles of the silicone defoaming agent composition improves the initial defoaming property and the defoaming durability. However, the dispersion stability of the composite particles in the foaming liquid, and when the silicone antifoam composition is in the emulsion form, the dispersion stability of the composite particles in the emulsion depends on the distribution of the zeta potential of the composite particles. The wider it gets, the lower it gets. This is because the wider the distribution width of the zeta potential is, the more chances the composite particles attract each other, that is, the chance of aggregation increases.

Since the potential of the foam film of the foaming liquid changes from moment to moment, it is important to be able to use various channels of the composite particles of the silicone antifoam composition. For that purpose, it is necessary to stably disperse the composite particles in the foaming liquid. Therefore, in order to satisfy both the initial defoaming property and the defoaming durability, it is necessary to set the upper limit value of the predetermined zeta potential distribution width according to the purpose.

  When the silicone antifoam composition is in the emulsion form, in order to secure the stability as an emulsion, it is necessary to set the upper limit value of the predetermined distribution width of the zeta potential for the reason described above. Similarly, when importance is placed on the dispersion stability of the composite particles in the foaming liquid, it is preferable to set the upper limit value of the predetermined zeta potential distribution width.

  Of the compositional and morphological inhomogeneities for widening the distribution width of the zeta potential of the composite particles of the silicone antifoaming agent described above, the silica particles that largely contribute to the morphological inhomogeneity are mainly The larger the mass ratio of silica to oil in the silicone defoamer composition, the higher the initial defoaming property. However, in the case where it is compatible with the defoaming persistence or when the dispersion stability of the particles of the emulsion is ensured, a predetermined upper limit value is set for the mass ratio of silica to oil content in consideration of the zeta potential of the composite particles. There is a need.

In the present invention, the condition of the foam to be defoamed changes depending on the transitional state from the start of foam formation to the completion of foam formation in the foam liquid of the composite particle group at the start of foam formation. By ensuring the dispersibility of the composite particles, it is easy to create a situation in which any of the composite particles in the composite particle group exists inside the foam, and the composite particles extend to the inner surface of the envelope film of the foam and the interface of the foam film. Set the width of the zeta potential of the composite particle group according to the foaming liquid so that it is possible to suppress bubbles due to tension decrease and defoam from both sides of the pinhole effect or the needle effect to break the bubbles. To do.
In the transient situation, it is considered that whether compositional nonuniformity or morphological nonuniformity dominates the distribution width of the zeta potential depends on temporal and local conditions. Moreover, it can be presumed that the predominance of either compositional non-uniformity or morphological non-uniformity affects whether defoaming is predominantly suppression or defoaming. Therefore, it is possible to control to a certain extent whether the defoaming-based composition or the defoaming-based composition by properly using the two factors of the silicone defoaming agent composition, for example, the amount ratio of silica and the shear rate during emulsion preparation.

In any form of silicone defoamer other than compound or emulsion, it is considered that the defoaming performance will be improved due to the similar behavior in the foaming liquid, so the relationship of the zeta potential of the particles is theoretically established. Should be. However, it is difficult for these antifoaming agents to make a water dispersion state for measuring the zeta potential. Therefore, in the present invention, the silicone antifoam composition is limited to the compound or emulsion form.

The procedure for developing a silicone antifoam composition in view of the present invention will be described.
1. Check the restrictions such as the viscosity of silicone oil and the type of organic oil that can be used, depending on the application and the type of foaming liquid.
2. Consider a composition in which the types of silicone oil, silica, and organic oil are increased as much as possible, and the amount of silica is also increased as much as possible. (Make the zeta potential of the composite particles as wide as possible)
3. When the defoaming agent composition is in the emulsion form, a production method in which the shear rate at the time of producing the emulsion is reduced as much as possible is studied. (Make the zeta potential of the composite particles as wide as possible)
4. Depending on the use and purpose, a few conditions are optimized so as to balance the required initial defoaming property, defoaming durability, and dispersion stability.

The procedure for producing the silicone antifoam composition developed by the above-described development procedure will be described.
A step of selecting the type and / or amount of each of the oil component and the silica component according to the type of the foaming liquid, and mixing the selected oil component and the silica component, and silicone defoaming containing composite particles of the oil component and silica Of the agent composition, the step of sampling the produced silicone antifoam composition and measuring the distribution width of the zeta potential of the composite particles, and the transition from the start of foam formation to the completion of foam formation from the foaming liquid. In order to suppress the bubble formation in the static state, the distribution step of the measured zeta potential, the selection step and / or the adjustment step, and the measurement step until the threshold value set according to the foaming liquid or more. repeat.
When the silicone antifoam composition is in a compound form, the zeta potential is measured in a water-dispersed state, and in the case of an emulsion form, the silicone antifoam composition is prepared by shearing at a predetermined shear rate during emulsion preparation. Then, the zeta potential is measured in the form of emulsion.

To knead the oil and silica to form a compound, a kneading machine such as a gate mixer, a kneader, a pressure kneader, a biaxial kneading group, or an intensive mixer can be used. Appropriately, conditions are selected such that sufficient compositional nonuniformity and morphological nonuniformity within one particle and between particles appear when composite particles are formed by applying time and temperature. In some cases, a method of forming a chemical bond between oil and silica may be selected.
The mass ratio of silica to oil is a factor that affects the distribution width of the zeta potential of the composite particles. The preferable range of the mass ratio depends on the type of the foaming liquid and the target defoaming performance, but the mass part of silica to 100 mass parts of the oil content is 0.5 mass part or more and 40 mass parts or less. Preferably. If it is less than 0.5 part by mass, the distribution width of the zeta potential is not sufficiently wide and sufficient defoaming performance cannot be obtained. Further, when it exceeds 40 parts by mass, it is difficult to satisfy both the initial defoaming property and the defoaming durability, and when the defoaming agent is in the form of emulsion, the stability as an emulsion is lowered, for example, particles are precipitated. Problems arise. More preferably, it is in the range of 1 part by mass or more and 30 parts by mass or less.

When the silicone antifoam composition is in the emulsion form, the preferable content of the oil component in 100 parts by mass of the emulsion is in the range of 1 part by mass or more and 90 parts by mass or less. If it is less than 1 part by mass, sufficient emulsification accuracy cannot be obtained and the yield is lowered, and if it exceeds 90 parts by mass, the viscosity of the aqueous emulsion becomes high and the handleability becomes poor. More preferably, it is in the range of 2 parts by mass or more and 70 parts by mass or less.

A known method can be used for forming the compound into an emulsion. As the emulsifier, a polyoxyethylene alkylene-modified organopolysiloxane may be used to prepare a self-emulsifying emulsion, or a nonionic surfactant may be used to prepare a normal emulsion. When an anionic surfactant or a cationic surfactant is used, the surface of the defoaming agent composition covered with these ionic surfactants has a uniform charge, and the zeta having a wide distribution range as in the present invention is used. No electric potential is obtained, and strong defoaming performance is exhibited only for some bubbles. Therefore, the use of nonionic surfactants is highly preferred for realizing the present invention.

When a self-emulsifying defoamer composition is prepared using polyoxyethylene alkylene-modified organopolysiloxane, the amount of polyoxyethylene alkylene-modified organopolysiloxane used is 1 part by mass or more and 30 parts by mass in 100 parts by mass of the emulsion. It is preferably not more than a part. This is because if it is less than 1 part by mass, the emulsification cannot be sufficiently carried out, and if it exceeds 30 parts by mass, the distribution width of the zeta potential is not widened. More preferably, it is 2 parts by mass or more and 20 parts by mass or less.
When a normal emulsion is prepared using a nonionic surfactant, the amount of the nonionic surfactant used is preferably 1 part by mass or more and 30 parts by mass or less in 100 parts by mass of the emulsion. This is because if it is less than 1 part by mass, the emulsification cannot be sufficiently carried out, and if it exceeds 30 parts by mass, the distribution width of the zeta potential is not widened. More preferably, it is 2 parts by mass or more and 20 parts by mass or less.
The polyoxyethylene alkylene-modified organopolysiloxane or nonionic surfactant may be used alone or in combination of two or more, but the total content is 1 part by mass in 100 parts by mass of the emulsion. It is preferably not less than 50 parts by mass. This is because if it is less than 1 part by mass, emulsification cannot be sufficiently carried out, and if it exceeds 50 parts by mass, the width of the distribution of the zeta potential is not widened. More preferably, it is 2 parts by mass or more and 30 parts by mass or less.

The method for producing the silicone antifoam composition in the emulsion form of the present invention is not particularly limited as long as it is within the range of the above method, but it can be produced by a known method. For example, it can be prepared by mixing and emulsifying the above components using a conventional mixer suitable for preparing an emulsion, for example, a homogenizer, a colloid mill, a homomixer, a high speed stator rotor agitator and the like.
Shear rate applied to the composite particles during the emulsion making is, 5,000 S ^-1 or more, and, 100,000 s ^-1 or less. If the shear rate is less than 5,000 s ⁻¹ , the dispersion stability of the emulsion particles is poor, the particles are likely to settle, and the defoaming sustainability tends to be insufficient. Further, when it exceeds 100,000 s ^-1 , the variation in the composition surface and / or the morphological surface within the composite particles and / or between the composite particles becomes too small, so that the distribution width of the zeta potential becomes narrow and the sufficient defoaming performance is obtained. Does not come out. More preferably, it is 7,000 s ⁻¹ or more and 50,000 s ⁻¹ or less.

The silicone antifoam composition in the emulsion form of the present invention is a polyoxyalkylene alkyl such as polyoxyethylene tridecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene octadecyl ether, etc. within a range not impairing the object of the present invention. It may contain ethers, polyoxyethylene hydrogenated castor oil, nonionic surfactants such as polyoxyethylene sorbitan acid ester, and ionic surfactants such as sodium lauroyl glutamate and sodium lysine dilauroyl glutamate.
The amount of the surfactant is preferably 50 parts by mass or less , more preferably 30 parts by mass or less, in 100 parts by mass of the emulsion. If it exceeds 50 parts by mass, not only the environment is adversely affected, but also the cohesive force of the silica particles is reduced, and the storage stability of the product and the handling property upon dilution are impaired.

The silicone antifoam composition in the emulsion form of the present invention, as long as the object of the present invention is not impaired, as a preservative, salicylic acid, sodium benzoate, sodium dehydroacetate, potassium sorbate, phenoxyethanol, methyl paraoxybenzoate, It may also include butyl paraoxybenzoate.
Further, other additives can be added to the same composition of the present invention as long as they do not violate the gist of the present invention. For example, a pH adjuster, a colorant, an antioxidant, a deodorant, a cross-linking agent, various catalysts, an emulsion stabilizer, various organic solvents, chelating agents and the like can be added.

The type of water used for the silicone antifoam composition in the emulsion form of the present invention is not particularly limited, but it is preferable to use ion-exchanged water, preferably pH 2 to 12, more preferably pH 4 to 10. Ion-exchanged water is used.

The particle size of the emulsion particles in the silicone antifoam composition in the emulsion form of the present invention is preferably in the range of 0.1 μm or more and 1000 μm or less. If it is less than 0.1 μm, sufficient defoaming performance cannot be exhibited, and if it exceeds 1000 μm, problems such as particle sedimentation occur. The range of 0.5 μm or more and 500 μm or less is more preferable. In the present invention, the average particle size can be measured, for example, by a particle size distribution measuring device N4Plus manufactured by Coulter.

As described above, the silicone antifoam composition in the emulsion form of the present invention can stably control the particle size by the oil component and silica particles containing silicone as an essential component, and the production method thereof, and thus the dispersion of the particle size can be suppressed. Since it can be made narrower, storage stability and stability during application deployment are enhanced.

The zeta potential of the composite particles of the silicone antifoam composition according to the present invention shows a similar tendency to the defoaming performance and stability regardless of what is measured by any method or device. However, regarding the concentration of the composite particles in the aqueous dispersion in the measurement of the zeta potential, there is a range in which an appropriate value can be obtained. The concentration of the composite particles in the aqueous dispersion is preferably 10 ppm or more and 50,000 ppm (5%) or less. Even if it is less than 10 ppm or exceeds 50,000 ppm (5%), an appropriate value may not be obtained. Therefore, when the silicone antifoam composition is in the emulsion form, it is diluted or concentrated with water so as to obtain the preferable composite particle concentration. In the case of the compound form, it is dispersed in water at the concentration. If necessary, a surfactant or the like is appropriately used for dispersion.
The pH of the aqueous dispersion for measuring the zeta potential also affects the zeta potential and the measurement result. When the pH of the electromotive Awaeki is known in advance, it may be such as to measure the zeta potential to match to the pH. Comparing zeta potentials makes sense to compare under the same pH.

The preferred distribution width of the zeta potential of the composite particles of the silicone antifoam composition according to the present invention varies in absolute value depending on the type of the foaming liquid and the desired defoaming performance, but most commonly, There are such preferred ranges. That is, in the cumulative relative frequency distribution of the zeta potentials measured when the pH of the aqueous dispersion to be measured was 7 using the laser Doppler electrophoresis method, the difference between the integrated value of 10% and the integrated value of 90% was 6 mV or more. And preferably 60 mV or less. If it is less than 6 mV, the initial defoaming property is not sufficient, and if it exceeds 60 mV, it becomes difficult to satisfy both the initial defoaming property and the defoaming sustainability. When the defoaming agent is in the emulsion form, the dispersion stability of the particles is low. descend. More preferably, it is 10 mV or more and 40 mV or less.

As described above, by setting the distribution width of the zeta potential of the composite particles of the silicone antifoam composition, whether to prioritize the initial defoaming property, or to emphasize both the initial defoaming property and the defoaming durability, or Whether or not importance is attached to the stability of the emulsion as a product can be selected according to the application. For example, these priorities vary depending on the allowable range of foam height and the shape of the container containing the foaming liquid. As an example of the application, when the waste liquid is stored in a narrow and deep pool and the waste liquid is frequently exchanged, and the bubbles tend to overflow, the initial defoaming property is emphasized, and since a wide and shallow pool is used, the bubbles will overflow. It is difficult, and when left for a long period of time, it is necessary to satisfy both the initial defoaming property and the defoaming durability.
Further, whether to suppress the foaming mainly or to break the foaming mainly can be used to some extent depending on the application. By setting the balance between the compositional non-uniformity and the morphological non-uniformity according to the application. For example, in applications where it is difficult for bubbles to rise even a little, the contribution of compositional non-uniformity is increased in order to cause foam suppression mainly, and it is acceptable for bubbles to form, but the bubbles may break at some growth stage. In applications where it is better to foam and not grow further, the contribution of morphological heterogeneity is increased.

  INDUSTRIAL APPLICABILITY The silicone antifoam composition and the method for producing the same of the present invention effectively act in all processes involving foaming such as chemical industry, food industry, petroleum industry, yarn production industry, textile industry and pharmaceutical industry. In the product development and product manufacturing of the defoaming agent, which has been large in trial and error so far, the present invention makes it possible to predict the defoaming performance, and the defoaming composition exhibits high defoaming performance and stable defoaming performance. And a manufacturing method thereof can be provided.

Furthermore, the silicone antifoam composition of the present invention can be expected to be able to adjust the balance between the initial defoaming property and the defoaming durability and the balance between the defoaming performance and the dispersion stability, depending on the use and purpose.
In addition, it is expected that it is possible to control which of foam suppression and foam breakage is caused predominantly, depending on the application and purpose.

Next, the present invention will be described with reference to examples. The present invention is not limited to this. Further, the zeta potential measuring method, the defoaming performance evaluation method, and the dispersion stability evaluation in Examples and Comparative Examples were performed as follows.
In addition, in the performance evaluation test, even a part of the results has a failure result is described as a comparative example.

<Zeta potential measurement method>
In measuring the zeta potential of the composite particles of the silicone antifoam composition, water having a concentration of the composite particles set within a range of 10 to 100 ppm in a neutral phosphate buffer solution diluted 2-fold with ion-exchanged water. A dispersion was prepared. When the silicone antifoam composition is in the compound form, it is dispersed at a shear rate of 20,000 s ⁻¹ using a surfactant, and when it is in the emulsion form, the concentration of the composite particles falls within a predetermined range. Prepared by diluting with water or concentrating. In each case, the pH of the aqueous dispersion was adjusted to 7.
The zeta potential was measured by a laser Doppler electrophoresis method using a Malvern Nano-ZS90 type machine. The measurement was performed at 25 ° C.
In the cumulative relative frequency distribution of the zeta potential, the difference between the integrated value of 10% and the integrated value of 90% was defined as the zeta potential distribution width.

<Dispersion stability evaluation method>
In evaluating the dispersion stability of the composite particles of the silicone antifoam composition, an aqueous dispersion was prepared in which the concentration of the composite particles was set to 1% by mass in ion-exchanged water. When the silicone antifoam composition is in the compound form, it is dispersed by appropriately using a surfactant such as polyoxyethylene sorbitan fatty acid ester, and in the case of the emulsion form, water is added so that the concentration of the composite particles falls within a predetermined range. Prepared by diluting with or concentrating.
30 g of the prepared aqueous dispersion was put into a 50 ml screw tube, and after storage for 1 month at 25 ° C., the presence or absence of creaming and sedimentation was confirmed.
Evaluation criteria;
◯: creaming, no sedimentation separation, Δ: creaming, sedimentation tendency, x: creaming, sedimentation separation
Pass ◯ or △.

<Defoaming performance evaluation method>
A test foaming liquid was prepared by adding 1.5% by mass of the foaming liquid to ion-exchanged water and further adding the silicone antifoam composition. At this time, the concentration of the composite particles in the test foaming liquid was adjusted to 100 ppm. When the silicone antifoam composition was in a compound form, it was dispersed using a surfactant as appropriate.
100 ml of this test foaming liquid was put into a 500 ml graduated cylinder having a diameter of 50 mm, and air was blown by an air amplifier at a flow rate of 1.5 L / min using a Kinoshita glass ball filter 504G-1. The foam volume was recorded 10 seconds after the start of air feeding, and the initial defoaming property was evaluated.
As the foaming liquid, two kinds of a foaming liquid 1, an alkyl ether sulfate, and a foaming liquid 2, polyoxyethylene alkyl ether, were prepared and evaluated.
Evaluation criteria of initial defoaming property;
Five-level evaluation criteria were set according to the volume of the foam after 10 seconds. Pass 3 or more.
Less than 5:10 ml, 4:10 ml or more and less than 100 ml, 3: 100 ml or more and less than 200 ml, 2: 200 ml or more and less than 300 ml, 1: 300 ml or more The defoaming persistence was evaluated by evaluating the above initial defoaming property. After that, air feeding was continued for 20 minutes under the same condition as it was, the volume of the foam at the time of 20 minutes was recorded, and the defoaming performance was evaluated by the same evaluation method as above.
Evaluation criteria for defoaming persistence;
Five-level evaluation criteria were set according to the volume of foam after 20 minutes. Pass 3 or more.
5: Less than 50 ml, 4: 50 ml or more and less than 200 ml, 3: 200 ml or more and less than 300 ml, 2: 300 ml or more, bubbles remain in the cylinder, 1: Bubble overflows from the cylinder.
As a comprehensive evaluation of the defoaming performance, the case where both the initial defoaming property and the defoaming durability are passed is regarded as passing.

<Example 1>
All "parts" shown below are based on mass unless otherwise specified. The unit% means the ratio of the corresponding siloxane unit to the total number of siloxanes in all the siloxanes.
It is composed of (CH ₃ ) ₂ SiO _2/2 units of 99.2% and (CH ₃ ) ₃ SiO _1/2 units of 0.8%, and 0.03% of all polydimethylsiloxane units have silicon atom-modified ethoxy groups. 100 parts of polydimethyl siloxane (as silicone oil A) and 5.0 parts of hydrophilic fumed silica (as silica 1) having a BET surface area of 200 m ² / g are closely contacted by using a disc type dissolver. Mixed in. A compound was prepared by heating this mixture at 150 ° C. for 4 hours.
The zeta potential distribution width of the compound was 18 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 45 ml, and therefore the evaluation was 4. Since the foaming liquid 2 had a volume of 40 ml after 10 seconds, the evaluation was 4.
With respect to the evaluation of the defoaming durability, the foaming liquid 1 had a volume of 95 ml after 20 minutes, and thus the evaluation was 4. In the case of the foaming liquid 2, it was 85 ml after 20 minutes, so the evaluation was 4.
Table 1 shows the composition of the silicone defoaming agent composition in the above compound form, the measurement result of the zeta potential distribution width, the dispersion stability, and the defoaming performance result.
Next, the above compound was dispersed by appropriately using polyoxyethylene sorbitan fatty acid ester to prepare an emulsion. The shear rate was 120,000 s ^-1 . The width of the zeta potential distribution of the produced emulsion was 5.5 mV.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 220 ml, so the evaluation was 2 and the test was unacceptable.
Therefore, the shear rate was reset to 20,000 s ⁻¹ and rework was performed.
The width of the zeta potential distribution of the produced emulsion was 17 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 40 ml, and therefore the evaluation was 4. Since the foaming liquid 2 had a volume of 35 ml after 10 seconds, the evaluation was 4.
With respect to the evaluation of the defoaming durability, the foaming liquid 1 had a volume of 90 ml after 20 minutes, and therefore the evaluation was 4. Since the foaming liquid 2 had a volume of 80 ml after 20 minutes, the evaluation was 4.
Table 2 shows the composition of the silicone defoaming agent composition in the form of emulsion, the measurement result of the zeta potential distribution width, the dispersion stability, and the defoaming performance result. However, the shear rate shall be that at the final rework, and the evaluation results of dispersion stability and defoaming performance shall be after the final rework.

<Example 2>
In Example 1, instead of 100 parts by mass of the silicone oil A, 50 parts by mass of the silicone oil A and 99.7% of (CH ₃ ) ₂ SiO _2/2 unit and (CH ₃ ) ₃ SiO _1/2 unit 0 The same method as in Example 1 except that 50 parts by mass of polydimethylsiloxane having a silicon atom-modified ethoxy group (as silicone oil B) accounts for 50% by mass of 0.03% of all polydimethylsiloxane units. A compound was prepared in.
The distribution width of the zeta potential of the compound was 19 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 20 ml, and therefore the evaluation was 4. Since the foaming liquid 2 had a volume of 9 ml after 10 seconds, the evaluation was 5.
The evaluation of the defoaming persistence was 4 in the foaming liquid 1, since the volume of the foam at the time of 20 minutes was 85 ml. Since the foaming liquid 2 had a volume of 70 ml after 20 minutes, the evaluation was 4.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 18 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 20 ml, and therefore the evaluation was 4. Since the foaming liquid 2 had a volume of 15 ml after 10 seconds, the evaluation was 4.
With respect to the evaluation of the defoaming persistence, the foaming liquid 1 had a volume of 70 ml after 20 minutes, so the evaluation was 4. Since the foaming liquid 2 had 65 ml after 20 minutes, the evaluation was 4.

<Example 3>
A compound was prepared in the same manner as in Example 1 except that 70 parts by mass of silicone oil A and 30 parts by mass of isoparaffin as a mineral oil were used instead of 100 parts by mass of silicone oil A in Example 1.
The distribution width of the zeta potential of the compound was 39 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 12 ml, so the evaluation was 4. Since the foaming liquid 2 had a volume of 5 ml after 10 seconds, the evaluation was 5.
The evaluation of the defoaming persistence was 4 in the foaming liquid 1, since the volume of foam at the time of 20 minutes was 55 ml. The effervescent liquid 2 was 52 ml after 20 minutes, so the evaluation was 4.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 37 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 13 ml, and therefore the evaluation was 4. Since the foaming liquid 2 had a volume of 12 ml after 10 seconds, the evaluation was 4.
The evaluation of the defoaming persistence was 4 in the foaming liquid 1 since the volume of foam at the time of 20 minutes was 54 ml. The effervescent liquid 2 had an evaluation of 4 since it was 51 ml after 20 minutes.

<Example 4>
In Example 1, 2.5 parts by mass of silica 1 and 2.5 parts by weight of hydrophilic fumed silica having a BET surface area of 300 m ² / g (referred to as silica 2) were used instead of 5.0 parts by mass of silica 1. A compound was prepared in the same manner as in Example 1 except that the parts were used.
The distribution width of the zeta potential of the compound was 37 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
With respect to the evaluation of the defoaming persistence, the foaming liquid 1 had an evaluation of 5 because the volume of the foam at the time of 20 minutes was 48 ml. In the foaming liquid 2, the amount was 42 ml after 20 minutes, so the evaluation was 5.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 35 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. The effervescent liquid 2 had a rating of 5 since it was 7 ml after 10 seconds.
The evaluation of the defoaming durability was 5 in the foaming liquid 1, since the volume of foam at the time of 20 minutes was 49 ml. The effervescent liquid 2 had an evaluation of 5 since it was 43 ml after 20 minutes.

<Example 5>
In Example 1, 50 parts by mass of silicone oil A and 50 parts by mass of silicone oil B were used instead of 100 parts by mass of silicone oil A, and 5.0 parts by mass of silica 1 was replaced by 2. A compound was produced in the same manner as in Example 1 except that 5 parts by mass and 2.5 parts by mass of silica 2 were used.
The distribution width of the zeta potential of the compound was 39 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
The evaluation of the defoaming persistence was 4 in the foaming liquid 1, since the volume of foam at the time of 20 minutes was 55 ml. The effervescent liquid 2 was 52 ml after 20 minutes, so the evaluation was 4.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 37 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 8 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
The evaluation of the defoaming persistence was 4 in the foaming liquid 1 since the volume of foam at the time of 20 minutes was 54 ml. The effervescent liquid 2 had an evaluation of 4 since it was 53 ml after 20 minutes.

<Example 6>
A compound was prepared in the same manner as in Example 1 except that silica 1 was changed to 5.0 parts by mass in place of 5.0 parts by mass.
The distribution width of the zeta potential of the compound was 7 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 160 ml, and therefore the evaluation was 3. The effervescent liquid 2 had an evaluation of 3 since it was 155 ml after 10 seconds.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the volume of the foam after lapse of 20 minutes was 270 ml, and therefore the evaluation was 3. With the foaming liquid 2, the amount was 260 ml after 20 minutes, so the evaluation was 3.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The produced emulsion had a zeta potential distribution width of 7 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 155 ml, and therefore the evaluation was 3. The effervescent liquid 2 was 150 ml after 10 seconds, so the evaluation was 3.
The evaluation of the defoaming persistence was 3 in the foaming liquid 1, since the volume of the foam at the time of 20 minutes was 245 ml. In the foaming liquid 2, it was 240 ml after 20 minutes, so the evaluation was 3.

<Example 7>
A compound was prepared in the same manner as in Example 1, except that the amount of silica 1 was changed to 30 parts by mass instead of 5.0 parts by mass.
The distribution width of the zeta potential of the compound was 55 mV.
The evaluation of dispersion stability was Δ.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of the feeding of the air was 5 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 4 ml after 10 seconds, the evaluation was 5.
The evaluation of the defoaming persistence was 5 in the foaming liquid 1 since the volume of foam at the time of 20 minutes was 30 ml. Since the foaming liquid 2 had a volume of 25 ml after 20 minutes, the evaluation was 5.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 6 mV.
The evaluation of dispersion stability was Δ.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of the feeding of the air was 5 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 3 ml after 10 seconds, the evaluation was 5.
The evaluation of the defoaming persistence was 5 in the foaming liquid 1 since the volume of foam at the time of 20 minutes was 30 ml. In the foaming liquid 2, it was 28 ml after 20 minutes, so the evaluation was 5.

<Example 8>
An emulsion was prepared from the compound prepared in Example 1 in the same manner as in Example 1. The shear rate during the final rework was 7,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 25 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
With respect to the evaluation of the defoaming durability, the foaming liquid 1 had a volume of 75 ml at 20 minutes, and therefore the evaluation was 4. In the foaming liquid 2, the amount was 60 ml after 20 minutes, so the evaluation was 4.

<Example 9>
An emulsion was prepared from the compound prepared in Example 1 in the same manner as in Example 1. The shear rate during the final rework was 50,000 s ⁻¹ .
The width of the zeta potential distribution of the produced emulsion was 12 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 130 ml, and therefore the evaluation was 3. In the foaming liquid 2, the amount was 115 ml after 10 seconds, so the evaluation was 3.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the volume of the foam at the time of 20 minutes was 185 ml, and therefore the evaluation was 4. In the foaming liquid 2, since it was 180 ml after 20 minutes, the evaluation was 4.

<Comparative Example 1>
A compound was prepared in the same manner as in Example 1, except that the amount of silica 1 in Example 1 was changed to 5.0 parts by mass instead of 5.0 parts by mass.
The distribution width of the zeta potential of the compound was 5 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 310 ml, and therefore the evaluation was 1. Since the foaming liquid 2 had a volume of 180 ml after 10 seconds, the evaluation was 3.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the foam overflowed from the cylinder after 20 minutes, so the evaluation was 1. The effervescent liquid 2 had an evaluation of 2 since it was 320 ml after 20 minutes.
Next, an emulsion was prepared from the above compound by the same method as in Example 18. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 5 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 305 ml, so the evaluation was 1. The effervescent liquid 2 had an evaluation of 3 since it was 175 ml after 10 seconds.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the foam overflowed from the cylinder after 20 minutes, so the evaluation was 1. The effervescent liquid 2 had an evaluation of 2 since it was 325 ml after 20 minutes.
Therefore, in both the compound form and the emulsion form, the foaming liquid 1 failed in both initial defoaming property and defoaming durability. In both the compound form and the emulsion form, the foaming liquid 2 passed the initial defoaming property but failed the defoaming durability.

<Comparative example 2>
A compound was prepared in the same manner as in Example 1 except that 50 parts by mass of silica 1 was used instead of 5.0 parts by mass.
The distribution width of the zeta potential of the compound was 70 mV.
The evaluation of dispersion stability was x.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 7 ml, so the evaluation was 5. Since the foaming liquid 2 had a volume of 6 ml after 10 seconds, the evaluation was 5.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the foam overflowed from the cylinder after 20 minutes, so the evaluation was 1. With the foaming liquid 2, the rating was 1 because the foam overflowed from the cylinder after 20 minutes.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 67 mV.
The evaluation of dispersion stability was x.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 7 ml, so the evaluation was 5. The effervescent liquid 2 had a rating of 5 since it was 7 ml after 10 seconds.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the foam overflowed from the cylinder after 20 minutes, so the evaluation was 1. With the foaming liquid 2, the rating was 1 because the foam overflowed from the cylinder after 20 minutes.
Therefore, both the foaming liquid 1 and the foaming liquid 2 passed the initial defoaming property in both the compound form and the emulsion form, but failed in the defoaming persistence.

<Comparative example 3>
In Example 1, the same as Example 1 except that instead of 100 parts by mass of silicone oil A, 35 parts by mass of silicone oil A, 35 parts by mass of silicone oil B and 30 parts by mass of isoparaffin as mineral oil were used. A compound was prepared by the method.
The distribution width of the zeta potential of the compound was 65 mV.
The evaluation of dispersion stability was x.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the volume of the foam at the time of 20 minutes was 330 ml, so the evaluation was 2. The effervescent liquid 2 had an evaluation of 2 since it was 315 ml after 20 minutes.
Next, an emulsion was prepared from the above compound by the same method as in Example 1. The shear rate at the final rework was 20,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 64 mV.
The evaluation of dispersion stability was x.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
With respect to the evaluation of the defoaming persistence, in the foaming liquid 1, the volume of the foam at the time of 20 minutes was 325 ml, so the evaluation was 2. Since the foaming liquid 2 had a volume of 310 ml after 20 minutes, the evaluation was 2.
Therefore, both the foaming liquid 1 and the foaming liquid 2 passed the initial defoaming property in both the compound form and the emulsion form, but failed in the defoaming persistence.

<Comparative example 4>
An emulsion was prepared from the compound prepared in Example 1 in the same manner as in Example 1. The shear rate at the final rework was 3,000 s ^-1 .
The width of the zeta potential distribution of the produced emulsion was 55 mV.
The evaluation of dispersion stability was x.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 9 ml, and therefore the evaluation was 5. Since the foaming liquid 2 had a volume of 8 ml after 10 seconds, the evaluation was 5.
With respect to the evaluation of the defoaming durability, the foaming liquid 1 had a rating of 1 because the foam overflowed from the cylinder at the time point of 20 minutes. With the foaming liquid 2, the volume of the foam was 290 ml after 20 minutes, and therefore the evaluation was 3.
Therefore, the foaming liquid 1 passed the initial defoaming property, but failed the defoaming persistence. Foaming liquid 2 passed both the initial defoaming property and the defoaming durability.

<Comparative Example 5>
An emulsion was prepared from the compound prepared in Example 1 in the same manner as in Example 1. The shear rate during the final rework was 150,000 s ⁻¹ .
The width of the zeta potential distribution of the produced emulsion was 6 mV.
The evaluation of dispersion stability was ◯.
In the evaluation of the initial defoaming property, in the foaming liquid 1, the volume of the foam 10 seconds after the start of feeding the air was 210 ml, so the evaluation was 2. The foaming liquid 2 had an evaluation of 3 since it was 195 ml after 10 seconds.
With respect to the evaluation of the defoaming durability, the foaming liquid 1 had a foam volume of 305 ml after 20 minutes, so the evaluation was 2. With the foaming liquid 2, it was 275 ml after 20 minutes, so the evaluation was 3.
Therefore, in the foaming liquid 1, both the initial defoaming property and the defoaming persistence were unacceptable. Foaming liquid 2 passed both the initial defoaming property and the defoaming durability.

As is clear from Examples and Comparative Examples in Tables 1 and 2, the distribution width of the zeta potential of the composite particles of the silicone defoaming agent composition tends to become wider as the types of oil and / or silica increase. there were. Further, the larger the mass% of silica to the oil, the wider. In addition, the smaller the shear rate at the time of producing the emulsion, the wider.
In Comparative Example 1 in which the zeta potential was 5 mV, both the foaming liquid 1 and the foaming liquid 2 failed the comprehensive evaluation of the defoaming property. In Comparative Example 5 in which the zeta potential was 6 mV, the foaming liquid 1 failed the comprehensive evaluation of the defoaming property, but the foaming liquid 2 passed. Therefore, in Example 6 in which the zeta potential was 7 mV, both the foaming liquid 1 and the foaming liquid 2 passed the comprehensive evaluation of the defoaming property.
Therefore, the lower limit threshold of the distribution width of the zeta potential of the composite particles of the silicone defoaming agent composition is between 6 mV and 7 mV in the foaming liquid 1 and between 5 mV and 6 mV in the foaming liquid 2. Was shown.
Similarly, from the results of Example 7, Comparative Example 4, and Comparative Example 3, the upper limit threshold of the distribution width of the zeta potential is between 54 mV and 55 mV in the foaming liquid 1 and 55 mV in the foaming liquid 2. It was shown to be present between 64 mV.
Thus, the difference in the appropriate range of the distribution width of the zeta potential depending on the foaming liquid was shown.
However, when the distribution width of the zeta potential exceeded 50 mV, the defoaming persistence tended to decrease, and the dispersion stability of the composite particles also decreased.

INDUSTRIAL APPLICABILITY The silicone antifoam composition and the method for producing the same of the present invention effectively act in all processes involving foaming such as chemical industry, food industry, petroleum industry, yarn production industry, textile industry and pharmaceutical industry. In the product development and product manufacturing of the defoaming agent, which has been large in trial and error so far, the present invention makes it possible to predict the defoaming performance, and the defoaming composition exhibits high defoaming performance and stable defoaming performance. And a manufacturing method thereof can be provided. Furthermore, it can be expected that the balance between the initial defoaming property and the defoaming durability and the balance between the defoaming performance and the dispersion stability can be adjusted depending on the use and purpose. In addition, it is expected that it is possible to control which of foam suppression and foam breakage is caused predominantly, depending on the application and purpose.

Claims (1)

A silicone defoaming agent composition of a type that defoams by previously adding to a foaming liquid,
Contains a composite particle group of oil and silica having silicone as an essential component,
By allowing any of the composite particles in the composite particle group to reach the inner surface of the envelope film forming the foam formed by the foaming liquid, so that foam suppression and foam breaking are possible,
The distribution width of the zeta potential of the composite particle group is set according to the foaming liquid,
A silicone defoaming composition comprising: