JPS6142309A - Powdery defoaming agent - Google Patents

Abstract

PURPOSE:To obtain a flowable powdery defoaming agent having good water dispersibility and showing an excellent defoaming property, by using organopolysiloxane and cyclodextrin. CONSTITUTION:A powdery defoaming agent consists of 15-50wt% of an organopolysiloxane composition consisting of 80-98pts.wt. of organopolysiloxane, of which the average composition is represented by formula (wherein R<1> is an 1- 20C monovalent hydrocarbon group, 0<=a<=1 and 1.9<=a+b<=2.20) and 20-2pts. wt. of fine powdery silica, and 85-50wt% of cyclodextrin. Because cyclodextrin has capacity taking in an org. substance, organopolysiloxane is taken in said cyclodextrin to take a form covered with cyclodextrin and a flowable powder is obtained. This defoaming agent is easily collapsed in water and organopolysiloxane is supplied to show excellent defoaming capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a powder antifoaming agent, particularly a powder antifoaming agent, which has excellent workability, fluidity, antifoaming properties,
This invention relates to a powder antifoaming agent that has excellent dispersibility in aqueous systems and does not change over time.

(Prior Art) Various antifoaming agents are already known for the purpose of extinguishing various types of foam produced industrially.

In particular, those containing organopolysiloxane as an effective antifoaming ingredient are widely used. This silicone antifoaming agent is usually used in a solvent-type or emulsion-type liquid form, but this liquid antifoaming agent C2 is used when the object to be treated is a powder product (2 is difficult to operate). In addition to disadvantages,
Because it has the disadvantage that it is easily subject to changes over time,
Powdered antifoaming agents have been developed in which silicone resin is adsorbed to various powders, and these include 1) organopolysilochitin components, water-soluble resins such as lamethylcellulose and polyvinyl alcohol, or gum acacia and gum tragalant; 2) The organopolysiloxane component is encapsulated with an ultraviolet curable substance; 3) The organopolysiloxane component is encapsulated with an inorganic or They are broadly classified into three types: those dispersed or coated on organic water-soluble substances.

However, in case 1), the water-soluble resin or rubber that makes up the outer wall of the capsule swells and collapses due to moisture, and as a result, the antifoaming agent component inside the capsule is released. Because it has hygroscopic properties, it becomes sticky even with a small amount of moisture, and as a result, the smooth powder form may become sticky or lumpy over time.
It has the drawbacks of dryness, poor storage stability, and loss of fluidity when added to a powdered substance during use. Regarding the above-mentioned item 2), it is known that a polysiloxane containing a vinyl group and a polysiloxane containing a hydrosilyl bond (!E81H) or a polysiloxane containing a mercapto group are crosslinked by ultraviolet irradiation and encapsulated. is not easily destroyed by water or heat, so water-based foaming does not work effectively, and defoaming performance (there are two problems. Also, 3), for example, magnesium hydroxide, magnesium carbonate, magnesium oxide, sodium bicarbonate, A method using lactose, crystalline α-cellulose with a particle size of about 20 mμ, cellulose derivatives, polyvinyl alcohol, gelatin, etc. as a carrier, and a method in which a carbonate l niorganosylochitin component is adsorbed, and silicate and gelatin are adsorbed on this. , a method of microencapsulating with cellulose derivatives, a method of using solid organopolysilochitin, etc. are known, but these generally tend to become sticky,
They have the disadvantage that they contain a large amount of antifoaming agent component, and they also have the common disadvantage of poor dispersibility in aqueous systems.

(Structure of the Invention) The present invention relates to a powder antifoaming agent that solves the above-mentioned disadvantages. ,0≦a
Organopolysilochitin 80 to 981r spear part and fine powder silica 20 represented by ≦1.1.9≦a+b≦2.203
- Organopolysilochitin composition 1 consisting of 2 parts
5-50% and 2) cyclodextrin 85-50%
It is characterized by consisting of %.

Namely, as a result of various studies conducted by the present inventors on modification of powder antifoaming agent, it was found that when cyclodextrin is added to an organopolysiloxane composition consisting of organopolysiloxane and finely powdered silica as antifoaming agent components. This cyclodextrin has a truncated conical structure, and the outside is hydrophilic due to the action of hydroxyl groups, whereas the inner wall cavity is nonpolar and hydrophobic, and has the ability to take in organic substances. Since the organosiloxane is coated with cyclodextrin, it becomes a fluid powder, but since cyclodextrin is not hygroscopic, this product does not change over time, and furthermore, the outer wall side is hydrophilic. Therefore, it easily disintegrates in water and quickly supplies organopolysiloxane as an antifoaming agent component to the foaming system, and exhibits excellent antifoaming performance, providing various advantages that conventional powder antifoaming agents do not have. The present invention was completed by conducting research on the type and amount of cyclodextrin used.

The organopolysiloxane composition as component 1) constituting the powder antifoaming agent of the present invention is made of organopolysiloxane and finely powdered silica. This organopolysiloxane has an average compositional formula of Ra (OH,)b810
, -a-b, and this R'' is a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a decyl group,
Same or different carbon number 1 selected from alkyl groups such as octadecyl group, alkenyl groups such as vinyl group, allyl group, aryl group such as phenyl group, styryl group, etc.
~20 unsubstituted or substituted monovalent hydrocarbon groups, where a is O≦
It is assumed that 1.90≦a+b≦2.20 and 1.90≦a+b≦2.20. In addition, this organopolysiloxane may be linear, branched, or resin-like,
The viscosity may be anything from a liquid with several tens of centistokes to a rubber-like one with several million centistokes, but regarding the above a value, the smaller a is, the stronger the antifoaming performance is; The affinity with organic substances increases, the repellency phenomenon that was a drawback of conventional silicones is avoided, and it begins to exhibit vain tuple properties, so that 0≦a≦1
．． It is preferable to set it in the range of 0. There are no special restrictions on the physical properties or shape of the finely powdered silica blended into this organosilochitin, and it may be made by either a wet method or a dry method. It may also be one treated with silane, alkoxysilane, silazane, aminosilane, or the like.

This organopolysiloxane resin composition is made by mixing the above-mentioned organopolysiloxane and finely powdered silica, but for the purpose of improving the antifoaming effect, the two are often combined to some extent, and in some cases, Alternatively, a binder may be added to the silica, or a catalyst may be added to react the organopolysiloxane with the lanol groups on the silica surface. Note that if the amount of finely powdered silica blended in this organopolysiloxane composition is too small, a sticky feeling will occur, and if it is too large, antifoaming properties will be insufficient.
The amount of finely powdered silica is 20 to 2 parts by weight per 0 to 98 parts by weight.

Next, whether the cyclodextrin used as the component 2) used in the powder antifoaming agent of the present invention is one that disperses and adsorbs the organopolysiloxane described above or is used as a carrier for coating it, or is it suitable for starch? Pasirrus (Bao)
It is obtained by the action of a cyclodextrin-producing enzyme called ν clodextonase produced by 11 microorganisms, and 6 to 12 units of glucose (glucose) are cyclically formed by α-1,4-glycosidic bonds. It has a structure of being connected. Therefore, it has a truncated cone-like three-dimensional structure, and depending on the orientation of the hydroxyl groups of glucose, the outside of the truncated cone becomes hydrophilic or the inside becomes lipophilic. When blended with the organobori ν loxene composition, this blend becomes a fluid powder that does not change over time, but since cyclodextrin is hydrophilic on the outside, it has good water dispersibility; Since it easily disintegrates in water and elutes the organopolysilochitin as an anti-foaming component, according to Koreponi, it is a powder that is stable and does not change over time, and when it defoams, it quickly dissolves in water (bidispersed). The advantage is that a powder antifoam agent is obtained which exhibits excellent antifoam properties.

In addition, this cyclodextrin uses starch, a natural product, as a starting material and is designated as a natural food additive. If the requirements are satisfied, this powdered antifoaming agent has the advantage that it can also be used as a food additive.

In addition, regarding the compounding ratio of this cyclodextrin and 1) organopolysiloxane composition as the rFt component, if the amount of cyclodextrin added is too small, stickiness may occur or the fluidity will be deteriorated, and if it is too large, the antifoaming agent may be Therefore, it is necessary to range from 85 to 50% by weight of cyclodextrin to 15 to 50% by weight of the organopolysiloxane composition, but preferably from 20 to 45% by weight of the organopolysiloxane composition. The amount of cyclodext 9 is 80 to 55% by weight.

The powder antifoaming agent of the present invention can be obtained by stirring and mixing predetermined amounts of the above-described components 1) and 2). This may be carried out by using a chlorinated solvent or water as a dispersion medium and removing them after mixing. In addition, nonionic surfactants such as polyoxyethylene fatty acid esters or nonionic surfactants such as polyoxyethylene fatty acid esters may be used to improve the dispersibility of these solvents. Anionic and cationic surfactants, as well as water-soluble substances such as polyvinyl alcohol, carboxymethylcellulose, methylcellulose, polyethylene glycol, etc. may be added.

The following is an example of the present invention. In the example, 1 is the capital, and the viscosity is a value measured at 25°C.

Example 1 Dimethylpolysiloxane 95 with a viscosity of 500 o8
90 parts of cyclodextrin and 70 parts of ethanol were added to 10 parts of organopolysilochitin composition A consisting of 5 parts of powder and 5 parts of finely powdered silica, and the mixture was stirred and mixed for 1 hour, and then the ethanol was removed by heating under reduced pressure to defoam the powder. 100 parts of agent 1 were prepared, and powder antifoam agents n to 2 were prepared in the same manner using the compounding ratios shown in Table 5 of IPsI.

Next, these powder antifoaming agents were placed in a clean glass bottle, and the bottle was tilted to examine whether it moved easily, that is, whether it was sticky or not, and its fluidity, and the results shown in Table 181 were obtained. It has been confirmed that in order to obtain a flowable powder, the organopolysilochitin composition should be 50% or less.

Example 2 Weighed 100 g of 082% sodium oleate aqueous solution into two 11 measuring cylinders, added 0.3 g each of the powdered antifoaming agents ■ to ■ prepared in Example], and passed them through a glass pole filter. When we measured the change over time in the amount of foaming [foam + device (m)] by blowing air for 1/min, we found that w
The results shown in Table I2 were obtained, and from the viewpoint of antifoaming performance, this powder antifoaming agent should contain at least 15% by weight of organopolysilochitin A, preferably at least 20% by weight. It turned out that it was necessary.

I8 2 Table

Claims (1)

[Claims] 1, 1) Average compositional formula R_a(CH_3)_bSiO_4_-_a_-_b(
Here, R^1 is a monovalent hydrocarbon group having 1 to 20 carbon atoms, 0≦
a≦1, 1.90≦a+b≦2.20) Organopolysiloxane composition consisting of 80 to 98 parts by weight of organopolysiloxane and 20 to 2 parts by weight of finely powdered silica, 15 to 50% by weight 2) A powder antifoaming agent characterized by comprising 85 to 50% by weight of cyclodextrin.