JPS5951565B2 - Continuous production method of silicone aqueous liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a continuous process for producing a stable, grease-like aqueous silicone fluid.

Conventionally, in order to obtain an O/W emulsion by dispersing hydrophobic liquid substances such as fats, oils, paraffin, and synthetic oils in water, these hydrophobic liquid substances were mixed with surfactants, protective colloids, etc. using a propeller-type stirrer. , methods of dispersing in water using devices such as colloid mills, homogenizers, and ultrasonic emulsifiers are widely adopted.

However, organopolysilicone oil has extremely high hydrophobicity, so it is difficult to form a stable aqueous emulsion.

For this reason, silicone oils are rolled together with an emulsifier and a relatively small amount of water to apply strong shearing force to form a relatively viscous paste, which is then diluted with water to form a stable aqueous emulsion. Method(
(See Japanese Patent Publication No. 46-10162) was proposed. However, when this method is used, there is a problem that oil spots and oil separation phenomena are observed in the emulsion diluted with water. This is probably because the above-mentioned roll kneading is an open system in the atmosphere, so that water in the kneaded material evaporates during the shear kneading. The present invention was completed as a result of intensive research to solve these problems.This invention consists of shearing and stirring 100 parts by weight of diorganopolysiloxane, 0.1 to 100 parts by weight of an emulsifier, and 5 to 20 parts by weight of water. It is continuously supplied into a cylindrical container equipped with a mechanism, and the inside of the container is filled with O, 5 kg/
While maintaining a pressurized state of cm G or more, the shear rate is 5.
A grease-like silicone aqueous liquid having a viscosity of 100,000 centipoise (25°C) or more is continuously taken out from the product outlet of the container by performing shear stirring at a rate of 0.01/sec or more. In particular, the shearing and stirring mechanism has at least three
It is characterized by having two discs arranged coaxially and at regular intervals.

According to the method of the present invention, it is possible to continuously obtain a stable, greasy aqueous dispersion of a diorganopolysiloxane that is significantly hydrophobic, and it is possible to obtain an oil spot even in a particularly highly viscous organopolysiloxane oil. , an aqueous silicone emulsion with no oil separation can be easily obtained.

Further, the method of the present invention has the advantage that there is no particular need for pre-emulsification or pre-mixing of raw material components, and the process can be operated completely continuously. The method of the present invention will be explained in detail below.

The present invention continuously performs the desired emulsification operation using a cylindrical container equipped with an internal shearing and stirring mechanism consisting of at least three discs arranged coaxially and at regular intervals around a rotating shaft. However, the first part of the attached drawing
The figure is a schematic vertical cross-sectional view of a cylindrical container equipped with this shearing and stirring mechanism, and FIGS. 2A and 2B are schematic cross-sectional views taken along line A-A in FIG. The figures are shown in each figure.

In these figures, 1 is a cylindrical container, 2 is a rotating shaft, 3, 3
' is a disk attached to the rotating shaft.

It is desirable that at least three or more discs are provided on the rotating shaft. Figure 2a has no holes. thing, also the second
Although FIG. b shows a shape in which a plurality of holes 4 are provided through which liquid can pass, it is preferable to provide holes 4 in terms of shearing and stirring effects. Also, it is a combination of a disc with holes and a disc with no holes at all. Good too. At least three discs 3, 3' are required to be installed on the rotating shaft, and five or more discs are generally desirable. The periphery of these disks 3, 3' and the cylindrical container 1
If the distance (clearance) between the inner surface and the inner surface is too large, the shearing action between them will be insufficient. , and the desired emulsification will not be carried out, so it is preferable that the thickness be 2 cm or less, and generally it is desirable that it be in the range of 0.2 to 1.6 cm. Note that a jacket for temperature regulation may be provided on the outer periphery of the cylindrical container. In the method of the present invention, the diorganopolysiloxane to be emulsified is continuously charged together with an emulsifier and water from the raw material feed port 5 of the above-mentioned device. In order to achieve the purpose of the present invention of obtaining aqueous silicone liquid, it is necessary to add 0.1 to 100 parts of an emulsifier to 100 parts by weight of diorganopolysiloxane.
parts by weight (preferably 1 to 50 parts by weight), and 5 parts by weight of water.
-20 parts by weight (preferably 7 to 16 parts by weight).

In particular, if the amount of water is less than 5 parts by weight, it will be difficult to obtain an O/W type grease-like emulsion;
If the amount is more than 1 part by weight, the viscosity of the mixed system of the charged components becomes low, making it impossible to homogenize the mixture to obtain a grease-like material using the above-mentioned apparatus, and as a result, it becomes impossible to obtain a stable dally-like aqueous liquid. The raw material diorganopolysiloxane usually has a molecular weight of several centistokes (at 25°C) or more, preferably 100 to 70,000, although it depends on the type of emulsifier used.
Any type of oil may be used as long as it is centistokes (25°C), and emulsifiers that are conventionally used for silicone emulsification are appropriately selected and used, including long-chain alkyl sulfates. , alkyl sulfonates, anionic surfactants such as polyoxyethylene alkyl phenyl ether sodium sulfate, cationic surfactants such as benzyl ammonium salts, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, sorbitan monoesters Examples of nonionic surfactants include:

When diorganopolysiloxane, emulsifier, and water are charged in predetermined proportions, fine silica powder may be added together if necessary to obtain a grease-like material containing fine silica powder. As the silicate fine powder, wet (precipitated) silica, dry (humid) silica, or these fine silica powders surface-treated with silazane, organohalosilane, etc. are used. In addition, it is not necessary to premix each component in advance, and it is sufficient to supply each component at a predetermined ratio to one end of a cylindrical container, and each component is supplied between each disk. As it passes through, it is mixed by shearing and becomes a grease-like substance.

The rotational speed of the stirring mechanism is required to be such that the shearing rate is 501/sec or more (preferably 500 to 15001/sec), but this shearing rate in the present invention is in accordance with the following definition. shall be. The ingredients that are continuously charged by the above operation are mixed uniformly and finally turned into a grease-like aqueous liquid and taken out from the outlet 6. At this time, the raw ingredients are forced into the feed port 5 with a pump, By adjusting the flow rate from the adjustable slit 7 so that the inside of the container 1 is pressurized to 0.5 kg/Cm2G or more, the desired uniform emulsification can be achieved satisfactorily. .

Of course, the pressure inside the container is determined by the relationship between the amount of raw material supplied and the amount flowing out from the slit, and by adjusting these factors, the pressure inside the container can be maintained at a predetermined value. This preferred pressure range is 1-4 kg/CIn2G. When operated under the above conditions, the raw material components continuously supplied into the cylindrical container 1 from the inlet 5 are slit: ・7
By controlling the flow rate from the emulsion, strong shear agitation is performed under pressure by high-speed rotation of the discs 3, 3'', and as a result, extremely uniform and stable emulsification is achieved.
If the pressure is lower than 0.5 kg/Cm·G, strong shearing of the raw material components within the cylindrical container 1 will not occur, making it impossible to achieve the desired uniform emulsification. In addition, in order to achieve uniform mixing of the diorganopolysiloxane and water, the cylindrical container 1 is filled with particles having a diameter in the range of 0.5 to 5 mm, such as sand grains, glass beads, alumina particles, tungsten particles, etc. A stirrer may also be operated in this manner, which results in more intense shear agitation.

At this time, it is desirable to adjust the slit gap so that the filled particles do not pass through the slit 7 and flow out. The greasy aqueous liquid obtained by the method of the present invention can be used as it is as a mold release agent, polishing agent, medical ointment, or cosmetic base without diluting with water; As a result, a stable silicone emulsion can be easily obtained, and the emulsion particles have a size of 0.5 μm or less, and are stable without separation even when stored at 70° C. for 3 months or more.

Next, examples of the present invention and comparative examples will be given.

Example 1 100 parts by weight of dimethylpolysiloxane terminally blocked with trimethylsilyl groups having a viscosity of 5000 centistokes at 25°C, 10 parts by weight of poly(oxyethine), o-nonyl phenyl ether, and 10 parts by weight of water were individually mixed. Using a metering pump, the solution was quantitatively supplied from the bottom side into 21 cylindrical containers each having 7 disks and cooling jackets using the apparatus shown in the drawing.

The shear agitation was performed at a disc rotation speed of 2000 rpm, a shear rate of 12001/sec, and a system pressure of 1.5 kg/Cm2.
G: The test was conducted at an internal temperature of 40°C.

A transparent grease-like substance was obtained from the outlet of the container, and its viscosity was 10,000 poise (at 25°C) using a BH-type rotational viscometer.
That's all. The consistency measured according to JIS K256O was 66. When the resistance of this product was measured using a tester, it was found to be an O/W type emulsion which exhibited electrical conductivity and whose continuous phase was water. In addition, even if it was left in a sealed state at 70° C. for one year, it remained very stable without any change. To 120 parts by weight of the above transparent greasy substance, 180 parts by weight of water.
When the weight part was added and shaken for 60 minutes using a shaker,
Complete emulsion was obtained to obtain a white milky silicone emulsion with a silicone content of 33%.

This emulsion was a stable emulsion without floating silicone oil and did not separate even after being left at 70° C. for 3 months. In addition, in the above experimental example, the system pressure was set to 1
．． 5kg/Cn]2G, but shear agitation was performed under the same conditions except that this pressure was changed to 0.7 or 0.3kg/Cm2G. 180 parts by weight of water was added to 120 parts by weight of each of the obtained grease-like substances to prepare an emulsion. The stability of each emulsion thus obtained was investigated and the results were as follows.

Comparative Example 1 When stirring and mixing was carried out under the same conditions as in Example 1 except that the rotation of the disk was changed to a shear rate of 401/sec, a mixture with a viscosity of 10,000 centistokes (25°C) was obtained. Ta.

This was diluted with water (the dilution ratio was the same as in Example 1) to form an emulsion, and when it was left to stand for 3 days, it separated into two layers.
Comparative Example 2 When stirring and mixing was carried out under the same conditions as in Example 1 except that the slit width of the cylindrical container was widened so that no pressurized state was created, a mixture with a viscosity of 100,000 centistokes (25°C) was obtained. Ta.

When this was diluted with water in the same proportion as in Example 1 and left for 3 days, it did not separate into two layers, but some silicone components were liberated on the surface. Comparative Example 3 The proportions of each component used were the same as in Example 1, but kneading was carried out using three rolls as a shear mixing means.
A mixture of 100,000 centistokes (25° C.) was obtained.

This product was diluted with water in the same proportion as in Example 1 and left to stand for 3 days. Although it did not separate into two layers, a portion of the silicone component was liberated on the surface. Comparative Example 4 In Comparative Example 3, a Gaulin homogenizer was used instead of the three rolls for mixing, and a mixture of 200,000 centistokes (25° C.) was obtained.

This product was diluted with water in the same proportion as in Example 1 and left to stand for 3 days. Although it did not separate into two layers, a portion of the silicone component was liberated on the surface. Comparative Example 5 In Comparative Example 3, when mixing was performed using a colloid mill instead of the three rolls, the resulting mixture had a viscosity of 10,000 centistokes (25°C) or less, and
After being left for 4 hours, it was separated into two layers.

Comparative Example 6 In Comparative Example 3, a propeller type stirrer was used instead of the three rolls for mixing, and the resulting mixture had a viscosity of 10,000 centistokes (25°C) and had a silicone component on the surface. It was free and separated into two layers after being left for 3 days.

Example 3 In a mixing device similar to that used in Example 1, 100 parts by weight of dimethylpolysiloxane (50,000 centistokes, 25°C) with hydroxyl groups endblocked at both molecular chain ends, and poly(oxyethylene) were added.
.

. They were quantitatively supplied in a ratio of 5 parts by weight of lauryl ether, 3 parts by weight of poly(oxyethylene)5 lauryl ether, and 7 parts by weight of water. However, the emulsifier was supplied in a liquid state by mixing the two in advance and heating the mixture to 60°C.

Further, the shear rate and the pressure inside the container were the same as in Example 1. As a result, a transparent grease-like substance is obtained from the outlet, and this substance has a viscosity of 10,000 poise or more (at 25°C),
The consistency was 35.

When 180 parts by weight of water was added to 120 parts by weight of this grease-like substance and the mixture was shaken for 60 minutes using a shaker, it was completely converted into an emulsion, and even after being kept at 70°C for 3 months, it remained completely stable and separated. When this was further diluted 100 times with water, no oil spots, oil separation, or creaming were observed even after one week of standing.

Example 4 In a mixing apparatus similar to that used in Example 1, 75 mol% of dimethylsiloxane units and 25% of diphenylsiloxane units were added.
Poly(
oxyethylene),.

They were quantitatively supplied at a ratio of 15 parts by weight of dodecyl ether and 15 parts by weight of water. However, the shear rate and pressure inside the container were the same as in Example 1.

As a result, a cloudy white grease-like substance was obtained from the outlet, and the viscosity of this substance was 500 poise (25°C).

When 170 parts by weight of water was added to 130 parts by weight of this grease-like substance and the mixture was shaken for 30 minutes using a shaker, it was completely formed into an emulsion, which remained completely stable and separated even after being kept at 70°C for 3 months. I didn't wake up.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of a cylindrical container equipped with a shear stirring mechanism, and FIGS. 2A and 2B are schematic cross-sectional views taken along line A--A in FIG. 1, respectively. 1: Cylindrical container, 2: Rotating shaft, 3, 3': Disc, 4: Hole,
5... Supply port, 6... Product outlet, 7... Slit.

Claims (1)

[Claims] 1 100 parts by weight of diorganopolysiloxane, 0 emulsifier
．． 1 to 100 parts by weight and 5 to 20 parts by weight of water are continuously supplied into a cylindrical container equipped with a shear stirring mechanism,
While maintaining the inside of the container under pressure of 0.5 kg/cm^2G or more, perform shear agitation at a shear rate of 501/sec or more, and remove the product from the product outlet of the container at a temperature of 100,000 centipoise (25°C) or more. 1. A method for continuously producing a grease-like aqueous silicone liquid, which comprises continuously taking out a viscous grease-like aqueous silicone liquid. 2. Claim 1, wherein the shearing and stirring mechanism comprises at least three discs arranged coaxially and at regular intervals on a rotating shaft coaxially installed with the cylindrical container. The continuous manufacturing method described.