JP3549956B2 - Method for continuous production of organopolysiloxane emulsion - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for continuously producing an organopolysiloxane emulsion, and more particularly, to a method for producing an organopolysiloxane emulsion having excellent homogeneity and storage stability with high productivity.
[0002]
[Prior art]
Organopolysiloxane emulsions are widely used in industry as lubricants, release agents, fiber treatment agents, glass fiber treatment agents, cosmetic bases, polishes, paint additives and the like.
As a method for producing such an organopolysiloxane emulsion, a method of mixing a liquid organopolysiloxane as a raw material, an emulsifier, and water with a mixer having a stirring action such as a Henschel mixer or a kneader mixer, or a shearing action of a colloid mill or the like is used. There is known a method of mixing with a feeding mixer.
However, these methods are inferior in productivity and cannot produce a large amount of homogeneous organopolysiloxane continuously. In particular, a high-viscosity organopolysiloxane could not be emulsified to produce a homogeneous organopolysiloxane emulsion. Therefore, a method of continuously supplying an organopolysiloxane, an emulsifier, and water to a mixing device having a shearing and stirring mechanism to impart a shearing action and emulsify the mixture has been studied. For example, in JP-B-59-51565, a shearing and stirring mechanism in which an organopolysiloxane oil, an emulsifier, and water are provided in a cylindrical container with stirring blades having three or more disks fixed at a fixed interval on a rotating shaft. A method of continuously producing an organopolysiloxane emulsion by continuously supplying the mixture to a mixing device equipped with a stirring blade and performing shear stirring with a stirring blade has been proposed. However, the organopolysiloxane emulsion obtained by this method is inferior in storage stability and has a problem that water separation occurs when left for a long period of time.
[0003]
[Problems to be solved by the invention]
As a method for solving the above-mentioned problems, the present inventors have previously made it possible to continuously mass-produce a homogeneous and highly dispersible organopolysiloxane emulsion using a mixing device equipped with a special shear stirring mechanism. A method has been proposed (see Japanese Patent Application No. 7-9248). As a result of further study, it has been found that, when producing the organopolysiloxane emulsion, the raw material is mixed while blowing an inert gas into the raw material to obtain a more uniform and stable storage. The present inventors have found that an organopolysiloxane emulsion having excellent properties can be obtained, and have reached the present invention.
That is, an object of the present invention is to improve the mixing state of raw materials by a simple method, thereby enabling continuous mass production of an emulsion having excellent homogeneity and storage stability. Is to provide a continuous production method.
[0004]
[Means for solving the problem and its operation]
The present invention relates to a continuous production of an organopolysiloxane emulsion in which a raw material comprising a liquid or raw rubber-like organopolysiloxane, an emulsifier, and water is continuously supplied to a mixing device provided with a shearing and stirring mechanism to give a shearing action to emulsify. The present invention relates to a method for continuously producing an organopolysiloxane emulsion, which comprises emulsifying while blowing an inert gas into the raw material.
[0005]
Hereinafter, the present invention will be described with reference to the apparatus shown in the drawings.
FIG. 1 is a schematic view showing an example of an apparatus for carrying out a method for continuously producing an organopolysiloxane emulsion according to the present invention.
In FIG. 1, a liquid or raw rubber-like organopolysiloxane, an emulsifier and water are continuously supplied from a raw material supply port 2. These raw materials are supplied independently of each other or supplied as a premixed mixture. The inert gas is continuously supplied from the inert gas supply port 15. These are mixed and emulsified in a mixing device 1 provided with a shear stirring mechanism, and are discharged from a discharge port 3 as an organopolysiloxane emulsion.
[0006]
The organopolysiloxane used in the present invention is not particularly limited as long as it is a liquid or raw rubber-like organopolysiloxane at room temperature. A typical example of such an organopolysiloxane is a compound represented by the following average unit formula.
Formula: RaSiO _{(4-a) / 2} (where R is an alkyl group such as a methyl group, an ethyl group, and a propyl group, an aryl group such as a phenyl group and a tolyl group, and one of carbon-bonded hydrogen atoms of these groups. (Part or all of them are substituted or unsubstituted monovalent hydrocarbon groups such as chloromethyl group, 3,3,3-trifluoropropyl group, and a is a number of 1.9 to 2.1.)
Examples of such an organopolysiloxane include dimethylpolysiloxane having both ends of trimethylsiloxy group, dimethylpolysiloxane having both ends of silanol group, dimethylsiloxane having both ends of trimethylsiloxy group and phenylmethylsiloxane copolymer, and dimethyl having both ends of silanol group. Siloxane / phenylmethylsiloxane copolymer, dimethylsiloxane / diphenylsiloxane copolymer with capped trimethylsiloxy groups at both ends, dimethylsiloxane / diphenylsiloxane copolymer with capped silanol groups at both ends, dimethylsiloxane / methyl capped with trimethylsiloxy groups at both ends , 3,3-trifluoropropyl) siloxane copolymer, dimethylsiloxane / methyl (3,3,3-trifluoropropyl) siloxane blocked with silanol groups at both ends Coalescence and the like.
The molecular structure may be linear, partially branched linear, network-like, or the like. Of these, linear organopolysiloxanes are preferably used.
It should be noted that the organopolysiloxane used in the present invention may contain an additive such as silica fine powder, if necessary, as long as the object of the present invention is not impaired.
[0007]
The emulsifier used in the present invention is a component for emulsifying a liquid or raw rubber-like organopolysiloxane in water. Examples of such emulsifiers include nonionic surfactants such as polyoxyalkylene ether, polyoxyalkylene alkylphenol ether, polyoxyalkylene alkyl ester, polyoxyalkylene sorbitan alkyl ester, polypropylene glycol, diethylene glycol, sodium laurate, and stearic acid. Fatty acid salts such as sodium, sodium oleate and sodium linolenate; alkylbenzenesulfonic acids and salts thereof such as hexylbenzenesulfonic acid, octylbenzenesulfonic acid and dodecylbenzenesulfonic acid; octyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide; Alkyl sulfonate, sodium polyoxyethylene alkyl phenyl ether sulfate Anionic surface active agents, alkyl trimethyl ammonium chloride, and a cationic surface active agents such as benzyl ammonium salt. Two or more of these surfactants may be used in combination.
The compounding amount of this component is an amount sufficient to emulsify the liquid or raw rubber-like organopolysiloxane in water, and is usually in the range of 0.1 to 100 parts by weight based on 100 parts by weight of the organopolysiloxane. It is.
[0008]
Tap water, ion-exchanged water and the like are used as the water used in the present invention. The compounding amount of this component is a necessary and sufficient amount to emulsify and disperse the liquid or raw rubber-like organopolysiloxane, and is usually in the range of 1 to 2,000 parts by weight based on 100 parts by weight of the organopolysiloxane. is there.
[0009]
The inert gas used in the present invention promotes the emulsification of the organopolysiloxane emulsion, and is essential for obtaining a homogeneous and highly stable emulsion. Examples of the inert gas include air, nitrogen gas, argon gas, carbon dioxide gas and the like. Among these, air and nitrogen gas are preferred from the viewpoint of safety, availability, and the like. The supply rate of the organopolysiloxane is 0.01 to 100 (Nl / hr) as the ratio of the blowing rate of the inert gas (Nl / hr) to the supply rate of the liquid or raw rubber-like organopolysiloxane (kg / hr). ) / (Kg / hr), preferably 0.1 to 10 (Nl / hr) / (kg / hr). If this ratio is less than 0.01 (Nl / hr) / (kg / hr), it will not be possible to obtain a homogeneous and highly stable emulsion. On the other hand, if it exceeds 100 (Nl / hr) / (kg / hr), the emulsion will pass without being sufficiently sheared and agitated by the shearing agitation mechanism, and the unemulsified organopolysiloxane will be contained in the emulsion.
It is not clear why these inert gases promote emulsification and stabilize the emulsion. Generally, when producing an emulsion, the inclusion of air bubbles has been considered to adversely affect the stability of the emulsion. This is because the mixed air bubbles not only adsorb the emulsion on its interface and consume it, but also adsorb and float the emulsified droplets. For this reason, it has been considered that air bubbles must be avoided when producing an emulsion. However, when an emulsion is continuously produced by applying a shearing action, the continuously supplied inert gas promotes the stirring and mixing of the raw materials when the organopolysiloxane and water pass through the shearing and stirring mechanism. It is thought that the emulsifier may be sufficiently adsorbed on the surface of the organopolysiloxane droplets dispersed in water.
[0010]
The type of the mixing device having a shear stirring mechanism used in the present invention is not particularly limited as long as it is a device having a shear stirring mechanism. Among them, a mixing device provided with a shear stirring mechanism proposed by the present inventors in Japanese Patent Application No. 7-9248 is preferably used. Explaining the outline of this mixing device, this mixing device has a turbine rotor having blades that are obliquely inclined with respect to a radial direction in an axial direction in a casing between a supply port and a discharge port of a cylindrical casing. A first-stage shear-stirring mechanism comprising a stator disposed on the outer periphery of the rotor, a turbine-type rotor having blades spirally curved in the axial direction, and a second stage comprising a stator disposed on the outer periphery of the rotor. This is a mixing device in which at least two sets of a shearing and stirring mechanism at the stage are arranged in series in the raw material supply direction and via a relaxation zone between the mechanisms. One example is shown in FIGS. 1 to 5 described later.
In FIG. 1, reference numeral 1 denotes a cylindrical casing which is placed horizontally in the axial direction, and a supply port 2 for a raw material is provided at one end, and a discharge port 3 for discharging the kneaded emulsion is provided at the other end. Has been. The inert gas supply port 15 is provided downstream of the material supply port 2. The rotating shaft 4 is inserted into the cylindrical casing 1 at the axis. In the figure, the rotating shaft 4 is inserted from the left end side of the cylindrical casing 1, extends to near the supply port 2 at the right end, and is driven by a motor (not shown) outside the casing. .
Rotors 5 and 7 are fixed to the rotation shaft 4 at an end portion and an intermediate portion on the supply port 2 side, respectively. Further, the inner peripheral wall of the cylindrical casing 1 is surrounded by the outer peripheral sides of the rotors 5 and 7. The stators 6 and 8 fixed to are provided through small gaps. In this manner, the rotor 5 and the stator 6 constitute a first-stage shear-stirring mechanism 9, the rotor 7 and the stator 8 constitute a second-stage shear-stirring mechanism 10, and A relaxation space 11 having a relatively large volume is provided between the eye shear stirring mechanism 9 and the second-stage shear stirring mechanism 10.
[0011]
The rotor 5 constituting the first-stage shear stirring mechanism 9 is configured as a turbine-type rotor, and a plurality of blades 5a extend radially and conically toward the supply port 2 side (see FIGS. 2 and 5). . Each of the plurality of blades 5a is substantially parallel to the axial direction in a plan view, but is attached to the axial direction in a side view and attached to the radial direction in an axial view. Has been.
[0012]
On the other hand, the stator 6 constituting the shear stirring mechanism 9 has a substantially cone-shaped inner peripheral surface, and has a concave groove 6b extending in the axial direction on the inner peripheral surface. The rotor 5 is inserted inside the cone-shaped stator 6 with a small gap between the rotor 5 and the outer peripheral end of the blade 5a, and the minimum gap is set to 2 mm or less, more preferably 1 mm or less. (See FIG. 2).
In addition, the rotor 7 constituting the second-stage shear stirring mechanism 10 is configured as a turbine-type rotor in the same manner as described above, but is sheared at a point that a plurality of blades 7a are formed spirally in the axial direction. It is different from the stirring mechanism 9. Moreover, the radial height of the blade 7a is shorter than the blade 5a of the rotor 5 of the shearing and stirring mechanism 9 (see FIG. 3).
[0013]
The stator 8 of the shear stirring mechanism 10 is formed substantially in a cone shape, and has a plurality of linear grooves 8b extending in the axial direction on the inner peripheral surface. The rotor 7 is inserted into the stator 8 with a small gap between the rotor 7 and the outer peripheral surface of the spiral blade 7a. As shown in FIG. 1, the shape of this gap is formed so as to gradually narrow in a wedge shape from the upstream side to the downstream side, and the minimum gap is set to 2 mm or less, more preferably 1 mm or less.
On the downstream end surface (surface perpendicular to the axial direction) of the rotor 7 of the second-stage shear stirring mechanism 10, a large number of saw blade-shaped projections 12 are provided so as to project rearward, and are provided on the stator portion 13 side. A large number of the saw blade-shaped projections 13a are alternately arranged in the radial direction with small gaps. Moreover, the arrangement of the projections 12 and 13a is helically curved and radial in the radial direction (see FIGS. 1 and 4).
[0014]
In the method for producing an organopolysiloxane emulsion according to the present invention, at least the liquid or raw rubber is supplied to the raw material supply port 2 of the mixing apparatus in which at least the first-stage shear-stirring mechanism 9 and the second-stage shear-stirring mechanism 10 are arranged in series. The three types of raw materials comprising organopolysiloxane, emulsifier, and water are supplied independently of each other, or supplied as a pre-mixed mixture thereof. The inert gas is supplied from the supply port 15 independently of these three types of raw materials.
First, the first-stage shearing and stirring mechanism 9 mainly performs a suction action of the raw material because the blades 5a of the rotor 5 are radially inclined obliquely in the radial direction when viewed in the axial direction. By applying a shearing action (cutting action) to the three types of raw materials between the outer peripheral surface of the stator and the inner wall of the stator 6, the liquid or raw rubber-like organopolysiloxane is atomized and emulsified to perform initial emulsification. Here, the shearing action is to give a shearing rate of 100 / sec or more.
The mixture initially emulsified by the first-stage shear stirring mechanism 9 is supplied to the relaxation space 11 after being squeezed by the intermediate flow path 14, and once released from the compressed state in the relaxation space 11, It is sucked into the second-stage shear stirring mechanism 10.
In the second-stage shearing and stirring mechanism 10, the crushing action is performed by the main body mechanism portion of the spiral blade 7 a of the rotor 7 and the stator 8, and the saw blade-like projection 12 and the stator portion 13 provided on the downstream end face are further provided. The grinding action is performed by the shearing action based on the engagement with the saw blade-shaped projection 13a.
The mixture introduced into the space surrounded by the blades 7a of the rotor 7 and the inner wall surface of the stator 8 undergoes a phase inversion or rotation action by the action of the blades 7a that are obliquely curved in the axial direction, and changes the phase in the radial direction. Change in the circumferential direction. The mixture is subjected to a reversing or rotating action, and at the same time, a shearing action (cutting action) is applied between the outer peripheral face of the blade 7a and the inner peripheral face of the stator 8 provided with the plurality of linear grooves 8b, so that the mixture is finer and more uniform. Is emulsified. Here, the shearing action is such that a shearing rate of 100 / sec or more is applied as described above.
[0015]
The mixture emulsified in this way is further finely emulsified in the grinding portion of the sawtooth-shaped projections 12 and 13a on the downstream side to form a homogenous organopolysiloxane emulsion having high dispersibility. Is discharged from the discharge port 3.
[0016]
The organopolysiloxane emulsion obtained by the continuous production method of the present invention is usually obtained as an emulsion in which organopolysiloxane is emulsified and dispersed in water. The organopolysiloxane emulsion obtained by the continuous production method of the present invention usually has an average particle diameter in the range of 0.1 to 50 µm.
[0017]
The organopolysiloxane emulsion of the present invention obtained as described above is used as it is or by diluting it with water to prepare an organopolysiloxane emulsion suitable for each application, and a lubricant, a release agent, It is used as a fiber treatment agent, glass fiber treatment agent, cosmetic oil agent, polishing agent, defoaming agent, paint additive and the like.
[0018]
Embodiment 1
Using the mixing apparatus 1 shown in FIG. 1, 100 parts by weight of dimethylpolysiloxane having a capped trimethylsiloxy group at both ends (viscosity 300,000 centipoise at 25 ° C.), 9.0 parts by weight of polyoxyethylene lauryl ether, and cetyl 3.4 parts by weight of trimethylammonium chloride and 3.6 parts by weight of ion-exchanged water are continuously supplied, and compressed air is supplied from the inert gas supply port 15 to the siloxane at a ratio of 1.0 (Nl). / Hr) / (kg / hr), and the mixture was continuously subjected to shear stirring operation to produce an emulsion of dimethylpolysiloxane.
Here, the rotation speed of the rotating shaft of the mixing apparatus was set to 4,200 rpm, and the minimum interval of the shearing and stirring mechanism was set to 0.2 mm. The pressure at the raw material supply port 2 was 0.4 kg / cm ² G, and the discharge pressure of the emulsion at the discharge port 4 was 0.0 kg / cm ² G.
The emulsion of dimethylpolysiloxane obtained by the above-mentioned shear stirring operation was a translucent paste-like emulsion in which dimethylpolysiloxane was uniformly dispersed and emulsified in water. When the average particle size of the obtained dimethylpolysiloxane emulsion was measured, it was 0.3 μm. The emulsion prepared by adding 71 parts by weight of water to 100 parts by weight of the obtained paste emulsion is very stable without separation of dimethylpolysiloxane and water even when stored at room temperature for 6 months or more. It was something.
[0019]
Embodiment 2
A device in which two mixing devices shown in FIG. 1 are connected in series is used, and raw rubber-like two-terminal trimethylsiloxy group-blocked dimethylpolysiloxane (having a viscosity of 1050 at 25 ° C.) is supplied to the raw material supply port 2 of the first mixing device. A mixture of 42 parts by weight of 10,000 centistokes) and 58 parts by weight of isoparaffin (viscosity of 2.4 centistokes at 40 ° C., specific gravity of 0.79) was homogeneously dissolved (viscosity at 25 ° C. of this mixture was 100,000 centistokes). 100 parts by weight, 10 parts by weight of polyoxyethylene lauryl ether and 5.0 parts by weight of ion-exchanged water are continuously supplied, and compressed air is supplied from an inert gas supply port 15 to the above-mentioned ratio of the supply amount of dimethylpolysiloxane. , 1.0 (Nl / hr) / (kg / hr), followed by uniform stirring and mixing. From the discharge port 3 of the mixing device was discharged as a translucent pasty emulsion (dimethylpolysiloxane content 36.5 wt%). Subsequently, 22.4 parts by weight of the paste emulsion and 82.4 parts by weight of water for dilution (corresponding to 71 parts by weight with respect to 100 parts by weight of the paste emulsion discharged from the first mixing device) were added in two units. The raw material was continuously supplied to the raw material supply port 2 of the eye mixing device and subjected to a uniform shearing operation to produce a dimethylpolysiloxane raw rubber emulsion (dimethylpolysiloxane content: 21.3% by weight).
Here, the rotation speed of the rotary shaft 4 of the first mixing device was set to 4,200 rpm, and the minimum gap between the first and second stages of the shear stirring mechanisms 9 and 10 was set to 0.2 mm. The shear rates of the first and second stage shearing and stirring mechanisms 9 and 10 were set to 93,000 / sec and 70,000 / sec, respectively. The pressure in the raw material supply port 2 and discharge port 3 of the mixing device of the first unit above were respectively 0.4 kg / cm ² G and 0.0 kg / cm ² G.
Further, the rotation speed of the rotating shaft 4 of the second mixing device was set to 3,000 rpm, and the minimum gap between the first and second stage shearing and stirring mechanisms 9 and 10 was set to 0.2 mm, respectively. The shear rates of the first and second stages of the shear stirring mechanisms 9 and 10 were set to 66,000 / sec and 50,000 / sec, respectively. The pressures at the raw material supply port 2 and the discharge port 3 of the second mixing apparatus were 0.0 kg / cm ² G and 0.0 kg / cm ² G, respectively.
The emulsion of dimethylpolysiloxane obtained by the above-mentioned shearing and stirring operation was a milky white emulsion in which raw rubber-like dimethylpolysiloxane was uniformly dispersed and emulsified in water, and had an average particle diameter of 0.4 μm. This dimethylpolysiloxane emulsion was very stable without leaving dimethylpolysiloxane and water even when left at room temperature for 10 months.
[0020]
[Comparative Example 1]
In Example 1, dimethylpolysiloxane, an emulsifier, and water were mixed in the same manner as in Example 1 except that blowing of compressed air was stopped to obtain a paste emulsion. The measured average particle size of this emulsion was 0.4 μm. An emulsion prepared by adding 71 parts by weight of water to 100 parts by weight of this paste-like emulsion was allowed to stand at room temperature for one day, after which dimethylpolysiloxane and water were separated.
[0021]
【The invention's effect】
In the method for producing an organopolysiloxane emulsion of the present invention, a raw material composed of a liquid or raw rubber-like organopolysiloxane, an emulsifier, and water is continuously supplied to a mixing device equipped with a shearing and stirring mechanism to emulsify by giving a shearing action. A method for continuously producing an organopolysiloxane emulsion, wherein the emulsification is performed while continuously blowing an inert gas into the raw material, wherein the homogeneity and the storage stability are maintained. It is characterized in that an organopolysiloxane emulsion excellent in water content can be continuously mass-produced.
[Brief description of the drawings]
FIG. 1 is a schematic view of a mixing apparatus for performing a method for continuously producing an organopolysiloxane emulsion according to the present invention.
FIG. 2 is a sectional view taken along the line AA of FIG. 1;
FIG. 3 is a sectional view taken along line BB of FIG. 1;
FIG. 4 is a sectional view taken along the line CC of FIG. 1;
FIG. 5 is a perspective view of a rotor provided in a first-stage shear stirring mechanism of the apparatus of FIG. 1;
[Explanation of symbols]
Reference Signs List 1 cylindrical casing 2 supply port 3 discharge port 4 rotating shaft 5, 7 rotor (turbine type rotor)
5a, 7a Blade 6, 8 Stator 8b Straight groove 9, 10 Shear stirring mechanism 11 Relaxation space (relaxation area)
12 Serrated Blade 13 Stator 13a Serrated Blade 14 Channel 15 Inert Gas Supply Port

Claims (4)

A method for continuously producing an organopolysiloxane emulsion in which a raw material composed of a liquid or raw rubber-like organopolysiloxane, an emulsifier, and water is continuously supplied to a mixing device provided with a shearing and stirring mechanism to give a shearing action and emulsify. A method for continuously producing an organopolysiloxane emulsion, wherein emulsification is performed while blowing an inert gas into a raw material. A mixing device having a shearing and stirring mechanism is provided in a casing between a supply port and a discharge port of a cylindrical casing, a turbine-type rotor having blades inclined obliquely to a radial direction in an axial direction, and a rotor outer periphery. , A first stage shearing and stirring mechanism comprising a stator disposed in the first stage, a turbine type rotor having blades spirally curved in the axial direction, and a second stage shearing comprising a stator disposed on the outer periphery of the rotor. The method according to claim 1, wherein the mixing device is a mixing device in which at least two sets with a stirring mechanism are arranged in series in the raw material supply direction and via a relaxation zone between the mechanisms. The ratio of the blowing amount of the inert gas (Nl / hr) to the supply amount of the liquid or raw rubber-like organopolysiloxane (kg / hr) is 0.01 to 100 (Nl / hr) / (kg / hr). A method for continuously producing an organopolysiloxane emulsion according to claim 1. The method for continuously producing an organopolysiloxane emulsion according to claim 1, wherein the inert gas is air.

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