JPH08253588A - Preparation of organopolysiloxane - Google Patents

Abstract

PURPOSE: To prepare an organopolysiloxane by continuously hydrolyzing and condensing an organosilane in a reaction column into which the organosilane and water are fed, and stirred and mixed by means of vibration along the line of stream in the reaction column. CONSTITUTION: In the preparation of an organopolysiloxane where one or more than one kinds of organosilanes as expressed by the general formula Ra SiX4-a (wherein R: H, same or different monovalent hydrocarbon groups, X: hydrolyzable group, (a): an integer of 0-3) and water are continuously fed into the inlet of a tubular reaction column and the organosilane is hydrolyzed to form an organopolysiloxane in the reaction column and the organopolysiloxane is taken out from the outlet of the reaction column, the organosilane and water are stirred by means of vibration along the direction of stream in the reaction column. Preferably, stirring blades which vibrate reciprocally along the direction of stream of the organosilane and water are installed within the reaction column and the reciprocal vibration of the stirring blade agitates the organosilane and water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to feeding organosilane and water into a reaction tower and vibrating them along the flow direction in the reaction tower to stir and mix them to obtain organosilane. The present invention relates to a method for producing an organopolysiloxane that continuously hydrolyzes / condenses

[0002]

2. Description of the Related Art A method for producing an organopolysiloxane by hydrolysis / condensation of an organosilane has been widely adopted in the silicone production industry. A commonly-used method for hydrolyzing an organosilane is a batch method in which the other is dropped into a reaction vessel containing either water or organosilane. In this batch method, the ratio of water and organosilane is different at the beginning of dropping and at the end of dropping, and it is not possible to always bring water and organosilane into contact with each other at a constant ratio for hydrolysis, so that a uniform quality is obtained. It is difficult to stably manufacture the product. Therefore, it becomes necessary to stabilize the reaction system to facilitate the control of the hydrolysis reaction, and therefore a large amount of an organic solvent is used for the purpose of lowering the reaction concentration and increasing the compatibility between water and organosilane. Often added. However, since the organic solvent to be added, especially the water-soluble alcohol, is discharged into the wastewater generated in the subsequent washing step, there is a problem that the purification treatment of this wastewater becomes large. In addition, the addition of an organic solvent causes a problem that the yield per batch is reduced and the productivity is deteriorated.

In order to solve the problems in performing hydrolysis by the batch method as described above, a continuous hydrolysis method has been proposed in which water and organosilane are brought into contact with each other at a fixed ratio. Examples of such continuous hydrolysis methods include those disclosed in JP-A-58-69890 and JP-A-58-126893.
And Japanese Patent Application Laid-Open No. 2-8223, a method in which organosilane and water are continuously fed into a stirring tank to hydrolyze, for example, Japanese Patent Publication Nos. 29-7898 and 46-33583. As described in the publication, a method of continuously supplying and hydrolyzing organosilane and water or steam in a tubular or tower reactor, for example, Japanese Patent Publication Nos. 48-14149 and 60-2313, As described in JP-A-51-146424, a method in which organosilane and water are continuously fed into a packed column to cause hydrolysis, for example, JP-A-60-172991 is described. As described above, there is a method in which organosilane and water are continuously supplied into the static tubular reactor for hydrolysis. These methods may only supply organosilane and water continuously, but in order to carry out liquid-liquid mixing of organosilane and water, for example, nitrogen bubbling or rotary stirring in a reactor is performed. Has also been done.

However, in any of the above methods, the liquid-liquid mixing of organosilane and water tends to be insufficient especially at the initial stage of the hydrolysis reaction, and for example, hydrolyzability of methyltrichlorosilane or the like, which easily causes condensation and gelation. When continuous hydrolysis is attempted in a system in which a large amount of an organosilane having 3 or more groups is present, it is difficult to control the hydrolysis reaction, and a large amount of high molecular weight organopolysiloxane is likely to be contained. In order to reduce the proportion of the high molecular weight organopolysiloxane, the result is that a large amount of organic solvent must be used as in the batch method, and the molecular weight distribution of the obtained organopolysiloxane is controlled. It has the drawback of being difficult to do. for that reason,
In particular, there is a demand for a hydrolysis method in which good liquid-liquid mixing is performed from the initial stage of the reaction.

The present invention has been made in view of the above circumstances.
The liquid-liquid mixing of the organosilane and water can be improved, and particularly, the liquid-liquid mixing from the beginning of the hydrolysis reaction should be sufficient, for example, a large amount of the organosilane having three or more hydrolyzable groups. It is an object of the present invention to provide a method for producing an organopolysiloxane capable of continuously hydrolyzing an organosilane while controlling the hydrolysis reaction of the existing system.

[0006]

Means for Solving the Problems and Actions The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, the following general formula (1) _Ra SiX _4-a (1) Wherein R is a hydrogen atom or the same or different monovalent hydrocarbon group, X is a hydrolyzable group such as a halogen group or an alkoxy group, and a is an integer of 0 to 3) or 1 or 2
When at least one kind of organosilane and water are fed into the reaction tower and hydrolyzed, the organosilane and water are vibrated along the flow direction in the reaction tower to perform liquid-liquid mixing. By doing so, it is possible to carry out hydrolysis by making liquid-liquid mixing of water and organosilane good from the beginning of the reaction, and a low proportion of organopolysiloxane having a desired molecular weight distribution, particularly a high molecular weight one, and having a number average The inventors have found that an organopolysiloxane having a low molecular weight can be efficiently obtained, and completed the present invention.

That is, the present invention provides the following general formula (1) _Ra SiX _4-a (1) (wherein R is a hydrogen atom or the same or different monovalent hydrocarbon group, and X is a hydrolyzed group). A decomposable group, a is an integer of 0 to 3) and one or more kinds of organosilanes represented by the formula (2) are continuously fed together with water into the reaction column through the inlet of the cylindrical reaction column. In the method for producing an organopolysiloxane, which comprises hydrolyzing the organosilane to produce an organopolysiloxane, and allowing the organopolysiloxane to flow out of the outlet of the reaction tower, the organosilane and water are flowed in the same direction. Provided is a method for producing an organopolysiloxane, which comprises vibrating and stirring along a line.

The present invention will be described in more detail below. The organosilane used in the production method of the present invention is represented by the following general formula (1) R _a SiX _4-a (1)

Here, R in the above formula is a hydrogen atom or a monovalent hydrocarbon group. The monovalent hydrocarbon group has 1 carbon atom.
To 12, particularly 1 to 10, for example, alkyl groups such as methyl group, ethyl group, propyl group, cycloalkyl groups such as cyclohexyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group, etc. And R in one molecule may be the same or different. Also,
X is a hydrolyzable group, and specific examples thereof include a halogen atom such as chlorine, a methoxy group, an ethoxy group and the like, and an alkoxy group having 1 to 10 carbon atoms, particularly 1 to 3 carbon atoms. In the production method of the present invention, such organosilanes may be used alone or in combination of two or more.

In the production method of the present invention, the organosilane and water fed into the reaction vessel as raw materials may be a mixed solution with an organic solvent. The type of the organic solvent is not particularly limited as long as it dissolves in the above-mentioned organosilane and water and is inert to the reaction product. Examples of such an organic solvent include alcohols such as methanol, ethanol, 1-propanol and 2-propanol, ketones such as acetone and methyl ethyl ketone, and aromatic hydrocarbons such as toluene and xylene.

Here, the hydrolysis of the above organosilane of the present invention can be carried out by a known method, and the introduction amount of the organosilane is 0.5 to 20 cm / s at a linear velocity per unit area of the reaction tower, The amount of water introduced may be 0.5 to 20 cm / s at a linear velocity per unit area of the reaction tower. When an organic solvent is used, organosilane: organic solvent = 2: 1 to 4 (volume ratio). ), Water: organic solvent = 200:
It can be set to 1 to 50 (volume ratio). For the hydrolysis, a known catalyst such as an acid or alkali can be used in a usual amount. The reaction temperature is not particularly limited and may be appropriately selected depending on the reaction conditions, but is preferably 0 to 100 ° C. However, the method of controlling the temperature in the reactor in this way largely differs depending on the reaction conditions at that time. For example, when organochlorosilane is used as the organosilane, ≡S in the organochlorosilane
The method of controlling the temperature in the reactor differs depending on the amount of water of hydrolysis for the i-Cl group. That is, since the dehydrochlorination reaction due to the reaction of organochlorosilane and water is an endothermic reaction, the temperature of the reaction product is lowered, but when excess water is fed to the organochlorosilane ≡Si—Cl group, Hydrogen chloride produced as a by-product during the dehydrochlorination reaction is dissolved in water, and the temperature of the reaction product rises due to the heat of dissolution. On the contrary, when a small amount of water is fed into the ≡Si—Cl group, the temperature of the reaction product decreases due to the latent heat of vaporization of hydrogen chloride.
When the reaction heat due to hydrolysis is small, the temperature change in the reactor is almost due to the behavior of this hydrogen chloride. The method of controlling the temperature in the reactor greatly differs. Therefore, in order to control the reaction temperature when the organosilane is hydrolyzed and condensed, it is necessary to control the temperature by heating or cooling the inside of the reaction apparatus in consideration of the above.

Thus, in the production method of the present invention, the above-mentioned organosilane and water are continuously flown into the reaction tower through the inlet of the tubular reaction tower to generate silanol groups by hydrolysis of the organosilane, The condensation of the silanol groups forms a siloxane bond to form an organopolysiloxane, and the organopolysiloxane is continuously discharged from the outlet of the reaction tower. The organosilane and water are mixed in the reaction tower. By vibrating and stirring along the flow direction at 1, the liquid-liquid mixing of the organosilane and water is made better than at the time of supplying into the reaction tower, and the contact ratio of these is adjusted to It is possible to control the hydrolysis of silane from the initial stage of the reaction.

Here, it is preferable that each liquid is continuously fed at a constant flow rate from the lower side of the reaction tower in the same direction by using a pump or the like. Further, for the operation of vibrating the liquid in the reaction tower, it is preferable to dispose a stirring blade that vibrates along the flow direction of the liquid in the reaction tower, and vibrate the liquid by the vibration of the stirring blade to mix the liquid. is there. in this case,
It is desirable to feed each liquid into the reactor while preliminarily vibrating the stirring blade, because the organosilane and water are fed into the reactor and at the same time, they vibrate and mix. In addition,
The number of stirring blades installed in the reactor may be one or plural.

As an apparatus for carrying out such a manufacturing method, an apparatus as shown in FIG. 1 is used.

Here, in FIG. 1, reference numeral 1 denotes a cylindrical reaction tower whose upper and lower end surfaces are closed, and an organosilane feed port 2 and a water feed port 3 are formed at the side and lower end sides of this reaction tower, respectively. An organosilane tank 6 is connected to the silane inlet 2 via a metering pump 4 and a valve 5, and a water tank 9 is connected to the water inlet 3 via a metering pump 7 and a valve 8. And water are fed into the reaction tower 1 through the silane feed port 2 and the water feed port 3, respectively, at a predetermined flow rate. Incidentally, the catalyst,
Other additive components such as an organic solvent are appropriately fed together with the organosilane and / or water.

An organopolysiloxane outlet 10 is provided on the upper end side of the side of the reaction tower 1, and the outlet 10 has a receiving tank 14 equipped with a thermometer 11, a stirrer 12, and a cooler 13. It is connected.

Further, in the reaction section 1a in the reaction tower 1,
The vibration shaft 15 is arranged along the axial direction. The lower end of the vibrating shaft 15 extends to the vicinity of the bottom surface inside the reaction tower 1, and the upper end penetrates the upper end surface of the reaction tower 1 in a liquid-tight manner and projects upward, and is connected to a driving device (not shown) to vibrate. Axis 15
Can vibrate vertically in the reaction tower 1. Further, a stirring blade 16 composed of a spiral blade is attached to the vibrating shaft 15. In this case, the stirring blades 16 are arranged so as to face each other in the flow direction of the organosilane and water, and are vertically vibrated integrally with the vertical vibration of the vibrating shaft 15.
The organosilane and water are vertically agitated.

Here, it is preferable that the vibration distance (amplitude) of the vibration shaft 15 is 2 to 10 mm, especially 2 to 6 mm, and the vibration frequency is 10 to 100 Hz, especially 10 to 60 Hz. Further, the shape of the stirring blade 16 is appropriately selected, and may be a spiral blade, a disk shape, or the like, and the number of the blades may be appropriately selected and may be one, but at least the silane and the water inlet. Place a stirring blade in the vicinity of a few points,
It is preferable that the silane and water flowing into the reaction tower 1 are immediately vibrated so that they can be mixed.

The organopolysiloxane produced by the hydrolysis / condensation reaction in the reaction tower 1 as described above is
As shown in FIG. 1, it is preferable that the liquid is allowed to flow into the receiving tank 14, but stirring or heating may be further performed in this receiving tank. After completion of the predetermined hydrolysis and condensation reaction, by-products such as catalyst and acid are removed by a method such as washing with water, and if necessary, removal of organic solvent, dehydration, filtration, concentration adjustment, etc. are performed. .

As explained above, according to the production method of the present invention, not only the hydrolysis reaction of organosilane can be made continuous, but liquid-liquid mixing from the initial stage of the reaction is sufficient. Therefore, even in a system in which a large amount of an organosilane having three or more hydrolyzable groups is present, it becomes easy to control the hydrolysis reaction. For example, in order to shorten the reaction time, it is possible to reduce the reaction time between water and the organosilane. Even if the feeding speed is increased, it is possible to obtain an organopolysiloxane having a low molecular weight distribution, particularly a low proportion of high molecular weight ones.

[0021]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 An organopolysiloxane was produced using the apparatus shown in FIG. Here, the inner diameter of the reaction tower was 37.5 mm, the tube length was 265 mm, and it was made of glass. The diameter of the spiral stirring blade was 25 mm, and the receiver was a 2 liter separable flask.

First, a mixed solution of trichloromethylsilane: trichlorophenylsilane: dimethyldichlorosilane: toluene = 1: 1: 2: 4 (weight ratio, the same applies hereinafter) as an organosilane mixed solution, and 2- as a water mixed solution. A mixed solution of propanol: acetone: water = 3: 5: 200 was used, and the vibrating shaft had a stirring blade with a frequency of 50 Hz,
It was vibrated so that the amplitude was 5 mm. Next, the organosilane mixed solution was 162 ml / min and the water mixed solution was 13 ml / min.
The flow rate was adjusted by each pump so that the residence time in the reaction tower was 1 ml / min, and the residence time in the reaction tower was 1 minute, and the introduction into the reaction tower was started.

Then, the pressure was kept at normal pressure, and the organosilane was hydrolyzed and condensed in the reaction tower without heat retention or heating. At this time, the temperature inside the reaction tower was 50 ± 10 ° C. at 100 mm from the lower surface of the reaction tower.
The liquid discharged from the outlet of the reaction tower is stored in the receiving tank,
Each pump was stopped when about 2 liters had accumulated. Then, the inside of the receiving tank was adjusted to 65 ± 5 ° C., and the reaction was continued by stirring at 200 rpm for 1 hour. Next, in order to remove the catalyst (hydrogen chloride) and terminate the polymerization, water washing was performed until the washing liquid became neutral. Further, it was dehydrated and filtered to obtain an organopolysiloxane.

The obtained organopolysiloxane was adjusted to a concentration of 50 wt% by adding toluene,
When the viscosity at 25 ° C. was measured with an Ostwald viscometer, it was 29.8 cSt. The molecular weight of this organopolysiloxane (polystyrene-equivalent number average molecular weight,
The same applies hereinafter) was 1320.

Example 2 In Example 1, 54 ml / min of the organosilane mixed solution and 44 ml of the water mixed solution were used.
/ Min, and an organopolysiloxane was obtained in the same manner as in Example 1 except that the residence time in the reaction tower was adjusted to 3 minutes. The temperature 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Example 1.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 and found to be 27.5 cSt.
Met. In addition, its molecular weight was 1,290.

Example 3 In Example 1, the organosilane mixed solution was 27 ml / min, and the water mixed solution was 22 ml.
/ Min, and an organopolysiloxane was obtained in the same manner as in Example 1 except that the residence time in the reaction tower was adjusted to 6 minutes. The temperature 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Example 1.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 and found to be 26.3 cSt.
Met. The molecular weight was 1,260.

Comparative Example 1 An organopolysiloxane was obtained in the same manner as in Example 1 except that vibration was not applied during the feeding of the organosilane mixed solution and the water mixed solution. It was The temperature at 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Example 1.
Was similar to.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 and found to be 61.0 cSt.
Met. The molecular weight was 6240.

[Comparative Example 2] The same reaction tower as in Example 1 was used, except that the vibrating shaft and the stirring blade were replaced by a function that nitrogen gas could be fed into the reaction tower from the lower part at a constant flow rate. In addition to feeding vibrations while feeding the organosilane mixed solution and the water mixed solution into the reaction tower, nitrogen gas was fed from the bottom of the reaction tower at 600 ml / min. An organopolysiloxane was obtained in the same manner as in 1. The temperature 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Example 1.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 to find that it was 50.0 cSt.
Met. The molecular weight was 5,120.

Comparative Example 3 In Comparative Example 2, the organosilane mixed solution was 54 ml / min, and the water mixed solution was 44 ml.
/ Min, and an organopolysiloxane was obtained in the same manner as in Comparative Example 2 except that the residence time in the reaction tower was adjusted to 3 minutes. The temperature 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Comparative Example 2.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 and found to be 31.0 cSt.
Met. The molecular weight was 1340.

[Comparative Example 4] In Comparative Example 2, the organosilane mixed solution was 20 ml / min, and the water mixed solution was 16 ml.
/ Min, and an organopolysiloxane was obtained in the same manner as in Comparative Example 2 except that the residence time in the reaction tower was adjusted to 8 minutes. The temperature 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Comparative Example 2.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 and found to be 29.5 cSt.
Met. The molecular weight was 1,300.

[Comparative Example 5] The same reaction tower as in Example 1 except that a vibrating shaft and a stirring blade were replaced by a rotating shaft and four two flat blades attached to the rotating shaft at intervals of 50 mm. Was used in the same manner as in Example 1 except that the rotating shaft was rotated at 600 rpm instead of giving vibration while feeding the organosilane mixed solution and the water mixed solution into the reaction tower. A polysiloxane was obtained. In addition,
The temperature 100 mm from the lower surface of the reaction tower during the hydrolysis and condensation reaction was the same as in Example 1.

The viscosity of the obtained organopolysiloxane was measured in the same manner as in Example 1 and found to be 51.5 cSt.
Met. The molecular weight was 5,230.

Table 1 shows the liquid-liquid stirring / mixing method in the reaction tower, the residence time in the reaction tower, and the viscosity of the organopolysiloxane obtained by these methods in the production methods of the above Examples and Comparative Examples. Show.

[0041]

[Table 1]

From Table 1, according to the production method of the present invention, liquid-liquid mixing of organosilane and water can be improved and continuous hydrolysis can be achieved even in a system in which a large amount of organosilane, which tends to be condensed and gelled, is present. It is recognized that the production method of the present invention can be suitably carried out by vibrating and mixing the organosilane and water along the flow direction thereof. Further, according to the production method of the present invention, the liquid retention time per unit volume of the reaction column is reduced as compared with the method of the comparative example, and even if the productivity is increased, the liquid-liquid mixing is good, so that the high molecular weight It is also recognized that it is possible to prevent hydrolysis and to carry out continuous hydrolysis.

[0043]

EFFECTS OF THE INVENTION According to the present invention, more efficient hydrolysis is carried out in order to improve the liquid-liquid mixing of organosilane and water and obtain an organopolysiloxane having a molecular weight distribution tailored to the purpose. Thus, organopolysiloxanes having various molecular weight distributions can be easily produced, and particularly organopolysiloxanes having a low proportion of high molecular weight can be efficiently obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of an organopolysiloxane manufacturing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 Reaction Tower 2 Organosilane Inlet 3 Water Inlet 6 Organosilane Tank 9 Water Tank 10 Organopolysiloxane Outlet 15 Vibration Shaft 16 Stirrer

Claims (3)

[Claims] 1. The following general formula (1) R _a SiX _4-a (1) (wherein R is a hydrogen atom or the same or different monovalent hydrocarbon group, and X is a hydrolyzable group. , A is an integer of 0 to 3) and one or more kinds of organosilane represented by the formula (1) are continuously fed together with water into the reaction column through the inlet of the cylindrical reaction column, and the organosilane is introduced in the reaction column. In a method for producing an organopolysiloxane, which comprises hydrolyzing a silane to produce an organopolysiloxane and letting the organopolysiloxane flow out from an outlet of the reaction tower, the organosilane and water are flowed along the flow direction thereof. A method for producing an organopolysiloxane, which comprises vibrating and stirring. 2. A stirring blade capable of reciprocating vibration is disposed in the reaction tower along the flow direction of the organosilane and water.
The manufacturing method according to claim 1, wherein the organosilane and water are vibrated and stirred by reciprocally vibrating the stirring blade. 3. The vibration distance is 2 to 10 mm and the vibration frequency is 10.
The manufacturing method according to claim 1 or 2, which is -100 Hz.