JPH0543694A - Continuous production of siloxane polymer - Google Patents

Abstract

PURPOSE:To continuously produce a siloxane polymer using a heat-decomposable basic catalyst as the polymn. catalyst to improve the properties thereof, the economy and the productivity. CONSTITUTION:A process for producing a siloxane polymer comprises the step (a) of introducing a cyclopolysiloxane preheated, a heat-decomposable basic catalyst and part of a chain terminator to be used into a static mixer 1 to premix them, the step (b) of passing the resulting premixture through a static mixer 3 capable of giving such a sufficient residence time as to complete the polymn. of the polysiloxane kept under pressure while introducing the rest of the chain terminator into the initial part of the reaction zone of the static mixer 3, and the step (c) of passing the reaction mixture through a static mixer 6 capable of heating the reaction mixture at a temp. of at least the decomposition temp. of the heat-decomposable basic catalyst and giving such a sufficient residence time as to completely decompose the heat- decomposable basic catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous process for producing a siloxane polymer, and more particularly to a continuous process for producing a siloxane polymer using a pyrolytic base catalyst.

[0002]

2. Description of the Prior Art Hitherto, siloxane polymers and copolymers have generally been manufactured by a batch polymerization method using an acid or a base as a catalyst.

That is, in this batch-type polymerization method, a siloxane monomer, for example, dimethyltetramer (octamethylcyclotetrapolysiloxane) is inserted into a polymerization vessel and dried by distilling or refluxing siloxane vapor in a molecular sieve column. Next, after heating the dry siloxane monomer to about 155 ° C., potassium hydroxide, for example, as a polymerization catalyst is added in the form of a pulverized slurry of methyltetramer, and the polymerization is allowed to proceed with stirring. As the polymerization reaction progresses, the monomer is added to the end of the polymer chain and gradually forms a long polymer. When polymerization proceeds in this way and a siloxane polymer having a desired viscosity is obtained, for example, water is added as a chain terminator to terminate the polymerization reaction. Thereafter, the potassium hydroxide added as a polymerization catalyst is neutralized with a neutralizing agent such as phosphoric acid,
Finally, the silanol-terminated siloxane polymer is obtained by separating the unreacted monomer by distillation.

However, in the above batch type polymerization method,
There is a problem that the characteristics of the product vary from batch to batch. Therefore, as a new method replacing the batch polymerization method, the following continuous production method has been proposed.

For example, in JP-A-56-11927, an alkali metal hydroxide or a silanolated product of cyclopolysiloxane is mixed as a polymerization catalyst, and the mixture is extruded using a static mixer. In this method, a chain terminating agent such as water is introduced into the polymerization reaction region of the system, and after sufficient residence time to complete the polymerization, the polymerization catalyst is neutralized to continuously produce a siloxane polymer. It is disclosed.

[0006]

By the way, with the recent widespread application of siloxane polymers to the field of electric and electronic materials, the alkali metal contained in the siloxane polymers causes a problem of electrical failure. This is because the alkali metal salt, which is a neutralization product of the polymerization catalyst used in the above method, cannot be completely separated and removed from the siloxane polymer and remains partially.

To solve this problem, a method of using a thermal decomposition type base catalyst as a polymerization catalyst, which is known as one of batch polymerization methods, is effective.

However, in this method, the viscosity of the reaction product increases rapidly due to the addition of the thermal decomposition type base catalyst, so that a helical ribbon type stirrer having a strong stirring force must be used, and many of them are used to drive this. In addition to requiring electric power energy, there is a problem that a series of steps from polymerization to decomposition of catalyst and removal of unreacted monomer takes an extremely long time and productivity is low. In addition, since it is a batch system, there is a problem that the characteristics of the product have variations as described above.

The present invention has been made to address such a problem, and uses a thermal decomposition type base catalyst as a polymerization catalyst and a siloxane having good characteristics by a continuous production method which does not cause variations in characteristics. An object of the present invention is to provide a continuous method for producing a siloxane polymer, which is capable of producing a polymer stably, economically and with good productivity.

[0010]

The continuous method for producing a siloxane polymer of the present invention comprises: (a) preheated cyclopolysiloxane, a thermal decomposition type base catalyst, and a total amount of a part of chain stopper. And (b) passing the premix through a static mixer maintained under pressure to provide a residence time sufficient to complete the polymerization of the cyclopolysiloxane, and at the beginning of the reaction zone of the static mixer. Introducing the remaining chain terminator into the portion of (c), (c) heating the reaction mixture to a temperature above the decomposition temperature of the thermal decomposition type base catalyst, and sufficient to completely decompose the thermal decomposition type base catalyst. It is characterized in that it is passed through a static mixer that gives different residence times.

As the monomer used as a starting material in the present invention, any cyclopolysiloxane can be used, but normally, a hexamer dimethylcyclosiloxane is used, and a tetramer dimethylcyclosiloxane is used. Is preferred. It is desirable to use a sufficiently dried monomer (water content of 20 ppm or less) as the monomer, and if necessary, degassing treatment may be performed before preliminary heating to dry the monomer. Preheating of the monomer is carried out in order to promptly initiate the ring-opening polymerization of the monomer in the next step, and the polymerization temperature is usually 80-
The temperature is raised to 100 ° C, preferably 85-95 ° C. In addition,
The amount of the monomer supplied is appropriately determined depending on the polymerization temperature and the catalyst addition amount that determine the reaction rate of the polymerization, the degree of polymerization of the polymer to be obtained, the volume of a static mixer that is a polymerization vessel, and the like.

The thermal decomposition type base catalyst used in the present invention includes tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and tetraalkylammonium silanolate obtained by silanolating these. Examples thereof include tetramethylammonium silanolate, which has good compatibility with cyclopolysiloxane. This tetramethylammonium silanolate is thermally decomposed by heating at 130 to 160 ° C. for about 3 hours as shown in the following formula (I).

(CH ₃ ) ₄ NO-[(CH ₃ ) ₂ SiO] _m -N (CH ₃ ) ₄ → 2 (CH ₃ ) ₃ N + CH ₃ -[(CH ₃ ) ₂ SiO] _m -CH ₃ ... (I) The amount of the thermally decomposable base catalyst introduced is appropriately in the range of 50 to 300 ppm with respect to the cyclopolysiloxane as the monomer.

Further, as the chain terminator used in the present invention, water, a low molecular weight triorganosilyldiorganopolysiloxane having a monovalent hydrocarbon group with an organic group of 2 to 20 silicon atoms, and this low molecular weight triorgano Examples of the silyldiorganopolysiloxane include those whose organic group contains an aliphatic unsaturated group, and these are selected according to the end use of the siloxane polymer as a product. That is, the properties of the obtained siloxane polymer differ depending on the chain terminator used. For example, when water is used, a silanol-terminated diorganosiloxane as shown by the formula (II) is obtained as a polymerization product. When a low molecular weight triorganosilyldiorganopolysiloxane having a monovalent hydrocarbon group and 2 to 20 silicon atoms is used, a triorganosilyl-terminated diorganopolysiloxane represented by the formula (III) is obtained. can get. Furthermore, when the low molecular weight triorganosilyldiorganopolysiloxane whose organic group contains an aliphatic unsaturated group is used, a triorganosilyl-terminated diorgano group containing an aliphatic unsaturated group as shown in formula (IV) is used. An organopolysiloxane is obtained.

[0015]

[Chemical 1]

[0016]

[Chemical 2]

[0017]

[Chemical 3]

(Wherein R represents a lower saturated or unsaturated alkyl or aryl group such as methyl, ethyl, propyl, vinyl or phenyl, and n is about 50 to 20.
00. ) Specifically, examples of the low molecular weight triorganosilyldiorganopolysiloxane having a monovalent hydrocarbon group having 2 to 20 silicon atoms as an organic group include trimethylsilyldimethylpolysiloxane and the like. Examples of the triorganosilyldimethylpolysiloxane having a molecular weight whose organic group contains an aliphatic unsaturated group include vinyldimethylsilyldimethylpolysiloxane.

The total amount of the chain terminator introduced defines the average molecular weight of the resulting siloxane polymer. Therefore, the introduction amount of the chain stopper is determined according to the average molecular weight of the desired siloxane polymer. In the present invention,
This chain terminator is introduced separately during premixing and during the polymerization reaction. The chain terminator introduced at the time of pre-mixing has the function of the original chain terminator and the function of adjusting the viscosity of the starting component at the time of introduction into the static mixer in the next step. Introducing a part of the total amount of the chain terminator introduced is an essential condition for achieving the continuous production of the siloxane polymer aimed at by the present invention. Therefore, the amount of pre-mixing introduced is such that the amount necessary for adjusting the viscosity is introduced, and the amount required for chain termination is finally determined together with the amount introduced into the static mixer for the subsequent polymerization. Will be introduced. In particular,
When water is used as a chain terminator, introduction of a total amount of 100 to 4,000 ppm, based on the monomeric cyclopolysiloxane, polymerizes a silanol-terminated diorganosiloxane having a viscosity of 100 to 1,000,000 centipoise at 25 ° C.
Among them, introduction in the range of 50 to 300 ppm is preferable during premixing. When a low molecular weight triorganosilyldiorganopolysiloxane having 2 to 20 silicon atoms and an organic group having a monovalent hydrocarbon group is used as a chain terminator, the terminal triorganosilyl group is added to the monomer cyclopolysiloxane. It is necessary to adjust the concentration, but the total amount is 300-20,000 ppm
By the introduction of the above, a triorganosilyl-terminated diorganosiloxane having a viscosity of 100 to 1,000,000 centipoise at 25 ° C. is polymerized and produced, of which 50 to 500 p
Introduction in the pm range is preferred. Furthermore, when the low molecular weight triorganosilyldiorganopolysiloxane whose organic group contains an aliphatic unsaturated group is used as the chain terminator, it is necessary to adjust the concentration of the triorganosilyl group at the terminal, as described above. Introducing a total amount of 750 to 50,000 ppm with respect to the monomeric cyclopolysiloxane,
A triorganosilyl-terminated diorganosiloxane having a viscosity at 100 DEG C. of 1 to 1,000,000 centipoise is polymerized, and it is preferable to introduce the triorganosilyl-terminated diorganosiloxane in the range of 300 to 20,000 ppm during premixing.

Next, the method of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an example of an apparatus for continuously producing a siloxane polymer used in the practice of the present invention.

In the present invention, first, a cyclopolysiloxane as a starting material, for example, octamethylcyclotetrasiloxane monomer as a tetrameric dimethyl cyclic siloxane monomer, can be discharged at a constant flow rate, for example, a diaphragm type. It is continuously and quantitatively introduced into the in-line mixer for premixing, for example, the static mixer 1 via the monomer supply line A by the positive displacement pump P ₁ . The diaphragm type constant capacity pump has a high discharge pressure,
Moreover, since there is no sealing surface between the drive unit and the drive unit, it is preferably used in this case. A monomer preheater 2 is inserted in the monomer supply line A, and cyclopolysiloxane is used in the monomer preheater 2 at a polymerization temperature, for example, 80 to 100 ° C.
It is preheated to a certain degree and introduced into the static mixer 1. For the monomer preheating group 2, for example, a heat exchanger is used.

On the other hand, a thermal decomposition type base catalyst such as tetramethylammonium silanolate, and a chain stopper such as water as a part of the total amount introduced can be discharged at a constant flow rate like the monomer, respectively. Is continuously and quantitatively introduced into the static mixer 1 through the catalyst supply line B and the chain terminator supply line C by, for example, the plunger type constant volume pumps P ₂ and P ₃ , and is mixed with the preheated monomer. .. The plunger type constant capacity pump can be supplied with high accuracy with a small flow rate, and is therefore preferably used in this case. Besides, a gear type constant capacity pump and the like are also preferably used.

, These monomers, a thermal decomposition type base catalyst,
The purpose of this is to mix the chain terminator so that it has a uniform composition, adjust the viscosity to an appropriate level, and send it out to the static mixer 3 for subsequent polymerization. This static mixer 1
Although a dynamic mixer can be used instead of the above, the use of a static mixer is more preferable from the viewpoint of handleability and the like. As the dynamic mixer, for example, an inline mixer having a 2- to 3-stage paddle type agitator and capable of high speed dispersion at a rotation speed of 800 to 2,000 rpm is used. In these mixers, the introduction of the thermal decomposition type base catalyst and the chain stopper is performed on the mixer so that the chain stopper does not reduce the activity of the thermal decomposition type base catalyst or cause the introduction nozzle to be clogged. It is desirable to introduce them so that they do not come into contact with each other through addition ports provided at different positions. Further, in the case of the static mixer 1, it is further desirable that the tip of the nozzle is located at the central portion of the pipe body that constitutes the static mixer 1, and this can prevent the mixture on the pipe wall from staying.

In this way, for example, the static mixer 1
The premixture of the monomer, the pyrolytic base catalyst, and the chain terminator mixed in 1. is subjected to a residence time of, for example, 4 to 5 minutes, and then a static mixer 3 for performing main polymerization, for example, L / D 50 to 50. A static mixer is installed in about 100 pipes and is introduced into a mixer having a jacket in which a heat medium for temperature control circulates. This static mixer 3
Is kept under a pressure of, for example, 10 to 20 kg / cm ² to suppress the decomposition of the thermal decomposition type base catalyst, while maintaining a polymerization temperature, for example, a substantially constant internal temperature of 80 to 100 ° C. to the pre-mixture. On the other hand, a residence time sufficient to complete the polymerization of the monomer is uniformly provided. In the static mixer, the pre-mixture introduced into the static mixer 3 has a viscosity increased due to the polymerization of the monomer due to the catalytic action of the uniformly dispersed thermal decomposition type base catalyst. It is desirable to use one having a high number of divided layers, for example, an SMX type or SMV type static mixer manufactured by Sulzer Co. is preferably used. Then, in the first part of the reaction zone of this static mixer, a chain terminator is introduced which defines the degree of polymerization of the monomers. The introduction may be done once, but in order to prevent pressure loss, 2-3
It is desirable to introduce it in a batch. In the example shown in the figure,
Through a chain stopper supply line D and a chain stopper supply line E downstream thereof, a supply pump capable of discharging at a constant flow rate, for example, plunger type constant volume pumps P ₄ , P ₅
Will be introduced in two parts. It should be noted that the introduction point of the chain terminator is preferably at the central portion of the tubular body constituting the static mixer 3 as in the case of premixing, and this can prevent the mixture from staying on the tubular wall. ..

While passing through the static mixer 3 in this manner, the cyclopolysiloxane monomer polymerized to a desired degree of polymerization is mixed with the unreacted monomer and the thermal decomposition type base catalyst, etc. After returning to normal pressure by the pressure control valve 4, the decomposition temperature of the thermal decomposition type base catalyst, for example, the decomposition temperature of the thermal decomposition type base catalyst, is reduced by a heating device 5 such as a heat exchanger for the purpose of deactivating the activity of the thermal decomposition type base catalyst. After being heated at 130 to 160 ° C., it is then introduced into a temperature-controllable static mixer 6 which gives a residence time sufficient for the pyrolytic base catalyst to completely decompose. As the static mixer 6 used here, the same kind as that used for the polymerization can be used. While the reaction mixture introduced is passing through the static mixer 6, a temperature higher than the decomposition temperature of the thermal decomposition type base catalyst, for example, 160
It is heated at ~ 200 ° C and the pyrolytic base catalyst is completely decomposed and discharged.

The reaction mixture leaving the static mixer 6 is subsequently heated in a heating device 7 such as a heat exchanger at a temperature not lower than the boiling point of the unreacted monomer, for example, 200 to 220 ° C.
For example, it is introduced into a gas-liquid separator 8 which maintains the system pressure at 2 to 10 mmHg and separated into unreacted monomer and a desired polymer product. Then, the unreacted monomer and polymer product separated here are respectively fed to the monomer discharge line F.
The polymer is discharged from the polymer discharge line G to the outside by being cooled by cooling devices 9 and 10 such as heat exchangers inserted in both lines.

[0028]

In the continuous production method of the siloxane polymer of the present invention, during the premixing of the monomer and the thermal decomposition type base catalyst,
Since a part of the chain terminator is also added and mixed at the same time, it becomes possible to create a nearly ideal continuous mixed flow in the static mixer for the subsequent polymerization, using the pyrolytic base catalyst, and the cyclodecomposition type catalyst. The polysiloxane can be successfully polymerized to continuously produce a siloxane polymer having a desired uniform degree of polymerization.

Depending on the chain terminator used, silanol-terminated diorganosiloxane, triorganosilyl-terminated diorganopolysiloxane, aliphatic unsaturated group-containing triorganosilyl-terminated diorganopolysiloxane,
It is possible to produce a siloxane polymer that can be used in a wide variety of applications.

[0030]

EXAMPLES Examples will be described below.

Example 1 An octamethylcyclotetrasiloxane monomer was polymerized under the conditions shown in Table 1 to obtain a silanol terminated polymer.

That is, octamethylcyclotetrasiloxane monomer having a water content of 20 ppm preheated to about 90 ° C. by a monomer preheater together with tetramethylammonium silanolate (KOH equivalent 100 ppm) and water 90 ppm was used as shown in Table 1.
Under the conditions shown in, a small static mixer (inner diameter 6 inches, length 4.7 m, L / D = 1.0 SMX type static mixer interpolator, jacket with circulating heat transfer oil for temperature control on the outer circumference) And) were continuously and quantitatively introduced and mixed.

Next, this mixture was heated at a temperature of 100 ° C. and a pressure of 1
Polymerization static mixer controlled to 3.0 kg / cm ² (8 inch inner diameter, 4.7 m length, L / D = 1.0 SMX static mixer made by Sulzer Co., Ltd., with heat transfer oil for temperature control on the outer circumference. While having a circulating jacket), 220 ppm of water with respect to the monomer was introduced by a plunger type constant volume pump near the inlet of this static mixer for polymerization.

Then, the reaction mixture discharged from the static mixer for polymerization was returned to normal pressure by a pressure control valve, heated to about 140 ° C. by a heat exchanger, and then controlled at a temperature of 180 ° C. Static mixer (inner diameter 10 inches, length 4.7m,
L / D = 1.0 SMX static mixer made by Sulzer Co., Ltd. was inserted, and the outer circumference was equipped with a jacket for circulating a heat transfer oil for temperature control.

Furthermore, the reaction mixture discharged from this small static mixer for catalytic pyrolysis was heated to a temperature of 2 by a heat exchanger.
After heating to 10 ° C, the system was introduced into a gas-liquid separation tank with the system pressure maintained at 5 mmHg, and unreacted monomer was removed from the top to obtain a silanol-terminated diorganopolysiloxane with a viscosity at 25 ° C of 110,000 centipoise. It was The amount of residual monomer in the obtained silanol-terminated diorganosiloxane was 2.3%, and the polymerization rate was 86%.

Example 2 The production conditions were changed as shown in Table 1, except that the introduction of the chain terminator was carried out during premixing and at the inlet of the static mixer for polymerization in two steps. The same equipment and the same materials as in Example 1 were used to polymerize octamethylchlorotetrasiloxane monomer to obtain a silanol-terminated diorganopolysiloxane having a viscosity at 25 ° C. of 8,500 centipoise. The amount of residual monomer in the obtained silanol-terminated diorganosiloxane was 5.2%, and the polymerization rate was 80%.

Example 3 The same apparatus and the same material as in Example 2 except that trimethylsilyldimethylpolysiloxane having 4 silicon atoms was used as a chain terminator and the production conditions were changed as shown in Table 1. The octamethylchlorotetrasiloxane monomer was polymerized to obtain trimethylsilyl-terminated dimethylpolysiloxane having a viscosity at 25 ° C of 11,000 centipoise. The amount of residual monomer in the obtained trimethylsilyl-terminated diorganosiloxane was 1.8%, and the polymerization rate was 87%.

Example 4 The same apparatus as in Example 2 except that vinyldimethylsilyldimethylpolysiloxane having 20 silicon atoms was used as a chain terminator and the production conditions were changed as shown in Table 1. Octamethylchlorotetrasiloxane monomer was polymerized with the same material to obtain a vinyldimethylsilyl-terminated dimethylpolysiloxane having a viscosity of 3,050 centipoise at 25 ° C. The amount of residual monomer in the obtained vinyldimethylsilyl-terminated dimethylpolysiloxane was 2.0%, and the polymerization rate was 83%.

[0039]

[Table 1]

[0040]

As described above, according to the present invention,
Since the thermal decomposition type base catalyst is used as the polymerization catalyst and can be completely decomposed and removed, the problem of characteristic deterioration due to the residual neutralization reaction product such as the conventional acid or base catalyst is solved.

Further, since a siloxane polymer having a desired uniform degree of polymerization can be continuously produced by using such a thermal decomposition type base catalyst, a batch process using a conventional thermal decomposition type base catalyst is performed. Compared with the polymerization method, the characteristics of the product do not vary, and a siloxane polymer with good characteristics can be manufactured stably, economically and with good productivity.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus used for carrying out the method of the present invention.

[Explanation of symbols]

1, 3, 6 ... Static mixer 2 ... Monomer preheater 3 ... Degassing gas tank for polymerization 4 ... Pressure adjusting valve 5, 7 ... Heating device 8 ... Gas-liquid separation Cooling device P ₁ , ₂ , ₃ , ₄ , _5, ... Constant volume pump

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[Procedure amendment]

[Submission date] October 18, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

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[Correction content]

[0011] As the monomer used as the starting material in the present invention can be any cyclo polysiloxanes, usually 3-6 mer dimethylcyclopropane polysiloxysilane <br/> hexane is used, inter alia tetramer Dimethyl cyclopo
The use of polysiloxane is preferable. It is desirable to use a sufficiently dried monomer (water content of 20 ppm or less), and if necessary, it may be dried by degassing before preheating. The preheating of the monomer is carried out in order to promptly start the ring-opening polymerization of the monomer in the next step, and the polymerization temperature is usually raised to 80 to 100 ° C, preferably 85 to 95 ° C using a heat exchanger or the like. Let it warm. The amount of the monomer supplied is appropriately determined depending on the polymerization temperature and the catalyst addition amount that determine the reaction rate of the polymerization, the degree of polymerization of the polymer to be obtained, the volume of a static mixer that is a polymerization vessel, and the like.

[Procedure Amendment 2]

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[0017]

[Chemical 3]

[Procedure 3]

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[Correction content]

In the present invention, firstly, cyclo polysiloxane starting material, octamethylcyclotetrasiloxane polysiloxanolate <br/> San monomer is dimethyl cyclic siloxane example tetramer, ejectable supplied at a constant flow rate pump,
For example, it is continuously and quantitatively introduced into the in-line mixer for premixing, for example, the static mixer 1 through the monomer supply line A by the diaphragm type constant capacity pump P ₁ . The diaphragm type constant displacement pump has a high discharge pressure and does not have a sealing surface between the diaphragm type constant capacity pump and the drive unit, and is therefore preferably used in this case. In the monomer supply line A,
The monomer preheater 2 is inserted, and the cyclopolysiloxane is added to the monomer preheater 2 at a polymerization temperature, for example, 80 to
It is preheated to about 100 ° C. and introduced into the static mixer 1. For the monomer preheating group 2, for example, a heat exchanger is used.

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The static mixer 1 mixes these monomers, the thermal decomposition type base catalyst and the chain terminator so as to have a uniform composition, adjusts the viscosity to a suitable level, and the static mixer 3 for the subsequent polymerization. It is for sending to. A dynamic mixer may be used in place of the static mixer 1, but the use of a static mixer is more preferable from the viewpoint of handleability and the like. As a dynamic mixer, for example, 2
~ 3-stage paddle type agitator with rotation speed 800-2,000
r. p. An in-line mixer capable of high speed dispersion is used. In these mixers, the introduction of the thermal decomposition type base catalyst and the chain stopper is performed on the mixer so that the chain stopper does not reduce the activity of the thermal decomposition type base catalyst or cause the introduction nozzle to be clogged. It is desirable to introduce them so that they do not come into contact with each other through addition ports provided at different positions. In the case of static mixer 1,
Further, it is desirable to position the tip of the nozzle at the central portion of the tube body that constitutes the static mixer 1, and this can prevent the mixture on the tube wall from staying.

[Procedure Amendment 5]

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The reaction mixture discharged from the static mixer 6 is subsequently heated by a heating device 7 such as a heat exchanger to a temperature higher than the boiling point of the unreacted monomer, for example, 200 to 220 ° C., and then, for example, the system pressure. Is introduced into the gas-liquid separator 8 holding 2 to 10 mmHg to separate the unreacted monomer and the desired polymer product. Then, the unreacted monomer and polymer product separated here are supplied from the monomer discharge line F and the polymer discharge line G, respectively, to a cooling device 9, 1 such as a heat exchanger inserted in both lines.
It is cooled by 0 and discharged to the outside.

[Procedure Amendment 6]

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Example 3 The same apparatus and material as in Example 2 except that trimethylsilyldimethylpolysiloxane having 4 silicon atoms was used as a chain terminator and the production conditions were changed as shown in Table 1. The octamethyl chlorotetrasiloxane monomer is polymerized to give a viscosity of 1100 at 25 ° C.
0 centipoise trimethylsilyl terminated dimethyl polysiloxane was obtained. The amount of residual monomers in the obtained trimethylsilyl-terminated diorganosiloxane was 1.8%, and the polymerization rate was 87%.

[Procedure Amendment 7]

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Example 4 The same apparatus as in Example 2 except that vinyldimethylsilyldimethylpolysiloxane having 20 silicon atoms was used as a chain terminator and the production conditions were changed as shown in Table 1. By polymerizing octamethylchlorotetrasiloxane monomer with the same material, the viscosity at 25 ° C is 3,
050 centipoise vinyldimethylsilyl terminated dimethylpolysiloxane was obtained. The amount of residual monomer in the obtained vinyldimethylsilyl-terminated dimethylpolysiloxane was 2.0%, and the polymerization rate was 83%.

Claims (4)

[Claims] 1. A preheated cyclopolysiloxane, a pyrolytic base catalyst, and a total amount of a part of a chain stopper are premixed, and (b) the premix is pressurized. Passing through a static mixer that is maintained to provide sufficient residence time to complete the polymerization of the cyclopolysiloxane and introduce the remaining chain terminator into the first portion of the reaction zone of the static mixer,
Then, (c) the reaction mixture is passed through a static mixer that is heated to a temperature equal to or higher than the decomposition temperature of the pyrolytic base catalyst and that has a residence time sufficient to completely decompose the pyrolytic base catalyst. A continuous process for producing a siloxane polymer. 2. The continuous process for producing a siloxane polymer according to claim 1, wherein the chain stopper is water. 3. The siloxane polymer according to claim 1, wherein the chain terminator is a low molecular weight triorganosilyldiorganopolysiloxane having a monovalent hydrocarbon group as an organic group and having 2 to 20 silicon atoms. Continuous manufacturing method. 4. The continuous process for producing a siloxane polymer according to claim 3, wherein the organic group of the low molecular weight triorganosilyldiorganopolysiloxane of the chain terminator contains an aliphatic unsaturated group.