JPH0216768B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an organosilicon polymer containing Si, B, and O as the main skeletal components, and more specifically, a method for producing a high molecular weight organosilicon polymer containing Si, B, and O as the main skeletal components. Regarding how to. Conventionally, organosilicon polymers containing Si, B, and O as main skeleton components are well known. for example,
The manufacturing method of polyborodimethylsiloxane is RL
Vale (J.Chem.Soc.P2252 (1960)), and a method for producing polyborodiphenylsiloxane was disclosed by Yajima et al. in JP-A-53-50299. The polymers produced by this method have a low molecular weight, are soluble in various organic solvents, and do not have sufficient thermal stability, which limits their applications. To obtain the polymer of
Either react for a long time at high temperatures such as 500℃ or higher, or
There was a problem in that it required steps such as radiation irradiation and radical polymerization. As mentioned above, the main skeleton components are Si, B, and O.
The method for producing high molecular weight organosilicon polymers containing these materials has not yet been fully developed. It is therefore an object of the present invention to provide an improved production method for obtaining high molecular weight organosilicon polymers containing Si, B and O as the main skeleton components. As a result of intensive research to achieve the above object, the present inventors have discovered that Si, B, and O are formed as main skeletal components by reacting an organosilicon compound such as diphenyldichlorosilane with a boron compound such as boric acid. When producing an organosilicon polymer containing
By reacting in a solvent to form an oligomer, then gradually evaporating the solvent to form a prepolymer, and finally reacting in the substantial absence of a solvent, high molecular weight polymers can be produced in a short time at low reaction temperatures. It was discovered that this method can be easily manufactured, and the present invention was developed based on this finding. That is, in the present invention, when producing an organosilicon polymer by continuously reacting an organosilicon compound and a boron compound in an inert gas atmosphere at a temperature of less than 150°C, first, the organosilicon compound and the boron compound are reacted together. is reacted in a solvent to form an oligomer,
The main method is to gradually volatilize the solvent over a period of 3 to 8 hours to obtain a prepolymer, and then to react in the substantially absence of a solvent until a high molecular weight polymer insoluble in methanol is obtained. The gist of this paper is a method for producing an organosilicon polymer containing Si, B, and O as skeleton components. The organosilicon compound used in the present invention has the general formula () (However, in the formula, R ₁ and R ₂ represent a hydrogen atom, an alkyl group, or an aryl group, and X ₁ and X ₂ represent a halogen atom or an alkoxy group.) enylmethyldichlorosilane,
Examples include compounds such as benzylmethyldichlorosilane. Examples of the boron compound used in the present invention include boric acid, boric anhydride, boric acid metal salts, boron halides, and boric acid esters. Examples of the solvent used in the reaction in the present invention include aliphatic hydrocarbons such as n-hexane, aromatic hydrocarbons such as benzene, di-n-
Examples include ethers such as butyl ether. In the present invention, such a solvent is preferably used in the same amount to 5 times the total weight of the organic silicon compound and boron compound as raw materials, and particularly preferably in the same amount to 2 times the total weight of the organic silicon compound and boron compound. In order to obtain an organosilicon polymer by the method of the present invention, it is preferable to heat it to a temperature in the range of 50°C to 150°C, particularly 80°C to 140°C, in an inert atmosphere such as nitrogen gas or argon gas. In the present invention,
First, it is necessary to react the organosilicon compound and the boron compound in a solvent, and the reaction time is preferably 2 to 24 hours, particularly 4 to 18 hours. Next, it is necessary to carry out the reaction while gradually volatilizing the solvent over a period of 3 to 8 hours, and then to carry out the reaction in substantially no solvent until a high molecular weight polymer is obtained. By performing the reaction while gradually volatilizing the solvent, a prepolymer can be obtained that can be reacted in the absence of a solvent to give a high molecular weight polymer. If the time to react while gradually volatilizing the solvent is less than 3 hours, it will be difficult to obtain a high molecular weight polymer through the subsequent reaction, whereas if it exceeds 8 hours, side reactions may occur or oligomers may scatter. This is not preferable because the yield may decrease. The reaction time in the absence of a solvent is preferably 2 to 12 hours, particularly 4 to 12 hours. In the present invention, the molar ratio of the organosilicon compound to the boron compound is preferably 1:9 to 9:1, particularly preferably 1:2 to 2:1. In the present invention, the method of evaporating the solvent from the reaction system is not particularly limited. Normally, when reacting in a solvent, the solvent evaporated by heating is liquefied in a reflux condenser and returned to the reaction system, but if a distillation condenser is used instead of the reflux condenser, the solvent can be distilled out of the reaction system. You can force it. The organosilicon polymer obtained by the method of the present invention contains Si, B, and O as main skeleton components, and has, for example, the following general formula () (In the formula, R ₃ and R ₄ represent a hydrogen atom, an alkyl group, or an aryl group.) By using the method of the present invention, high molecular weight organosilicon polymers can be obtained. That is, according to the present invention, it is possible to obtain a polymer that is insoluble in benzene, hexane, methanol, etc., and its molecular weight is so high that it cannot be measured by ordinary methods such as vapor pressure osmosis. For example, the molecular weight and solubility in methanol of polyborodiphenylsiloxane are as shown in Table 1, and the larger the molecular weight of polyborodiphenylsiloxane, the more difficult it is to dissolve in methanol. In this case, a methanol-insoluble polymer can be obtained. Furthermore, the method of the present invention can provide an organosilicon polymer in good yield, so it is of great value industrially.

[Table] Hereinafter, the present invention will be explained in more detail using Examples. In addition, "parts" in the examples indicate parts by weight unless otherwise specified. Moreover, "O/" represents a phenyl group. In addition, the number average molecular weight is determined by KNAUER's
Measured with methanol solvent using vapor pressure osmosis method using VAPOUR PRESSURE OSMOMETER. Example 1 750 parts of diphenyldichlorosilane and boric acid were placed in a four-necked Virex glass separable flask.
Add 1000 parts of di-n-butyl ether as a solvent, and add 120 parts of di-n-butyl ether as a solvent.
After 6 hours of reaction at a temperature of .degree. C., the reaction solution became slightly cloudy. Thereafter, di-n-butyl ether as a solvent was gradually evaporated by distillation over a period of 6 hours until substantially no solvent was present, and a white precipitate remained. Thereafter, the reaction was continued under the same conditions for 4 hours. The white precipitate after the reaction was washed until residual HCl was no longer detected.
600 parts of white powder was obtained. Elemental analysis of this material revealed that C = 63.6%.
H=4.75%, Si=22.0%, and B=1.24%.
Furthermore, since this product is insoluble in various solvents such as benzene, hexane, methanol, and chloroform, it was not possible to measure its molecular weight by vapor pressure osmosis. On the other hand, when we measured the infrared absorption spectrum of this product, we found absorption based on phenyl groups at 3000 to 3100 cm ^-1 at 1585 cm ^-1 , 1485 cm ^-1 , 1430 cm ^-1 , and 1190 cm -1 .
cm ^-1 , 1100cm ^-1 , 1030cm ^-1 , and 1000cm ^-1 Si ^- O/
An absorption based on (Si)-O-Bi was observed at 1340 cm ^-1 and an absorption based on Si-O was observed at 1080 cm ^-1 . It was confirmed that it is an organosilicon polymer having the skeleton unit shown by. Furthermore, when the solvent was evaporated for 4 hours in the above method, 620 parts of a white powder insoluble in methanol was obtained. Furthermore, for comparison, we set this time to 2 hours or 10 hours, and when the time was 2 hours, the obtained powder was soluble in methanol (molecular weight 5300), and the yield was
The resulting powder was insoluble in methanol, and the yield was 490 parts. Example 2 The reaction was carried out in the same manner as in Example 1, except that paraxylene was used as a solvent instead of di-n-butyl ether and the temperature was changed from 120°C to 110°C. Six hours after the start of the reaction, the reaction solution was nearly transparent.
Thereafter, the temperature was raised to 130° C. and the solvent, paraxylene, was gradually evaporated by distillation over a period of 6 hours until substantially no solvent was present, leaving a white precipitate. Thereafter, the mixture was reacted for 4 hours and washed with methanol to obtain 625 parts of white powder.
This product was also insoluble in various solvents such as benzene, hexane, methanol, and chloroform, and its molecular weight could not be measured by vapor pressure osmosis, but the results of infrared absorption spectrometry showed that the organic It was similar to silicon compounds. Comparative Example 1 750 parts of diphenyldichlorosiloxane and 120 parts of boric acid were placed in the same Pyrex glass separable flask used in Example 1, 1000 parts of di-n-butyl ether was added, and a nitrogen stream of 25 ml/min was added. The reflux reaction was carried out at 120°C for 24 hours. After separating the resulting mixture of colorless transparent resin and white precipitate from the solvent, it was washed with hot methanol until residual HCl was no longer detected, and almost all of the colorless and transparent resin was dissolved in methanol. Part of the white precipitate was dissolved. The amount of colorless resinous material recovered from the methanol solution was 391 parts, and its number average molecular weight was 970. On the other hand, the white precipitate
134 parts, and its number average molecular weight was 1240.

Claims (1)

[Claims] 1. When producing an organosilicon polymer by continuously reacting an organosilicon compound and a boron compound in an inert gas atmosphere at a temperature below 150°C, first, the organosilicon compound and the boron compound are reacted in a solvent. to form an oligomer, and then add 3 solvents.
After gradually volatilizing over ~8 hours to form a prepolymer, Si is used as the main skeletal component, and then reacted in the substantial absence of a solvent until a high molecular weight polymer insoluble in methanol is obtained. A method for producing an organosilicon polymer containing B and O.