JPH02289623A - Production of alpha,omega-hydroxyfluoroalkyl polysiloxane - Google Patents

Abstract

PURPOSE:To obtain the subject polysiloxane storable over a long period and having easily controllable viscosity by polymerizing a specific cyclotrisiloxane in the presence of a polymerization catalyst such as lithium hydroxide and a polymerization accelerator such as diorgano-phthalate and terminating the polymerization reaction with a neutralizing agent. CONSTITUTION:The objective polysiloxane having desired viscosity is easily produced by polymerizing a cyclotrisiloxane of formula I (R1 is univalent 1-8C hydrocarbon group; R2 is 1-10C fluoroalkyl) in the presence of (A) a polymerization catalyst consisting of lithium hydroxide or an organosiloxane lithium salt produced by mixing and heating lithium hydroxide and an organosiloxane and (B) a polymerization accelerator consisting of a phthalic acid diorgano ester and/or an o-alkoxybenzene and terminating the polymerization reaction by adding a neutralizing agent [preferably chloroethane of formula II (X is H or C1)].

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a method for producing fluorosilicone oil,
In particular, α shows almost no change in viscosity over time. This article relates to a method for producing ω-hydroxyfluoroalkylborosiloxane. <<Prior Art>> Conventionally, fluorinated silicone compositions have been used that have improved solvent resistance, water repellency, chemical resistance, etc. of silicone compositions. A typical example of such a fluorinated silicone composition is a terminal silanol fluorosilicone oil, the synthesis method of which is described in US Pat. No. 4,287,353. This synthesis method uses 0.005 to 0.00 parts by weight per 100 parts by weight of methylfluoroprobyl siloxane. I
O parts by weight of polymerization catalyst (KOH or NaOH), O. 0
2 to 5.0 parts by weight of water and 0.01 to 2.0 parts by weight of polyethylene glycol dimethyl ether are mixed as a polymerization reaction accelerator, polymerized, and neutralized with hydrochloric acid, silyl phosphoric acid, etc. to obtain fluorosilicone oil. It is something.

In this method, it is stated that by using triethylene glycol dimethyl ether or the like as a polymerization reaction accelerator, the polymerization initiation temperature can be lowered, the polymerization time can be shortened, and the amount of volatile siloxane generated during the reaction can be suppressed. There is. <<Problem to be solved by the invention>> However, since the above reaction proceeds rapidly, it is difficult to control the viscosity, and the viscosity of the fluorosilicone oil after production changes significantly over time, making long-term storage impossible. It had a decisive drawback.

The inventors of the present invention should solve the above drawbacks.As a result of intensive study,
Polymerization is carried out by using lithium hydroxide or an organosiloxane glue salt obtained by heating and mixing lithium hydroxide and organosiloxane as a polymerization catalyst, and phthalic acid diorganoester or orthodialkoxybenzene as a polymerization reaction promoter. Viscosity change over time of fluorosilicone oil produced by being able to extend the polymerization time until sufficient viscosity control is possible while maintaining a low temperature, and by using chloroethane as a neutralizing agent to terminate the polymerization reaction. The present invention was achieved by discovering that the change can be significantly prevented.

Therefore, a first object of the present invention is to provide a method for producing fluorosilicone oil whose viscosity can be easily controlled.

A second object of the present invention is to provide a method for producing fluorosilicone oil that has almost no change in viscosity over time and can be stored for a long period of time.

<<Means for Solving the Problems>> The above objects of the present invention are to prepare a lithium salt of an organosiloxane obtained by heating and mixing cyclotrisiloxane represented by lithium hydroxide or lithium hydroxide and an organosiloxane. Polymerization is carried out using a phthalic acid diorganoester and/or orthoalkoxybenzene as a polymerization catalyst and a polymerization promoter, preferably << has the general formula CHX. CCIX. (X represents a hydrogen atom or a chlorine atom) is used as a neutralizing agent to stop the polymerization reaction.
This was achieved by a method for producing ω-hydroxyfluoroalkylborosiloxane. In the above general formula (1), Rl represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and R- represents a fluoroalkyl group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms.

Specific examples of R1 include alkyl groups such as methyl group, ethyl group, probyl group, and butyl group, cycloalkyl groups such as cyclohexyl group, alkenyl groups such as vinyl group and allyl group, and aryl groups such as phenyl group and tolyl group. , or a chloromethyl group in which part or all of the hydrogen atoms of these groups are substituted with a halogen atom, a cyano group, etc., 3.3.3-}
Examples thereof include a lifluoroppropyl group, a 2-cyanoethyl group, and among these, a methyl group, a vinyl group, a phenyl group, and a 3,3.3-}lifluoroppropyl group are particularly preferred. Specific examples of R2 include trifluoromethyl group, pentafluoroethyl group, 3,3.3-trifluoropropyl group, C.I. F. CH. CH. Cs F+tCHg CHt
Among them, 3,3.3-}refluoropropyl group is particularly preferred.

Specific examples of the cyclotrisiloxane represented by the general formula (1) include cyclotrisiloxanes obtained by arbitrarily combining the groups listed above as specific examples of Rl and Rt, such as 1,3.5- Trimethyl-1.3.5-
}Lis(3,3,3-trifluoropropyl)cyclotrisiloxane can be mentioned. During the synthesis of silanol-terminated fluoroalkyl polysiloxanes, volatile cyclosiloxane is generally produced as a by-product. In the present invention, in order to suppress this by-product, lithium hydroxide, which is weakly basic compared to sodium hydroxide, potassium hydroxide, etc., is used as a polymerization catalyst.

In addition, the above-mentioned by-product of volatile siloxane can also be suppressed by carrying out the polymerization reaction at a low temperature.
The viscosity of the polysiloxane is determined by the amount of water in the reaction system, since the terminals of the fluoroalkyl polysiloxane produced by the ring-opening polymerization reaction are reacted with water and blocked with hydroxyl groups. Therefore, in order to obtain a fluoroalkylpolysiloxane with the desired viscosity, it is necessary to have a certain amount of water in the reaction system, so the reaction temperature should be lower than the boiling point of water. It is preferable that there be. Therefore, in the present invention, it is preferable to carry out the reaction at a temperature of 40 to 95°C, and a polymerization reaction promoter is used for this purpose. In the present invention, phthalic acid diorganoester and/or orthoalkoxybenzene is particularly used as the polymerization reaction accelerator. Specific examples of this accelerator include dimethyl phthalate, diethyl phthalate,
Examples include diallyl phthalate, orthodimethoxybenzene, orthodiethoxybenzene.

By using the combination of the above-mentioned polymerization catalyst and polymerization reaction promoter, the polymerization reaction is carried out at a temperature of 40 to 95°C, and the by-product of volatile cyclosiloxane is suppressed, and the viscosity of the product is sufficiently controlled. The polymerization reaction can be moderately promoted to the extent that Since the above polymerization reaction is carried out under alkaline conditions, by adding a neutralizing agent to neutralize the reaction system, the polymerization reaction can be stopped when the product reaches a desired viscosity. However, when an acidic compound is used as a neutralizing agent, it is not possible to prevent the terminal hydroxyl group from condensing even after the polymerization reaction has been terminated due to the free acidic compound remaining after neutralization. It is inevitable that the viscosity of the produced fluorosilicone oil increases over time. Therefore, in the present invention, instead of the neutralizing agent having the above-mentioned drawbacks, it is preferable to use the general formula C H
X Z C C i. Chloroethane represented by X t (X represents a hydrogen atom or a chlorine atom) is used. Among these chloroethanes, especially 1, 1.2.2
-Tetrachloroethane is preferred. That is, when this neutralizing agent is added to a system where an alkaline component is present, the neutralizing agent dehydrochlorinates and neutralizes the reaction system in an amount that neutralizes the alkaline component, so chloroethane remains after neutralization. Even if this happens, no acidic compound that causes condensation of the terminal hydroxyl group remains in the product after termination of the polymerization reaction, and the product has good storage stability.

In carrying out the present invention, first, a raw material represented by 1,3.5-}limethyltris(3,3.3-}lifluoroprobil)cyclotrisiloxane is heated to a predetermined temperature while stirring, and the polymerization catalyst is heated to a predetermined temperature. of lithium hydroxide and a polymerization reaction accelerator such as dimethyl phthalate and/or orthodimethoxybenzene. The amount of lithium hydroxide added is preferably 0.005 to 0.50 parts by weight based on 100 parts by weight of cyclotrisiloxane as a raw material,
In particular, it is preferably in the range of 0.05 to 0.15. If the catalyst amount is less than 0.005 parts by weight, the polymerization reaction will not proceed sufficiently even if a sufficient amount of polymerization reaction accelerator is added, and the catalyst amount will be less than 0.50 parts by weight.
Adding a catalyst in an amount greater than parts by weight not only makes it difficult to control the viscosity of the product because the reaction becomes too fast even without adding a polymerization reaction promoter, but also increases the amount of volatile cyclotrisiloxane by-product. So I don't like it.

In addition, the amount of dimethyl phthalate and/or orthodialkoxybenzene used is 1
It is preferably in the range of 0.005 to 2.0 parts by weight, particularly preferably in the range of 0.6 to 0.20 parts by weight.

The above-mentioned polymerization catalyst and polymerization reaction promoter are usually used together with an appropriately selected organic solvent such as tetrahydrofuran so that they can be quickly and uniformly mixed into the reaction system. Further, it is preferable to use the lithium hydroxide catalyst as a lithium salt of an organosiloxane obtained by heating and mixing it with a small amount of organosiloxane in advance to improve the catalytic activity. The organosiloxane in this case is not particularly limited in its organic substituents, but from the viewpoint of product purity, the same substituents Rl and / or those having R2 are preferred. Examples of such organosiloxane include cyclotrisiloxane, cyclopentasiloxane, and cyclohexasiloxane having Rl and R2 as organic substituents.

Furthermore, in order to easily block the molecular chain ends of the fluoroalkylpolysiloxane produced by ring-opening polymerization with hydroxyl groups, it is preferable to incorporate water into the reaction system before adding the catalyst.

The polymerization reaction is started as described above, and a neutralizing agent such as trichloroethane is added at the time when a product with a desired viscosity is obtained to neutralize the reaction system and stop the polymerization reaction.

Volatile components in the reaction system can be appropriately removed by distillation. <<Effects of the Invention>> As detailed above, the present invention has the advantage of appropriately controlling the polymerization reaction rate by combining a lithium hydroxide polymerization catalyst with a phthalic acid diorganoester and/or an orthoalkoxybenzene polymerization reaction accelerator. , an α,ω-hydroxyfluoroalkylborisiloxane having a desired viscosity can be easily obtained.

In addition, by using chloroethane as a neutralizing agent, the storage stability of the produced fluorosilicone oil can be greatly improved, so the present invention is of great significance.

<<Examples>> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1. 1,3.5-}limethyltris(3,3.3-trifluoropropyl)cyclotrisiloxane was placed in a reaction vessel, heated to 65°C with stirring, and then a 1:1 mixture of water and tetrahydrofuran was added. Add .8g and 10
Mix and stir for a minute. Next, 0.4 g of methyltrifluoropropyl polysiloxane mixture containing 6% LiOH,
Dimethyl phthalate 0.45g and tetrahydrofuran 1
．． Polymerization was initiated by adding 5 g of the mixture. As the reaction progressed, the temperature in the reaction system gradually rose to 80°C and the viscosity of the liquid also rose. After 5 hours of reaction, 3.4g
The polymerization reaction was terminated by neutralizing the reaction system by adding 1,1,2,2-tetrachloroethane. The resulting product has a viscosity of 17,000 at 25°C.
The volatile content, which is a centivoise and is a measure of the amount of volatile cyclotrisiloxane produced as a by-product, was 2.70% under conditions of 150°C/3 hours.

No change in viscosity was observed even after 15 days at 70°C.

Example 2. 1,3.5-} 500 g of trimethyltris(3.3.3-trifluoropropyl)cyclotrisiloxane was placed in a reaction vessel, heated to 65°C without stirring, and then water and tetrahydrofuran were mixed 1:1. Add 1.6g of liquid,
Mixing and stirring were performed for 10 minutes. Next, 0.4 g of silicone mixture containing 6% LiOH, 0.4 g of dimethyl phthalate
A mixture of 5 g and 1.5 g of tetrahydrofuran was added to initiate polymerization. As the reaction progressed, the temperature in the reaction system gradually rose to 80°C and the viscosity of the liquid also rose. 5
After reacting for an hour, the polymerization reaction was terminated by adding 3.4 g of 1.1.2.2-tetrachloroethane for neutralization.

The resulting product has a viscosity of 41,000 at 25°C.
It was centiboise and had a volatile content of 2.24% under conditions of 150°C/3 hours. No change in viscosity was observed even after 15 days at 70°C.

Example 3. 1,3.5-}trimethyltris(3,3.3trifluorobutyl)cyclotrisiloxane (500 g) was placed in a reaction vessel and heated to 80°C with stirring, followed by 2 g of a 1:1 mixture of water and tetrahydrofuran. was added and mixed and stirred for 10 minutes. Next, a mixture of 0.4 g of a silicone mixture containing 6% LiOH, 0.45 g of dimethyl phthalate, and 1.5 g of tetrahydrofuran was added to initiate polymerization. As the reaction progresses, the temperature in the reaction system increases to 90°C.
The viscosity of the liquid also increased. After carrying out the reaction for 5 hours, 3.4 g of 1. 1, 2. The polymerization reaction was terminated by neutralizing by adding 2-tetrachloroethane.

The resulting product had a viscosity of 7.000 centipoise at 25°C and a volatile content of 4.48% under conditions of 150°C/3 hours. No change in viscosity was observed even after 15 days at 70°C.

Example 4. 500 g of 1,3,5-trinotyltris(3,3,3-trifluoroprobyl)cyclotrisiloxane was placed in a reaction vessel and heated to 60°C with stirring, followed by a 1:1 mixture of water and tetrahydrofuran. 1.6g was added.

After mixing and stirring for 10 minutes, 0.4 g of silicone mixture containing 6% LiOH and 0.4 g of diaryl phthalate were added.
A mixture of 5 g and 1.5 g of tetrahydrofuran was added to initiate polymerization. As the reaction progressed, the temperature in the reaction system gradually rose to 70°C and the viscosity of the liquid also rose. After reacting for 5 hours, the polymerization reaction was terminated by adding 3.4 g of 1,1.2.2-tetrachloroethane for neutralization.

The viscosity of the obtained product at 25°C is 13,250
centipoise, and the volatile content was 2.80% under the conditions of 150°C/3 hours. No change in viscosity was observed even after 15 days at 70°C. Example 5.1 , 3.5-} 500g of trimethyltris(3,3.3trifluoropropyl)cyclotrisiloxane was placed in a reaction vessel and heated to 80°C with stirring, followed by 0.8g of a 1:1 mixture of water and tetrahydrofuran. was added.1
After mixing and stirring for 0 minutes, 0.5 g of silicone mixture containing 6% LiOH and 0.5 g of diethyl phthalate were added.
A mixed solution of 1.5 g of tetrahydrofuran and 1.5 g of tetrahydrofuran was added to initiate polymerization. As the reaction progresses, the temperature in the reaction system increases to 95
The temperature gradually rose to °C, and the viscosity of the liquid also rose accordingly. After 6 hours of reaction, 3.4 g of 1.1,2.2-
The polymerization reaction was terminated by neutralizing by adding tetrachloroethane. The viscosity of the resulting product at 25°C is 112,500 centipoise;
The volatile content was 1.80% under the conditions of /3 hours. No change in viscosity was observed even after 15 days at 70°C. Example 6. 500 g of 1,3,5-trimethyltris(3,3,3-trifluoroprobyl)cyclotrisiloxane was placed in a reaction vessel and heated to 80°C without stirring, followed by a 1:1 mixture of water and tetrahydrofuran. 1.8g was added.

After mixing and stirring for 10 minutes, a mixed solution of 0.4 g of a silicone mixture containing 6% LiOH, 0.3 g of ortho-dimethoxybenzene, and 1.5 g of tetrahydrofuran was added to initiate polymerization. As the reaction progressed, the temperature in the reaction system gradually rose to 90°C, and the viscosity of the liquid increased accordingly. After carrying out the reaction for 6 hours, 3.4 g of 1.
The polymerization reaction was terminated by neutralizing by adding 1.2.2-tetrachloroethane. 25 of the product obtained
The viscosity at °C is 51,000 centivoise,
The residual content was 2.19% under the conditions of 150°C/3 hours. No change in viscosity was observed even after 15 days at 70°C. Example 7. 1,3.5-} 2000 g of tris(3.3.3-trifluoropropyl)cyclotrisiloxane was placed in a reaction vessel, heated to 75°C without stirring, and then mixed with water and tetrahydrofuran in a ratio of 1:1. 6.4 g of the mixture was added. After mixing and stirring for 10 minutes, LiOHO. Ig,
2.0 g of dibutyl phthalate and 6.0 g of tetrahydrofuran
g of the mixed solution was added to initiate polymerization. As the reaction progressed, the temperature in the reaction system gradually rose to 85°C, and the viscosity of the liquid also rose accordingly. After carrying out the reaction for 5 hours, 15
．． The polymerization reaction was terminated by neutralization by adding 0 g of 1.1.2-}lichloroethane.

The resulting product had a viscosity of 12.100 centipoise at 25°C and a volatile content of 3.2% at 150°C/3 hours. No change in viscosity was observed even after 15 days at 70°C.

Example 8. 1,3.5-}trimethyltris(3,3.3-trifluoropropyl)cyclotrisiloxane (2000 g) was placed in a reaction vessel and heated to 90°C with stirring, followed by a 1:1 mixture of water and tetrahydrofuran 3. .2g was added. After mixing and stirring for 10 minutes, add 0.15 g of LiOH.
, a mixed solution of 1.5 g of ortho-diethoxybenzene and 6.0 g of tetrahydrofuran was added to initiate polymerization.

As the reaction progressed, the temperature in the reaction system gradually rose to 95°C, and the viscosity of the liquid also rose accordingly. After reacting for 6 hours, the polymerization reaction was terminated by adding 20.0 g of 1.1,1.22-pentachloroethane for neutralization.

The viscosity of the obtained product at 25°C was 62. OOO
centipoise, and the volatile content was 4.0% under conditions of 150° C./3 hours. No change in viscosity was observed even after 15 days at 70°C.

Comparative example 1. α,ω-Hydroxyfluoroalkylborisiloxane was synthesized by the following method as a trace of US Pat. No. 4,287,353.

500g of 1,3.5-trimethyltris(3.3.3trifluoroprobyl)cyclotrisiloxane was placed in a reaction vessel, heated to 42°C while stirring with a stirring bar, and then water and 1 pair of tetrahydrofuran were added. 1.8 g of the mixed solution was added. After mixing and stirring for 10 minutes, add 1 portion of NaOH.
Ring-opening polymerization was started by adding a mixed solution of 0.4 g of a methyl trifluoropropylborisiloxane mixture containing 0%, 0.35 g of triethylene glycol dimethyl ether, and 1.5 g of tetrahydrofuran. As the reaction progressed, the temperature rose from 42°C to 51°C, and the viscosity of the liquid gradually increased accordingly.

One hour after the start of the reaction, 1.0 g of acetic acid was added to stop the polymerization reaction. The resulting product has a viscosity of 39,000 centivoise at 25°C and a viscosity of 150°C/3
The volatile content over time was 8.3%.

When the product was maintained at 70°C, its viscosity increased to about 110,000 centivoids after 15 days, and its storage stability was extremely poor.

Comparative example 2. 500 g of 1,3,5-trimethyltris(3,3,3-trifluoroprobyl)cyclotrisiloxane was placed in a reaction vessel and heated to 75°C without stirring, followed by a 1:1 mixture of water and tetrahydrofuran. 1.8g was added.

Next, a mixture of 0.8 g of methyltrifluoropropyl polysiloxane mixture containing 10% NaOH and 1.5 g of tetrahydrofuran was added, and the mixture was mixed and stirred at 75°C for 10 hours, but no increase in viscosity was observed. There wasn't. still,
After that, as a result of gradually increasing the temperature and stirring, 120
The initiation of the polymerization reaction was observed at °C. After 1 hour had passed, 1.0 g of acetic acid was added to stop the polymerization reaction.

The viscosity of the product obtained at 25°C is 101,00
0 centipoise, and the volatile content was 18.5% under conditions of 150'c/3 hours. The results of the above examples and comparative examples demonstrate that the method of the invention is highly suitable for controlling the viscosity of products.

Incidentally, the changes over time in the viscosity of each product are summarized as shown in FIG. 1, which shows that the products of the present invention have excellent storage stability.

[Brief explanation of drawings]

FIG. 1 shows α. It represents the change in viscosity of ω-hydroxyfluoropropyl polysiloxane over time.

Claims (1)

[Claims] 1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (R^1 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, R^2 is the number of carbon atoms (1 to 10 fluoroalkyl groups) is polymerized using lithium hydroxide or a lithium salt of organosiloxane obtained by heating and mixing lithium hydroxide and organosiloxane as a polymerization catalyst, and phthalic acid is used as a polymerization catalyst. Diorganoester and/or
Alternatively, a method for producing α,ω-hydroxyfluoroalkylpolysiloxane, which comprises polymerizing using orthoalkoxybenzene as a polymerization accelerator, and then adding a neutralizing agent to stop the polymerization reaction. 2) The production method according to claim 1, wherein the neutralizing agent is chloroethane represented by the general formula CHX_2CClX_2 (X represents a hydrogen atom or a chlorine atom).