JPS6317093B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION This invention relates to fluorosilicone compositions and, in particular, to methods of making fluorosilicone polymers by polymerizing fluoro-substituted polysiloxanes in the presence of certain superior chain terminators. Processes for making diorganopolysiloxane polymers, particularly high molecular weight diorganopolysiloxane polymers, are well known. In the case of alkyl- and aryl-substituted polymers, the method of preparation involves using the appropriate diorganodichlorosilane and hydrolyzing it. Most of the acid and water are then removed from the resulting hydrolyzate, and then an alkali metal hydroxide is added thereto. The mixture is then heated to an elevated temperature for a period sufficient to cause preferential distillation of the desired cyclic polysiloxane. Such methods, known as decomposition methods, produce cyclic polysiloxanes containing from 3 to 10 repeating SiO units, but most cyclic polysiloxanes are cyclotrisiloxanes or cyclotetrasiloxanes. Additionally, this decomposition process can be conducted such that the majority of the cyclic polysiloxane formed is either cyclotetrasiloxane or cyclotrisiloxane. If it is desired to produce diorganopolysiloxane polymers with methyl and phenyl substituents, it is desirable to form the maximum amount of cyclic tetrasiloxane. The cyclic tetrasiloxane is then collected in relatively pure form and a small amount of basic equilibration catalyst and a suitable amount of chain terminator are added to it and the mixture of these components is heated to an elevated temperature for a moderate period of time to form a high molecular weight dihydrogen. An organopolysiloxane polymer is prepared, ie, a polymer having a viscosity in the range of 500,000 to 30,000,000 centipoise at 25°C, more preferably a viscosity in the range of 1,000,000 to 3,000,000 centipoise at 25°C. After the polymerization reaches its maximum level, the mixture is cooled, a neutralizing agent is added to it to neutralize the basic catalyst, and excess cyclic tetrasiloxane is removed to yield the desired diorganopolysiloxane polymer. obtain. It should be noted that such methods are those conventionally used in the production of high molecular weight diorganopolysiloxane polymers. However, it is 500000 at 25℃
It can be used to prepare low molecular weight diorganopolysiloxane polymers, such as those with viscosities of ~1,000,000 centipoise. It should be noted that it is the amount of chain terminator present in the reaction mixture that determines the molecular weight of the final diorganopolysiloxane polymer formed during the polymerization reaction. Such chain terminators are usually diorganopolysiloxane polymers chain terminated with low molecular weight triorganosiloxy end groups such as disiloxanes, trisiloxanes, and the like. An example of a chain terminator suitable for such a process is, for example, hexymethyldisiloxane. The amount of such chain terminator in the reaction mixture determines the amount of chain terminator available for end-terminating the polymer made from the cyclic polysiloxane, and thus it affects the final amount of the diorganopolysiloxane polymer. Determine the molecular weight of It will be appreciated that the lower the relative amount of chain terminator, the higher the molecular weight of the final polymer, and the greater the presence of chain terminator, the lower the molecular weight of the final polymer. 25℃
One method for preparing silanol-terminated diorganopolysiloxane polymers having molecular weights in the 1000-100000 centipoise viscosity range or higher is to use a suitable low molecular weight silanol material as a chain terminator and The desired amount of chain terminator is added to a mixture of the desired cyclotetrasiloxane and the appropriate amount of acidic or basic equilibration catalyst and the mixture is equilibrated to produce the desired polymer. Such low molecular weight silanol-terminated diorganopolysiloxane polymers are undesirable as chain terminators for the production of high viscosity diorganopolysiloxane polymers. This is because, in the presence of fillers, the silanol groups present in the polymer prior to curing of the composition may cause the composition to become overly structured to the point that it is virtually useless. This is because it works. Therefore, the presence of silanol groups or moisture is important for high viscosity dielectrics having organic groups selected from alkyl and aryl groups, such as methyl and phenyl groups, which are intended for heat-vulcanizable (cross-linked) silicone rubber compositions. It is undesirable for the production of organopolysiloxane polymers. Therefore, the fact that silanol groups could be advantageously introduced into high molecular weight diorganopolysiloxane polymers containing fluorinated substituents was surprising. However, for the preparation of diorganopolysiloxane polymers having fluorinated substituents, it is necessary to consider the conventional methods for preparing such polymers. High viscosity diorganopolysiloxane polymers containing fluorinated substituents with triorganosiloxy ends are prepared by first selecting a suitable fluorinated substituent-containing diorganodichlorosilane and hydrolyzing it. Ru. The acidity of the collected hydrolyzate is then reduced to a suitable level and the hydrolyzate is then separated from excess water.
A suitable amount of an alkali metal hydroxide catalyst is then added to the thus purified hydrolyzate and the hydrolyzate is heated to a temperature of about 200°C or higher to form the cyclic trisiloxane having a fluorinated substituent. It is preferentially distilled out as an overhead distillate. In fluorine-containing silicone chemistry, it is known that cyclic trisiloxanes react more easily to form polymers than the corresponding cyclic tetrasiloxanes. Therefore, a cyclic trisiloxane with suitably formed fluorinated substituents is selected, to which a basic polymerization catalyst is added together with an appropriate amount of a triorganosiloxy-terminated low molecular weight polymer, and the resulting The mixture is heated to an elevated temperature to form the desired diorganopolysiloxane polymer. however,
Such fluorinated substituent-containing cyclic trisiloxanes can be rapidly polymerized to form the desired high or low molecular weight polymers and are therefore suitable for use with conventional low molecular weight triorganosiloxy-terminated diorganopolymers. It has been found that siloxane chain terminators, fluorinated or not, do not react sufficiently quickly in the cyclic trisiloxane reaction mixture.
That is, such conventional chain terminators may require 4 to 6 hours to properly react with the cyclic trisiloxane reaction mixture to form a diorganopolysiloxane polymer with the desired molecular weight. Admitted. Without the use of such slow-acting, low molecular weight, triorganosiloxy-terminated chain terminators, any low or high viscosity fluorinated substituent-containing diorganopolysiloxane polymers will be fluorinated. It can be formed within one hour by equilibration reaction of group-containing cyclic trisiloxanes. Therefore, if the chain terminator can react more rapidly in the fluorinated substituent-containing cyclic trisiloxane reaction mixture,
High viscosity polymers with viscosities of 500,000 to 30,000,0000 centipoise, more preferably 1,000,000 to 3,000,000 centipoise at 25°C may be produced with equilibration reaction times as short as one hour. Therefore, in the polymerization of fluorinated substituent-containing cyclic trisiloxanes, a suitable chain terminator is required to produce a high viscosity polymer having a viscosity of 500,000 to 300,000 centipoise at 25°C in a short period of about 1 hour. It was extremely desirable to find out. This would provide a more efficient and economical method for the production of fluorinated substituent-containing silicone polymers, and thus for the production of fluorinated substituent-containing silicone elastomer compositions. In this regard, the chain terminators selected for such processes produce polymers with good physical properties comparable to polymers with fluorinated substituents made by prior art processes. It was desirable to give. The present invention is based on the formula (a): (RR ¹ SiO) _t (1) (wherein R and R ¹ represent a group selected from a monovalent hydrocarbon group and a fluorinated monovalent hydrocarbon group, If the cyclic polysiloxane is a mixture, a portion thereof shall be a fluorinated monovalent hydrocarbon;
(t represents 3) cyclic polysiloxane or mixture thereof, formula (b): (wherein R ² and R ³ represent a group selected from a monovalent hydrocarbon group and a halogenated monovalent hydrocarbon group, and s represents an integer from 2 to 50) and (c) a basic The present invention provides a method for producing a fluorosilicone polymer, which comprises a first step of reacting a polymerization catalyst and a second step of neutralizing the basic polymerization catalyst. In the above method, the cyclic polysiloxane is prepared by formula (1) in which R represents an alkyl group, preferably an alkyl group having 1 to 8 carbon atoms or a phenyl group, and R ¹ represents a fluoroalkyl group, for example 3,3,3 A cyclic trisiloxane corresponding to the -trifluoropropyl group is preferred. Furthermore, as another gist of the present invention, formula (a): (R ⁴ R ⁵ SiO) _t (3) (wherein R ⁴ and R ⁵ are a monovalent hydrocarbon group and a fluorinated monovalent hydrocarbon and a mixed group thereof, t
represents 3), (b) a chain terminator of the formula: R ⁶ OH, in which R ⁶ represents an aliphatic monovalent hydrocarbon radical having at least 6 carbon atoms; c) a first step of reacting a basic polymerization catalyst;
The present invention provides a method for producing a fluorosilicol polymer, which comprises a second step of neutralizing a basic polymerization catalyst. This second method of the invention can also be used to prepare polymers other than diorganopolysiloxane polymers with fluorinated substituents. However, this process is particularly advantageously used for the production of diorganopolysiloxane polymers with fluorinated substituents. In both of the above two methods of the present invention, high molecular weight diorganopolysiloxane polymers having fluorinated substituents, e.g.
It is particularly preferred for the production of polymers with viscosities in the range of 30,000,000 centipoise. In both methods, the cyclic siloxane is preferably a cyclic trisiloxane. This is because the advantages of using the new chain terminators mentioned above are significant in equilibration reactions of cyclic trisiloxanes, particularly in polymerization reactions of cyclic trisiloxanes with fluorinated substituents. In the first process of the present invention for making diorganopolysiloxane polymers, the process is limited to making diorganopolysiloxane polymers with fluorinated substituents. Therefore, in formula (1), R is preferably an alkyl group having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, etc.; an aryl group, such as phenyl, methyl-phenyl,
Monovalent hydrocarbon groups selected from ethyl-phenyl and the like; cycloalkyl groups such as cyclohexyl, cycloheptyl and the like; and alkenyl groups such as vinyl and the like. In particular, R is preferably an alkyl group having 1 to 8 carbon atoms such as a methyl group, or a phenyl group. Further, in formula (1), R ¹ is a fluorinated monovalent hydrocarbon group, particularly preferably 3,3,3
- a fluoroalkyl group such as a trifluoropropyl group. In this method it is particularly preferred that t is 3, ie that the cyclic siloxane is a cyclic trisiloxane. In the chain terminator of formula (2), R ² and R ³ are groups selected from the group consisting of monovalent hydrocarbon groups and halogenated monovalent hydrocarbon groups, such as alkyl groups having 1 to 8 carbon atoms; phenyl , methylphenyl, etc.; cycloalkyl groups; alkenyl groups, such as vinyl, allyl, etc.; and fluoroalkyl groups, such as 3,3,3-trifluoropropyl. It will be clear that R ² and R ³ can both be alkyl groups or groups chosen from alkyl and aryl groups, such as methyl and phenyl groups. However, in particularly preferred embodiments R ² and
One of R ³ is an alkyl or aryl group having 1 to 8 carbon atoms, such as a methyl or phenyl group, and the other is a fluoroalkyl group, such as a 3,3,3-trifluoropropyl group. preferable. In formula (2), s is an integer from 2 to 50. Typically, one method for producing diorganopolysiloxane polymers with low molecular weight silanol end groups of formula (2) as described below involves about 70% of the polymer having three siloxy units, disiloxy, tetra siloxy, pentasiloxy, hexasiloxy,
A polymer mixture containing about 30% of a diorganopolysiloxy polymer mixture with silanol end groups such as heptasiloxy, octasiloxy, etc. is obtained. Therefore, in the method of the present invention, it is possible to use a single type of polymer, but it is also possible to use diorganopolysiloxane polymers containing silanol end groups in which s in formula (2) takes various integer values. It should be understood that mixtures can also be used and are typically used. The method for producing a cyclic polysiloxane having a fluorinated substituent will be specifically described below. In the first step, as known in the prior art, a diorganodichlorosilane having an appropriate fluorine substituent is added. selected and hydrolyzed it in water. After hydrolyzing these diorganodichlorosilanes in water, excess water and acid are separated from the hydrolyzate (hereinafter abbreviated as hydrolyzate). The hydrolyzate can then be washed with water and treated with a weak base such as sodium bicarbonate to neutralize the acid. If the acid content of the hydrolyzate is below the standard value, collect the hydrolyzate and add an alkali metal hydroxide such as sodium hydroxide to it.
The hydrolyzate mixture is added at a concentration of 0.1 to 5% by weight and heated to a high temperature above 200° C. under atmospheric or reduced pressure to preferentially convert the hydrolyzate to cyclic siloxanes and convert it into an overhead distillate. Distilled as In this way, cyclic polysiloxanes having 3 to 10 SiO groups, mainly cyclic trisiloxanes and cyclic tetrasiloxanes, can be distilled off from the top of the column from the hydrolyzate. In the process of the invention, this decomposition step is carried out in such a way that the cyclic trisiloxane is preferentially obtained as the overhead distillate, since it is particularly easy to carry out when applied to the polymerization of cyclic trisiloxanes. . This makes the cracking reactor temperature high enough to boil cyclic trisiloxanes with fluorinated substituents and not high enough to boil higher boiling cyclic polysiloxanes. This is achieved by holding the Therefore, using such a method, most of the hydrolyzate can be converted into cyclic trisiloxane, which can be separated and collected from the hydrolyzate mixture by distillation. These cyclic trisiloxanes are then used as main reactants for the preparation of polymers with fluorinated substituents, which are the object of this invention. It will be appreciated that diorganodichlorosilanes and therefore cyclic trisiloxanes usually have methyl, 3,3,3-trifluoropropylsiloxy groups as basic substituents or siloxy groups in their molecules. . This is because such groups are included in fluorinated substituent-containing cyclic trisiloxanes which are easily prepared. At this point, it is necessary to explain the method for producing the chain terminator of formula (2). Methods for making such chain terminators are well described in US Pat. No. 3,853,832. However, to explain the description of the patent specification, firstly, a cyclic trisiloxane, which can be a dimethyl or diphenyl cyclic trisiloxane as mentioned above or preferably a methyl 3,3,3-trifluoropropyl cyclic trisiloxane, is selected. To this was added acetone and 19% distilled water equivalent to the weight of the cyclic trisiloxane, and to this mixture was added 0.1 to 5% by weight.
acid activated clay (commercially available from Filtrol Corforation, Los Angeles, Calif.). It will be appreciated that such acid-activated clays act as catalysts in the reaction mixture. The resulting mixture is heated under reflux for 16 hours, during which time an additional amount of water is added. Heating temperature ranges from 50 to 75°C. After a total of 16 to 24 hours of heating, a mixture of acetone, a low molecular weight diorganopolysiloxane polymer with silanol end groups having formula (2) above, water and clay is obtained. The resulting mixture is passed through Celite (a type of diatomaceous earth) to separate the white clay. The mixture is then heated and the solvent mixture, ie acetone and water, is distilled off by stripping. Finally, the mixture is heated to 70-100° C. in a nitrogen stream to remove residual acetone and water. Thus, a polymer with three siloxy units 70~
A mixture of polymers containing 90% and the remainder having 2, 4, 5, 6 and 7 siloxy units and trace amounts of 8
A reaction mixture is obtained which is a low molecular weight diorganopolysiloxane polymer with silanol end groups of formula (2) consisting of a polymer with siloxy units. The polymer typically has a viscosity in the range of 100 to 200 centipoise at 25 DEG C. and a silanol content of 5 to 7% by weight. It should be noted that the method described above is not the only method for the preparation of the silanol-terminated chain terminator of formula (2), and other methods may also be used. For example, a hydrolyzed and purified hydrolyzate of diorganodichlorosilane can be utilized as a chain terminator in the process of the present invention. It should also be noted that the presence of a fluoroalkyl substituent in the silanol-terminated chain terminator of formula (2) is not essential. Therefore, a silanol type chain terminator of formula (2) having only a methyl substituent, a methylphenyl or diphenyl substituent, or having a substituent other than a fluoroalkyl substituent may be used as a chain terminator in the method of the present invention. can be used. Furthermore, cyclic polysiloxanes, preferably cyclic trisiloxanes or cyclic tetrasiloxanes, may be used in the process of the invention. Cyclic trisiloxanes having fluorinated substituents are preferred in the process of the present invention for the production of both low molecular weight and high molecular weight fluorinated substituent-containing diorganopolysiloxanes. Particular preference is given to using cyclic trisiloxanes.
Therefore, the desired amount of chain terminator is mixed into the cyclic polysiloxane of formula (1) and at least 10 ppm of basic polymerization catalyst is added. It is particularly preferred that such basic polymerization catalyst is an alkali metal hydroxide such as potassium hydroxide. See, for example, US Pat. No. 3,002,951. However, other basic polymerization catalysts, such as alkali metal silanolates and also complex alkali metal salts, can also be used in the process of the invention as well as in the prior art. The resulting mixture is then heated to a high temperature.
For example, heating to a temperature of 120-180°C, preferably 140-180°C for 5 minutes to 4 hours, optimally 30 minutes to 1 hour, produces a linear fluorinated substituent-containing diorganopolysiloxane with silanol end groups. Produces a polymer. The process of the present invention has been found to be useful in preparing high viscosity linear diorganopolysiloxane polymers containing fluorinated substituents. Such a polymer is 25
It has a viscosity of 500000 to 300 million centipoise at °C. At least 400 ppm in the production of such high viscosity fluorinated substituent-containing polymers.
of silanol-type chain terminator and at least 10 ppm
It should be noted that preference is given to using mixtures containing basic polymerization catalysts. More preferred is the use of 400-2000 ppm silanol-type chain terminator and 20-50 ppm basic polymerization catalyst. Furthermore, it should be noted that the polymerization reaction time can vary within the range of 5 minutes to 4 hours, but is usually about 5 minutes to 2 hours, more preferably about 30 minutes to 1 hour. After this polymerization time, a neutralizing agent is added to the reaction mixture to neutralize the catalyst. Such a neutralizing agent is described in US Patent Application Serial No. 854562 filed on November 25, 1977 (Razzano
It may be a silyl phosphate such as those described in et al. Chlorsilane, acetic acid and various other weak acids may also be used as neutralizing agents. The advantage of silyl phosphate is that, like the acetic acid neutralizer, it can be used as a buffer in the polymerization mixture without the need for back titration to reach the neutralization point. After neutralizing the reaction mixture, the mixture is heated to a temperature of at least 150 DEG C. for at least one hour and excess cyclic polysiloxane is removed by stripping to yield the desired polymer. It should be noted that using this method it is possible to obtain the desired polymers containing small amounts of volatile or cyclic polysiloxanes of 5% or less in the equilibrium mixture. Viscosity of 500000-300000000 centipoise at 25℃,
More preferably, a fluorinated substituent-containing linear diorganopolysiloxane polymer with silanol end groups as described above having a viscosity of 1000000 to 300000000 centipoise is used, which is supplemented with various types of fillers, especially polymeric bases. It has been found that compounds can be formed with 5 to 300 parts of filler per 100 parts. The filler is selected from silica fillers and extender fillers. Examples of silica fillers, particularly reinforcing silica fillers, are fumed and precipitated silicas and especially silicas treated with cyclic tetrasiloxanes such as those described in U.S. Pat. No. 2,938,009 and further treated with silazane and diethylhydroxylamine. It is a reinforced silica filler. Processing aids, such as those described in U.S. Pat. No. 4,089,833, are added to the mixture of polymeric base and filler that is typically compounded in a dough mixer. Such processing aids prevent the resulting composition from undergoing structural changes prior to curing and from sticking to compounding mills, as described in that patent. Various other additives may be added to these components, such as oil resistance additives, flame retardants such as carbon black and platinum, and compression set prevention additives such as rare earth octoates. can. To the resulting mixture, an organic peroxide type catalyst such as dicumyl peroxide, dibenzoyl peroxide, etc., such as those described in US Pat. The material is cured to form a silicone elastomer with fluorinated substituents. Silicone rubber compositions having such fluorinated substituents, particularly silicone rubber compositions containing thermally crosslinkable fluorinated substituents, are particularly useful because they produce silicone elastomers with excellent solvent resistance. All conventional methylphenyl type polymer bases intended for the production of thermally crosslinkable silicone rubber compositions are compounded with water or, if the polymer base has silanol groups, with fillers. It should be noted that compounding becomes impossible as this results in a composition that crumbles or forms structures. It should further be noted that in such compositions containing peroxide catalysts, the peroxide catalysts are activated by heating them to temperatures above 100°C. The present invention also provides flnorinated SiH olefin platinum catalyzed compositions containing fluorinated substituents such as those described in U.S. Pat. No. 4,061,609.
substituted SiH olefin platinnm catalyzed
It can also be used to make polymeric bases that are useful for composites. In the method of the present invention described above,
The cyclic siloxane of formula (1) need not be a pure substance, but may be a mixture of a cyclic trisiloxane and a cyclic tetrasiloxane, the cyclic trisiloxane containing a fluorine substituent; Cyclic tetrasiloxanes can also have vinyl or methylvinyl substituents. Such cyclic tetrasiloxanes or methylvinyl cyclic trisiloxanes are present in the reaction mixture to introduce vinyl groups into the final polymer formed, thereby allowing the composition to undergo peroxide catalyzed crosslinking. A thermally crosslinkable fluorinated substituent-containing silicone elastomer can be formed. While the process of the invention described above can be used advantageously, further improvements and extensions according to the invention are provided for the cyclic polysiloxanes of the formula (3) which have no fluorinated substituents. Formula to polysiloxane
R ⁶ OH (wherein R ⁶ is at least 6 carbon atoms,
High molecular weight alcohols (more preferably aliphatic monovalent hydrocarbon groups having at least 10 carbon atoms, such as from 10 to 30 carbon atoms), such as octadecanol, hexadecanol, tetradecanol, oleyl alcohol This can be achieved by reacting a chain terminator such as. Such high molecular weight alcohols are particularly suitable for high viscosity linear diorganopolysiloxane polymers, e.g.
300000000 centipoise, more preferably 1000000
It has also been found to be advantageous for use as a chain terminator in processes for the preparation of polymers with viscosities of .about.30,000,000 centipoise. These high molecular weight chain terminators will be incorporated into the mixture at substantially the same rate as the silanol type chain terminators of formula (2). These alcohol-type chain terminators are available at lower cost and do not require special methods for their manufacture. Such higher alcohol type chain terminators can be used as chain terminators in equilibration reactions in the preparation of both polymers with fluorinated substituents and polymers without fluorinated substituents. Therefore, in formula (3), R ⁴ and R ⁵ represent a group selected from the group consisting of a monovalent hydrocarbon group, a fluorinated monovalent hydrocarbon group, and a mixed group thereof, and t
represents 3. R ⁴ and R ⁶ are alkyl groups having 1 to 8 carbon atoms such as methyl, ethyl, propyl, etc.;
Alkenyl groups such as vinyl, allyl, etc., cycloalkyl groups such as cyclohexyl, cycloheptyl, etc., aryl groups such as phenyl, methyl-phenyl, ethyl phenyl, etc., and 3 to 8 carbon atoms such as 3,3,3-trifluoropropyl. may be a group selected from fluoroalkyl groups. Additionally, the reaction mixture of cyclic polysiloxanes may include cyclic trisiloxanes and cyclic tetrasiloxanes or higher cyclic siloxanes. It is also preferred that the cyclic siloxane is either a cyclic trisiloxane or a mixture of a cyclic trisiloxane and a cyclic tetrasiloxane. In a particularly preferred embodiment in this case, R ⁴ in the compound of formula (3) is an alkyl group having 1 to 8 carbon atoms, for example a methyl group, and R ⁶ is a 3,3,3-trifluoropropyl group. , t is 3. Such a cyclic trisiloxane is mixed with a cyclic tetrasiloxane in which t is 4, R ⁴ is methyl, and R ⁶ is vinyl. Such mixtures are necessary for the preparation of high molecular weight vinyl group-containing fluorinated substituent-containing diorganopolysiloxane polymers which are useful in the preparation of thermally crosslinkable silicone elastomers having fluorinated substituents. The method for producing the fluorinated substituent-containing cyclic trisiloxane is the same in this embodiment as described above. Methyl vinyl cyclic tetrasiloxanes are prepared in a similar manner by using the appropriate diorganodichlorosilanes. The only difference is
In the decomposition step, the reaction mixture is heated to a higher temperature in order to preferentially distill off the cyclic tetrasiloxane from the top of the column. An improved method allows cyclic tetrasiloxane to be distilled overhead at maximum efficiency by condensing the boiling cyclic trisiloxane and returning it to the cracking reactor for use in the reaction again. It can be disassembled.
Therefore, after a suitable cyclic siloxane is obtained, it is mixed together in the appropriate proportions and a commercially available higher alcohol type chain terminator is added to the mixture in the desired proportions. Then, an appropriate amount of basic polymerization catalyst is added. Regarding the concentration of chain terminators, use higher alcohol type chain terminators at a concentration of at least 50 ppm to 200 ppm,
The basic polymerization catalyst is also used at a concentration of at least 10 ppm, more preferably 20 to 50 ppm. In the preparation of polymers that do not contain fluorinated substituents, only cyclic tetrasiloxanes may be used with higher alcohol type chain terminators and basic equilibration catalysts such as alkali metal hydroxides. The resulting mixture is heated to a temperature above 140 DEG C. for a period ranging from 2 to 24 hours until a maximum amount of the preferred high viscosity polymer is obtained. The reaction mixture is then cooled, the basic equilibrated catalyst is neutralized with a mild acid such as silyl phosphate or acetic acid, and the unreacted cyclic siloxane is removed by stripping to leave the desired polymer. In the production of polymers with fluorinated substituents, cyclic trisiloxanes with fluorinated substituents are used alone or in the form of mixtures with vinyl group-containing cyclic trisiloxanes or methyl-vinyl cyclic trisiloxanes. , an appropriate amount of an alcohol-type chain terminator and a basic polymerization catalyst at the concentration shown below,
For example, in the presence of potassium hydroxide or potassium silanolate, at a temperature of 120 to 180°C, usually for 5 to 4 minutes.
Polymerization is carried out by heating for a period of time, more preferably from 5 minutes to 2 hours, particularly preferably from 30 minutes to 1 hour. After said polymerization time has elapsed, the basic polymerization catalyst is neutralized with a mild acid, such as silyl phosphate, preferably for the reasons mentioned above, or another mild acid, such as acetic acid. The same basic polymerization catalyst used in the previous embodiment and described in the aforementioned US Pat. No. 3,002,951 may be used in this embodiment. Further, as a chain terminator, any high molecular weight aliphatic alcohol, preferably having 6 to 30 carbon atoms, can be used.
It should also be noted that high molecular weight aliphatic alcohols having 10 to 30 carbon atoms, more preferably 10 to 30 carbon atoms, can be used in this process. After the polymerization reaction is completed, the reaction mixture is cooled, a neutralizing agent is added, and the reaction is preferably terminated within 30 minutes to 1 hour. The reaction mixture is then cooled and a neutralizing agent for the basic polymerization catalyst is added, such as silylphonate for the reasons mentioned above. Unreacted cyclic siloxane is then removed leaving the desired polymer. Removal of unreacted cyclic siloxane is carried out by heating the reaction mixture to a temperature of 150 DEG C. for at least 1 hour.
Although this second aspect of the invention can be used to prepare diorganopolysiloxane polymers of various viscosities, it is especially suitable for the preparation of high molecular weight linear diorganopolysiloxane polymers containing fluorinated substituents. It should be noted that it is preferable to use Therefore, the formula: (In the formula, R ⁸ and R ⁹ represent a group selected from a monovalent hydrocarbon group and a halogenated monovalent hydrocarbon group, and R ¹⁰
is at least 6, more preferably at least 10
, usually represents an aliphatic group having 10 to 30 carbon atoms, and n represents a polymer with a viscosity of 500,000 to 500,000 at 25°C.
300000000 centipoise (an integer varying within a range) is obtained. Typically R ⁸ and
R ⁹ can be any group or substituent shown for R ⁴ and R ⁵ in the cyclic trisiloxane of formula (3), and R ³ is preferably an alkyl group having 1 to 8 carbon atoms, R ⁹ is a 3,3,3-trifluoropropyl group,
Preferably, R ¹⁰ is an octadecyl group. Such compounds, preferably from 1000000 at 25°C
A compound with a viscosity of 300000000 centipoise was selected and used as the polymer base, and this
5 to 300 parts per 100 parts of filler, particularly preferably a reinforcing silica filler selected from fumed silica and precipitated silica, preferably a reinforcing silica filler selected from fumed silica and precipitated silica, preferably
Silica fillers treated with cyclic polysiloxanes or treated with silazane or diethyl-hydroxylamine as described in US Pat. No. 2,938,009 can optionally be added. The mixture of these ingredients, which is usually compounded in a dough mixer, is provided with various necessary processing aids, such as those described in the aforementioned U.S. Pat. No. 4,089,833, and in the first embodiment of the invention. The various other ingredients listed are added, a peroxide catalyst is blended into the resulting mixture, and the resulting mixture is heated to a temperature of 100°C or higher to form the fluorinated substituents with excellent solvent resistance as described above. It is possible to produce silicone elastomers with It is observed that the fluorinated substituent-containing silicone elastomers produced by the above process have good physical properties comparable to such elastomers produced by prior art processes. Additionally, such fluorinated substituent-containing polymers and dimethyl polymers prepared by the method of the present invention may be used in SiH olefin platinum-catalyzed compositions such as those described in the aforementioned U.S. Pat. No. 4,061,609. It is something. Next, the present invention will be further explained with reference to Examples. However, it goes without saying that these do not limit the present invention in any way. In the examples, all parts are by weight. Example 1 Methylfluoropropylcyclotrisiloxane and octadecanol as shown in Table 1 below are charged to a reactor and the resulting mixture is heated to 135°C and purged with nitrogen to remove traces of moisture. Removed. Methylvinylcyclotrisiloxane and sodium hydroxide catalyst were added to initiate the polymerization reaction. After 38 minutes, the reaction was stopped by removing the heating bath and introducing carbon dioxide gas. Finally, the polymer was neutralized by mixing with silyl phosphate in a dough mixer. Volatile matter is the first
Measurements were made as described in the table. The method for measuring volatile content is by heating the polymer in a shallow dish at 135° C. under 15 mm vacuum for 45 minutes and measuring the weight loss. Table 1 shows the Williams plasticity of the resulting polymer before and after removal of volatiles. The experimental results are shown in Table 1.

[Table] Two of these polymers were mixed with 100 parts of polymer, 3 parts of dimethylsilanol oil processing aid, 4 parts of linear vinyl rubber processing aid with high vinyl content containing 13.5 mol% vinyl groups, and tetramer treatment. Compounding treatment was carried out by mixing 23 parts of the fumed silica filler and 0.2 parts of red iron oxide. The compounded ingredients are mixed with bis(2,
It was pressure cured with 1.6 parts of 4-dichlorobenzoyl) peroxide. These compositions are shown as Compositions C and D in Table 2 below. The physical properties of these crosslinked cured compositions cured under the conditions in Table 2 are shown in Table 2.

[Table] Example 2 Polymers were prepared by the method of the present invention using silanol-type chain terminators with fluorinated substituents and by the prior art method. After preparing the polymer by the prior art method and the method of the present invention, the polymer is heated to 350° C. for 15 minutes in the presence of moist nitrogen acting as a hydrolyzing agent.
Heating for minutes increased the tendency of the polymer to decompose. The results are shown in Table 3. Table 3 shows the weight loss of the polymers under the above tests.

[Table] The results in Table 3 show that polymers prepared using silanol-type chain terminators, particularly fluorinated substituent-containing silanol-type chain terminators, are compared to polymers made using trimethylsiloxy-type chain terminators. This shows that the stability is almost the same. Example 3 In a clean, dry reactor, 500 parts (1.06 moles) of methyl 3,3,3-trifluoropropylsiloxane cyclic trimer (FS), 1,3,5,7-tetramethyl-1,3,5 , 1.43 parts (0.001 mol) of 7-tetravinylsiloxane cyclic tetramer (VT),
and 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)trisiloxane-1,5-diol 0.49 parts (1.001 mol)
was loaded. The reactor contents were heated to 120-140°C and 25 parts of trimer was removed to reduce the water content.
Purged with nitrogen until the concentration was below 10 ppm. The reactor temperature was adjusted to 140° C. and when this temperature was reached, 0.98 parts of sodium fluorosilanolate (giving the equivalent of 0.025 g of sodium hydroxide) was added. Polymerization was carried out under stirring for 8-10 minutes and then allowed to stand for up to 35 minutes before neutralizing the catalyst with silyl phosphate (corresponding to a 13% solution of H ₃ PO ₄ ).
Then, the polymer was heated to 150-160℃ to reduce the volatile content to 0.8±0.5%.
Volatiles were removed by holding until a level of .
A highly tough rubber with a Williams plasticity of 255 was obtained. This polymer had a solution viscosity of 2.112 (measured at 77° for a 2% solution in ethyl acetate). Compounding gave this rubber a crosslinked (vulcanized) rubber with good properties. Composition Polymer 100 Polydimethyl containing 13.5% vinyl groups on the chain 4 HO[-Si(Me) ₂ -O]- ₆ H 3 Humid silica ^*1 23 Rare earth metal octoate 0.2 TS-50 ^*2 1.6 *1 Fumed silica treated with 1,3,5,8-octamethylsiloxane cyclic tetramer *2 Bis(2,4-dichlorobenzoyl) peroxide, 50% active paste; *Cadox TS-50, Nowry
Manufactured by Chemical Corp. (located in New York) *Luperco CST, Lucidol Div.
Made by Pennwalt Corp. (located in New York)

【table】

[Table] Example 4 500 parts (1.06 mol) of fluorosilicone trimer and methylvinyl trimer were placed in a clean, dry reactor.
1.43 parts (0.001 mol) and 0.61 parts (0.0012 mol) of 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)trisiloxane-1,5-diol was loaded. The contents of the reactor were heated to 120-140°C and the system was dried as in Example 1 and the reactor temperature was increased to 140°C.
Adjusted to. As a catalyst, sodium fluorosilanolate was added in an amount equivalent to 0.017 part (0.00042 mol) of sodium hydroxide. Polymerization was terminated after 35 minutes by neutralization with silyl phosphate. The resulting rubber was then devolatilized at 150-160°C to a volatile content of 0.8±0.5%. Thus, a rubber with a Williams plasticity of 258 was obtained. This polymer had a solution viscosity of 2.177 (measured at 77° as a 2% ethyl acetate solution) and a torque reading of 800 m·g on the Prabender at a shear rate of 40 rpm at 37°C. This rubber is Example 3
When compounded and crosslinked according to the method of Pressure crosslinking (vulcanization) 10 minutes/287〓; Post-baking 4 hours/
400〓 Properties Hardness Shore A 41 Tensile Strength psi 1095 Elongation % 650 Tear Strength (Type C) lbs 135 Compression Set 22hr/300〓 38% 〃 22hr/350〓 25% Example 5 Clean Dry Reactor 210 parts (0.45 mol) of fluorosilicone trimer, methyl vinyl trimer
0.6 part (0.007 mol) and 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl)trisiloxane-1,5-diol
0.104 part (0.0002 mol) was charged. This polymerization mixture was prepared according to the method described in Examples 3 and 4.
It was then dried to remove 10 parts of fluorosilicone trimer. Then colloidal sodium hydroxide (particle size 25-30 microns) in 1,3,5,7-octamethyl-siloxane cyclic tetramer.
0.007 part (0.00018 mol) was added as catalyst.
Polymerization was carried out for 35 minutes, then the catalyst was neutralized and the rubber was devolatilized according to the method described in Example 1. A rubber with a Williams plasticity of 305 was obtained. This rubber recorded a torque of 880 m·g on a Brabender at 37° C. at a shear rate of 40 rpm. This polymer gave a solution viscosity of 2.541 (measured at 77° for a 2% solution in ethyl acetate).

Claims (1)

[Claims] 1 (a) Formula: (RR ¹ SiO) _t (wherein R is selected from the group consisting of an alkyl group and a phenyl group, and R ¹ is a 3,3,3-trifluoropropyl group) and t represents 3) cyclic polysiloxane, formula (b): (wherein R ² is selected from the group consisting of an alkyl group and a phenyl group, R ³ is a 3,3,3-trifluoropropyl group, and s represents an integer from 2 to 50); and (c) a basic polymerization catalyst of 1000000 to 300000000 centipoise at 25°C, consisting of a first step of reacting the basic polymerization catalyst under less than 10 ppm of moisture in the reaction medium, and a second step of neutralizing the basic polymerization catalyst. A method for producing a fluorosilicone polymer having viscosity. 2 In the first step, the chain terminator has s of 2,
3, 4, 5, 6, 7 and 8. 3. The production method according to claim 1, wherein in the first step, the basic polymerization catalyst is an alkali metal hydroxide. 4 In the first step, the chain terminator (b) is at least 400 ppm and the basic polymerization catalyst (c) is at least 10 ppm.
The manufacturing method according to claim 1, which is used in a proportion of . 5. The manufacturing method according to claim 1, wherein the first step is carried out at a temperature in the range of 120 to 180°C. 6. The manufacturing method according to claim 1, wherein the first step is carried out for 5 minutes to 4 hours. 7. The production method according to claim 1, wherein in the second step, the basic polymerization catalyst is neutralized with silyl phosphate. 8 After the second step, further add the mixture to at least
2. The method according to claim 1, further comprising the step of heating to a temperature of 150 DEG C. for at least 1 hour and removing volatile components by stripping.