JPS5833885B2 - Manufacturing method of polysiloxane oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing low viscosity silanol chain-terminated silicone oils from cyclic tetrasiloxanes.

More specifically, the present invention provides a method for converting a low molecular weight silanol chain-terminated diorganopolysiloxane oil into a cyclic tetrasiloxane in which at least one of the silicon-bonded organo groups in the diorganopolysiloxane has 3 or more carbon atoms. It relates to a method of manufacturing from

Low viscosity silanol chain-terminated silicone oils, particularly fluorosilicone oils, have utility in a variety of applications, including their use in vulcanizable silicone elastomers.

For silicones with silicon-bonded alkyl or haloalkyl substituents containing three or more carbon atoms, known methods for preparing such silicone oils require silicone cyclic trimers as starting materials. shall be.

However, silicone cyclic trimers are difficult materials to obtain in high yields, whereas silicone cyclic tetramers are much easier to prepare in high yields.

However, it has been argued that cyclic tetramers cannot be directly polymerized.

See Pierce US Pat. No. 2,979,519.

However, it has now been discovered that silicone cyclic tetramers, which are difficult to polymerize, can be polymerized in the presence of water to produce silanol chain-terminated silicone oils that can be made into commercially successful rubbers.

This new successful polymerization appears to involve proper selection of polymerization catalyst and temperature.

For example, cesium hydroxide, or even potassium hydroxide,
Alternatively, using these syralates, silicone oil can be obtained from the cyclic tetramer with a yield of 50%.

Silanol chain-terminated copolymers of fluorosilicone and diorganosilicone can also be prepared by adding water to the polymerizable mass of the corresponding cyclics.

As already mentioned, a significant disadvantage associated with the prior art process is that the required cyclic trisiloxanes are formed in low yields during the initial cracking of the dihalosilane ice melt with potassium or cesium hydroxide.

Cyclic tetrasiloxanes are formed in larger amounts.

For this reason, maximizing the yield of cyclic trisiloxanes from cracking processes requires the use of less energy efficient high reflux distillation methods - this is because cyclic trisiloxanes are more readily produced by known methods. Even with the tendency to react, the overall process means that methods that form polymers rather than cyclic trisiloxanes are still more expensive than methods that use cyclic tetrasiloxanes.

U.S. Patent Application No. 463,435 dated April 24, 1974
The issue discloses the following unexpected discoveries:

According to the present invention, the presence of a selected type of catalyst in a temperature range hitherto unimagined on the lower end side causes at least one of the organo substituents bonded to a silicon atom to become a carbon atom. Cyclic tetrasiloxanes of three or more aliphatic or haloaliphatic compounds, such as -CH2CH2R5 (R5 is, for example, a perfluoroalkyl group), can be readily equilibrated in high yields.

The patent also states that cyclic tetrasiloxanes can be equilibrated to provide either low molecular weight oils or high molecular weight diorganopolysiloxane gums, the latter being suitable for forming heat vulcanizable silicone rubber compositions. Disclosed.

The present invention is primarily concerned with carrying out such equilibrium reactions in the presence of small amounts of water to produce silanol chain-terminated oils.

Accordingly, a first object of the present invention is to provide a silanol chain-terminated low molecular weight diorganopolysiloxane homopolymer in which one of the organo groups bonded to the silicon atom is aliphatic or haloaliphatic with at least 3 or more carbon atoms. Another object of the present invention is to provide a method for producing copolymer oil in high yield.

One of the organo groups bonded to the silicon atom has 3 carbon atoms.
Provides a means for producing low molecular weight diorganopolysiloxane oils chain-terminated with or more aliphatic or haloaliphatic groups, silanols, from cyclic tetrasiloxanes and/or mixtures of cyclic tetrasiloxanes containing such groups. This is the object of the present invention.

A cyclic tetrasiloxane or a mixture of cyclic tetrasiloxanes is equilibrated at relatively low temperatures in the presence of a selected catalyst to form an aliphatic compound in which at least one of the organo groups bonded to the silicon atom has 3 or more carbon atoms. or a haloaliphatic group with a viscosity of i,ooo~10 at 25°C
It is another object of the present invention to provide a method for producing low molecular weight diorganopolysiloxane oils chain-terminated with 0,000 centipoise silanols.

Using cyclic tetrasiloxanes as a starting material, at least one of the organo groups bonded to the silicon atom is -CH
It is also an object of the present invention to provide a process for producing a silanol chain-terminated diorganopolysiloxane oil having a viscosity of 1.000 to 100,000 centipoise at 25°C, where 2CH2R5 is perf and R5 is perfluoroalkyl.

In accordance with the above purpose, at least one of the ork groups is 3
an aliphatic or haloaliphatic group having 1 or more carbon atoms and a viscosity of 1.000 to ioo, oo at 25°C
Provided by the present invention is a method for producing a silanol chain-terminated diorganopolysiloxane oil that is o centipoise,
The process comprises (a J(i) formula % formula %) where R is each independently methyl, ethyl, vinyl or phenyl and R1 is alkyl containing 3 to 8 carbon atoms, 3 to an alkyl halide containing 8 carbon atoms or a cycloalkyl containing 5 to 8 carbon atoms; 20 to 100 mole φ of the entire composition is ((:),
40 to 14 pIMn in the presence of 5 to 300 pIMn of a catalyst selected from KOH, COH and their syralates, and water.
(b) after reaching equilibrium;
The goal is to neutralize the catalyst in the reaction mixture and (c) recover the desired product.

In a preferred embodiment, after reaching equilibrium, the catalyst is treated with an inorganic acid such as phosphoric acid or with formula R8'btx4-b (R6 haalkyl, cycloalkyl, vinyl or phenyl;
Preferably it is alkyl or cycloalkyl having 1 to 8 carbon atoms, X is bromine or chlorine, and b is 0 to 8.
Neutralize with an organosilane compound represented by 3).

In a preferred embodiment, the silanol chain-terminated diorganopolysiloxane oil product is recovered in substantially pure form as follows.

That is, after the equilibration and neutralization steps, the reaction mixture was
Heat to 150-200° C. under mHg vacuum to strip off all volatiles leaving the desired product.

Generally, the cyclic tetrasiloxane composition is prepared in the presence of water for 1
/4 to 20 hours, preferably 50 minutes to 10 hours to form a silanol chain-terminated diorganopolysiloxane oil.

For maximum efficiency, the cyclic tetrasiloxane contains 1. trifunctional silanes should be less than 20 pIMII, monofunctional siloxanes should be less than 200 pIMII, and cyclic siloxanes other than tetrasiloxanes should be less than 0.5 by weight.

R1 substituent in tetrasiloxane is R5R5CH2CH
2, in which R5 is a perfluoroalkyl group having 1 to 6 carbon atoms, especially trifluoromethyl.

Viscosity i, ooo~100,000 at 25°C by this method
Produces centipoise low molecular weight oil.

It will be obvious to those skilled in the art that the molecular weight can be controlled by adding water to the tetramer that polymerizes during equilibration.

The more water there is, the lower the viscosity will be; the less water, the higher it will be.

Silanol chain-terminated low molecular weight diorganopolysiloxane oils can be converted to room temperature curable silicone elastomers by known methods.

These diorganopolysiloxanes can be further polymerized to high molecular weight gums with non-bonded rearrangement catalysts such as tin carboxylates, amines and amine salts.

The gums can be cured, for example with peroxide catalysts, to silicone elastomers.

In all cases, the presence of fluoroalkyl substituents increases oil resistance.

R and R1 in the cyclic tetrasiloxanes of the above formula (1)
The groups may be monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups of the type well known for use in bonding to silicon atoms.

As already mentioned, to realize the benefits of the invention it is necessary that one of the above two groups, for example at least the R1 group, contains 3 or more carbon atoms.

In the above formula (1), R is individually methyl, ethyl, vinyl or phenyl, and R1 is alkyl having 3 to 8 carbon atoms, halogen having 3 to 8 carbon atoms, such as propyl, butyl, etc. Alkyl oxides such as 3-chloro”
Lopropyl, 4-chlorophthyl, 3-fluoropropyl,
3,3-difluoropropyl, 3,3,3-trifluoropropyl, etc., and cycloalkyls having 5 to 8 carbon atoms such as cyclopentyl, cyclohexyl, cycloheptyl, etc.

Preferably, R1 is -CH2CH2R5 (wherein R5
is a substituent of perfluoroethyl, etc.).

More preferably R1 is 3,3,3 trifluoropropyl and R is methyl or ethyl.

A small amount of R in the vinyl form increases the resistance of any product to subsequent curing, for example with peroxide, to a silicone elastomer.

In formula (ii), there is no need to limit the comonomer to a tetramer in order to secure the advantages of the present invention.

In the present invention, trimers, tetramers, hexamers, heptamers, etc., that is, X is preferably in the range of 3 to 10, preferably 3 to 6
Mixtures of cyclics can be used.

However, if dihalosilanes are hydrolyzed according to the preferred embodiments described above, the average of The method of the invention begins with the production of cyclic tetrasiloxanes.

The process begins with the production of cyclic tetrasiloxanes.

and the cyclic tetrasiloxanes preferably have the formula RI
Diorganodihalogensilane of R8iX2 (wherein R and R1 are as defined above for formula (:) and X is a halogen such as chlorine or bromine, preferably chlorine) obtained from.

These diorganodihalogensilanes of 99% purity are added to water at room temperature.

It is preferred to use about 2 to 10 moles of water per mole of diorganodihalogensilane.

Most preferably, after adding the diorganodichlorosilanes to the water, 20 parts by weight of HCI are included in the hydrolysis mixture.

Hydrolysis can be carried out without a solvent, but it can also be carried out in the presence of a water-immiscible solvent such as toluene, xylene, benzene and the like.

When a solvent is used, the melted ice can be easily separated from the acid aqueous solution.

Therefore, it may be preferred to add the solvent to the water before adding the organohalosilanes to the water, or to add the solvent after adding the organohalosilanes or organohalosilanes mixture to the water.

Most preferably, a water-immiscible organic solvent is added to the water prior to addition of the diorganedihalosilanes.

The use of very pure diorganodihalosilanes prevents undesirable by-product acids, such as trifunctional siloxanes, from being incorporated into the melted ice.

The organohalosilanes and, if used, a water-immiscible solvent are added to the water with stirring over a period of 1/2 to 2 hours.

The ice melt dissolved in the water-immiscible solvent phase is then separated from the aqueous phase.

The thawed ice is then brought to pH with a mild base such as sodium bicarbonate.
to about 7 to 8, neutralizing any residual amounts of acid, especially any hydrochloric acid, that may be trapped in the ice melt, especially in the presence of water-immiscible organic solvents.

Preferably, the melted ice product dissolved in the water-immiscible organic solvent phase is primarily cyclic polysiloxanes containing 3 to 10 silicon atoms, with some silanol chain-terminated low molecular weight lines. diorganopolysiloxanes.

When a water-immiscible organic solvent is used, the ice melt is then heated to an elevated temperature and all solvent is removed from the siloxane ice melt by overhead distillation.

The melted ice product from which most of the solvent has been removed can then be subjected to cracking by adding 0.1 to 5 parts by weight, preferably 0.1 to 2 parts by weight of a cracking catalyst such as potassium hydroxide or cesium hydroxide. can.

It is preferable that the amount of catalyst is 0.5 to 2 parts by weight of the melted ice.

Then, the resulting mixture of ice melt and cracking catalyst is preferably heated under a vacuum of 1 to 100 mflHg.
Heat to a high temperature of 50° C. or higher, for example 150 to 200° C., for 1 to 5 hours.

During such heating, the mixture of cyclic polysiloxanes,
Specifically, cyclic tripolysiloxanes, cyclic tetrapolysiloxanes and cyclic pentapolysiloxanes are distilled continuously from the top of the column.

This cranking process with potassium hydroxide or cesium hydroxide increases the formation of the three types of cyclics mentioned above.

For example, 95% by weight of the melted ice can be converted into cyclic trisiloxanes, cyclic tetrasiloxanes and cyclic pentasiloxanes.

This maximizes the formation of cyclic tetrapolysiloxanes from the initial melt, and these cyclic tetrapolysiloxanes are used in the process of the invention.

As is self-evident, a solvent may be used to aid cracking.

Whatever solvent is used, such as cracker process oil, must have a boiling point so high that it will not be distilled overhead with the cyclic trisiloxanes, cyclic tetrasiloxanes, and cyclic pentasiloxanes.

A mixture of cyclic polysiloxanes from 1 to 100111 mH
g pressure, preferably 1 to 20 ynHg pressure, 80 to 20
By distilling at a temperature around 0° C., cyclic tetrasiloxanes can be separated from cyclic trisiloxanes and cyclic pentasiloxanes by known distillation means.

These distillation procedures provide substantially pure cyclic tetrasiloxanes and the cyclic tri- and pentasiloxanes are recycled back to the cracking vessel.

When these tri- and penta-cyclics are mixed with additional ice melt and subjected to the cracking method described above, a mixture of cyclic trisiloxanes, cyclic tetrasiloxanes and cyclic pentasiloxanes is again produced in a yield of 95%.

By such a distillation purification method, substantially pure cyclic tetrasiloxane of the formula (i) can be obtained from the siloxane ice melt in a yield of 70 to 80%.

The cyclic tetrasiloxane contains less than 200 parts of monofunctional siloxy units and less than 20 parts of trifunctional siloxy units, respectively, and 0 to 5 parts by weight of other cyclic siloxanes, i.e., cyclic trisiloxanes or cyclic pentasiloxanes. It will be done.

The content of these impurities should be controlled.

Compounds of formula (ii) can be prepared in an analogous manner, but
It is not necessary to isolate the tetracyclic compound prior to use if desired.

However, isolation is preferred.

For the preparation of the silanol chain-terminated oil, the cyclic tetrapolysiloxane of formula (i) above, alone or in combination with the cyclic polysiloxane (il), is placed in a suitable container.

Preferably, no solvent is used with the cyclic polysiloxane composition.

Two critical aspects are controlled: the temperature of the reaction and the nature of the catalyst.

For example, the above KOH or C80H is 5 to 300 ppI1
It is used in an amount of 1, more preferably 10 to 1 oopml.

The reaction is carried out at a temperature of 40 to 140°C, more preferably 40 to 110°C for homopolymers of formula (i).

Cesium hydroxide and its syralates are preferably used at a reaction temperature of 70 to 90°C.

Potassium hydroxide is most efficient at temperatures of 105-140°C.

Cesium hydroxide and potassium hydroxide are, of course, well-known substances and commercially available.

Syralates are also well known in silicone chemistry and can be obtained, for example, by reacting the corresponding hydroxide with any diorganopolysiloxane fluid or even a cyclic polysiloxane such as octamethylcyclotetrasiloxane.

The cyclic tetrasiloxanes of formulas (1) and (1:) above, the catalyst and water are heated or cooled to the indicated temperature range for 1 to 20 hours, preferably 50 minutes to 10 hours, at which point equilibrium is reached.

Water can be present at an initial stage, but is preferably added incrementally during equilibration, as exemplified below.

The amount of water used is 10% of the cyclic siloxanes (i) and (11).
Cyclic siloxanes (1) and (ii) may vary widely, such as from 0.025 to 1 part water per 100 parts water.
Preferably, 0.05 to 0.2 parts per part of water are used.

At the end of equilibration, 50 to 80 weight pounds of the desired silanol chain-terminated low molecular weight oil will be added to the mixture based on the starting cyclic siloxanes (i) and (il).

Thus, at equilibrium, 20-50% of the mixture
The diorganopolysiloxane that is being decomposed to form the cyclic polysiloxane and the cyclic polysiloxane formed in the diorganopolysiloxane oil are present in the same amount. There is.

Once this equilibrium point is reached, the reaction mixture is optionally cooled and then reagents are added to neutralize the catalyst.

As mentioned above, many neutralizing agents can be used, including phosphoric acid or those of the formula R' S i
8 alkyl or cycloalkyl, vinyl or phenyl group, X is bromine or chlorine, and b is O~3
It is preferred to use either organohalosilanes or halosilanes represented by

This step is necessary to ensure that the final product is stable against moisture, heat, etc.

After neutralization, the reaction mixture is heated to an elevated temperature, e.g., 150-200° C., under a vacuum of 1-100 mmHg to strip off any cyclic polysiloxanes, and any cyclics are recycled into the equilibration vessel. It can be circulated.

This leaves a silanol chain-terminated low molecular weight diorganopolysiloxane oil with the properties described above.

Obviously, such silanol chain-terminating oils can include gums, fillers such as fumed or precipitated silica, extending fillers such as zinc oxide, iron oxide, titanium oxide, diatomaceous earth, etc., crosslinking agents such as silicates and alkoxyalkylsilanes, Heat aging additives such as iron oxides, pigments, catalysts such as titanium salts, and any other additives customary in producing useful compounds can be mixed.

In a preferred embodiment of the invention, the silanol-containing products of this step are further condensed to high molecular weight polymers and copolymers by well-known methods. can be reacted.

If desired, a mutual solvent may be used to increase the solubility of the catalyst in the siloxane.

Among the group of catalysts are metal salts of monocarboxylic acids such as lead 2-ethyl octoate, dibutyltin diacetate,
Dibutyltin di-2-ethylhexoate, dibutyltin dilaurate, butyltin tri-2-ethylhexoate,
Iron 2-ethylhexoate, cobalt 2-ethylhexoate, manganese 2-ethylhexoate, zinc 2-ethylhexoate, stannous octoate, tin naphthinate, zirconium uraoctoate, antimony octoate, bismuth Included are naphthinate, tin oleate, tin butyrate, zinc naphthinate, zinc stearate and titanium naphthinate.

Preferred are stannous carboxylic acids and orthotitanates and their partial condensates.

Another class of catalysts are titanium esters such as tetrabutyl titanate, tetra-2-ethylhexyl titanate, tetraphenyl titanate, tetraoff decyl titanate, triethanolamine titanate, octylene glycol titanate, and bis-acetylacetonyl diisopropyl titanate. be.

Other suitable catalysts include amines such as hexylamine, dodecylamine, and amine salts such as hexylamine acetate, dodecylamine phosphate and quaternary amine salts such as benzyltrimethylammonium acetate and alkali metals such as potassium acetate. I can pass.

For the purposes of this invention, the amount of catalyst is not critical;
However, it is usually present in an amount of 0.05 to 2 parts based on the weight of the siloxane.

The most preferred catalysts are tin or iron carboxylates such as dibutyltin dilaurate, amines or amine salts.

The condensation occurs over a wide humidity range, e.g. from 20 to 200C, preferably from 080 to 150C.

Since water is produced as a result of the condensation, the water formed by refluxing in a solvent such as perfluorooctane is conveniently azeotroped into the trap.

Examples are shown below to illustrate the present invention, but the present invention is not limited in any manner by these Examples.

Example 1 100 parts of dichloro-(3,3,3-)lifluoropropyl)methylsilane are added to a sufficient amount of water at 5°C to give a HCI concentration of 20 parts in the aqueous layer after hydrolysis.

The ice melt is dissolved in water, washed with neutralized sodium bicarbonate solution, dried and the solvent is then removed by evaporation.

1% by weight of KOH was added to the melted ice and the mixture was passed under a distillation column under a vacuum of 5-10 mmHg at 190-200 mmHg.
Heat to °C.

L 3,5,7-titramethyltetrakis-1.3,5
．． 7-(3,3,3-)lifluoropropyl)cyclotetrasiloxane is recovered.

Place the L without stirring into a flask with a dry nitrogen purge.
3,5,7-titramethyltetrakis-L 3,5
, 50 parts of 7-(3,3,3-4lifluoropropyl)cyclotetrasiloxane.

This flask was heated to 80°C and the cesium silalate 4
Add 0 throat.

A clear increase in viscosity was observed after 20 minutes, and 0 at 30 minutes.
．． Add 2 vertical drops of water.

After another 10 minutes, add an additional 0.2 ml of water.

After a total polymerization time of 2 hours, the cesium catalyst is neutralized with a solution of 1 part phosphoric acid in tetrahydrofuran.

The deactivated polymer is dissolved in 2 volumes of ethyl acetate and this solution is added dropwise to 4 volumes of toluene.

The fluorosilicone oil insoluble in toluene was isolated by decantation of the solvent and the residual solvent was
The sample is removed by heating at 20 mmHg for 20 minutes in a C oven.

The viscosity is approximately 60,000 centipoise and the polymer yield I/i is 55%.

Silanol chain-terminated 3,3,3-trifluoropropylmethyl polysiloxane products are usefully used in their 11 room temperature vulcanizable compositions.

Part 11 of it is dissolved in perfluorooctane of IOF and 0.1 g of dibutyltin dilauret is added and the resulting water is refluxed into an azeotropic trap and converted to a high molecular weight gum.

The gum remaining after distillation of the solvent is a hydrocarbon solvent such as JP
-4 Useful in producing silicone elastomers with increased resistance to swelling by jet fuel.

Example 2 In a 100 cc resin flask equipped with a mechanical stirrer and a nitrogen drying stream, 1,3,5,7-tetramethyl-L 3,5,7-tetrakis (3°3,3- 1-'J
A mixture 3 consisting of fluoropropyl)cyclotetrasiloxane (1) and octamethylcyclotetrasiloxane (il), in which (1) has a 25 molar ratio of (1) and (11).
Enter 0 copies.

The batch is brought to 80° C. and maintained at this temperature for 20 minutes under a stream of dry nitrogen to dry the reactants.

Then, 0.3 methanol solution of cesium hydroxide catalyst
ml and then accelerate the rate of nitrogen purge to strip off the methanol.

After 45 minutes an increase in viscosity is observed and 0.1 r/Ll of water is added and the batch is maintained at 80° C. for 10 minutes.

Then add another 0.1 ml of water and keep the batch for 12 hours.

One drop of dimethyldichlorosilane is added to neutralize and deactivate the cesium hydroxide catalyst.

The batch is heated to 125° C. and a vacuum of 1 mm Hg is applied to remove volatiles.

Copolymer product remains.

The stripped cyclics can be directly repolymerized to form further copolymers.

The yield of copolymer is 84%.

Example 3 The procedure of Leprosy Example 2 can be repeated using a mixture of (i) and (1:) in a 75 molar ratio of (1).

A silanol chain terminated copolymer oil is obtained.

Example 4 The procedure of Example 2 is repeated using a mixture of (1) and (11) in which (1) is in a 60 molar ratio.

A silanol chain terminated copolymer oil is obtained.

Example 5 The method of Example 1 can be repeated, except that the reaction temperature is 110°C.

A somewhat less viscous product is obtained.

A simple method for producing low molecular weight silanol chain-terminated diorganopolysiloxane oils from cyclic tetrasilocanes in which one of the substituents bonded to the silicon atom is an aliphatic or monoaliphatic group having 3 or more carbon atoms. It can be seen that an efficient method is provided by the present invention.

These oils can be advantageously used as components in silicone compositions with outstanding properties.

Fluorosilicones are increasingly resistant to oil degradation.

In view of the above detailed description, many deformations will occur to those skilled in the art.

All such modifications are therefore included within the scope of the claims.

Claims (1)

[Claims] 1 (a) (N formula % formula %) (wherein R is methyl, ethyl, vinyl or phenyl and R1 is alkyl having 3 to 8 carbon atoms, 3 carbon atoms
-8 halogenated alkyl or C5-8 cycloalkyl);
:)Formula%Formula%) (In the formula, R is individually defined above, and × is 3
~10) and more powerful than the cyclic polysiloxane represented by
A composition in which (1) is present in an amount of 20 to 100 moles of the total amount of (1) and (11) is combined with a catalyst selected from KOH, CsOH and syralates thereof at a concentration of 5 to 300 pI.
(b) neutralize the catalyst in the reaction mixture after reaching equilibrium, and (c) recover the desired product, At least one of the organo groups is an aliphatic or haloaliphatic group having 3 or more carbon atoms, and the viscosity at 25°C is 1.0
00-100,000 centipoise silanol chain-stopped diorganopolysiloxane oil. 2 The catalyst is phosphoric acid and the formula R65iX4-b (R6 is selected from alkyl, cycloalkyl, vinyl and phenyl groups, X is selected from bromine and chlorine, and b is O-
3) The method according to claim 1, wherein the method is neutralized with a compound selected from compounds represented by 3). 3. The method of claim 1, wherein step (c) comprises heating the reaction mixture to 150-200° C. under a vacuum of 1-100 mm Hg to strip off all volatiles and leave the desired product. the method of. 4 Cyclic polysiloxane composition is reduced to 1/4 to 1/4 using a catalyst.
Claim 1 where the reaction takes place over a period of 20 hours.
The method described in section. 5 R' is R2CH2CH2- and R2 has 1 carbon atom
The method of claim 1, wherein the perfluoroalkyl group is -6. 6. The method according to claim 1, wherein R is CH3 and R1 is CF3CH2CH2. 7. The method of claim 6, wherein the cyclic tetrasiloxane (i) accounts for 100 moles of the composition. 8 Cyclic tetrasiloxane (1) is 25 to 75 of the composition
7. The method according to claim 6 for closing the mole.