Method of Producing Branched Silicone Oil Verfahren Zur Herstellung Von Verzweigtem Silikonöl Méthode Pour La Préparation D’Huile De Silicone Ramifiée

Europäisches Patentamt *EP000919583B1* (19) European Patent Office

Office européen des brevets (11) EP 0 919 583 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) Int Cl.7: C08G 77/10, C08G 77/08 of the grant of the patent: 30.10.2002 Bulletin 2002/44

(21) Application number: 98309427.7

(22) Date of filing: 18.11.1998

(54) Method of producing branched silicone oil Verfahren zur Herstellung von verzweigtem Silikonöl Méthode pour la préparation d’huile de silicone ramifiée

(84) Designated Contracting States: (74) Representative: Bubb, Antony John Allen et al DE FR GB Wilson Gunn Gee, Chancery House, (30) Priority: 28.11.1997 JP 34422497 Chancery Lane London WC2A 1QU (GB) (43) Date of publication of application: 02.06.1999 Bulletin 1999/22 (56) References cited: EP-A- 0 217 501 EP-A- 0 540 038 (73) Proprietor: SHIN-ETSU CHEMICAL CO., LTD. Chiyoda-ku Tokyo (JP) • PATENT ABSTRACTS OF JAPAN vol. 1997, no. 12, 25 December 1997 (1997-12-25) & JP 09 (72) Inventor: Aoki, Yoshitaka, 208701 A (SHIN ETSU CHEM CO LTD), 12 August Silicone Elec. Mat. Res. Ctr 1997 (1997-08-12) Matsuidacho, Usui-Gun, Gunma-Ken (JP)

Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 0 919 583 B1

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Description

[0001] The present invention relates to a method of producing a branched silicone oil and, more particularly, to a simplified method for producing a branched silicone oil having stable physical properties. 5 [0002] Branched silicone oils have excellent low-temperature characteristics and therein at least three units per molecule of terminal functional groups can be introduced, so that they have hitherto been utilized as hydraulic fluid, such as brake oil, and base oil for curable silicones [as disclosed in the gazettes, e.g., Japanese Tokko Sho 55-21781 (corresponding to US Patent 4,137,189 and GB Patent 1,582,371), Japanese Tokko Sho 59-43515 (corresponding to US Patent 3,833,505 and GB Patent 1,435,161) and Japanese Tokko Sho 59-41394, wherein the term "Tokko" means 10 an "examined patent publication"]. In recent years, branched silicone oils have also been used as a constituent of a silicone antifoaming agent to substantially extend the duration of antifoaming effect [as disclosed in, e.g., Japanese Tokkai Hei 5-271689 (corresponding to US Patent 5,376,301 and EP Patent 549,232), wherein the term "Tokkai" means an "unexamined published patent application"]. [0003] As methods of producing branched silicone oils, there have so far been known the method of condensing 15 hydrolysis products of an alkyltrichlorosilane and a dialkylpolysiloxane in the presence of an equilibration catalyst (Eu- ropean Patent No. 31532), the method of reacting a hydroxyl group-containing organopolysiloxane comprised of R3SiO1/2 units and SiO2 units with a diorganopolysiloxane having silanol groups at the both ends in the presence of a condensation or equilibration catalyst (European Patent No. 217501), and the method of mixing a diorganopolysiloxane with a vinyl monomer or a vinyl group-containing diorganopolysiloxane and causing a reaction between them by the 20 use of a radical polymerization initiating catalyst (European Patent No. 273448). [0004] However, the branched silicone oils produced by those methods fluctuate in finished viscosity in view of the nature of the reactions, and so they have a drawback of being not consistent in oil characteristics. [0005] In addition, there is known the method of using an alkyltrimethoxysilane or hydrolysis condensates thereof as the source of RSiO3/2 units and allowing it to undergo the equilibration reaction with a dialkylpolysiloxane. However, 25 the products obtained by such a method are liable to gelation because of the alkoxy groups remaining unreacted. Therefore, that method has a defect that the intended products cannot be obtained consistently. [0006] As a result of our intensive study which has been made for the purpose of simplified and consistent production of a branched silicone oil, it has been found that the intended purpose can be realized by using 1,1,1,3,5,7,7,7-octamethyl-3,5-dihydroxytetrasiloxane in the equilibration reaction of organopolysiloxanes, thereby achieving the present 30 invention. [0007] Therefore, an object of the present invention is to provide a method of producing a branched silicone oil simply and consistently. [0008] According to the present invention, there is provided a method of producing a branched silicone oil, which comprises mixing 100 parts by weight of an organopolysiloxane represented by the following formula (I) and/or an 35 organopolysiloxane represented by the following formula (II) with 0.1 to 100 parts by weight of an organopolysiloxane represented by the following formula (III), and causing the oranopolysiloxanes to undergo condensation and equilibration reactions by heating them in the presence of basic catalysts:

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10 wherein R1 and R2 are each a monovalent hydrocarbon group containing 1 to 20 carbon atoms, m is an integer from 3 to 7, and n is an integer of 0 or above;

wherein R3 is a monovalent hydrocarbon group containing 1 to 20 carbon atoms, p is a number from 1 to 100, and q is a number from 0 to 100. 25 [0009] The organopolysiloxanes of formulae (I) and (II) are generally used for industrial purpose, and so they are easily available as commercial products. [0010] Examples of a hydrocarbon group represented by R1,R2and R3 each include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl and octadecyl groups, cycloalkyl groups such as cyclopentyl and cyclohexyl groups, aryl groups such as phenyl and tolyl groups, and unsaturated alkyl 30 groups such as vinyl and allyl groups. It is desirable in the present invention that at least 90 mole % of the total hydrocarbon groups represented by R1. R2 and R3 be methyl groups. [0011] n is preferably from 10 to 1,000. p is a number from 1 to 100. This is because, when p is greater than 100, the organopolysiloxane of formula (III) is difficult to handle due to its high viscosity. In particular, it is advantageous to the present invention that p is from 2 to 10. q is a number from 0 to 100. This is because, when q is greater than 100, 35 the proportion of R(OH)SiO- units in formula (III) is relatively lowered; as a result, increasing the amount of organopolysiloxane of formula (III) mixed becomes necessary to decrease the production efficiency. In particular, it is advantageous to the present invention that q is from 0 to 10. [0012] The hydroxyl group-containing organopolysiloxanes represented by formula (III) can be easily produced using a known method, e.g., the method of reacting an organopolysiloxane represented by the following formula (IV) with 40 water through the dehydrogenation reaction in the presence of palladium-carbon catalyst:

50 [0013] The hydroxyl group-containing organopolysiloxane of formula (III) is mixed in an amount of 0.1-100 parts by weight per 100 parts by weight of the organopolysiloxane(s) represented by formula (I) and/or (II). Preferably, the amount of organopolysiloxane of formula (III) mixed is from 0.1 to 10 parts by weight. When the amount mixed is less than 0.1 parts by weight, the branched silicone oil obtained is insufficient in low temperature characteristic and anti- 55 foaming characteristic; while, when it is more than 100 parts by weight, fine gelled matter is formed as by-products. [0014] In other words, if the amounts of organopolysiloxanes (I) and/or (II), and (III) mixed are expressed in the proportions of structural units in the branched silicone oil as the final product, it. is desirable to mix them so that the 3 1 2 3 3 ratio [R 3SiO1/2] / ([R 2SiO2/2 and/or R 2SiO2/2]+[R 2SiO2/2])/[R SiO3/2] is (0.2-10) / (80-99.7) / (0.1-10) by mole %.

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By mixing these organopolysiloxanes in the foregoing proportions, the branched organopolysiloxanes as the final . product can acquire excellent low-temperature characteristic and antifoaming characteristic. The thus produced branched organopolysiloxanes have their viscosities in the range of about 100 to about 1000,000 cs at 25°C. [0015] In the present production method, the condensation reaction between hydroxyl groups and the equilibration 5 reaction are carried out at a temperature of 80-130°C in the presence of at least one basic catalyst selected from alkaline quaternary salts, such as tetrabutylphosphonium hydroxide and tetramethylammonium hydroxide, or the silanolates of those salts. Further, the present production method includes the step of completing the equilibration reaction by the addition of an alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide or caesium hydroxide, or the silanolate of such a hydroxide at a temperature of 130-200°C, and a step of neutralization. 10 [0016] Therefore, the basic catalysts usable in the present invention include not only the foregoing alkaline quaternary salts, such as tetrabutylphosphonium hydroxide, and the silanolates thereof but also alkali metal hydroxides and the silanolates thereof. [0017] The alkaline quaternary salts as recited above and the silanolates thereof function mainly so as to progress the condensation reaction between hydroxyl groups. In particular, the use of tetrabutylphosphonium hydroxide si- 15 lanolate (containing 10 % of tetrabutylphosphonium hydroxide) is advantageous to the present invention. [0018] Such a basic catalyst is added in a proportion of 500-5,000 ppm, preferably 750-3,000 ppm, to the total organopolysiloxanes. After the addition of the catalyst, the condensation reaction and the equilibration reaction attendant thereon are run for 0.5-4 hours at 80-130°C. Taking into account the distillation of water produced by the condensation reaction from the reaction system, it is desirable that the reaction temperature be set at 100-130°C. 20 [0019] The alkali metal hydroxides as recited above and the silanolates thereof are used for advancing the progress of the equilibration reaction. In view of such a purpose, the use of potassium hydroxide silanolate (containing 10 % of potassium hydroxide) is beneficial in particular. In order to complete the equilibration reaction, the foregoing basic catalyst is added and the stirring is continued for 1-10 hours at 130-200°C. The suitable amount of the catalyst added herein is from 250 to 3,000 ppm, particularly 500 to 2,000 ppm. 25 [0020] After the equilibration reaction, the neutralization is carried out in the present invention. Examples of a neu- tralizing agent usable herein include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, organic acids such as formic acid, acetic acid, propionic acid and malonic acid, organic acid substances such as ethylene chlorohydrin, tributyl phosphate, tricresyl phosphate and silyl phosphate, and carbon dioxide. Of these examples, organic acid substances are preferred over the others because of their good dispersibility in silicone oils. 30 Further, low molecular weight organopolysiloxanes formed as by-products may be removed, if desired. After neutralization, such by-products can be removed by the stripping operation carried out under the condition of 1-10 hours' heating at 100-300°C and reduced pressure. [0021] In accordance with the present production method, 100 parts by weight of the organopolysiloxane(s) of formula (I) and/or formula (II) is mixed with 0.1-100 parts by weight of the organopolysiloxane of formula (III), and the equili- 35 bration reaction between them is completed with ease by the addition of basic catalysts and heating under proper conditions. Thus, the organopolysiloxanes mixed are free from alkoxy groups or the like which are hard to undergo conversion and can be terminal groups of the product obtained. As a result, the branched silicone oil having stable physical properties can be obtained, and that with ease. [0022] The present invention will now be illustrated in greater detail by reference to the following examples. However, 40 the invention should not be construed as being limited to these examples. [0023] All "%" described below are by weight unless otherwise noted.

EXAMPLE 1

45 [0024] 1,1,1,3,5,7,7,7-Octamethyl-3,5-dihydroxytetrasiloxane in an amount of 8.5 g was mixed with 192 g of octamethylcyclotetrasiloxane and 0.2 g of tetrabutylphosphonium hydroxide silanolate (containing 10 % of tetrabutylphosphonium hydroxide), and heated for 2 hours at 110-120°C with stirring under a stream of nitrogen. During this process, vaporization of the water produced by condensation reaction was recognized. [0025] Further, the foregoing reaction mixture was admixed with 0.2 g of potassium hydroxide silanolate (containing 50 10 % of potassium hydroxide), and heated for 4 hours at 150-160°C with stirring. After the reaction system was cooled to 80-90°C, 0.2 g of ethylene chlorohydrin was added thereto, and stirred for 2 hours as the temperature was kept at 80-90°C. The reaction product obtained was heated for 2 hours at 150-160°C under the reduced pressure of 10 mmHg, thereby removing low molecular weight siloxanes therefrom. Thus, a branched silicone oil having a viscosity of 2,100 cs at 25°C was obtained. This branched silicone oil was confirmed by 29Si-NMR analysis to have the following com- 55 position:

[(CH3)3SiO1/2]/[(CH3)2SiO2/2]/[CH3SiO3/2] = 2.1/95.8/2.1 (mole %).

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EXAMPLE 2

[0026] Another branched silicone oil having a viscosity of 120,000 cs at 25°C was produced in the same manner as in Example 1, except that the amount of 1,1,1,3,5,7,7,7-octamethyl-3,5-dihydroxytetrasiloxane used was changed to 5 1.7 g and the amount of octamethylcyclotetrasiloxane used was changed to 198 g. The composition of this branched silicone oil determined by 29Si-NMR analysis was as follows:

[(CH3)3SiO1/2]/[(CH3)2SiO2/2]/[CH3SiO3/2] = 0.4/99.2/0.4 (mole %). 10 COMPARATIVE EXAMPLE 1

[0027] The co-hydrolysis product having the composition of [(CH3)3SiO1/2]/[(CH3)2SiO2/2]/[CH3SiO3/2] = 1.0/1.0/1.0 (mole %), which was prepared from trimethylchlorosilane, dimethyldichlorosilane and methyltrichlorosilane, was mixed 15 in an amount of 2.4 g with 197.60 g of octamethylcyclotetrasiloxane. In the resulting mixture, the ratio of the units prepared was [(CH3)3SiO1/2]/[(CH3)2SiO2/2]/[CH3SiO3/2] = 0.4/99.2/0.4 (mole %). [0028] The foregoing mixture was further admixed with 0.2 g of potassium siliconate, and stirred at 150-160°C. By 30 minutes' stirring, the reaction mixture caused gelation.

20 Claims

1. A method of producing a branched silicone oil, which comprises mixing 100 parts by weight of an organopolysiloxane represented by the following formula (I) and/or an organopolysiloxane represented by the following formula 25 (II) with 0.1 to 100 parts by weight of an organopolysiloxane represented by the following formula (III) and causing the oranopolysiloxanes to undergo condensation and equilibration reactions by heating them in the presence of basic catalysts:

wherein R1 and R2 are each a monovalent hydrocarbon group containing 1 to 20 carbon atoms, m is an integer from 3 to 7, and n is an integer of 0 or above; 50

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wherein R3 is a monovalent hydrocarbon group containing 1 to 20 carbon atoms, p is a number from 1 to 100, and q is a number from 0 to 100.

2. A method of producing a branched silicone oil according to claim 1, wherein p in formula (III) is 2 and q in formula 5 (III) is 0.

3. A method of producing a branched silicone oil according to claim 1 or 2, wherein n in formula (II) is an integer from 10 to 1,000.

10 4. A method of producing a branched silicone oil according to any one of claims 1 to 3; wherein at least 90 mole % of the total hydrocarbon groups represented by R1, R2 and R3 are methyl groups.

5. A method of producing a branched silicone oil according to any one of claims 1 to 4, wherein the amount of organopolysiloxane of formula (III) mixed is from 0.1 to 10 parts by weight. 15 6. A method of producing a branched silicone oil according to any one of claims 1 to 5; wherein the condensation and equilibration reactions are caused by heating to 80-130°C in the presence of at least one basic catalyst selected from a group consisting of alkaline quaternary salts and the silanolates thereof, and the equilibration reaction is completed by further adding an alkali metal hydroxide or a silanolate thereof and heating to 130-200°C, and then 20 a neutralization step is introduced.

7. A method of producing a branched silicone oil according to claim 6; wherein the alkaline quaternary salts are tetrabutylphosphonium hydroxide and tetramethylammonium hydroxide, and the alkali metal hydroxide is sodium hydroxide, potassium hydroxide or caesium hydroxide. 25 8. A method of producing a branched silicone oil according to claim 6 or 7; wherein the amount of alkaline quaternary salt or silanolate thereof used is from 500 to 5,000 ppm and the amount of alkali metal hydroxide or silanolate thereof is from 250 to 3,000 ppm.

30 Patentansprüche

1. Verfahren zur Herstellung von verzweigtem Silikonöl, welches umfasst das Mischen von 100 Gewichtsanteilen eines Organopolysiloxans repräsentiert durch die nachfolgende Formel (I) und/oder ein Organopolysiloxan ent- 35 sprechend der nachfolgenden Formel (II) mit 0,1 bis 100 Gewichtsteilen eines Organopolysiloxans wie es durch die nachfolgende Formel (III) wiedergegeben wird und wobei veranlasst wird, dass die Organopolysiloxane Kon- densations- und Equilibrierungsreaktionen unterzogen werden durch Erhitzung in Anwesenheit eines basischen Kathalysators:

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wobei R1 und R2 jede eine einwertige Hydrokarbongruppe mit 1 bis 20 Kohlenstoffatomen sind, m eine ganze Zahl von 3 bis 7 und n eine ganze Zahl 0 oder größer bedeuten; 15

wobei R3 eine einwertige Hyrokarbongruppe mit 1 bis 20 Kohlenstoffatomen, p eine Zahl von 1 bis 100 und q eine Zahl von 0 bis 100 ist. 30 2. Verfahren zur Herstellung eines verzweigten Silikonöls nach Anspruch 1, dadurch gekennzeichnet, dass pin Formel (III) 2 und q in Formel (III) 0 ist.

3. Verfahren zur Herstellung eines verzweigten Silikonöls nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass 35 n in Formel (II) eine ganze Zahl von 10 bis 1000 ist.

4. Verfahren zur Herstellung eines verzweigten Silikonöls nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass wenigstens 90 Mol-Prozent der gesamten Hydrokarbongruppen, die durch R1,R2und R3 repräsentiert werden, Methylgruppen sind. 40 5. Verfahren zur Herstellung eines verzweigten Silikonöls nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass der Betrag an Organopolysiloxan der Formel (III), der beigemischt wird, zwischen 0,1 und 10 Gewichts- anteilen liegt.

45 6. Verfahren zur Herstellung eines verzweigten Silikonöls nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die Kondensation und Equilibrierungsreaktionen durch Erhitzen auf 80 bis 130 °C in Anwesenheit wenigstens eines basischen Katalysators verursacht werden, welcher aus einer Gruppe, bestehend aus alkalischen quaternären Salzen und deren Silanolaten besteht, und die Equilibrierungsreaktion durch zusätzliches Beifügen eines Alkalimetallhydroxids oder eines Solanolats davon und Erhitzen auf 130 bis 200 °C vervollständigt wird und 50 dass dann ein Neutralisierungsschritt durchgeführt wird.

7. Verfahren zur Herstellung eines verzweigten Silikonöls nach Anspruch 6, dadurch gekennzeichnet, dass die alkalischen quaternären Salze Tetrabutylphosphoniumhydroxidund Tetramethylammoniumhydroxidsind und dass das Alkalimetallhydroxid Natriumhydroxid, Kaliumhydroxid oder Cäsiumhydroxid ist. 55 8. Verfahren zur Herstellung eines verzweigten Silikonöls nach Anspruch 6 oder 7, dadurch gekennzeichnet, dass der Betrag des verwendeten alkalischen quaternären Salzes oder dessen Silanolates zwischen 500 bis 5000 ppm und der Betrag an Alkalimetallhydroxid oder dessen Silanolats zwischen 250 und 3000 ppm liegt.

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Revendications

1. Procédé de production d'une huile de silicone ramifiée, comprenant les étapes consistant à mélanger 100 parties en poids d'un organopolysiloxane représenté par la formule (I) suivante et/ou d'un organopolysiloxane représenté 5 par la formule (II) suivante avec 0,1 à 100 parties en poids d'un organopolysiloxane représenté par la formule (III) suivante et faire subir aux organopolysiloxanes des réactions de condensation et d'équilibrage en les chauffant en présence de catalyseurs basiques :

dans lesquelles R1 et R2 sont chacun un groupe hydrocarboné monovalent contenant de 1 à 20 atomes de carbone, 30 m est un nombre entier de 3 à 7, et n est un nombre entier de 0 ou plus ;

40 dans laquelle R3 est un groupe hydrocarboné monovalent contenant de1à20atomes de carbone, p est un nombre de 1 à 100, et q est un nombre de 0 à 100.

2. Procédé de production d'une huile de silicone ramifiée selon la revendication 1, dans lequel p dans la formule (III) 45 vaut 2 et q dans la formule (III) vaut 0.

3. Procédé de production d'une huile de silicone ramifiée selon la revendication 1 ou 2, dans lequel n dans la formule (II) est un nombre entier de 10 à 1000.

50 4. Procédé de production d'une huile de silicone ramifiée selon l'une quelconque des revendications 1 à 3 ; dans lequel au moins 90 % en moles des groupes hydrocarbonés totaux représentés par R1,R2et R3 sont des groupes méthyle.

5. Procédé de production d'une huile de silicone ramifiée selon l'une quelconque des revendications 1 à 4, dans 55 lequel la quantité mélangée d'organopolysiloxane de formule (III) est de 0,1 à 10 parties en poids.

6. Procédé de production d'une huile de silicone ramifiée selon l'une quelconque des revendications 1 à 5 ; dans lequel on provoque les réactions de condensation et d'équilibrage par chauffage à 80-130°C en présence d'au

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moins un catalyseur basique choisi dans un ensemble constitué de sels quaternaires alcalins et des silanolates de ceux-ci, et on complète la réaction d'équilibrage en ajoutant, en outre, un hydroxyde de métal alcalin ou un silanolate de celui-ci et en chauffant à 130-200°C, et ensuite on introduit une étape de neutralisation.

5 7. Procédé de production d'une huile de silicone ramifiée selon la revendication 6 ; dans lequel les sels quaternaires alcalins sont de l'hydroxyde de tétrabutylphosphonium et de l'hydroxyde de tétraméthylammonium, et l'hydroxyde de métal alcalin est de l'hydroxyde de sodium, de l'hydroxyde de potassium ou de l'hydroxyde de césium.

8. Procédé de production d'une huile de silicone ramifiée selon la revendication 6 ou 7 ; dans lequel la quantité utilisée 10 de sel quaternaire alcalin ou de silanolate de celui-ci est de 500 à 5000 ppm et la quantité d'hydroxyde de métal alcalin ou de silanolate de celui-ci est de 250 à 3000 ppm.