A METHOD OF PREPARING ALKYL FUNCTIONALIZED POLYSILOXANE

Abstract

A method of preparing alkyl functionalized polysiloxane, comprising: I) reacting silane oligomer with hydroxyl-terminated polysiloxane in the presence of Catalyst 1, and II) reacting the product of Step (I) with an endcapper in the presence of Catalyst 2. This method could flexibly adjust the polymerization degree and viscosity of the desired long-chain alkyl functionalized polysiloxane for different application fields and introduce multiple alkyl functional groups and further functional groups to obtain bifunctionalized polysiloxane, moreover this method could greatly reduce the proportion of undesired cyclosiloxanes in the equilibrium product and the reaction is mild, easy to operate and environmentally friendly.

Claims

1-13. (canceled)

14. A method of preparing alkyl functionalized polysiloxane, comprising: I) reacting silane oligomer (A) with hydroxyl-terminated polysiloxane (B) in the presence of Catalyst 1, the silane oligomer (A) comprises cyclic oligomer (A1) of Formula I, ##STR00005## where R.sup.1 is independently at each occurrence a C6-C18 alkyl, R.sup.2 is independently at each occurrence a C1-C5 alkyl, m is an arbitrary number between 3 and 20, the hydroxyl-terminated polysiloxane (B) is of Formula IV: ##STR00006## where IV is independently at each occurrence a C1-C5 alkyl or phenyl, and p is an arbitrary number between 3 and 150, and II) reacting the product of Step (I) with an endcapper in the presence of Catalyst 2 to give the alkyl functionalized polysiloxane.

15. The method of claim 14, wherein the silane oligomer (A) comprises more than 20 wt % of cyclic oligomer (A1), based on the total weight of silane oligomer (A).

16. The method of claim 14, wherein the silane oligomer (A) comprises more than 30 wt % of cyclic trimer and tetramer of Formula I, based on the total weight of silane oligomer (A).

17. The method of claim 16, wherein the silane oligomer (A) comprises more than 30 wt % of cyclic trimer of Formula I, based on the total weight of silane oligomer (A).

18. The method of claim 14, characterized in that the silane oligomer (A) further comprises linear oligomer (A2) of Formula II, ##STR00007## where R.sup.3 is methyl, ethyl or hydrogen, R.sup.4 is independently at each occurrence a C6-C18 alkyl, R.sup.5 is independently at each occurrence a C1-C5 alkyl, and n is an arbitrary number between 2 and 20.

19. The method of claim 18, wherein the hydroxyl-terminated polysiloxane (B) is of Formula IV: ##STR00008## where IV is independently at each occurrence a C1-C5 alkyl or phenyl, and p is an arbitrary number between 10 and 100.

20. The method of claim 14, wherein the endcapper (C) is of Formula V: ##STR00009## where R.sup.b is methyl, vinyl, hydrogen, aminopropyl, aminoethylaminopropyl or glycidylpropyl, R.sup.c is independently at each occurrence a C1-C5 alkyl, and q is an arbitrary number between 0 and 20.

21. The method of claim 14, wherein the reaction of Step (I) is carried out at a temperature of from 80° C. to 110° C.

22. The method of claim 14, wherein the reaction of Step (II) is carried out at a temperature of from 100° C. to 140° C.

23. The method of claim 14, wherein the silane oligomer (A) is prepared by the process as below comprising: i) reacting dialkoxysilane of Formula III with water in the presence of Catalyst 3 and an organic solvent, and the molar ratio of water to dialkoxysilane is greater than 0.5:1,
R.sup.6.sub.2R.sup.7R.sup.8Si  III where R.sup.6 is methoxy or ethoxy, R.sup.7 is a C6-C18 alkyl, R.sup.8 is a C1-C5 alkyl; and ii) removing by-products, water, Catalyst 3 and organic solvent.

24. The method of claim 23, wherein the molar ratio of water to dialkoxysilane is greater than 2:1.

25. The method of claim 23, wherein Catalyst 3 is an acidic catalyst.

26. The method of claim 23, wherein the organic solvent is ethanol or acetonitrile.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] The present invention is further illustrated by the following examples, but is not limited to the scope thereof. Any experimental methods with no conditions specified in the following examples are selected according to the conventional methods and conditions, or product specifications.

[0054] Characterization of Molecular Weight Distribution

[0055] PSS SECcurity gel permeation chromatography is used to separate silane hydrolyzed oligomers with different degrees of polymerization, and each molecular weight is determined by comparison with the reference. Tetrahydrofuran is used as the solvent, and PLgel 5 um guard and PLgel 5 um 100 A provided by Agilent are used as the columns. The temperature of the column oven is 45° C., the feed rate is 1 ml/min, and the injection volume is 20 μl.

[0056] Characterization of Molecular Structure [0057] .sup.1H NMR spectroscopy [0058] Test solvent: deuterated chloroform (TMS-free) [0059] Spectrometer: Bruker Avance III HD 400 [0060] Sampling head: 5 mm BBO probe [0061] Measured parameters: [0062] Pulse sequence (Pulprog)=zg30 [0063] TD=65536 [0064] NS=64 [0065] SW=18 ppm [0066] AQ=4.54 s [0067] D1=5 s

[0068] Some measurement parameters may need to be adjusted appropriately depending on the type of spectrometer.

[0069] 29Si NMR spectroscopy

[0070] Test solvent: deuterated benzene (containg relaxation reagent chromium acetylacetonate and no internal standard substance added) [0071] Spectrometer: Bruker Avance III HD 400 [0072] Sampling head: 5 mm BBO probe [0073] Measured parameters: [0074] Pulse sequence=zgig60 [0075] TD=65536 [0076] NS=2048 [0077] SW=200 ppm [0078] AQ=2.04 s [0079] D1=5 s

[0080] Some measurement parameters may need to be adjusted appropriately depending on the type of spectrometer.

[0081] Determination of Viscosity of Polysiloxane

[0082] The viscosities of polysiloxanes are measured by Brookfield viscometer using a No. 3 spindle at 25° C. and 300 rpm for 30 s.

[0083] Determination of Viscosity of the Composition

[0084] It is carried out in accordance with DIN EN ISO 3219: Determination of viscosity of polymers and resins in the liquid state or as emulsions or dispersions using a rotational viscometer with defined shear rate (ISO 3219:1993).

[0085] The raw materials used in the Examples are all commercially available, with detailed information as follows: [0086] Hydroxyl-terminated polydimethylsiloxane, WACKER® FINISH WS 62 M, having a dynamic viscosity of 50-110 mPa.Math.s, measured at 25° C. according to DIN 51562, supplied by Wacker Chemicals; [0087] Phosphonitrilic chloride, WACKER® PNCL 2/100 PERCENT, supplied by Wacker Chemicals; [0088] 1,1,3,3-tetramethyldisiloxane, supplied by Guike New Material; [0089] Tetramethyldivinyldisiloxane, supplied by TCL; [0090] Alumina A, spherical alumina powder having an average particle size of 40 μm; [0091] Alumina B, spherical alumina powder having an average particle size of 5 μm; [0092] Zinc oxide, non-spherical zinc oxide powder having an average particle size of 5 μm; [0093] Hydrogen-terminated polydimethylsiloxane C1, having a dynamic viscosity of 85 mPa.Math.s at 25° C., supplied by Wacker Chemicals, referred to as H Polymer C1 thereafter; [0094] Hydrogen-terminated polydimethylsiloxane C2, having a dynamic viscosity of 1,040 mPa.Math.s at 25° C., supplied by Wacker Chemicals, referred to as H Polymer C2 thereafter; [0095] Vinyl-terminated polydimethylsiloxane C2, ELASTOSIL® VINYLPOLYMER 120, having a dynamic viscosity of 120 mPa.Math.s, supplied by Wacker Chemicals, referred to as V Polymer C2 thereafter.

Synthesis Example 1

[0096] 68.5 g of dodecyl diethoxymethylsilane, 110 g of ethanol and 1.22 g of 5% hydrochloric acid aqueous solution were added to a flask at room temperature, stirred, then 25 g of water was added dropwise to the flask to carry out reaction at room temperature for 4 h and then was subject to 65° C. for 1 h to give a white solid precipitate. Afterwards the precipitate was transferred to a distillation flask, which was subjected to rotary evaporation at 85° C. and 100 mbar for 1 h to give oligomers of hydrolyzed dodecyl diethoxymethylsilane. As determined by NMR, the oligomers comprise 53.60 wt % of trimethyltridodecylcyclotrisiloxane D.sub.3.sup.C12H25, 18.17 wt % of tetramethyltetradodecylcyclotetrasiloxane D.sub.4.sup.C12H25, 6.83 wt % of CH.sub.3(OR)(C.sub.12H.sub.25)SiO.sub.1/2 unit (wherein R is —C.sub.2H.sub.5 or H, mainly —C.sub.2H.sub.5) and 21.40 wt % of CH.sub.3(C.sub.12H.sub.25)SiO.sub.2/2 unit and cyclic pentamer, cyclic hexamer and cyclic oligomers with higher polymerization degrees. As determined by GPC, the oligomers comprise 52.17 wt % of trimer, 18.75 wt % of tetramer, 6.36 wt % of pentamers and 22.73 wt % of hexamer and oligomers with higher polymerization degrees.

Synthesis Example 2

[0097] 68.5 g of dodecyl diethoxymethylsilane, 20.87 g of ethanol and 0.14 g of 5% hydrochloric acid aqueous solution were added to a flask at room temperature, stirred, then 4.08 g of water was added dropwise to the flask to carry out reaction at room temperature for 4 h and then was subject to 65° C. for 1 h to give a white solid precipitate. Afterwards the precipitate was neutralized with sodium carbonate and then was transferred to a distillation flask, which was subjected to rotary evaporation at 85° C. and 100 mbar for 1 h to give oligomers of hydrolyzed dodecyl diethoxymethylsilane. As determined by NMR, the oligomers comprise 19.38 wt % of trimethyltridodecylcyclotrisiloxane D.sub.3.sup.C12H25, 2.76 wt % of tetramethyltetradodecylcyclotetrasiloxane D.sub.4.sup.C12H25, 65.00 wt % of CH.sub.3(OR)(C.sub.12H.sub.25)SiO.sub.1/2 unit (wherein R is —C.sub.2H.sub.5 or H, mainly —C.sub.2H.sub.5) and 11.63 wt % of CH.sub.3(C.sub.12H.sub.25)SiO.sub.2/2 unit and cyclic pentamer, cyclic hexamer and cyclic oligomers with higher polymerization degrees.

Synthesis Example 3

[0098] 200 g of hydroxyl-terminated polydimethylsiloxane, 30.8 g of the oligomers of hydrolyzed dodecyl diethoxymethylsilane obtained by Synthesis Example 1 and 0.0592 g of phosphonitrilic chloride were added to a flask, stirred, and heated to 95° C. to carry out reaction at 95° C. and 50 mbar for 0.5 h with nitrogen flow. Then 6 g of 1,1,3,3-tetramethyldisiloxane was added to the flask and heated to 120° C. to react for 5 h. Upon completion of the reaction, sodium carbonate solid was added to treat phosphonitrilic chloride at 50° C. for 1.5 h, and then was filtered. Afterwards the resulting reactant was transferred to a distillation flask, distilled at 170° C. and 30 mbar for 1.5 h to remove low boilers, and cooled to room temperature to give an alkyl functionalized hydrogenpolydimethylsiloxane, referred to as H Polymer 1, of the following structural formula with a dynamic viscosity of 95 mPa.Math.s at 25° C.

(H(CH.sub.3).sub.2SiO).sub.1.88((CH.sub.3).sub.2SiO).sub.60.95((CH.sub.3)(C.sub.12H.sub.25)SiO).sub.3.02(Si(CH.sub.3).sub.2(OH)).sub.0.09(Si(CH.sub.3).sub.2(OC.sub.2H.sub.5)).sub.0.03

Synthesis Example 4

[0099] 220 g of hydroxyl-terminated polydimethylsiloxane, 7.7 g of the oligomers of hydrolyzed dodecyl diethoxymethylsilane obtained by Synthesis Example 1 and 0.0573 g of phosphonitrilic chloride were added to a flask, stirred, and heated to 95° C. to carry out reaction at 95° C. and 50 mbar for 0.5 h with nitrogen flow. Then 1.5 g of 1,1,3,3-tetramethyldisiloxane was added to the flask and heated to 120° C. to react for 5 h. Upon completion of the reaction, sodium carbonate solid was added to treat phosphonitrilic chloride at 50° C. for 1.5 h, and then was filtered. Afterwards the resulting reactant was transferred to a distillation flask, distilled at 170° C. and 30 mbar for 1.5 h to remove low boilers, and cooled to room temperature to give an alkyl functionalized hydrogenpolydimethylsiloxane, referred to as H Polymer 2, of the following structural formula with a dynamic viscosity of 1,155 mPa.Math.s at 25° C.

(H(CH.sub.3).sub.2SiO).sub.1.63((CH.sub.3).sub.2SiO).sub.241.14((CH.sub.3)(C.sub.12H.sub.25)SiO).sub.3.78(Si(CH.sub.3).sub.2(OH)).sub.0.35(Si(CH.sub.3).sub.2(OC.sub.2H.sub.5)).sub.0.02

Synthesis Example 5

[0100] 200 g of hydroxyl-terminated polydimethylsiloxane, 41 g of the oligomers of hydrolyzed dodecyl diethoxymethylsilane obtained by Synthesis Example 1 and 0.52 g of 25% tetramethylammonium hydroxide aqueous solution were added to a flask, stirred, and heated to 95° C. to carry out reaction at 95° C. and 40 mbar for 40 min with nitrogen flow. Then 8.35 g of tetramethyldivinyldisiloxane was added to the flask and heated to 120° C. to react for 2 h, afterwards 2.4 g of hydroxyl-terminated polydimethylsiloxane was added and reaction was continued at 120° C. for 2 h. Upon completion of the reaction, the resulting mixture was further heated to 175° C. to decompose the catalyst for 1.5 h. Then the resulting reactant was transferred to a distillation flask, distilled at 175° C. and 30 mbar for 1.5 h to remove low boilers, and cooled to room temperature to give an alkyl functionalized vinylpolydimethylsiloxane, referred to as V Polymer 1, of the following structural formula with a dynamic viscosity of 102 mPa.Math.s at 25° C.

((H.sub.2C═CH(CH.sub.3).sub.2SiO).sub.1.70((CH.sub.3).sub.2SiO).sub.52.33((CH.sub.3)(C.sub.12H.sub.25)SiO).sub.3.81(Si(CH.sub.3).sub.2(OH)).sub.0.07(Si(CH.sub.3).sub.2(OC.sub.2H.sub.5)).sub.0.23

Comparative Synthesis Example 6

[0101] 632 g of hydroxyl-terminated polydimethylsiloxane, 25.9 g of dodecyl diethoxymethylsilane and 0.51 g of 25% tetramethylammonium hydroxide aqueous solution were added to a flask, stirred, and heated to 95° C. to carry out reaction at 95° C. and 30 mbar for 30 min with nitrogen flow. Then 14.9 g of tetramethyldivinyldisiloxane was added to the flask and heated to 120° C. to react for 2 h, afterwards 11.8 g of hydroxyl-terminated polydimethylsiloxane was added and reaction was continued at 120° C. for 2 h. Upon completion of the reaction, the resulting mixture was further heated to 175° C. to decompose the catalyst for 1.5 h. Then the resulting reactant was transferred to a distillation flask, distilled at 175° C. and 30 mbar for 1.5 h to remove low boilers, and cooled to room temperature to give an alkyl functionalized vinylpolydimethylsiloxane, referred to as V Polymer C1, of the following structural formula with a dynamic viscosity of 110 mPa.Math.s at 25° C.

((H.sub.2C═CH(CH.sub.3).sub.2SiO).sub.1.12((CH.sub.3).sub.2SiO).sub.63.14((CH.sub.3)(C.sub.12H.sub.25)SiO).sub.0.68(Si(CH.sub.3).sub.2(OH)).sub.0.08(Si(CH.sub.3).sub.2(OC.sub.2H.sub.5)).sub.0.80

Synthesis Example 7

[0102] 170.7 g of hydroxyl-terminated polydimethylsiloxane, 35 g of the oligomers of hydrolyzed dodecyl diethoxymethylsilane obtained by Synthesis Example 2 and 0.12 g of 25% tetramethylammonium hydroxide aqueous solution were added to a flask, stirred, and heated to 95° C. to carry out reaction at 95° C. and 100 mbar for 1 h with nitrogen flow. Then 2.95 g of tetramethyldivinyldisiloxane was added to the flask and heated to 120° C. to react for 3 h. Upon completion of the reaction, the resulting mixture was further heated to 175° C. to decompose the catalyst for 1.5 h. Then the resulting reactant was transferred to a distillation flask, distilled at 175° C. and 30 mbar for 1.5 h to remove low boilers, and cooled to room temperature to give an alkyl functionalized vinylpolydimethylsiloxane, referred to as V Polymer 2, of the following structural formula with a dynamic viscosity of 125 mPa.Math.s at 25° C.

((H.sub.2C═CH(CH.sub.3).sub.2SiO).sub.0.28((CH.sub.3).sub.2SiO).sub.50.26((CH.sub.3)(C.sub.12H.sub.25)SiO).sub.3.60(Si(CH.sub.3).sub.2(OH)).sub.0.05(Si(CH.sub.3).sub.2(OC.sub.2H.sub.5)).sub.1.66

[0103] According to table 1, H Polymer 1-2, V Polymer 1 and H Polymer C1-C2, V Polymer C1-C2 were mixed with thermally conductive fillers respectively, and the viscosities of the resulting compositions were measured at shear rates of 1 s.sup.−1 and 10 s.sup.−1.

TABLE-US-00001 TABLE 1 Components/g Composition 1 Composition C1 Composition 2 Composition C2 Composition 3 Composition C3 Composition C4 H Polymer 1 10 / / / / / / H Polymer C1 / 10 / / / / / H Polymer 2 / / 10 / / / / H Polymer C2 / / / 10 / / / V Polymer 1 / / / / 10 / / V Polymer C1 / / / / / 10 / V Polymer C2 / / / / / / 10 Alumina A 25 25 25 25 25 25 25 Alumina B 36 36 36 36 36 36 36 Zinc oxide 29 29 29 29 29 29 29 Viscosity of Composition/mPa .Math. s D = 1 s.sup.−1 819,500 963,000 2,940,000 4,245,000 103,450 771,000 1,660,000 D = 10 s.sup.−1 256,000 319,000 407,000 560,000 26,800 191,000 195,000

[0104] Table 1 shows that H Polymer 1-2 are more effective in lowering the viscosity of the composition than corresponding H Polymer C1-C2 with similar viscosities at the same thermally conductive filler loading, thereby improving the thermal conductivity of the composition. V Polymer 1 has a very significant advantage in lowering the viscosity of the composition than V Polymer C2 and also performs better compared to V Polymer C1 synthesized by a non-inventive method, which is related to the number of long-chain alkyls introduced.

[0105] According to table 2, H Polymer 1-2 and H Polymer C1-C2 were mixed with thermally conductive fillers respectively, and the viscosities of the resulting compositions were measured at shear rates of 1 s.sup.−1 and 10 s.sup.−1.

TABLE-US-00002 TABLE 2 Composition Composition Composition Composition Components/g 5 C5 6 C6 H Polymer 1 10 / / / H Polymer C1 / 10 / / H Polymer 2 / / 10 / H Polymer C2 / / / 10 Alumina A 60 60 60 60 Alumina B 30 30 30 30 Viscosity of Composition/mPa .Math. s D = 1 s.sup.−1 13,300 40,200 133,500 253,000 D = 10 s.sup.−1 11,600 23,200 126,000 183,000

[0106] Table 2 shows that H Polymer 1-2 are more effective in lowering the viscosity of the composition than corresponding H Polymer C1-C2 with similar viscosities at the same thermally conductive filler loading, thereby improving the thermal conductivity of the composition.

[0107] Table 3 lists the viscosity changes of H Polymer 1-2 after being left at room temperature for 10 months. The viscosity changes are within ±5%, showing a good storage stability.

TABLE-US-00003 TABLE 3 Viscosity after 10 M Initial viscosity at room temperature Viscosity (mPa .Math. s) (mPa .Math. s) change H Polymer 1 95 95  0% H Polymer 2 1,155 1,190 +3%