Reactive silicone oil, and preparation method and application thereof

Abstract

The application provides a reactive silicone oil and a preparation method and application thereof. The preparation method of the reactive silicone oil comprises the following steps: S1, under the protection of nitrogen, trimethyl monochlorosilane is added into a mixed solution of hydroxyl silicone oil, an acid-binding agent and an organic solvent, and reaction is carried out at 40-50 DEG C for 2-3 h, and then the reaction is cooled to room temperature; S2, methyl dichlorohydrogen silane is added into the system of step S1, and reaction is carried out at 30-50 DEG C for 2-3 h, and then the system is cooled and filtered, and the filtrate is obtained by removing low boiling; S3, under the protection of nitrogen, both end vinyl silicone oil, platinum catalyst, the product of step S2 and an additive are mixed, and reaction is carried out at 65-80 DEG C for 2-3 h, and then low boiling is removed, and the product is obtained. The reactive silicone oil obtained by the preparation method of the application is used to replace dimethyl silicone oil in the rubber compound, which can reduce the viscosity of the pouring sealant, and greatly reduces the leakage problem caused by adding dimethyl silicone oil in the prior art.

Description

Technical Field

[0001] This invention relates to the field of silicone oil synthesis technology, and more specifically, to a reactive silicone oil, its preparation method, and its application. Background Technology

[0002] In the modern industrial field, silicone potting compounds with excellent properties such as high heat resistance, weather resistance and chemical corrosion resistance are widely used in electronics, machinery manufacturing, construction and other fields. Among them, two-component addition silicone potting compounds with hydrogen-containing silicone oil and vinyl silicone oil as base materials have the widest range of applications due to their mild curing conditions, no by-products generated during the curing process and suitable viscosity.

[0003] In the electronics field, potting compounds are used as sealants. However, their poor thermal conductivity prevents heat generated by electronic devices from dissipating in a timely manner, significantly reducing the reliability and lifespan of electronic components. Furthermore, insufficient strength and poor temperature and weather resistance of the compound also affect product lifespan. Therefore, two-component silicone potting compounds typically use spherical alumina or aluminum nitride with different particle sizes and mass ratios to improve the thermal conductivity of the potting compound. Simultaneously, the strength of the compound is controlled by adjusting the hydrogen content and crosslinking degree of the hydrogen-containing silicone oil. However, excessively high active hydrogen content in the hydrogen-containing silicone oil and the addition of high filler content can increase the viscosity of the compound, shortening the application time. Current technology often addresses this issue by adding dimethyl silicone oil to the system for plasticization. However, dimethyl silicone oil lacks reactivity, and over time, it will seep into the potting compound after curing. In particular, this seepage causes the potting compound to harden, generating varying degrees of stress, which can affect electronic components. Summary of the Invention

[0004] To address, or at least partially address, the problems existing in the prior art, this invention provides a reactive silicone oil, its preparation method, and its applications. Adding the reactive silicone oil prepared by the method of this invention to the potting compound can reduce the viscosity of the potting compound while avoiding the seepage problem caused by the addition of dimethyl silicone oil in the prior art. Furthermore, using the reactive silicone oil of this invention can also slightly improve the thermal conductivity of the potting compound.

[0005] The method for preparing reactive silicone oil provided by the present invention includes the following steps:

[0006] S1, under nitrogen protection, trimethylchlorosilane is added to a mixed solution of hydroxyl silicone oil, acid binder and organic solvent, and the reaction is carried out at 40-50°C for 2-3 hours. After the reaction is completed, the temperature is lowered to room temperature.

[0007] S2, add dimethylchlorosilane to the system of step S1, react at 30-50℃ for 2-3 hours, cool and filter, remove low boiling points from the filtrate to obtain the product;

[0008] S3, under nitrogen protection, the dual-terminated vinyl silicone oil, platinum catalyst, product of step S2 and additives are mixed and reacted at 65-80°C for 2-3 hours. Except for low boiling point, the product is obtained. The viscosity of the dual-terminated vinyl silicone oil is not greater than 60 mPa·s.

[0009] In a preferred embodiment of the present invention, in step S1, the hydroxyl value of the hydroxyl silicone oil is not less than 1% (≥1%). To further improve the reactive silicone oil's ability to reduce viscosity and enhance heat resistance, in step S1, the hydroxyl value of the hydroxyl silicone oil is preferably 1-12%, more preferably 8-10%.

[0010] In a preferred embodiment of the present invention, in step S1, the acid-binding agent is an anhydrous organic base such as triethylamine, tripropylamine, hexamethylenetetramine, or DBU, preferably tripropylamine.

[0011] In a preferred embodiment of the present invention, in step S1, the molar ratio of hydroxyl silicone oil, trimethylchlorosilane, and acid-binding agent is 1:(0.9-1.0):(2.05-2.2).

[0012] In one specific embodiment of the present invention, in step S1, the organic solvent can be a non-polar organic solvent, such as one or more of cyclohexane, n-hexane, isooctane, petroleum ether, etc., preferably isooctane. The amount of solvent can be the amount of solvent conventional in the art. In a preferred embodiment of the present invention, the amount of organic solvent in step S1 can be 80-200% of the mass of trimethylchlorosilane and dimethylchlorosilane.

[0013] In one specific embodiment of the present invention, in step S1, when adding trimethylchlorosilane, the dropping rate is controlled to ensure that the temperature of the reaction system does not exceed 40°C. After the reaction is completed in step S1, the temperature needs to be lowered to room temperature under nitrogen protection.

[0014] In a preferred embodiment of the present invention, in step S2, the molar ratio of dimethylchlorosilane to hydroxyl silicone oil is (1.0-1.1):1.

[0015] In one specific embodiment of the present invention, in step S2, when adding dimethylchlorosilane, the dropping rate is controlled to ensure that the temperature of the reaction system does not exceed 40°C. In step S2, the specific steps for "removing low-boiling points" are: vacuum distillation at 120–130°C and -0.02–-0.01 MPa until no obvious bubbles are observed.

[0016] In the present invention, in step S3, the dual-terminated vinyl silicone oil used is a low-viscosity dual-terminated vinyl silicone oil, and the viscosity value of the low-viscosity dual-terminated vinyl silicone oil is not greater than 60 mPa·s. In a specific embodiment of the present invention, a dual-terminated vinyl silicone oil with a viscosity value of 20-30 mPa·s is preferably used. In a preferred embodiment of the present invention, in step S3, the dual-terminated vinyl silicone oil is a dual-terminated vinyl silicone oil with a vinyl content of 1.65-3.5%, for example, low-viscosity dual-terminated vinyl silicone oils with vinyl contents of 1.65-1.75%, 2.2-2.7%, and 2.7-3.3% can be selected, and more preferably, low-viscosity dual-terminated vinyl silicone oils with a vinyl content of 2.7-3.3% can be selected.

[0017] In a preferred embodiment of the present invention, in step S3, the molar ratio of the dual-terminated vinyl silicone oil to the dimethylchlorosilane in step S2 is 1:(1-2).

[0018] In a preferred embodiment of the present invention, in step S3, the amount of platinum catalyst used is such that the Pt content in the reaction system (total amount of reactants in step S3) is 5-100 ppm, preferably 10-30 ppm. In a specific embodiment of the present invention, in step S3, the platinum catalyst can be a platinum-containing catalyst commonly used in the art, preferably triphenylphosphine platinum, and more preferably, the molar ratio of platinum to triphenylphosphine is 1:(1-2). In a preferred embodiment of the present invention, the preparation method of the platinum catalyst includes the following steps: under nitrogen protection, chloroplatinic acid is dissolved in isopropanol, triphenylphosphine is added, and the reaction is carried out at 50-60°C for 2 hours, followed by cooling to obtain the catalyst. The amount of isopropanol used is a commonly used amount in the art; for example, 0.5 g of chloroplatinic acid hexahydrate is treated with 10-15 mL of isopropanol.

[0019] In a preferred embodiment of the present invention, to further improve the reaction efficiency, in step S3, the auxiliary agent is butanone, acetaldehyde, acetylacetone, isopropylidene acetone, or boron trifluoride ether, preferably acetylacetone. In a preferred embodiment of the present invention, the mass ratio of the auxiliary agent to platinum in the platinum catalyst is (5-10):1.

[0020] In a preferred embodiment of the present invention, step S3 may include: under nitrogen protection, activating the dual-terminated vinyl silicone oil and platinum catalyst at 60-70°C for 20-30 min, adding the mixture of product S2 and additives dropwise at 65-80°C, and reacting at 65-80°C for 2-3 h after the addition is complete, until the low boiling point is removed, thus obtaining the product.

[0021] In a specific embodiment of the present invention, the specific steps of "removing low boiling points" in step S3 are: vacuum distillation at 120-135℃ and -0.06--0.05MPa until no obvious bubbles are observed.

[0022] Another object of the present invention is the application of the above-described preparation method or the reactive silicone oil obtained by the above-described preparation method in addition-type two-component silicone potting compounds.

[0023] The beneficial effects of this invention are as follows:

[0024] The reactive silicone oil obtained by the preparation method provided in this invention, when used instead of dimethyl silicone oil in adhesives (especially addition-type two-component silicone potting compounds), can reduce the viscosity of the potting compound, extend the pouring / extrusion time, and at the same time, avoid or greatly reduce the exudation problem caused by adding dimethyl silicone oil to reduce viscosity in the prior art. In addition, the thermal conductivity of the resulting potting compound is also slightly improved. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. In the present invention, unless otherwise specified, "%" refers to a percentage by mass. Unless otherwise specified, the hydroxyl silicone oil given in the embodiments of the present invention was purchased from Wuxi Quanli, and the double-ended vinyl silicone oil was purchased from Runhe Materials. In the embodiments of the present invention, the hydrogen content was tested according to standard HG / T 4658-2014, and the vinyl content was tested according to Appendix C of standard GB / T28610-2020.

[0026] Example 1

[0027] This embodiment provides a method for preparing reactive silicone oil, including the following steps:

[0028] (1) Preparation of hydrogen-containing silicone oil

[0029] Under nitrogen protection and at room temperature, 25.5 g of trimethylchlorosilane was added dropwise to a mixture of 100 g of hydroxyl silicone oil (molecular weight 400 g / mol) with a hydroxyl value of 8.5%, 75.2 g of tripropylamine, and 65 g of isooctane. The temperature was maintained below 40°C during the dropwise addition. After the addition was complete, the temperature was slowly raised to about 45°C and the reaction was maintained for 2 hours. Under nitrogen protection, the temperature was lowered to room temperature, and 25.1 g of dimethylchlorosilane was added dropwise. The temperature was maintained below 40°C during the dropwise addition. After the addition was complete, the temperature was raised to about 45°C and the reaction was stirred for another 2 hours. The mixture was cooled and filtered. The filtrate was then distilled under reduced pressure at about 125°C and -0.02 to -0.01 MPa until no obvious bubbles were observed. The mixture was cooled and filtered again to obtain 130.4 g of product with a hydrogen content of 0.178%.

[0030] (2) Preparation of reactive silicone oil

[0031] Under nitrogen protection, 511g of double-ended vinyl silicone oil with a vinyl content of 2.8% and a viscosity of 28mPa·s was mixed with a platinum catalyst (the amount of platinum catalyst was such that the platinum content in the reaction system was 28ppm), and activated at 63-65℃ for 0.5h. A mixture of the product of step (1) and the auxiliary agent acetylacetone (the amount of auxiliary agent was 150ppm) was added dropwise at 75-76℃. After the addition was completed, the reaction was kept at a constant temperature for 2h. The mixture was then distilled under reduced pressure at about 130℃ and -0.06 to -0.05MPa until no obvious bubbles were observed, yielding 639.8g of reactive silicone oil with a vinyl content of 1.12% and a viscosity of 42mPa·s.

[0032] The platinum catalyst in step (2) is prepared by dissolving 0.5g of chloroplatinic acid hexahydrate in 10ml of isopropanol, adding 0.28g of triphenylphosphine, and reacting at 58-60℃ for 2h.

[0033] Example 2

[0034] The method provided in this embodiment is the same as that in embodiment 1, except that 92.4g (0.25mol) of hydroxyl silicone oil with a hydroxyl value of 9.2% is used in step (1), and 461.6g (0.265mol) of double-ended vinyl silicone oil with a vinyl content of 3.1% and a viscosity of 22mPa·s is used in step (2) to obtain 582.7g of reactive silicone oil with a vinyl content of 1.21% and a viscosity of 38mPa·s.

[0035] Example 3

[0036] The method provided in this embodiment is the same as that in embodiment 1, except that 89.7g (0.25mol) of hydroxyl silicone oil with a hydroxyl value of 9.48% is used in step (1), and 596.3g (0.265mol) of low-viscosity dual-terminated vinyl silicone oil with a vinyl content of 2.4% and a viscosity of 41mPa·s is used in step (2), resulting in 712.4g of reactive silicone oil with a vinyl content of 1.01% and a viscosity of 51mPa·s.

[0037] Example 4

[0038] The method provided in this embodiment is the same as that in embodiment 1, except that in step (1), 115g (0.25mol) of hydroxyl silicone oil with a hydroxyl value of 7.39% and 28.3g of trimethylchlorosilane are used to obtain 656.4g of reactive silicone oil with a vinyl content of 1.12% and a viscosity of 54mPa·s.

[0039] Example 5

[0040] The method provided in this embodiment is the same as that in embodiment 1, except that 22.5g of dimethylchlorosilane is used in step (1) and 801.6g of double-ended vinyl silicone oil with a vinyl content of 1.6% and a viscosity of 51mPa·s is used in step (2) to obtain 928.2g of reactive silicone oil with a vinyl content of 0.82% and a viscosity of 66mPa·s.

[0041] Experimental Example

[0042] Addition-type silicone thermally conductive potting compound raw materials (raw materials used in experimental and control examples):

[0043] Double-ended vinyl silicone oil with a viscosity of 200 mPa·s and a vinyl content of 0.69% was purchased from Jinan Weizhen Chemical Co., Ltd.; hydrogen-containing silicone oil with a viscosity of 50 mPa·s and a hydrogen content of 0.55% was purchased from Ningbo Runhe High-Tech Materials Technology Co., Ltd.; dimethyl silicone oil with a viscosity of 50 mPa·s was purchased from Hubei Xin Sihai Chemical Co., Ltd.; the platinum catalyst was a self-made platinum(0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane catalyst with a Pt content of 3000 ppm; acetylene cyclohexanol was purchased from Dongguan Zhongxin Organosilicon Materials Co., Ltd.; spherical alumina with average particle sizes of 5 μm and 50 μm were purchased from Qinghe Chaotai Metal Materials Co., Ltd.

[0044] Component A was prepared by mixing and stirring 35 parts of dual-end vinyl silicone oil, 8 parts of the product obtained in each example and 0.15 parts of platinum catalyst, heating to 65°C, and adding 175 parts of spherical alumina (50μm and 5μm alumina mixed in a mass ratio of 6.5:3.5) in three batches and stirring for 0.5 hours. Heating was stopped and the mixture was discharged after cooling to room temperature.

[0045] Component B is prepared as follows: 30 parts of double-ended vinyl silicone oil and 9 parts of the products obtained in each example are placed in a mixing tank and stirred. The mixture is heated to 65°C, and 175 parts of spherical alumina (50μm and 5μm alumina are mixed in a mass ratio of 6.5:3.5) are slowly added and stirred for 0.5 hours. Heating is stopped, and the mixture is allowed to cool to below 50°C. Then, 6 parts of hydrogen-containing silicone oil (i.e., hydrogen-containing silicone oil with a viscosity of 50 mPa·s and a hydrogen content of 0.55%) and 0.015 parts of acetylenecyclohexanol are added and stirred for 20 minutes. The mixture is then discharged and packaged for later use.

[0046] Compare with Example 1

[0047] Component A is prepared by mixing 43 parts of dual-end vinyl silicone oil and 0.15 parts of platinum catalyst, heating to 65°C, adding 175 parts of spherical alumina (50μm and 5μm alumina mixed in a mass ratio of 6.5:3.5) in three batches, stirring for 0.5 hours, stopping heating, and discharging after cooling to room temperature.

[0048] Component B preparation: Place 39 parts of double-ended vinyl silicone oil in a mixing tank and stir. Heat the mixture to 65°C, then slowly add 175 parts of spherical alumina (50μm and 5μm alumina mixed in a mass ratio of 6.5:3.5) and stir for 0.5 hours. Stop heating and wait until the temperature drops below 50°C. Then add 6 parts of hydrogen-containing silicone oil (i.e., hydrogen-containing silicone oil with a viscosity of 50 mPa·s and a hydrogen content of 0.55%) and 0.015 parts of acetylene cyclohexanol and stir for 20 minutes. The mixture is then ready for dispensing and packaging.

[0049] Compare with Example 2

[0050] Component A is prepared by mixing and stirring 35 parts of dual-end vinyl silicone oil, 8 parts of 50 mPa·s dimethyl silicone oil and 0.15 parts of platinum catalyst, heating to 65°C, adding 175 parts of spherical alumina (50 μm and 5 μm alumina mixed in a mass ratio of 6.5:3.5) in three batches, stirring for 0.5 h, stopping heating, and discharging after cooling to room temperature.

[0051] Component B is prepared as follows: 30 parts of double-ended vinyl silicone oil and 9 parts of 50 mPa·s dimethyl silicone oil are placed in a mixing tank and stirred. The mixture is heated to 65°C, and 175 parts of spherical alumina (50 μm and 5 μm alumina are mixed in a mass ratio of 6.5:3.5) are slowly added and stirred for 0.5 h. Heating is stopped, and the mixture is allowed to cool to below 50°C. Then, 6 parts of hydrogen-containing silicone oil (i.e., hydrogen-containing silicone oil with a viscosity of 50 mPa·s and a hydrogen content of 0.55%) and 0.015 parts of acetylenecyclohexanol are added and stirred for 20 min. The mixture is then discharged and packaged for later use.

[0052] The A and B components of the experimental and control examples were mixed evenly at a mass ratio of 1:1, and after vacuum degassing, the mixture was poured into a mold and cured at room temperature for 24 hours to obtain the final product.

[0053] Performance tests were conducted, and the results are shown in Table 1. Test methods: Thermal conductivity was tested using a material thermal resistance and thermal conductivity tester according to ASTM D5470-2006; Shore A hardness was tested using a hardness tester according to GB / T 531.1-2008. Viscosity was tested using a DVNXHBCBG instrument with a CPA-52Z rotor at 25℃. Aging test: Continuous aging was performed in a 70℃ forced-air oven for 72 hours.

[0054] Table 1

[0055]

[0056] As shown in Table 1, the reactive silicone oil prepared in this invention has a viscosity-reducing effect comparable to that of dimethyl silicone oil, but its exudation after aging is significantly better than that of Control Example 2. Furthermore, under the same aging conditions, the hardness increase of the potting compound obtained by adding the reactive silicone oil provided in this invention is significantly smaller than that of Control Example 2. Additionally, the thermal conductivity of the potting compound obtained by adding the reactive silicone oil provided in this invention is slightly higher than that of Control Example 2, which had improved viscosity.

[0057] Finally, the method of this invention is merely a preferred embodiment and is not intended to limit the scope of protection of this invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a reactive silicone oil, characterized in that, Includes the following steps: S1, under nitrogen protection, trimethylchlorosilane is added to a mixed solution of hydroxyl silicone oil, acid-binding agent, and organic solvent, and the reaction is carried out at 40~50℃ for 2~3h. After the reaction is completed, the temperature is lowered to room temperature. The acid-binding agent is triethylamine, tripropylamine, hexamethylenetetramine, or DBU. S2, add dimethylchlorosilane to the system of step S1, react at 30~50℃ for 2~3h, cool down and filter, take the filtrate to remove low boiling points, and obtain the product. S3, under nitrogen protection, the dual-end vinyl silicone oil, platinum catalyst, product of step S2 and additives are mixed and reacted at 65~80℃ for 2~3h. Except for low boiling point, the product is obtained. The viscosity of the dual-end vinyl silicone oil is not greater than 60mPa·s. The additives are butanone, acetaldehyde, acetylacetone, isopropylidene acetone or boron trifluoride ether.

2. The preparation method according to claim 1, characterized in that, In step S1, the hydroxyl content in the hydroxyl silicone oil is ≥1%.

3. The preparation method according to claim 2, characterized in that, In step S1, the hydroxyl content in the hydroxyl silicone oil is 1~12%.

4. The preparation method according to claim 1, characterized in that, In step S1, the acid-binding agent is tripropylamine; The solvent is one or more of cyclohexane, n-hexane, isooctane, and petroleum ether, and the solvent is 80-200% by mass of a mixture of trimethylchlorosilane and dimethylchlorosilane.

5. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of hydroxyl silicone oil, trimethylchlorosilane, and acid-binding agent is 1:(0.9~1.0):(2.05~2.2).

6. The preparation method according to claim 1, characterized in that, In step S2, the molar ratio of dimethylchlorosilane to hydroxyl silicone oil is (1.0~1.1):

1.

7. The preparation method according to any one of claims 1 to 6, characterized in that, In step S3, the platinum catalyst is triphenylphosphine platinum, wherein the molar ratio of platinum to triphenylphosphine is 1:(1~2).

8. The preparation method according to claim 7, characterized in that, The preparation method of the platinum catalyst includes the following steps: under nitrogen protection, chloroplatinic acid hexahydrate is dissolved in isopropanol, triphenylphosphine is added and reacted at 50-60℃ for 2 hours, and then cooled to obtain the catalyst.

9. The preparation method according to claim 1, characterized in that, In step S3, the double-ended vinyl silicone oil is a double-ended vinyl silicone oil with a vinyl content of 1.5~3.5%; And / or, the adjuvant is acetylacetone.

10. The preparation method according to any one of claims 1 to 6, characterized in that, In step S3, the molar ratio of the dual-terminated vinyl silicone oil to the dimethylchlorosilane in step S2 is 1:(1~2), the amount of platinum catalyst used is such that the Pt content in the reaction system is 5~100ppm, and the mass ratio of the auxiliary to the platinum in the platinum catalyst is (5~10):

1.

11. The reactive silicone oil obtained by the preparation method according to any one of claims 1 to 10.

12. The preparation method according to any one of claims 1 to 10 or the reactive active silicone oil according to claim 11 in addition-type silicone potting compound.

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