Reactive silicone oil as well as preparation method and application thereof

Abstract

The invention provides reactive silicone oil as well as a preparation method and application thereof. The preparation method of the reactive silicone oil comprises the following steps: S1, under the protection of nitrogen, adding trimethylchlorosilane into a mixed solution of hydroxyl silicone oil, an acid-binding agent and an organic solvent, reacting at 40-50 DEG C for 2-3 hours, and cooling to room temperature after the reaction is finished; s2, adding methyl dichloro hydrogen-containing silane into a system in the step S1, reacting for 2-3 hours at the temperature of 30-50 DEG C, cooling, filtering, taking filtrate, and removing low boiling points to obtain a product; and S3, under the protection of nitrogen, mixing double-end vinyl silicone oil, a platinum catalyst, a product obtained in the step S2 and an auxiliary agent, carrying out a reaction at 65-80 DEG C for 2-3 h, and removing a low boiling point to obtain the product. The reactive silicone oil obtained by the preparation method provided by the invention is added into a glue material instead of dimethyl silicone oil, so that the effect of reducing the viscosity of the pouring sealant can be achieved, and meanwhile, the problem of seepage caused by adding the dimethyl silicone oil for reducing the viscosity in the prior art is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone oil synthesis, and more specifically, to reactive silicone oil and a preparation method and application thereof. Background Art

[0002] In the current industrial field, silicone potting adhesives 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, the two-component addition silicone potting adhesive with hydrogen silicone oil and vinyl silicone oil as the base material has the widest application due to its mild curing conditions, no by-products produced during the curing process and suitable viscosity.

[0003] In the field of electronics, potting glue is used as a sealant, but due to its poor thermal conductivity, the heat generated by electronic equipment cannot be dissipated in time, which greatly reduces the reliability and life of electronic components; at the same time, the strength of the glue is not strong enough and the temperature and weather resistance is poor, which will also affect the service life of the product. Therefore, two-component silicone potting glue usually uses spherical alumina or aluminum nitride filled with different particle sizes and mass ratios to improve the thermal conductivity of the potting glue, and at the same time, the strength of the glue is regulated by regulating the hydrogen content and cross-linking degree of hydrogen-containing silicone oil. However, the high mass fraction of active hydrogen in hydrogen-containing silicone oil and the addition of high-filling fillers will increase the viscosity of the glue, shortening the construction time. In the prior art, this problem is usually solved by adding dimethyl silicone oil to the system for plasticization, but dimethyl silicone oil has no reaction activity. As time goes on, dimethyl silicone oil will seep out of the potting glue after curing, especially after the oil seeps out, the potting glue will harden, produce different degrees of stress, and affect electronic components. Summary of the invention

[0004] In order to solve or at least partially solve the problems existing in the prior art, the present invention provides a reactive silicone oil and a preparation method and application thereof. Adding the reactive silicone oil obtained by the preparation method provided by the present invention to the adhesive can reduce the viscosity of the potting glue, and at the same time, the leakage problem caused by adding dimethyl silicone oil in the prior art will not occur. At the same time, the use of the reactive silicone oil of the present invention can also slightly improve the thermal conductivity of the potting glue.

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

[0006] S1, under nitrogen protection, add trimethyl monochlorosilane to a mixed solution of hydroxy silicone oil, acid binding agent and organic solvent, react at 40-50°C for 2-3h, and cool to room temperature after the reaction;

[0007] S2, adding dimethyl monochlorosilane to the system of step S1, reacting at 30-50° C. for 2-3 hours, cooling and filtering, removing low boiling points from the filtrate to obtain a product;

[0008] S3, under nitrogen protection, mixing bi-terminal vinyl silicone oil, platinum catalyst, the product of step S2 and auxiliary agent, reacting at 65-80° C. for 2-3 hours, and removing low boiling point to obtain; the viscosity of the bi-terminal vinyl silicone oil is not more than 60 mPa·s.

[0009] In a preferred embodiment of the present invention, in step S1, the hydroxyl value of the hydroxy silicone oil is not less than 1% (≥1%). In order to further improve the obtained reactive silicone oil to reduce the viscosity of the rubber and the heat resistance, in step S1, the hydroxyl value of the hydroxy 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 a non-aqueous organic base such as triethylamine, tripropylamine, hexamethylenetetramine, DBU, etc., preferably tripropylamine.

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

[0012] In a 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 the solvent can use the conventional amount of solvent in the art. In a preferred embodiment of the present invention, the amount of the organic solvent in step S1 can be 80-200% by mass of trimethyl monochlorosilane and dimethyl monochlorosilane.

[0013] In one embodiment of the present invention, in step S1, when adding trimethyl monochlorosilane, the dropping speed is controlled to control the temperature of the reaction system not to exceed 40° C. In step S1, after the reaction is completed, the temperature needs to be cooled to room temperature under the protection of nitrogen.

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

[0015] In a specific embodiment of the present invention, in step S2, when adding dimethyl monochlorosilane, the dropwise addition speed is controlled to control the temperature of the reaction system to not exceed 40° C. In step S2, the specific step of "removing low boiling points" is: distill under reduced pressure at 120 to 130° C. and -0.02 to -0.01 MPa until there are no obvious bubbles.

[0016] In the scheme of the present invention, in step S3, the double-terminal vinyl silicone oil used is a low-viscosity double-terminal vinyl silicone oil. In the present invention, the viscosity value of the low-viscosity double-terminal vinyl silicone oil is not more than 60mPa·s. In a specific embodiment of the present invention, it is preferred to use a double-terminal vinyl silicone oil with a viscosity value of 20 to 30mPa·s. In the present invention, in a preferred embodiment of the present invention, in step S3, the double-terminal vinyl silicone oil is a double-terminal vinyl silicone oil with a vinyl content of 1.65 to 3.5%. For example, low-viscosity double-terminal vinyl silicone oils with vinyl contents of 1.65 to 1.75%, 2.2 to 2.7%, and 2.7 to 3.3% respectively produced by Runhe New Materials can be selected, and low-viscosity double-terminal vinyl silicone oils with a vinyl content of 2.7 to 3.3% can be further preferred.

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

[0018] In a preferred embodiment of the present invention, in step S3, the amount of the platinum catalyst is such that the Pt content in the reaction system (the total amount of the reaction raw materials in step S3) is 5 to 100 ppm, preferably 10 to 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 further preferably the molar ratio of platinum to triphenylphosphine is preferably 1: (1 to 2). In a preferred embodiment of the present invention, the preparation method of the platinum catalyst comprises the following steps: under nitrogen protection, chloroplatinic acid is dissolved in isopropanol, triphenylphosphine is added and reacted at 50-60°C for 2h, and the temperature is lowered to obtain. Among them, the amount of isopropanol is the amount commonly used in the art, for example, 0.5g of chloroplatinic acid hexahydrate uses 10 to 15mL of isopropanol.

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

[0020] In a preferred embodiment of the present invention, the specific steps of step S3 may include: under nitrogen protection, activating the double-ended vinyl silicone oil and the platinum catalyst at 60-70°C for 20-30 minutes, adding a mixed solution of the S2 product and the auxiliary agent at 65-80°C, reacting at 65-80°C for 2-3 hours, and removing the low boiling point to obtain the product.

[0021] In a specific embodiment of the present invention, in step S3, the specific step of "removing low boiling points" is: distill under reduced pressure at 120 to 135°C and -0.06 to -0.05 MPa until there are no obvious bubbles.

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

[0023] The beneficial effects of the present invention are:

[0024] The reactive silicone oil obtained by the preparation method provided by the present invention is added to the adhesive (especially the addition type two-component silicone potting adhesive) instead of dimethyl silicone oil, which can reduce the viscosity of the potting adhesive and extend the pouring / extrusion time. At the same time, the problem of seepage caused by adding dimethyl silicone oil to reduce the viscosity in the prior art will not occur or will be greatly reduced. In addition, the thermal conductivity of the obtained potting adhesive is also slightly improved. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are further described in detail below in conjunction with the examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. In the present invention, unless otherwise specified, "%" is a mass percentage. Unless otherwise specified, the hydroxy silicone oil given in the embodiments of the present invention was purchased from Wuxi Quanli, and the double-terminal vinyl silicone oil was purchased from Runhe Materials. In an embodiment of the present invention, the hydrogen content is tested according to the standard HG / T 4658-2014, and the vinyl content is tested according to the standard GB / T28610-2020 Appendix C.

[0026] Example 1

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

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

[0029] Under nitrogen protection and room temperature, 25.5 g of trimethyl monochlorosilane 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 at no more than 40°C during the addition process. After the addition, the temperature was slowly raised to about 45°C and kept for reaction for 2 hours. The temperature was lowered to room temperature under nitrogen protection, and 25.1 g of dimethyl monochlorosilane was continued to be added dropwise. The room temperature was maintained at no more than 40°C during the addition process. After the addition, the temperature was raised to about 45°C and the reaction was continued with stirring for 2 hours. The temperature was lowered and filtered. The filtrate was taken and distilled under reduced pressure at about 125°C at -0.02 to -0.01 MPa until there were no obvious bubbles. The temperature was lowered and filtered again to obtain 130.4 g of a product with a hydrogen content of 0.178%.

[0030] (2) Preparation of reactive silicone oil

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

[0032] The preparation process of the platinum catalyst in step (2) is as follows: 0.5 g of chloroplatinic acid hexahydrate is dissolved in 10 ml of isopropanol, 0.28 g of triphenylphosphine is added, and the mixture is reacted at 58-60° C. for 2 h to obtain the catalyst.

[0033] Example 2

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

[0035] Example 3

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

[0037] Example 4

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

[0039] Example 5

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

[0041] Experimental example

[0042] Addition type silicone thermal conductive potting glue raw materials (raw materials used in experimental examples 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 Xinsihai Chemical Co., Ltd.; the platinum catalyst was a homemade platinum (0)-1,3-diethene-1,1,3,3-tetramethyldisiloxane catalyst with a Pt content of 3000 ppm; acetylene cyclohexanol was purchased from Dongguan Zhongxin Silicone Materials Co., Ltd.; spherical alumina with average particle sizes of 5 μm and 50 μm, respectively: purchased from Qinghe Chaotai Metal Materials Co., Ltd.

[0044] Prepare component A: mix and stir 35 parts of double-ended vinyl silicone oil, 8 parts of the product obtained in each example and 0.15 parts of platinum catalyst, heat to 65°C, add 175 parts of spherical alumina (50μm and 5μm alumina mixed in a mass ratio of 6.5:3.5) in three times, stir for 0.5h, stop heating, and discharge after cooling to room temperature.

[0045] Prepare component B: put 30 parts of double-ended vinyl silicone oil and 9 parts of the product obtained in each example into a stirring tank, stir, and heat to 65°C, slowly add 175 parts of spherical alumina (50μm and 5μm alumina are mixed in a mass ratio of 6.5:3.5), stir for 0.5h, stop heating, wait until it drops below 50°C, then add 6 parts of hydrogen-containing silicone oil (i.e., hydrogen-containing silicone oil with a viscosity of 50mPa·s and a hydrogen content of 0.55%) and 0.015 parts of acetylene cyclohexanol, stir for 20min, and then discharge the material and package it for use.

[0046] Comparative Example 1

[0047] Prepare component A: mix and stir 43 parts of double-ended vinyl silicone oil and 0.15 parts of platinum catalyst, heat to 65°C, add 175 parts of spherical alumina (50μm and 5μm alumina mixed in a mass ratio of 6.5:3.5) in three times, stir for 0.5h, stop heating, and discharge after cooling to room temperature.

[0048] Prepare component B: put 39 parts of double-ended vinyl silicone oil into a stirring tank, stir, and heat to 65°C, slowly add 175 parts of spherical alumina (50μm and 5μm alumina are mixed at a mass ratio of 6.5:3.5), stir for 0.5h, stop heating, 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 50mPa·s and a hydrogen content of 0.55%) and 0.015 parts of acetylene cyclohexanol, stir for 20min, and then discharge the material and package it for use.

[0049] Comparative Example 2

[0050] Prepare component A: mix and stir 35 parts of double-ended vinyl silicone oil, 8 parts of 50 mPa·s dimethyl silicone oil and 0.15 parts of platinum catalyst, heat to 65°C, add 175 parts of spherical alumina (50μm and 5μm alumina mixed in a mass ratio of 6.5:3.5) in three times, stir for 0.5h, stop heating, and discharge after cooling to room temperature.

[0051] Prepare component B: put 30 parts of double-ended vinyl silicone oil and 9 parts of 50mPa·s dimethyl silicone oil into a stirring tank and stir. Heat to 65°C, slowly add 175 parts of spherical alumina (50μm and 5μm alumina are mixed at a mass ratio of 6.5:3.5), stir for 0.5h, stop heating, wait until the temperature drops below 50°C, add 6 parts of hydrogen-containing silicone oil (i.e., hydrogen-containing silicone oil with a viscosity of 50mPa·s and a hydrogen content of 0.55%) and 0.015 parts of acetylene cyclohexanol, stir for 20min, and then discharge the material and package it for use.

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

[0053] The performance test was carried out, and the results are shown in Table 1. Test method: The thermal conductivity was tested according to ASTM D5470-2006 using a material thermal resistance and thermal conductivity tester; the Shore A hardness was tested according to GB / T 531.1-2008 using a hardness tester. The viscosity was tested at 25°C using an instrument DVNXHBCBG, rotor CPA-52Z. Aging test: Aging was carried out continuously for 72 hours in a 70°C forced air oven.

[0054] Table 1

[0055]

[0056] As can be seen from Table 1, the effect of reducing viscosity of the reactive silicone oil prepared by the present invention is comparable to that of dimethyl silicone oil, but the exudation after aging is significantly better than that of Control Example 2. At the same time, under the same aging conditions, the hardness increase of the potting compound obtained by adding the reactive silicone oil provided by the present invention is significantly less than that of Control Example 2. At the same time, the thermal conductivity of the potting compound obtained by adding the reactive silicone oil provided by the present invention is slightly improved compared to Control Example 2 with improved viscosity.

[0057] Finally, the method of the present invention is only a preferred embodiment and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a reactive silicone oil, characterized in that: The steps include: S1, under nitrogen protection, add trimethyl monochlorosilane to a mixed solution of hydroxy silicone oil, acid binding agent and organic solvent, react at 40-50°C for 2-3h, and cool to room temperature after the reaction; S2, adding dimethyl monochlorosilane to the system of step S1, reacting at 30-50° C. for 2-3 hours, cooling and filtering, removing low boiling points from the filtrate to obtain a product; S3, under nitrogen protection, mixing bi-terminal vinyl silicone oil, platinum catalyst, the product of step S2 and auxiliary agent, reacting at 65-80° C. for 2-3 hours, and removing low boiling point to obtain; the viscosity of the bi-terminal vinyl silicone oil is not more than 60 mPa·s.

2. The preparation method according to claim 1, characterized in that: In step S1, the hydroxyl value content of the hydroxy silicone oil is ≥ 1%, preferably 1-12%.

3. The preparation method according to claim 1, characterized in that: In step S1, the acid binding agent is triethylamine, tripropylamine, hexamethylenetetramine or DBU, preferably tripropylamine; The solvent is a non-polar organic solvent, including but not limited to one or more of cyclohexane, n-hexane, isooctane and petroleum ether. The solvent is 80-200% by mass of a mixture of trimethyl monochlorosilane and dimethyl monochlorosilane.

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

5. The preparation method according to claim 1, characterized in that: In step S2, the molar ratio of dimethyl monochlorosilane to hydroxy silicone oil is (1.0-1.1):

1.

6. The preparation method according to any one of claims 1 to 5, characterized in that In step S3, the platinum catalyst is triphenylphosphine platinum, wherein the molar ratio of platinum to triphenylphosphine is preferably 1:(1-2); Preferably, the preparation method of the platinum catalyst comprises the following steps: under nitrogen protection, dissolving chloroplatinic acid hexahydrate in isopropanol, adding triphenylphosphine, reacting at 50-60° C. for 2 h, and cooling to obtain the catalyst.

7. The preparation method according to claim 6, characterized in that: In step S3, the double-terminal vinyl silicone oil is a double-terminal vinyl silicone oil with a vinyl content of 1.5 to 3.5%; And / or, the auxiliary agent is butanone, acetaldehyde, acetylacetone, mesityl oxide or boron trifluoride etherate.

8. The preparation method according to any one of claims 1 to 7, characterized in that In step S3, the molar ratio of the double-terminal vinyl silicone oil to the dimethyl monochlorosilane in step S1 is 1:1, the amount of the platinum catalyst is such that the Pt content in the reaction system is 5-100 ppm, and the mass ratio of the auxiliary agent to the platinum in the platinum catalyst is (5-10):

1.

9. The reactive silicone oil obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the preparation method according to any one of claims 1 to 8 or the reactive active silicone oil according to claim 9 in addition-type organosilicon potting adhesive.

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