An organosilicon gel composition, its preparation method and application

Abstract

The present invention relates to the technical field of silicone materials, and discloses a silicone gel composition, a preparation method and an application thereof. The silicone gel composition comprises the following components in parts by mass: Component A: 70 - 120 parts of vinyl silicone oil; 10 - 55 parts of methyl vinyl MQ silicone resin; 5 - 20 parts of crosslinking agent; 1 - 7 parts of tackifier; Component B: 60 - 110 parts of vinyl silicone oil; 5 - 60 parts of methyl vinyl MQ silicone resin; 0.5 - 2 parts of catalyst; 0.5 - 2 parts of inhibitor; By mass, the methyl vinyl MQ silicone resin comprises the following raw materials for preparation: 90 - 150 parts of end-capping agent, 300 - 800 parts of silicate compound, 200 - 1000 parts of small molecule silicone compound, 10 - 30 parts by mass of solid acid catalyst, 150 - 300 parts of solvent. The silicone gel composition provided by the present invention has excellent yellowing resistance and oil separation resistance, and good high temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone materials, and particularly relates to a silicone gel composition, a preparation method thereof, and an application thereof. Background Art

[0002] Insulated gate bipolar transistor (IGBT) is a power semiconductor device composed of a bipolar junction transistor (BJT) and an insulated gate field effect transistor (MOS). It has significant performance advantages of small drive power and low saturation voltage drop, and plays two major functions of power switch and electric energy conversion in electronic components. It is widely used in new energy vehicles, industrial control, white household appliances, new energy power generation, rail transit and other fields. The IGBT module has fine circuits and is easily affected by environmental moisture, dust, salt spray or other pollutants, as well as external force vibration. Therefore, it is necessary to pot with silicone gel to play a protective role. However, most of the existing silicone gel products have the defects of easy oil separation and serious yellowing at high temperatures, and the working temperature is below 200°C.

[0003] CN 115558297 A discloses a high-temperature resistant silicone gel for potting, which can work at 200°C and is suitable for the encapsulation of electronic components in high-temperature environments. However, compounds containing nitrogen and phosphorus elements are added to the B component of this silicone gel. These compounds are likely to cause platinum catalyst poisoning, resulting in incomplete curing of the silicone gel. At the same time, the nitrogen-containing inhibitor is also likely to cause yellowing of the silicone gel at high temperatures, affecting transparency. Summary of the Invention

[0004] The present invention aims to at least solve the above technical problems existing in the prior art. For this reason, one of the purposes of the present invention is to provide a silicone gel composition; the second purpose of the present invention is to provide a preparation method of this silicone gel composition; the third purpose of the present invention is to provide an application of this silicone gel composition.

[0005] In order to achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0006] The first aspect of the present invention provides a silicone gel composition, including the following components in parts by mass:

[0007] Component A:

[0008]

[0009] Component B:

[0010]

[0011]

[0012] By mass parts, the methyl vinyl MQ silicone resin comprises the following raw materials for preparation: 90 - 150 parts of a capping agent, 300 - 800 parts of a silicate compound, 200 - 1000 parts of a small molecule organosilicon compound, 10 - 30 mass parts of a solid acid catalyst, and 150 - 300 parts of a solvent.

[0013] Preferably, the organosilicon gel composition comprises the following components by mass parts:

[0014] Component A:

[0015]

[0016] Component B:

[0017]

[0018] By mass parts, the methyl vinyl MQ silicone resin comprises the following raw materials for preparation: 90 - 150 parts of a capping agent, 300 - 800 parts of a silicate compound, 200 - 1000 parts of a small molecule organosilicon compound, 10 - 30 mass parts of a solid acid catalyst, and 150 - 300 parts of a solvent.

[0019] Preferably, the organosilicon gel composition does not contain compounds containing N and P elements.

[0020] Preferably, the mass ratio of Component A to Component B is (0.5 - 1.5):1; more preferably, the mass ratio of Component A to Component B is (0.8 - 1.2):1.

[0021] Preferably, the vinyl content of the vinyl silicone oil is 0.1 - 5 wt%.

[0022] Preferably, the viscosity of the vinyl silicone oil at 23°C is 100 - 3000 mPa·s.

[0023] Preferably, the vinyl silicone oil comprises at least one of end vinyl silicone oil, side vinyl silicone oil, and silicone oil with vinyl groups at both ends and side chains.

[0024] Preferably, in the raw materials for the preparation of the methyl vinyl MQ silicone resin, the solvent comprises water and an alcohol solvent.

[0025] Preferably, the mass ratio of water to the alcohol solvent is 1:(0.25 - 1).

[0026] Preferably, the alcohol solvent comprises at least one of methanol, ethanol, isopropanol, n-butanol, and isobutanol.

[0027] Preferably, the capping agent includes at least one of hexamethyldisiloxane and tetramethyldivinyldisiloxane; more preferably, the capping agent is a compound prepared by mixing hexamethyldisiloxane and tetramethyldivinyldisiloxane, and the mass ratio of hexamethyldisiloxane to tetramethyldivinyldisiloxane is 1:(0.1 - 10).

[0028] Preferably, the silicate compound includes at least one of methyl silicate, ethyl silicate, propyl silicate, butyl silicate, and ethyl polysilicate.

[0029] Preferably, the small molecule organosilicon compound includes at least one of dimethylsiloxane mixed cyclic bodies, tetramethylcyclotetrasiloxane, vinyl cyclic bodies, and linear silicone oil.

[0030] Preferably, the solid acid catalyst includes macroporous strong acid ion exchange resin.

[0031] Preferably, the methyl vinyl MQ silicone resin is prepared by a method including the following steps:

[0032] A1. Mix the capping agent and the solvent, add the solid acid catalyst, and heat for reaction;

[0033] A2. Dropwise add the silicate compound and heat for reaction;

[0034] A3. Add the small molecule organosilicon compound, collect the hydrolysis product, raise the temperature for polymerization reaction, remove impurities, and obtain the methyl vinyl MQ silicone resin.

[0035] Preferably, in step A1, the temperature of the heating reaction is 80 - 120°C.

[0036] Preferably, in step A1, the time of the heating reaction is 30 - 40 min.

[0037] Preferably, in step A2, the temperature of the heating reaction is 80 - 100°C.

[0038] Preferably, in step A2, the time of the heating reaction is 5 - 10 h.

[0039] Preferably, after the heating reaction in step A2, an operation of cooling to room temperature is further included.

[0040] Preferably, after adding the small molecule organosilicon compound in step A3, steps of standing for layer separation, removing the acid water layer, and filtering out the solid acid catalyst are further included.

[0041] Preferably, in step A3, the temperature of the temperature-raising polymerization reaction is 120 - 160°C.

[0042] Preferably, in the step A3, the time of the temperature-raising polymerization reaction is 3-6 h.

[0043] Preferably, in the step A3, the pressure range for impurity removal is -0.1 to -0.085 MPa.

[0044] Preferably, the removed impurities include moisture and small-molecule organosilicon compounds.

[0045] Preferably, the crosslinking agent includes hydrogen-containing silicone oil; the hydrogen content of the hydrogen-containing silicone oil is 0.05-0.5 wt%; the viscosity of the hydrogen-containing silicone oil at 23 °C is 10-100 mPa·s.

[0046] Preferably, the tackifier includes at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0047] Preferably, the catalyst includes a platinum catalyst; the concentration of the catalyst is 3000-5000 ppm.

[0048] Preferably, the inhibitor includes at least one of tetramethyldivinyldisiloxane, tetramethyltetravinylcyclotetrasiloxane, and ethynylcyclohexanol.

[0049] The second aspect of the present invention provides a preparation method of the organosilicon gel composition described in the first aspect of the present invention, including the following steps:

[0050] S1. Mix vinyl silicone oil, methyl vinyl MQ silicone resin, a crosslinking agent, and a tackifier to obtain component A;

[0051] S2. Mix vinyl silicone oil, methyl vinyl MQ silicone resin, a catalyst, and an inhibitor to obtain component B.

[0052] Preferably, in the step S1, stirring is assisted; the stirring is first carried out at a rate of 30-40 r / min for 50-70 min, and then stirred under vacuum conditions for 20-40 min.

[0053] Preferably, in the step S2, stirring is assisted; the stirring is first carried out at a rate of 30-40 r / min for 50-70 min, and then stirred under vacuum conditions for 20-40 min.

[0054] The third aspect of the present invention provides an application of the organosilicon gel composition described in the first aspect of the present invention in IGBT module potting.

[0055] Compared with the prior art, the beneficial effects of the present invention are:

[0056] 1) The silicone gel composition provided by the present invention has excellent yellowing resistance and oil bleeding resistance, good high-temperature resistance, and can work for a long time under high-temperature conditions of 200-230 °C; the components do not contain compounds containing N and P elements, which can reduce the yellowing of the silicone gel; the raw material methyl vinyl MQ silicone resin is synthesized by a solid acid, which can increase the proportion of the Q unit structure of the silicone gel, improve the three-dimensional network structure and also increase the proportion of inorganic components, which is beneficial to improving the yellowing resistance and oil bleeding resistance of the silicone gel composition;

[0057] 2) The preparation method of the silicone gel composition provided by the present invention is simple and suitable for industrial application. By adding epoxy silane as a tackifier, the adhesion of the silicone gel to the substrate can be improved;

[0058] 3) The silicone gel composition provided by the present invention can be well applied to the potting of IGBT modules under high-temperature conditions. Description of the Drawings

[0059] Figure 1 It is a color change diagram of the silicone gel composition in Examples 1-5 and Comparative Example 1 after aging at 230 °C for 1000 h;

[0060] Figure 2 It is an oil bleeding situation diagram of the silicone gel composition in Examples 1-5 and Comparative Example 1 after baking at 125 °C for 500 h;

[0061] Figure 3 It is a thermogravimetric analysis diagram of the silicone gel composition in Example 1 and Comparative Example 1. Detailed Embodiments

[0062] The content of the present invention will be further described in detail through specific examples below. The raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial channels or can be obtained by existing technical methods without special instructions. Unless otherwise specified, the test or measurement methods are conventional methods in the art.

[0063] 1. The methyl vinyl MQ silicone resin used in the following examples was prepared by the following steps:

[0064] 1) Add 120 parts by mass of a mixture of hexamethyldisiloxane and tetramethyldivinyldisiloxane (mass ratio 1:1), 150 parts by mass of deionized water, 75 parts by mass of methanol to a reactor, and then add 20 parts by mass of macroporous strong acid ion exchange resin, and stir and react at 100 °C for 35 min;

[0065] 2) Slowly add 550 parts by mass of methyl orthosilicate, and stir and react at 90 °C for 7.5 h, and cool the product to room temperature;

[0066] 3) Add 600 parts by mass of dimethylsiloxane mixed cyclic oligomers. After mixing, let it stand for stratification, remove the acidic water layer, filter out the macroporous strong acid ion exchange resin to obtain a hydrolysis product. Heat it to 140 °C for a polymerization reaction for 4.5 h, and remove water and small molecule organosilicon compounds under a negative pressure of -0.1 to -0.085 MPa to obtain a methyl vinyl MQ silicone resin.

[0067] 2. Unless otherwise specified, "parts" in the following examples all refer to "parts by mass".

[0068] Example 1

[0069] This example provides a silicone gel composition, and the components are shown in Table 1:

[0070] Table 1 Components and contents of the silicone gel composition in Example 1

[0071]

[0072] The preparation steps are as follows:

[0073] S1. Put vinyl silicone oil, methyl vinyl MQ silicone resin, hydrogen-containing silicone oil, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component A;

[0074] S2. Put vinyl silicone oil, methyl vinyl MQ silicone resin, platinum catalyst, and tetramethyldivinyldisiloxane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component B.

[0075] Example 2

[0076] This example provides a silicone gel composition, and the components are shown in Table 2:

[0077] Table 2 Components and contents of the silicone gel composition in Example 2

[0078]

[0079] The preparation steps are as follows:

[0080] S1. Put vinyl silicone oil, methyl vinyl MQ silicone resin, hydrogen-containing silicone oil, and γ-(2,3-epoxypropoxy)propyltriethoxysilane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component A;

[0081] S2. Put vinyl silicone oil, methyl vinyl MQ silicone resin, platinum catalyst, and tetramethyltetravinylcyclotetrasiloxane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component B.

[0082] Example 3

[0083] This example provides a silicone gel composition, and the components are shown in Table 3:

[0084] Table 3 Components and Contents of the Silicone Gel Composition in Example 3

[0085]

[0086] The preparation steps are as follows:

[0087] S1. Put vinyl silicone oil, methyl vinyl MQ silicone resin, hydrogen-containing silicone oil, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component A;

[0088] S2. Put vinyl silicone oil, methyl vinyl MQ silicone resin, platinum catalyst, and ethynylcyclohexanol into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component B.

[0089] Example 4

[0090] This example provides a silicone gel composition, and the components are shown in Table 4:

[0091] Table 4 Components and Contents of the Silicone Gel Composition in Example 4

[0092]

[0093] The preparation steps are as follows:

[0094] S1. Put vinyl silicone oil, methyl vinyl MQ silicone resin, hydrogen-containing silicone oil, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component A;

[0095] S2. Put vinyl silicone oil, methyl vinyl MQ silicone resin, platinum catalyst, and tetramethyldivinyldisiloxane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component B.

[0096] Example 5

[0097] This embodiment provides a silicone gel composition, and the components are shown in Table 5:

[0098] Table 5 Components and Contents of the Silicone Gel Composition in Example 5

[0099]

[0100]

[0101] The preparation steps are as follows:

[0102] S1. Put vinyl silicone oil, methyl vinyl MQ silicone resin, hydrogen-containing silicone oil, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component A;

[0103] S2. Put vinyl silicone oil, methyl vinyl MQ silicone resin, platinum catalyst, and tetramethyltetravinylcyclotetrasiloxane into a stirring kettle, stir for 60 min at a stirring rate of 35 r / min, and then stir under vacuum for 30 min to obtain Component B.

[0104] Comparative Example 1

[0105] The difference from Example 1 is only that a commercially available methyl vinyl MQ silicone resin is used to synthesize the silicone gel composition.

[0106] Performance Test

[0107] Mix Component A and Component B in Examples 1-5 and Comparative Example 1 at a mass ratio of 1:1 to obtain a silicone gel composition, and conduct the following performance tests on the silicone gel compositions in Examples 1-5 and Comparative Example 1.

[0108] 1. Viscosity: Refer to Standard GB / T 2794-2013 and test with a rotational viscometer.

[0109] 2. Penetration: Refer to Standard GB / T 269-1991. After keeping at 80 °C for 30 min, place it in the center of the test bench of the penetration tester, align the cone tip with the center of the specimen, set the penetration time to 5 seconds, turn on the test button, and multiply the instrument reading by 10 to obtain the penetration value.

[0110] 3. Working time: Refer to Standard GB / T 2794-2013. After uniformly stirring Component A and Component B and pouring them into a test container, control the sample temperature at 23 ± 2 °C, start the test timing, record the initial mixing viscosity, and stop timing when the mixing viscosity doubles. The time difference is the working time.

[0111] 4. Insulation Resistance: Refer to the standard IPC-TM-650. After the A and B components are stirred evenly, they are applied to a comb-shaped circuit board with a thickness of about 100 μm, and kept at a constant temperature of 80 °C for 30 min. After taking out and cooling to room temperature, it is tested with an Agilent 4339B high resistance meter.

[0112] 5. Oil Separation Property: Put the cured gel block on blotting paper, bake it at 125 °C for 500 h, and then take it out to observe the oil separation situation of the gel block on the paper.

[0113] The performance test results are shown in Table 6 below:

[0114] Table 6 Performance Test Results of Silicone Gel Compositions in Examples 1-5 and Comparative Example 1

[0115]

[0116] Table 6 shows the performance test results of the silicone gel compositions in Examples 1-5 and Comparative Example 1. It can be seen from Table 6 that after the silicone gel compositions in Examples 1-5 are aged at 200 °C for 1000 h, the change range of the cone penetration of the colloid is small, and good softness is still maintained; the insulation resistance of the silicone gel composition is higher than that of the silicone gel in the prior art, and the colloid has good insulation performance, which can meet the use requirements of high-power and high-heat-generating IGBT modules.

[0117] Figure 1 Figure showing the color change of the silicone gel compositions in Examples 1-5 and Comparative Example 1 after aging at 230 °C for 1000 h, where, Figure 1 (a)- Figure 1 (e) correspond to Examples 1-5 respectively, Figure 1 (f) represents Comparative Example 1. It can be seen from Figure 1 that after the silicone gel compositions in Examples 1-5 are aged at 230 °C for 1000 h, they only turn slightly yellow and still remain transparent, while the colloid in Comparative Example 1 turns severely yellow after aging at 230 °C for 1000 h, indicating that the silicone gel composition provided by the present invention has excellent yellowing resistance and can adapt to working temperatures above 200 °C. The commercially available methyl vinyl MQ silicone resin used in Comparative Example 1 is synthesized by the acid-catalyzed and alkali-neutralized method in the traditional process, and the residual acid and alkali will affect the heat resistance of the silicone gel.

[0118] Figure 2 Figure showing the oil separation situation of the silicone gel compositions in Examples 1-5 and Comparative Example 1 after baking at 125 °C for 500 h, where, Figure 1 (a)- Figure 1 (e) correspond to Examples 1-5 respectively, Figure 1 (f) represents Comparative Example 1. It can be seen from Figure 2It can be seen that after baking the silicone gel composition in Examples 1-5 at 125 °C for 500 h, only slight oil bleeding occurs, while after baking the colloid in Comparative Example 1 at 125 °C for 500 h, serious oil bleeding occurs, indicating that the silicone gel composition provided by the present invention has excellent oil bleeding resistance.

[0119] Figure 3 FIG. is a thermogravimetric analysis diagram of the silicone gel compositions in Example 1 and Comparative Example 1. From Figure 3 It can be seen that when the temperature is lower than 450 °C, the thermal stabilities of the silicone gel compositions in Example 1 and Comparative Example 1 are basically the same. When the temperature is higher than 450 °C, the weight loss of the silicone gel composition in Comparative Example 1 increases and the thermal stability decreases. Compared with Comparative Example 1, the silicone gel composition in Example 1 has less weight loss and relatively better thermal stability under high temperature conditions.

[0120] The silicone gel composition provided by the present invention uses a self-made methyl vinyl MQ silicone resin as a raw material, and a solid acid is used to synthesize the reinforcing agent methyl vinyl MQ silicone resin, eliminating the processes such as alkali neutralization and multiple water washes required when using liquid acids, effectively avoiding the destruction of the chemical bonds of the silicone gel by the residual acid and alkali under high temperature conditions, and at the same time simplifying the synthesis process, saving energy and protecting the environment. The silicone gel composition has excellent yellowing resistance and oil bleeding resistance, is resistant to high temperature aging, can adapt to working temperatures above 200 °C, and can be preferably applied to IGBT potting under high temperature conditions.

Claims

1. A silicone gel composition, characterized in that, It comprises components in the following parts by mass: Component A: 70 - 120 parts of vinyl silicone oil; 10 - 55 parts of methyl vinyl MQ silicone resin; 5 - 20 parts of crosslinking agent; 1 - 7 parts of tackifier; Component B: 60 - 110 parts of vinyl silicone oil; 5 - 60 parts of methyl vinyl MQ silicone resin; 0.5 - 2 parts of catalyst; 0.5 - 2 parts of inhibitor; By mass, the methyl vinyl MQ silicone resin comprises the following raw materials for preparation: 90 - 150 parts of end-capping agent, 300 - 800 parts of silicate compound, 200 - 1000 parts of small molecule organosilicon compound, 10 - 30 parts of solid acid catalyst, 150 - 300 parts of solvent; Among them, the end-capping agent is a compound of hexamethyldisiloxane and tetramethyldivinyldisiloxane with a mass ratio of 1: (0.1 - 10); the small molecule organosilicon compound includes at least one of dimethylsiloxane mixed cyclic body, tetramethylcyclotetrasiloxane, and vinyl cyclic body; the solid acid catalyst is macroporous strong acid ion exchange resin; The methyl vinyl MQ silicone resin is prepared by a method comprising the following steps; A1. Mix the end-capping agent and the solvent, add the solid acid catalyst, and heat for reaction; A2. Dropwise add the silicate compound and heat for reaction; A3. Add the small molecule organosilicon compound, collect the hydrolysis product, raise the temperature for polymerization reaction, and remove impurities to obtain the methyl vinyl MQ silicone resin.

2. The silicone gel composition according to claim 1, characterized in that, The organosilicon gel composition does not contain compounds containing N and P elements.

3. The silicone gel composition according to claim 1, wherein, The mass ratio of Component A to Component B is (0.5 - 1.5):

1.

4. The silicone gel composition according to claim 1, characterized in that, The vinyl content of the vinyl silicone oil is 0.1 - 5 wt%; And / or, the viscosity of the vinyl silicone oil at 23°C is 100 - 3000 mPa·s.

5. The silicone gel composition according to claim 1, wherein The silicate compound includes at least one of methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate, butyl orthosilicate, and ethyl polysilicate.

6. The silicone gel composition according to claim 1, wherein For the prepared methyl vinyl MQ silicone resin, in step A1, the temperature of the heating reaction is 80 - 120°C, and the time is 30 - 40 min; And / or, in step A2, the temperature of the heating reaction is 80 - 100°C, and the time is 5 - 10 h; And / or, in step A3, the temperature of the temperature-raising polymerization reaction is 120 - 160°C, and the time is 3 - 6 h; And / or, in step A3, the pressure range for impurity removal is -0.1 to -0.085 MPa.

7. The silicone gel composition according to claim 1, characterized in that, The crosslinking agent includes hydrogen-containing silicone oil; the hydrogen content of the hydrogen-containing silicone oil is 0.05 - 0.5 wt%; the viscosity of the hydrogen-containing silicone oil at 23°C is 10 - 100 mPa·s; And / or, the tackifier includes at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

8. A method for preparing the silicone gel composition according to any one of claims 1-7, characterized in that, It includes the following steps: S1. Mix the vinyl silicone oil, methyl vinyl MQ silicone resin, crosslinking agent, and tackifier to obtain Component A; S2. Mix vinyl silicone oil, methyl vinyl MQ silicone resin, catalyst and inhibitor to obtain Component B.

9. Application of the silicone gel composition according to any one of claims 1-7 in potting of IGBT modules.

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