Low-ring-reactivity silicone oil as well as preparation method and application thereof

Abstract

The invention provides low-ring reactive silicone oil and a preparation method and application thereof.The preparation method includes the steps that low-ring-terminated vinyl silicone oil, a platinum-containing catalyst and inorganic filler are mixed according to a certain proportion to obtain a component A, low-ring-side-chain hydrogen-containing silicone oil, an inhibitor and inorganic filler are mixed according to a certain proportion to obtain a component B, and the mass ratio of the component A to the component B is 1: (0.5-2). Wherein the low-ring-body vinyl-terminated silicone oil and the low-ring-body side-chain hydrogen-containing silicone oil are obtained by respectively carrying out polycondensation on hydroxyl-terminated silicone oil and a vinyl-terminated silicone oil end-capping agent and a side-chain hydrogen-containing silicone oil end-capping agent under the catalysis of phosphonitrile chloride, then neutralizing by using a crown ether neutralizer and carrying out heating and low-temperature removal, and the low-ring-body vinyl-terminated silicone oil and the low-ring-body side-chain hydrogen-containing silicone oil are low in ring content; when the silicon rubber is further applied to double-component addition type silicon rubber for electronic packaging, poor contact of contacts after long-term service of electric appliance components can be avoided; meanwhile, an organic amine neutralizer is not used, so that the adverse effect on a hydrosilylation platinum catalyst is avoided, the hydrosilylation rate is high, and the curing time is short.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon technology, specifically relating to a low-cyclic reactive silicone oil, its preparation method, and its application. Background Technology

[0002] Addition-cure silicone rubber is prepared by hydrosilylation reaction of vinyl-containing silicone oil and hydrogen-containing silicone oil containing active Si-H under a platinum catalyst. Addition-cure silicone rubber exhibits excellent weather resistance, flame retardancy, and high-temperature resistance, and is widely used in the electrical industry, often for encapsulating electronic components. CN120399457A discloses an addition-cure flame-retardant and high-temperature resistant silicone rubber and its preparation method, comprising the following raw materials in parts by weight: 80-120 parts of vinyl silicone oil with a viscosity of 6000-12000 mPa·s, 80-120 parts of vinyl silicone oil with a viscosity of 18000-25000 mPa·s, 7-15 parts of vinyl silicone oil with a vinyl content of 5%, 7-15 parts of hydrogen-containing silicone oil, 70-90 parts of fumed silica, 20-28 parts of an interface hydrophobic modifier, 1-3 parts of a platinum catalyst, and 2-5 parts of a flame retardant. CN116444797 discloses a two-component addition-type silicone rubber, comprising component A and component B; component A includes hydrogen-containing silicone oil, carbon black, and a tackifier; component B includes a platinum catalyst and divinyltetramethyldisiloxane. CN110484000A discloses an addition-type liquid silicone rubber, comprising component A and component B; component A includes: 100 parts of base rubber, 3-15 parts of vinyl-terminated side-chain vinyl silicone oil, 3-20 parts of vinyl-terminated silicone oil, and 1-1.5 parts of platinum catalyst; component B includes: 100 parts of base rubber, 3-20 parts of chain extender, 3-8 parts of vinyl-terminated silicone oil, 0.1-0.2 parts of inhibitor, and 1-15 parts of hydrogen-containing silicone resin; the raw materials of the base rubber include: 100 parts of vinyl-terminated silicone oil, 20-40 parts of fumed silica, and 3-9 parts of silazane treatment agent. CN109233627A discloses a two-component addition-type liquid silicone rubber for insulator coating, comprising component A and component B. Component A comprises, by weight, 100 parts of base silicone, 5-100 parts of vinyl silicone oil, and 1-5 parts of platinum catalyst; component B comprises, by weight, 0-60 parts of vinyl silicone oil, 2-10 parts of tackifier, 20-50 parts of crosslinking agent, and 0.3-3 parts of inhibitor.

[0003] The aforementioned existing two-component silicone rubbers all use hydrogen-containing silicone oil as a crosslinking agent, undergoing hydrosilylation with vinyl silicone oil under a platinum catalyst. Commercially available hydrogen-containing and vinyl silicone oils contain a certain amount of cyclic compounds during the manufacturing process. These cyclic compounds are low-molecular-weight cyclic siloxane byproducts, such as D3 (hexamethylcyclotrisiloxane), D4 (octamethylcyclotetrasiloxane), D5, D6, and up to D10. Silicone rubbers with high cyclic compound content used for potting electronic components can lead to poor metal contact during long-term service. The main reason is that these low-molecular-weight cyclic compounds are volatile. During operation, the internal temperature of electronic components rises, or the ambient temperature is high, accelerating the volatilization of these cyclic compounds from the rubber material into siloxane vapors. Upon encountering cooler surfaces, such as metal contacts and leads, these vapors re-condense into an electrically insulating film, significantly increasing contact resistance and even blocking current.

[0004] Using phosphazene chloride catalysts, reacting hydroxyl-terminated silicone oil with a side-chain hydrogen-containing silicone oil end-capping agent yields low-cyclic side-chain hydrogen-containing silicone oil, while reacting hydroxyl-terminated silicone oil with a vinyl-terminated silicone oil end-capping agent yields low-cyclic vinyl-terminated silicone oil. For phosphazene chloride catalysts, weak base amine compounds such as triethylamine, propylamine, triethylenenonamine, hexamethyldisilazane, hexamethylcyclotrisilazane, and tetramethyldivinylsilazane are generally used as neutralizing agents. The neutralized products are strong acid-weak base salts that remain in the system. Because nitrogen has a poisoning effect on platinum catalysts, it adversely affects the reaction rate of subsequent hydrosilylation reactions of the obtained vinyl-terminated silicone oil and side-chain hydrogen-containing silicone oil, slowing down the curing time. To complete the hydrosilylation reaction in a relatively short time, more platinum catalyst is required, thus increasing production costs.

[0005] Some literature uses magnesium oxide as a neutralizing agent, which does not introduce additional nitrogen elements. However, this production process not only requires an additional neutralization reactor, but also has difficult filtration, making it unsuitable for the preparation of low-cyclic side-chain hydrogen-containing silicone oils.

[0006] In summary, traditional two-component silicone rubber for encapsulating electronic components based on hydrosilylation may contain a large number of cyclic compounds in hydrogen-containing silicone oils and vinyl silicone oils, leading to poor contact during long-term service; or the cyclic compound content may be low, but the hydrosilylation rate is slower, resulting in a longer curing time. Summary of the Invention

[0007] To overcome the shortcomings of existing two-component hydrosilylation-based silicone rubbers, such as high dimethyl cyclic content or slow curing time, this invention proposes a low-cyclic-reactivity silicone oil and its preparation method, and applies it to two-component addition-type liquid silicone rubber. This invention involves the polycondensation of a low-viscosity hydroxyl-terminated silicone oil with a side-chain hydrogen-containing silicone oil end-capping agent and an alkenyl-containing silicone oil end-capping agent under the catalysis of phosphazene chloride. After neutralization with a crown ether neutralizer, the resulting products have low cyclic content and do not require the use of a weak organic amine base as a neutralizing agent. These are used as raw materials for two-component silicone rubber, simultaneously meeting the requirements of low cyclic content and fast curing time. Specifically, this invention provides the following technical solutions to address the above-mentioned technical problems:

[0008] A low-cyclic reactive silicone oil comprises component A and component B. Component A comprises the following raw materials: low-cyclic terminal vinyl silicone oil, platinum-containing catalyst, and inorganic filler. Component B comprises the following raw materials in parts by weight: low-cyclic terminal vinyl silicone oil, low-cyclic hydrogen-containing silicone oil, inhibitor, and inorganic filler. The mass ratio of component A to component B is 1:0.5-2.

[0009] The low-cyclic vinyl-terminated silicone oil is prepared from the following raw materials: 100 parts by weight of hydroxyl-terminated dimethyl silicone oil, 15-25 parts by weight of vinyl-terminated silicone oil capping agent, 0.001-0.005 parts by weight of phosphazene chloride catalyst, and 2-4 times the mass of phosphazene chloride catalyst crown ether neutralizer.

[0010] The low-cyclic hydrogen-containing silicone oil is prepared from the following raw materials: 100 parts by weight of hydroxyl-terminated dimethyl silicone oil, 40-60 parts by weight of hydrogen-containing silicone oil end-capping agent, 0.001-0.005 parts by weight of chlorinated phosphazene catalyst, and 2-4 times the mass of chlorinated phosphazene catalyst crown ether neutralizer.

[0011] Furthermore, the viscosity of hydroxyl-terminated dimethyl silicone oil at 25°C is 50-140 mm. 2 / s; The viscosity of the vinyl-terminated silicone oil end capping agent at 25°C is 10-40 mm. 2 / s, alkenyl content is 1.5-4%; the viscosity of the side-chain hydrogen-containing silicone oil end-capping agent at 25℃ is 10-40 mm. 2 / s, active hydrogen content 1-3%; preferably, the viscosity of hydroxyl-terminated dimethyl silicone oil at 25°C is 80-110 mm. 2 / s; The viscosity of the vinyl-terminated silicone oil end capping agent at 25°C is 15-22 mm. 2 / s, alkenyl content 2-3%; side-chain hydrogen-containing silicone oil end-capping agent viscosity 15-25 mm at 25℃ 2 / s, active hydrogen content 1.7-2.2%.

[0012] Further, the crown ether neutralizing agent is selected from at least one of 12-crown ether-4, 15-crown ether-5, 18-crown ether-6, dicyclohexyl-18-crown ether-6, dibenzo-18-crown ether-6, and naphtho-15-crown-5; and / or the phosphazene chloride is selected from [Cl3PNPCl2NPCl]. + At least one of PCl6, OCl2NPCl2NPCl2OH, OCl2(NPCl2)2NPCl2OH, OCl2(NPCl2)3NPCl2OH, OCl2PN(H)PCl2O, OCl2P(NPCl2)N(H)PCl2O, and OCl2P(NPCl2)NPCl3.

[0013] Furthermore, in the preparation of low-cyclic terminal vinyl silicone oil, the amount of chlorinated phosphazene catalyst is 0.001-0.002 parts by mass, and the amount of crown ether neutralizer is 2.5-3 times the mass of chlorinated phosphazene catalyst; in the preparation of low-cyclic side-chain hydrogen-containing silicone oil, the amount of chlorinated phosphazene catalyst is 0.001-0.002 parts by mass, and the amount of crown ether neutralizer is 2.5-3 times the mass of chlorinated phosphazene catalyst; even further, the crown ether neutralizer and non-polar organic solvent are added after being prepared as a solution with a solid content of 30-50% (e.g., 40% solid content), and the non-polar organic solvent is selected from at least one of toluene, ethyl acetate, propyl acetate, butyl acetate, petroleum ether, and C6-C15 alkanes.

[0014] Further, component A comprises the following raw materials: 40-60 parts by weight of low-cyclic terminal vinyl silicone oil, 2-10 ppm of platinum-containing catalyst (based on Pt), and 10-20 parts by weight of inorganic filler; component B comprises the following raw materials: 40-60 parts by weight of low-cyclic terminal vinyl silicone oil, 5-10 parts by weight of low-cyclic side-chain hydrogen-containing silicone oil, 0.1-0.5 parts of inhibitor, and 10-20 parts of inorganic filler.

[0015] Furthermore, the vinyl content of the terminal vinyl silicone oil is 0.4-0.6%, and the active hydrogen content of the side-chain hydrogen-containing silicone oil is 0.4-0.6%.

[0016] Further, the platinum-containing catalyst is selected from at least one of Karstedt's catalyst, chloroplatinic acid, platinum-carbon catalyst (Pt / C), Ashby's catalyst, and Speier catalyst, and the catalyst dosage is 1-10 ppm, preferably 2-5 ppm, based on Pt; the inorganic filler is selected from at least one of aluminum hydroxide, magnesium hydroxide, silica powder, alumina, and magnesium oxide; the inhibitor is selected from at least one of 2-methyl-3-butyn-2-ol, 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-methyl-1-dodecyn-3-ol, 3-phenyl-1-butyn-3-ol, and tetramethyltetravinylcyclotetrasiloxane.

[0017] This invention also provides a method for preparing the above-mentioned low-cyclic reactive silicone oil, comprising the following steps:

[0018] (S1) Hydroxyl-terminated dimethyl silicone oil and vinyl-terminated silicone oil end-capping agent are polycondensed in the presence of chlorinated phosphazene catalyst, then neutralized by adding a mixture of crown ether neutralizer and non-polar solvent, and finally degraded by heating to obtain low-cyclic vinyl-terminated silicone oil.

[0019] (S2) Preparation of low-cyclic side-chain hydrogen-containing silicone oil: Hydroxyl-terminated dimethyl silicone oil and side-chain hydrogen-containing silicone oil end-capping agent are polycondensed in the presence of chlorinated phosphazene catalyst, then a mixture of crown ether neutralizer and non-polar solvent is added for neutralization, and finally the temperature is raised to remove the low-cyclic side-chain hydrogen-containing silicone oil.

[0020] (S3) Low-cyclic end vinyl silicone oil, platinum-containing catalyst, and inorganic filler are mixed evenly to obtain component A;

[0021] (S4) Low-cyclic end vinyl silicone oil, low-cyclic side chain hydrogen-containing silicone oil, inhibitor, and inorganic filler are mixed evenly to obtain component B.

[0022] The present invention also provides the application of the above-mentioned low-cyclic reactive silicone oil in the encapsulation of electronic components.

[0023] The purpose of this invention is to address the shortcomings of existing two-component silicone rubbers used for encapsulating electronic components, which suffer from low cyclic content and / or slow hydrosilylation rates. This invention proposes a low-cyclic reactive silicone oil using phosphazene chloride as a catalyst. The resulting vinyl-terminated silicone oil and hydrogen-containing side-chain silicone oil have low D3 to D10 dimethyl cyclic content, overcoming the problem of poor metal contact after long-term service of electronic components. Furthermore, a crown ether neutralizer is used for neutralization, resulting in low-cyclic vinyl-terminated silicone oil and low-cyclic side-chain hydrogen-containing silicone oil, which can be further applied to components A and B of silicone rubber. These components do not contain nitrogen-containing organic components that affect the activity of the platinum catalyst and exhibit rapid curing speed. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the effect of two-component addition-curing liquid silicone rubber on circuit contacts in Example 2. In the diagram, 1 is a 220Va to 6Vd transformer; 2 is a color-coded resistor, 200Ω; and 3 is a white LED, U... e =3.0~3.2V, I max =20mA, the LED bead is exposed outside the electrical equipment casing; 4 is the contact position, which can be a spring connector or a switch; 5 is the main casing; 6 is a regular switch; 7 is a two-component addition-cured silicone rubber.

[0025] Figure 2 This is the circuit design diagram for the experiment on the influence of circuit contacts. Detailed Implementation

[0026] The technical solution of the present invention will be further explained and illustrated below with specific embodiments and comparative examples.

[0027] The raw materials involved in the examples and comparative examples include:

[0028] MH25 side-chain hydrogen-containing silicone oil end-capping agent, viscosity 25 mm at 25°C. 2 / s, active hydrogen content 1.62%, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.;

[0029] MH15 side-chain hydrogen-containing silicone oil end-capping agent, viscosity 15 mm at 25°C 2 / s, active hydrogen content 1.45%, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.;

[0030] The chloroplatinic acid catalyst was purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.

[0031] Karstedt's catalyst was purchased from Shanghai Siliconware Precision Materials Co., Ltd.

[0032] Hydroxyl-terminated dimethyl silicone oil, viscosity 75 mm at 25°C 2 / s, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.;

[0033] Aluminum hydroxide, 5μm, purchased from Aluminum Corporation of China Limited;

[0034] The 8300 inhibitor was purchased from Shanghai Siliconware Precision Materials Co., Ltd.

[0035] 621V20 end vinyl silicone oil sealing agent, viscosity 22mm 2 / s, vinyl content 2.90%, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.;

[0036] Potassium hydroxide silanol salt, concentration 15%, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.

[0037] Silicone phosphate grease, 9% concentration, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.

[0038] 621V20 end vinyl silicone oil sealing agent, viscosity 22mm 2 / s, vinyl content 2.90%, purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.;

[0039] Chlorinated phosphazene catalyst ([Cl3PNPCl2NPCl)) + PCl6 was purchased from Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.

[0040] HT-1A acidic clay, 200 mesh, activity ≥160H+mmol / kg, purchased from Anji County Zhongxin Activated Clay Co., Ltd.

[0041] Hexamethyldisilazane (HMDZ), Jiangxi Lanxing Xinghuo Organosilicon Co., Ltd.;

[0042] All other reagents or equipment not specified can be purchased through legitimate channels.

[0043] Preparation example a1

[0044] 292g of hydroxyl-terminated dimethyl silicone oil and 160g of MH25 side-chain hydrogen-containing silicone oil capping agent were added to the reactor. The temperature was raised to 60℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.005g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3.5 hours. After restoring to normal pressure, 0.038g of a 40% ethyl acetate solution of 18-crown ether-6 was added, and neutralization was carried out for 1 hour. The temperature was raised to 160℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, an active hydrogen content of 0.573% was obtained (measured by Fourier transform mid-infrared spectroscopy, reference standard: HG / T 4804-2015), and the viscosity at 25℃ was 160 mmHg. 2 / s of hydrogen-containing silicone oil with side chains.

[0045] Preparation Example a2

[0046] 290g of hydroxyl-terminated dimethyl silicone oil and 160g of MH15 side-chain hydrogen-containing silicone oil capping agent were added to a reactor. The temperature was raised to 60℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.005g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3.5 hours. After restoring to normal pressure, 0.038g of a 401% ethyl acetate solution of 15-crown ether-5 was added, and the mixture was neutralized for 1 hour. The temperature was then raised to 160℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, an active hydrogen content of 0.508% and a viscosity of 110 mmHg at 25℃ were obtained. 2 / s of hydrogen-containing silicone oil with side chains.

[0047] Comparative preparation example a1

[0048] 292g of hydroxyl-terminated dimethyl silicone oil, 160g of MH25 side-chain hydrogen-containing silicone oil capping agent, and 5g of HT-1A acidic clay were added to a reactor. The mixture was heated to 70℃ and reacted for 8 hours, followed by filtration. The temperature was then raised to 175℃ to remove 1H. The mixture was cooled to obtain an active H content of 0.571% and a viscosity of 150 mmHg at 25℃. 2 / s of hydrogen-containing silicone oil with side chains.

[0049] Comparative preparation example a2

[0050] 290g of hydroxyl-terminated dimethyl silicone oil, 160g of MH15 side-chain hydrogen-containing silicone oil capping agent, 300g of xylene, and 24g of concentrated sulfuric acid were added to a reactor and reacted at 40℃ for 6 hours. 26g of sodium carbonate was added for neutralization, and the reaction was continued for 2 hours, followed by standing for 2 hours. The supernatant was collected, filtered, and xylene was removed at 70℃ and -0.08MPa. The temperature was further increased to 130℃ to remove low-boiling-point substances, yielding a product with an H content of 0.509% and a viscosity of 110 mmHg at 25℃. 2 / s of hydrogen-containing silicone oil with side chains.

[0051] Comparative preparation example a3

[0052] 292g of hydroxyl-terminated dimethyl silicone oil and 160g of MH25 side-chain hydrogen-containing silicone oil capping agent were added to the reactor. The temperature was raised to 60℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.005g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3.5 hours. After restoring to normal pressure, 0.015g of HMDZ was added, and neutralization was carried out for 1 hour. The temperature was raised to 160℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, a product with an H content of 0.572% and a viscosity of 160 mmHg at 25℃ was obtained. 2 / s of hydrogen-containing silicone oil with side chains.

[0053] Comparative preparation example a4

[0054] 290g of hydroxyl-terminated dimethyl silicone oil and 160g of MH15 side-chain hydrogen-containing silicone oil capping agent were added to a reactor. The temperature was raised to 60℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.005g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3.5 hours. After restoring to normal pressure, 0.012g of n-octylamine was added, and the reaction was neutralized for 1 hour. The temperature was then raised to 160℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, an active hydrogen content of 0.510% was obtained, with a viscosity of 110 mmHg at 25℃. 2 / s of hydrogen-containing silicone oil with side chains.

[0055] The side-chain hydrogen-containing silicone oils prepared in the above preparation examples and comparative preparation examples were tested for cyclic content, and the results are shown in Table 1 below.

[0056] Table 1. Test of cyclic content in hydrogen-containing silicone oil

[0057]

[0058] Preparation Example b1

[0059] 925g of hydroxyl-terminated dimethyl silicone oil and 204.5g of 621V20 low-viscosity vinyl-terminated silicone oil capping agent were added to a reactor. The temperature was raised to 70℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.014g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3 hours. After restoring to normal pressure, 0.105g of a 40wt% ethyl acetate solution of 12-crown ether-4 was added, and neutralization was carried out for 1 hour. The temperature was raised to 170℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, a product with a vinyl content of 0.51% and a viscosity of 336 mmHg at 25℃ was obtained. 2 / s of end vinyl silicone oil.

[0060] Preparation Example b2

[0061] 925g of hydroxyl-terminated dimethyl silicone oil and 164.7g of 620V20 low-viscosity vinyl-terminated silicone oil capping agent were added to a reactor. The temperature was raised to 65℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.013g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3 hours. After restoring to normal pressure, 0.10g of a 40wt% solution of dicyclohexyl-18-crown ether-6 in ethyl acetate was added, and the mixture was neutralized for 1 hour. The temperature was then raised to 170℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, a product with a vinyl content of 0.43% and a viscosity of 485 mmHg at 25℃ was obtained. 2 / s of end vinyl silicone oil.

[0062] Comparative preparation example b1

[0063] 925g of hydroxyl-terminated dimethyl silicone oil, 204.5g of 621V20 low-viscosity vinyl-terminated silicone oil capping agent, and 15.6g of HT-1A acidic clay were added to a reactor. The mixture was heated to 70℃ and reacted for 8 hours, followed by filtration. The temperature was then raised to 175℃ to remove 1H. The mixture was cooled to obtain a product with a vinyl content of 0.50% and a viscosity of 315 mm at 25℃. 2 / s of end vinyl silicone oil.

[0064] Comparative preparation example b2

[0065] 925g of hydroxyl-terminated dimethyl silicone oil and 164.7g of 620V20 low-viscosity vinyl-terminated silicone oil capping agent were added to a reactor, along with 0.3632g of potassium hydroxide silanolate catalyst. The reaction was carried out for 3 hours. Then, 0.7065g of phosphate silicone grease was added for neutralization, and the reaction was carried out for 2 hours. The temperature was further increased to 170℃ to remove low-boiling-point substances, yielding a product with a vinyl content of 0.42% and a viscosity of 480 mmHg at 25℃. 2 / s of end vinyl silicone oil.

[0066] Comparative preparation example b3

[0067] 925g of hydroxyl-terminated dimethyl silicone oil and 204.5g of 621V20 low-viscosity vinyl-terminated silicone oil capping agent were added to a reactor. The temperature was raised to 70℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.014g of phosphazene chloride catalyst was added. The pressure was reduced to -0.1MPa, and the reaction was carried out for 3 hours. The pressure was restored to normal, and 0.042g of HMDZ was added. The reaction was neutralized for 1 hour. The temperature was raised to 170℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, a product with a vinyl content of 0.51% and a viscosity of 331 mmHg at 25℃ was obtained. 2 / s terminal vinyl silicone oil

[0068] Comparative preparation example b4

[0069] 925g of hydroxyl-terminated dimethyl silicone oil and 164.7g of 620V20 low-viscosity vinyl-terminated silicone oil capping agent were added to a reactor. The temperature was raised to 65℃, and the gauge pressure was -0.1MPa. After dehydration for 1 hour, the pressure was restored to normal, and 0.013g of phosphazene chloride catalyst was added. The pressure was then reduced to -0.1MPa, and the reaction was carried out for 3 hours. After restoring to normal pressure, 0.04g of n-octylamine was added, and neutralization was carried out for 1 hour. The temperature was raised to 170℃, and the gauge pressure was reduced to -0.1MPa. After dehydration for 1 hour, a product with a vinyl content of 0.43% and a viscosity of 472 mmHg at 25℃ was obtained. 2 / s of end vinyl silicone oil.

[0070] The cyclic content of the terminal vinyl silicone oils prepared in the above preparation examples and comparative preparation examples was tested, and the results are shown in Table 2 below.

[0071] Table 2. Test of End-Vinyl Silicone Oil Ring Content

[0072]

[0073]

[0074] As can be seen from Tables 1 and 2, the side-chain hydrogen-containing silicone oil and the terminal vinyl silicone oil prepared according to the method of the present invention have low cyclic content. Using the above-mentioned side-chain hydrogen-containing silicone oil and terminal vinyl silicone oil with low cyclic content of the present invention as raw materials for two-component silicone rubber, and using them as potting compounds for electronic components, can avoid the problem of poor contact caused by cyclic precipitation after long-term use.

[0075] Example 1

[0076] The side-chain hydrogen-containing silicone oil obtained above was subjected to a hydrosilylation reaction with the terminal vinyl silicone oil under the action of a platinum catalyst, and applied to the preparation of addition-type silicone rubber for two-component potting.

[0077] Component A is obtained by mixing 53 parts by mass of the vinyl-terminated silicone oil prepared in Preparation Example b1, Karstedt's catalyst (catalyst dosage is 5 ppm based on Pt), and 15 parts by mass of 5 μm aluminum hydroxide. Component B is obtained by mixing 47 parts by mass of the vinyl-terminated silicone oil prepared in Preparation Example b1, 5 parts by mass of the side-chain hydrogen-containing silicone oil prepared in Preparation Example a1, 0.2 parts by mass of 8300 inhibitor, and 15 parts by mass of 5 μm aluminum hydroxide. Component A and component B are mixed evenly at a mass ratio of 1:1.

[0078] Example 2

[0079] The other conditions are the same as in Example 1, except that the vinyl-terminated silicone oil prepared in Preparation Example b1 in both components A and B is replaced with an equal mass of vinyl-terminated silicone oil prepared in Preparation Example b2, and the side-chain hydrogen-containing silicone oil prepared in Preparation Example a1 in component B is replaced with an equal mass of the silicone oil prepared in Preparation Example a2.

[0080] Comparative Example 1

[0081] The other conditions are the same as in Example 1, except that the terminal vinyl silicone oil prepared in Preparation Example b1 in both components A and B is replaced with an equal mass of the terminal vinyl silicone oil prepared in Comparative Preparation Example b1, and in component B, the side-chain hydrogen-containing silicone oil prepared in Preparation Example a1 is replaced with an equal mass of the side-chain hydrogen-containing silicone oil prepared in Comparative Preparation Example a1.

[0082] Comparative Example 2

[0083] The other conditions are the same as in Example 1, except that the vinyl-terminated silicone oil prepared in Preparation Example b1 in both components A and B is replaced with an equal mass of the vinyl-terminated silicone oil prepared in Comparative Preparation Example b2, and in component B, the side-chain hydrogen-containing silicone oil prepared in Preparation Example a1 is replaced with an equal mass of the silicone oil prepared in Comparative Preparation Example a2.

[0084] Comparative Example 3

[0085] The other conditions are the same as in Example 1, except that the vinyl-terminated silicone oil prepared in Preparation Example b1 in both components A and B is replaced with an equal mass of the vinyl-terminated silicone oil prepared in Comparative Preparation Example b3, and in component B, the side-chain hydrogen-containing silicone oil prepared in Preparation Example a1 is replaced with an equal mass of the silicone oil prepared in Comparative Preparation Example a3.

[0086] Comparative Example 4

[0087] The other conditions are the same as in Example 1, except that the vinyl-terminated silicone oil prepared in Preparation Example b1 in both components A and B is replaced with an equal mass of the vinyl-terminated silicone oil prepared in Comparative Preparation Example b4, and in component B, the side-chain hydrogen-containing silicone oil prepared in Preparation Example a1 is replaced with an equal mass of the silicone oil prepared in Comparative Preparation Example a4.

[0088] Application Example 1

[0089] The surface drying time and the time to complete curing (Shore hardness reaching 50 HA) of the two-component addition-curing liquid silicone rubbers of the above embodiments and comparative examples were tested, and the results are shown in Table 3:

[0090] Table 3. Curing status of two-component addition-curing liquid silicone rubber

[0091]

[0092] Note: When examining the surface drying time and complete curing time of silicone rubber, the dosage of silicone rubber after uniform mixing of components A and B was 5g, and the container material was a polyphenylene sulfide (PPS) plastic part with an open top, 2.5cm long, 1.5cm wide and 2cm high.

[0093] As can be seen, the surface drying time and complete curing time of Examples 1 and 2 at 25℃ and 80℃ respectively are close to those of Comparative Examples 1 and 2, and are significantly better than those of Comparative Examples 3 and 4.

[0094] Application Example 2

[0095] The effects of two-component addition-cured liquid silicone rubber on circuit contacts were investigated, according to... Figure 1 Diagram, and Figure 2 The circuit diagram is used to assemble the experimental sample. First, five holes with a diameter of 3.1-3.2 mm are drilled in the cover of the main body 5. Each hole is large enough to accommodate a light-emitting diode (LED). Then, using small screws and 502 glue, the male connector 4-1 (JI-1P-7.4H) and female connector 4-2 (JL-1P-1.9H) are fixed to the inside of the cover, ensuring they are in contact. Next, using wires, the transformer 1, male connector 4-1, female connector 4-2, LED 3, and gold... The color-coded resistor 2 and the ordinary switch 6 are connected together. Before the experiment, ensure that the ordinary switch 6 and the light-emitting diode 3 are working properly. The experimental group is potted with two-component addition-curing liquid silicone rubber 7 (the blank group is 500g of octamethylcyclotetrasiloxane), with a dosage of 500g (according to the mass ratio of component A to component B of 1:1). The sample is placed in an aging test chamber. The transformer 1 and the ordinary switch 6 are both outside the aging test chamber, and the wires passing through the aging test chamber are protected with thermal insulation cotton. Table 4 shows the components and materials involved in the experimental design. The experimental results are shown in Table 5.

[0096] Table 4. Components and materials involved in the experimental design

[0097]

[0098] Table 5 shows the impact of type 5 liquid silicone rubber on circuit contacts.

[0099]

[0100] It is evident that in Application Comparative Example 1 and Application Comparative Example 2, which have higher toroidal content, the contacts (spring connectors or switches) of the corresponding electrical equipment are more prone to failure (open circuit), which in turn leads to abnormal light emission of the LED.

Claims

1. A low-cyclic reactive silicone oil, comprising component A and component B, wherein component A comprises the following raw materials: low-cyclic terminal vinyl silicone oil, platinum-containing catalyst, and inorganic filler; component B comprises the following raw materials in parts by weight: low-cyclic terminal vinyl silicone oil, low-cyclic hydrogen-containing silicone oil, inhibitor, and inorganic filler; the mass ratio of component A to component B is 1:0.5-2. The raw materials for preparing the low-cyclic-terminated vinyl silicone oil include: 100 parts by weight of hydroxyl-terminated dimethyl silicone oil, 15-25 parts by weight of vinyl-terminated silicone oil end-capping agent, 0.001-0.005 parts by weight of chlorinated phosphazene catalyst, and 2-4 times the mass of the chlorinated phosphazene catalyst crown ether neutralizer; The raw materials for preparing the low-cyclic hydrogen-containing silicone oil include: 100 parts by weight of hydroxyl-terminated dimethyl silicone oil, 40-60 parts by weight of hydrogen-containing silicone oil end-capping agent, 0.001-0.005 parts by weight of chlorinated phosphazene catalyst, and crown ether neutralizer at 2-4 times the mass of the chlorinated phosphazene catalyst.

2. The low-cyclic reactive silicone oil according to claim 1, characterized in that, The viscosity of hydroxyl-terminated dimethyl silicone oil at 25°C is 50-140 mm. 2 / s; The viscosity of the vinyl-terminated silicone oil end capping agent at 25°C is 10-40 mm. 2 / s, alkenyl content is 1.5-4%; the viscosity of the side-chain hydrogen-containing silicone oil end-capping agent at 25℃ is 10-40 mm. 2 / s, active hydrogen content 1-3%.

3. The low-cyclic reactive silicone oil according to claim 1, characterized in that, The viscosity of hydroxyl-terminated dimethyl silicone oil at 25°C is 80-110 mm. 2 / s; The viscosity of the vinyl-terminated silicone oil end capping agent at 25°C is 15-22 mm. 2 / s, alkenyl content 2-3%; side-chain hydrogen-containing silicone oil end-capping agent viscosity 15-25 mm at 25℃ 2 / s, active hydrogen content 1.7-2.2%.

4. The low-cyclic reactive silicone oil according to claim 1, characterized in that, The crown ether neutralizer is selected from at least one of 12-crown ether-4, 15-crown ether-5, 18-crown ether-6, dicyclohexyl-18-crown ether-6, dibenzo-18-crown ether-6, and naphtho-15-crown-5; and / or the phosphazene chloride is selected from [Cl3PNPCl2NPCl]. + At least one of PCl6, OCl2NPCl2 NPCl2OH, OCl2(NPCl2)2NPCl2OH, OCl2(NPCl2)3NPCl2OH, OCl2PN(H)PCl2O, OCl2P(NPCl2)N(H)PCl2O, and OCl2P(NPCl2)NPCl3.

5. The low-cyclic reactive silicone oil according to claim 1, characterized in that, In the preparation of low-cyclic terminal vinyl silicone oil, the amount of chlorinated phosphazene catalyst used is 0.001-0.002 parts by mass, and the amount of crown ether neutralizer used is 2.5-3 times the mass of chlorinated phosphazene catalyst; in the preparation of low-cyclic side-chain hydrogen-containing silicone oil, the amount of chlorinated phosphazene catalyst used is 0.001-0.002 parts by mass, and the amount of crown ether neutralizer used is 2.5-3 times the mass of chlorinated phosphazene catalyst. Furthermore, the crown ether neutralizer and the nonpolar organic solvent are added after being prepared into a solution with a solid content of 30-50%. The nonpolar organic solvent is selected from at least one of toluene, ethyl acetate, propyl acetate, butyl acetate, petroleum ether, and C6-C15 alkanes.

6. The low-cyclic reactive silicone oil according to claim 1, characterized in that, Component A includes the following raw materials: Component B comprises: 40-60 parts by weight of low-cyclic terminal vinyl silicone oil, 2-10 ppm of platinum-containing catalyst (based on Pt), and 10-20 parts by weight of inorganic filler; Component B comprises the following raw materials: 40-60 parts by weight of low-cyclic terminal vinyl silicone oil, 5-10 parts by weight of low-cyclic side-chain hydrogen-containing silicone oil, 0.1-0.5 parts of inhibitor, and 10-20 parts of inorganic filler.

7. The low-cyclic reactive silicone oil according to claim 1, characterized in that, The vinyl content of the terminal vinyl silicone oil is 0.4-0.6%, and the active hydrogen content of the side-chain hydrogen-containing silicone oil is 0.4-0.6%.

8. The low-cyclic reactive silicone oil according to claim 1, characterized in that, The platinum-containing catalyst is selected from at least one of Karstedt's catalyst, chloroplatinic acid, platinum-carbon catalyst (Pt / C), Ashby's catalyst, and Speier catalyst, with a catalyst dosage of 1-10 ppm (Pt), preferably 2-5 ppm; the inorganic filler is selected from at least one of aluminum hydroxide, magnesium hydroxide, silica powder, alumina, and magnesium oxide; the inhibitor is selected from at least one of 2-methyl-3-butyn-2-ol, 1-ethynylcyclohexanol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-methyl-1-dodecyn-3-ol, 3-phenyl-1-butyn-3-ol, and tetramethyltetravinylcyclotetrasiloxane.

9. A method for preparing the low-cyclic reactive silicone oil according to any one of claims 1-8, characterized in that, Includes the following steps: (S1) Preparation of low-cyclic vinyl-terminated silicone oil: Hydroxyl-terminated dimethyl silicone oil and vinyl-terminated silicone oil end-capping agent are polycondensed in the presence of phosphazene chloride catalyst, then a mixture of crown ether neutralizer and non-polar solvent is added for neutralization, and finally the low-cyclic vinyl-terminated silicone oil is obtained by heating. (S2) Preparation of low-cyclic side-chain hydrogen-containing silicone oil: Hydroxyl-terminated dimethyl silicone oil and side-chain hydrogen-containing silicone oil end-capping agent are polycondensed in the presence of chlorinated phosphazene catalyst, then a mixture of crown ether neutralizer and non-polar solvent is added for neutralization, and finally the temperature is raised to remove the low-cyclic side-chain hydrogen-containing silicone oil. (S3) Preparation of component A: Low-cyclic terminal vinyl silicone oil, platinum-containing catalyst, and inorganic filler are mixed evenly to obtain component A; (S4) Preparation of component B: Low-cyclic terminal vinyl silicone oil, low-cyclic side-chain hydrogen-containing silicone oil, inhibitor, and inorganic filler are mixed evenly to obtain component B.

10. The application of the low-cyclic reactive silicone oil according to any one of claims 1-8 in the packaging of electronic components.

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