One-component addition-cure silicone rubber, process for its production and use

Abstract

This invention discloses a one-component addition-cure silicone rubber, its preparation method, and its applications, relating to the field of organosilicon materials technology. The one-component addition-cure silicone rubber of this invention comprises vinyl polysiloxane, hydrogen-containing polysiloxane, a capsule-type plasticizer, and a capsule-type catalyst; wherein the melting point or softening point of the wall material of the capsule-type plasticizer is T1, and the melting point or softening point of the wall material of the capsule-type catalyst is T2, 50℃≤T1≤100℃, and T2≥T1+t, where t is 10~40℃; the content of the capsule-type plasticizer is greater than the content of the capsule-type catalyst; the plasticizer in the capsule-type plasticizer is a plasticizer capable of dissolving or swelling the wall material of the capsule-type catalyst. The one-component addition-cure silicone rubber of this invention possesses both low-temperature rapid curing and long-term storage stability, making it suitable for potting or bonding electronic components.

Description

Technical Field

[0001] This invention relates to the field of organosilicon materials technology, and in particular to a one-component addition-type silicone rubber, its preparation method, and its application. Background Technology

[0002] One-component addition-cure silicone rubber is widely used in potting, bonding, and protective coatings for electronic components due to its advantages such as no on-site mixing, no byproduct release, low shrinkage, and good deep curing properties. However, this field has long faced the dilemma of balancing "storage stability" and "low-temperature curing activity." To achieve a storage period of more than 6 months at room temperature, traditional one-component addition-cure silicone rubber formulations typically add a large amount of alkynyl alcohol inhibitors. This results in a curing onset temperature that is usually as high as 120°C to 150°C, which is unacceptable for many high-temperature-sensitive precision electronic components, such as certain sensors and OLED modules. To achieve low-temperature curing, existing technologies attempt to improve low-temperature curing performance by encapsulating the catalyst, i.e., using thermoplastic resin to encapsulate platinum catalysts to form catalyst microcapsules. To prevent the capsules from softening and leaking during summer transportation and to ensure storage stability, the glass transition temperature (Tg) or melting point (Tm) of the capsule wall material usually needs to be set above 110°C. This means that the curing reaction must be heated to above 110°C to break the capsule wall, still failing to achieve true low-temperature curing below 100°C, or even below 90°C. Therefore, developing a new type of silicone rubber system that can be stable at room temperature for a long time and can be rapidly cured at lower temperatures is a technical challenge that the industry urgently needs to solve. Summary of the Invention

[0003] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a single-component addition-cure silicone rubber that, using a specific dual-encapsulation synergistic system, achieves rapid curing at low temperatures below 100°C while ensuring storage stability.

[0004] The second objective of this invention is to provide a method for preparing a one-component addition-curing silicone rubber.

[0005] The third objective of this invention is to provide an application of a one-component addition-curing silicone rubber.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a one-component addition-type silicone rubber, comprising vinyl polysiloxane, hydrogen-containing polysiloxane, encapsulated plasticizer, and encapsulated catalyst; wherein the melting point or softening point of the wall material of the encapsulated plasticizer is T1, the melting point or softening point of the wall material of the encapsulated catalyst is T2, 50℃≤T1≤100℃, and T2≥T1+t, where t is 10~40℃; The content of the capsule-type plasticizer is greater than the content of the capsule-type catalyst; the plasticizer in the capsule-type plasticizer is a plasticizer that can dissolve or swell the wall material of the capsule-type catalyst.

[0007] The present invention constructs a dual-capsule synergistic system in a single-component addition-cure silicone rubber. The capsule-type plasticizer encapsulates a plasticizer that dissolves or swells the wall material of the capsule-type catalyst. The wall material has a low melting or softening point. When the temperature reaches T1 or above, the wall material of the capsule-type plasticizer melts or softens, releasing the plasticizer. The plasticizer can dissolve the wall material of the capsule-type catalyst, which has a higher melting or softening point, allowing the catalyst to be released even at temperatures below T2, thus achieving rapid low-temperature curing. At room temperature or under transportation conditions, including summer transportation conditions, because the melting or softening point of the capsule-type catalyst is at least 10°C higher than T1, it can remain stable during transportation, preventing catalyst leakage. That is, the plasticizer and catalyst are isolated by the capsule wall and do not come into contact with each other, ensuring excellent storage stability.

[0008] Specifically, during storage, both the encapsulated plasticizer and the encapsulated catalyst remain intact, isolated by the wall material. The wall material of the encapsulated catalyst has a high melting or softening point and high stability, resulting in good storage stability. During use, heating reaches the melting or softening point of the encapsulated plasticizer wall material, releasing the plasticizer. The plasticizer rapidly surrounds the encapsulated catalyst. Through the principle of "like dissolves like," the wall material dissolves or swells at temperatures far below the melting or softening point of the catalyst wall material, causing its structure to collapse. This releases the catalyst, catalyzing an addition reaction between vinyl polysiloxane and hydrogen-containing polysiloxane, achieving rapid low-temperature curing.

[0009] Furthermore, by changing the amount of encapsulated plasticizer added or the melting point of the wall material, the dissolution or swelling time of the plasticizer on the wall material of the encapsulated catalyst can be precisely adjusted to meet the needs of different process windows.

[0010] It should be understood that encapsulated plasticizers include a wall material and a core material, with the core material containing the plasticizer; encapsulated catalysts also include a wall material and a core material, with the core material containing the catalyst. The wall material encapsulates the surface of the core material to prevent its exposure. The melting point or softening point of the wall material is relative to the specific wall material; for example, some polymers do not have a fixed melting point, and in these cases, the melting point is used.

[0011] In the context of "content of capsule plasticizer is greater than content of capsule catalyst", "content" refers to mass content.

[0012] In some embodiments, the plasticizer can dissolve or swell the wall material of the capsule-shaped catalyst, but not the wall material of the capsule-shaped plasticizer. For the purposes of this invention, "the plasticizer can swell the wall material of the capsule-shaped catalyst" means that the plasticizer can cause the polymer chains of the wall material to expand, resulting in volume expansion, ultimately leading to cracking, pores, and the collapse of the wall material structure.

[0013] It should be noted that a relatively large amount of plasticizer is required in the encapsulated plasticizer to completely dissolve the wall material of the encapsulated catalyst. Therefore, even if slight leakage of the encapsulated plasticizer occurs during summer transportation, it will not affect the overall stability. However, even a tiny leakage of the catalyst will cause the system to undergo a curing reaction. Therefore, the one-component addition-cure silicone rubber obtained from the dual-encapsulation system of this invention exhibits excellent stability.

[0014] In some embodiments, 50℃≤T1≤90℃ and T2≥T1+t, where t is 20~40℃; preferably, 60℃≤T1≤90℃, or 50℃≤T1≤80℃, more preferably 60℃≤T1≤80℃; preferably, t is 25~35℃.

[0015] In some embodiments, the mass ratio of the encapsulated plasticizer to the encapsulated catalyst is (2~12):1. For example, this mass ratio can be 2:1, 4:1, 6:1, 8:1, 9:1, 10:1, 12:1, or any other value within the above range. Preferably, the mass ratio of the encapsulated plasticizer to the encapsulated catalyst is (3~10):1; more preferably (5~10):1.

[0016] In some embodiments, the one-component addition-type silicone rubber further includes fillers and / or inhibitors.

[0017] In some embodiments, the one-component addition-curing silicone rubber comprises, by weight, 100 parts of vinyl polysiloxane, 1-15 parts of hydrogen-containing polysiloxane, 10-60 parts of filler, 2-15 parts of encapsulated plasticizer, 0.2-5 parts of encapsulated catalyst, and 0-1 parts of inhibitor.

[0018] In some preferred embodiments, in the one-component addition-curing silicone rubber, based on 100 parts by weight of vinyl polysiloxane, the mass parts of hydrogen-containing polysiloxane can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, or any other value within the above range. Preferably, it is 1 to 10 parts; more preferably, it is 1 to 8 parts; more preferably, it is 2 to 6 parts; and even more preferably, it is 3 to 5 parts.

[0019] In some preferred embodiments, in the one-component addition-curing silicone rubber, based on 100 parts by weight of vinyl polysiloxane, the filler can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, or any other value within the above range. Preferably, it is 10-50 parts; more preferably, 10-40 parts; more preferably, 15-35 parts; and even more preferably, 20-30 parts.

[0020] In some preferred embodiments, in the one-component addition-curing silicone rubber, based on 100 parts by weight of vinyl polysiloxane, the mass parts of the encapsulated plasticizer can be 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 15 parts, or any other value within the above-mentioned mass part range. Preferably, it is 2 to 12 parts; more preferably, it is 3 to 10 parts; more preferably, it is 5 to 10 parts.

[0021] In some preferred embodiments, in the one-component addition-curing silicone rubber, based on 100 parts by weight of vinyl polysiloxane, the mass parts of the encapsulated catalyst can be 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 5 parts, or any other value within the above-mentioned mass part range. Preferably, it is 0.5 to 5 parts; more preferably, 0.5 to 3 parts; more preferably, 0.5 to 2 parts; and even more preferably, 0.5 to 1.5 parts.

[0022] In some preferred embodiments, in the one-component addition-curing silicone rubber, based on 100 parts by weight of vinyl polysiloxane, the mass fraction of the inhibitor can be 0 parts, 0.01 parts, 0.02 parts, 0.04 parts, 0.05 parts, 0.07 parts, 0.08 parts, 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, 0.9 parts, 1 part, or any other value within the above-mentioned mass fraction range. Preferably, it is 0.01 to 0.5 parts; more preferably, it is 0.01 to 0.1 parts; more preferably, it is 0.02 to 0.1 parts.

[0023] In some preferred embodiments, the one-component addition-type silicone rubber comprises, by weight, the following components: 100 parts of vinyl polysiloxane, 1-8 parts of hydrogen-containing polysiloxane, 10-40 parts of filler, 3-10 parts of encapsulated plasticizer, 0.5-3 parts of encapsulated catalyst, and 0.01-0.5 parts of inhibitor.

[0024] In some embodiments, the vinyl polysiloxane has a viscosity of 500-100000 mPa·s at 25°C; and a vinyl content of 0.2-0.3 mol%. A preferred viscosity is 500-10000 mPa·s; further preferably 500-2000 mPa·s; and even more preferably 500-1500 mPa·s.

[0025] In some embodiments, the hydrogen-containing polysiloxane has a viscosity of 10-100 mPa·s at 25°C and a hydrogen content of 0.1-2 wt%. A preferred viscosity is 10-50 mPa·s, more preferably 10-40 mPa·s, and even more preferably 20-40 mPa·s. A preferred hydrogen content is 0.1-1.5 wt%, more preferably 0.1-1 wt%, and even more preferably 0.5-1 wt%.

[0026] In some embodiments, the wall material of the capsule-type plasticizer includes at least one of paraffin wax, microcrystalline wax, and polyethylene wax.

[0027] In some embodiments, the wall material of the capsule-type catalyst includes at least one selected from polycarbonate, polymethyl methacrylate, polystyrene, and styrene-acrylonitrile copolymer.

[0028] In some embodiments, the plasticizer of the encapsulated plasticizer includes at least one selected from dibutyl phthalate (DBP), dioctyl phthalate (DOP), dioctyl adipate (DOA), tricresyl phosphate (TCP), and polyether. The polyether is preferably a low molecular weight polyether (weight average molecular weight 200-1000).

[0029] In some embodiments, the inhibitor includes at least one of 1-ethynyl-1-cyclohexanol (ECH), 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and dimethyl maleate.

[0030] In some embodiments, the filler comprises fumed silica and / or precipitated silica.

[0031] In some embodiments, the specific surface area of ​​the packing is 100~300m². 2 / g; preferably 150~250m 2 / g; more preferably 180~220m 2 / g.

[0032] In some embodiments, the filler undergoes a surface hydrophobic treatment. For example, hexamethyldisilazane (HMDS) is used for hydrophobic treatment.

[0033] In some embodiments, the average particle size of the encapsulated plasticizer is 5-50 μm; preferably 10-40 μm; more preferably 20-40 μm; and even more preferably 25-35 μm.

[0034] In some embodiments, the average particle size of the capsule catalyst is 2-20 μm; preferably 5-20 μm; more preferably 5-15 μm; and even more preferably 8-12 μm.

[0035] In some embodiments, the preparation method of the capsule-type plasticizer includes the following steps: mixing and emulsifying a molten or melted wall material with a plasticizer to obtain the capsule-type plasticizer.

[0036] In some preferred embodiments, the preparation method of the capsule-type plasticizer includes the following steps: mixing a molten or melted wall material with a plasticizer, adding an emulsifier for emulsification, rapidly cooling the resulting emulsion to allow the wall material to quickly solidify and encapsulate the plasticizer, forming a suspension; and subjecting the suspension to solid-liquid separation, purification, and drying to obtain the capsule-type plasticizer.

[0037] The emulsifier can be a 0.5-1.5% (w / w) aqueous solution of polyvinyl alcohol. The rapid cooling is achieved by adding 4-5 times the volume of cold water to the emulsion. The purification includes washing to remove the emulsifier. The drying temperature is 30-38°C.

[0038] In some embodiments, the mass ratio of the wall material to the plasticizer of the capsule-type plasticizer is 1:(3~5).

[0039] In some embodiments, the capsule-shaped catalyst is a capsule-shaped platinum catalyst. Optionally, the preparation method of the capsule-shaped platinum catalyst includes the following steps: The wall material is dissolved in an organic solvent, and a catalyst is added and mixed to form an oil phase. An emulsifier is added to the oil phase, and the mixture forms droplets. Heating evaporates the organic solvent, and the wall material precipitates and solidifies on the surface of the droplets to form a film, thus obtaining the capsule-type catalyst. The emulsifier is gelatin and / or sodium dodecylbenzenesulfonate.

[0040] In some preferred embodiments, the organic solvent includes dichloromethane; the mass fraction of the wall material in the solution obtained after the wall material is dissolved in the organic solvent is 10-15%.

[0041] In some preferred embodiments, the catalyst is added and then dispersed by ultrasonication for 5 to 15 minutes.

[0042] In some preferred embodiments, after adding gelatin or sodium dodecylbenzenesulfonate, the droplet size is controlled by adjusting the stirring speed. For example, the stirring speed is 3000~5000 rpm, controlling the droplet size to be between 5~15 μm. The gelatin or sodium dodecylbenzenesulfonate is added in the form of an aqueous solution, with a mass fraction of 0.5~1.5%.

[0043] In some preferred embodiments, heating to 40-50°C evaporates the organic solvent. If necessary, vacuum assistance and stirring can be activated.

[0044] In some preferred embodiments, after the organic solvent is completely evaporated, the solid particles are collected by centrifugation and purified to ensure that no free catalyst residue remains on the surface of the wall material. The particles are then dried to obtain the encapsulated catalyst. The purification step includes washing with anhydrous ethanol and / or deionized water. The drying temperature is 30–40°C.

[0045] In some embodiments, the mass ratio of the wall material to the catalyst in the capsule-shaped catalyst is 1:(1~2).

[0046] A second aspect of the present invention provides a method for preparing the single-component addition-type silicone rubber described in the first aspect of the present invention, comprising the following steps: Vinyl polysiloxane and hydrogen-containing polysiloxane are mixed, and fillers, encapsulated plasticizers and encapsulated catalysts are added and mixed at a temperature below 40°C to obtain the single-component addition-type silicone rubber.

[0047] In some embodiments, the preparation method includes the following steps: Vinyl polysiloxane and filler are heated and mixed to obtain a base material; hydrogen-containing polysiloxane and encapsulated plasticizer are added to the base material and mixed, with the material temperature controlled at <40℃; encapsulated catalyst is added and dispersed, with the material temperature controlled at <40℃, to obtain the one-component addition-type silicone rubber.

[0048] In some preferred embodiments, the temperature at which the vinyl polysiloxane and filler are heated and mixed is 100~200°C, preferably 120~180°C.

[0049] In some preferred embodiments, the base material is cooled to room temperature before adding the hydrogen-containing polysiloxane and the encapsulated plasticizer.

[0050] In some preferred embodiments, the hydrogen-containing polysiloxane and the encapsulated plasticizer are mixed by stirring at 200-400 rpm for 10-30 min.

[0051] In some preferred embodiments, the dispersion after adding the capsule catalyst is carried out by stirring at 80-200 rpm for 5-15 min.

[0052] In some preferred embodiments, after the capsule-shaped catalyst is dispersed, a vacuum degassing step is further included. The vacuum degassing time is 2-8 minutes. The temperature during the vacuum degassing process is controlled to be <40°C.

[0053] A third aspect of the present invention provides the application of the single-component addition-curing silicone rubber described in the first aspect of the present invention in the encapsulation, bonding or protection of electronic components.

[0054] The protection is achieved by forming a protective coating using the single-component addition-curing silicone rubber.

[0055] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a one-component addition-cure silicone rubber that achieves rapid low-temperature curing at 60-80°C by constructing a dual-capsule synergistic system, reducing the curing temperature from over 120°C to 80°C and saving energy consumption during curing. Simultaneously, the dual isolation of the plasticizer and catalyst through plasticizer and catalyst microcapsules avoids the defect of sacrificing shelf life in pursuit of low-temperature activity in traditional formulations. Furthermore, the processing window can be controlled by adjusting the amount of plasticizer microcapsules or the melting / softening point of the wall material. Therefore, the one-component addition-cure silicone rubber provided by this invention combines rapid low-temperature curing with long-term storage stability, making it suitable for potting or bonding electronic components, especially heat-sensitive substrates such as PET (polyethylene terephthalate) and PC (polycarbonate). Detailed Implementation

[0056] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0057] The raw materials used in the following embodiments and comparative examples of the present invention are described below: Vinyl polysiloxane: terminal vinyl polysiloxane, viscosity 1000 mPa·s (25℃), vinyl content 0.25 mol%, commercially available.

[0058] Filler: Fumed silica, specific surface area 200 m² 2 / g, hydrophobically treated with hexamethyldisilazane (HMDS), commercially available.

[0059] Hydrogen-containing polysiloxane: Side-chain hydrogen-containing silicone oil, hydrogen content 0.8wt%, viscosity 30mPa·s (25℃), commercially available.

[0060] Inhibitor: 1-Ethynyl-1-cyclohexanol (ECH), commercially available.

[0061] Capsule-type plasticizer: The core material is dibutyl phthalate (DBP), and the wall material is paraffin wax (melting point 68℃). The mass ratio of core material to wall material is 4:1 (based on the proportion of raw materials used in preparation). The average particle size is 30μm. The preparation method is as follows: The wall material is heated to 85-90℃ to melt, and then a plasticizer (core material) preheated to the same temperature is added. The mixture is stirred at 500-800 rpm to form an oil phase. This oil phase is slowly added to an emulsification tank containing a 1 wt% polyvinyl alcohol (PVA) aqueous solution (water temperature maintained at 85℃). Emulsification is carried out at a high-speed shear rate of 1500-2000 rpm for 15-20 minutes to form a stable O / W emulsion. While stirring, 4-5 times the volume of cold water (0-10℃) is rapidly added to the emulsification tank for rapid cooling, causing the paraffin wax to solidify quickly and encapsulate the core material, forming a suspension. The resulting suspension is filtered, and the solid is washed with deionized water to remove polyvinyl alcohol. Then, it is vacuum dried at 35℃ for 24 hours to obtain white spherical capsules, which are the capsule-type plasticizer.

[0062] Encapsulated catalyst: The core material is Karstedt platinum catalyst (platinum content 2000 ppm), and the wall material is polystyrene (PS, melting point approximately 240℃, softening point approximately 100℃, highly soluble in DBP). The mass ratio of core material to wall material is 3:2 (based on the proportion of raw materials used in preparation), and the average particle size is 10 μm. The preparation method is as follows: Polystyrene resin was dissolved in dichloromethane to prepare a 10% (w / w) solution. A platinum catalyst was then added to the solution, and the mixture was ultrasonically dispersed for 10 minutes to form a homogeneous oil phase. This oil phase was then injected into an aqueous solution containing 1 wt% sodium dodecylbenzenesulfonate (SDBS) under stirring. The droplet size was controlled to be approximately 10 μm by adjusting the stirring speed to 3000 rpm. Subsequently, the system was heated to 40–45°C, and the mixture was stirred at a medium speed of 1000 rpm with vacuum assistance to allow the dichloromethane to evaporate slowly. As the dichloromethane was lost, polystyrene precipitated on the droplet surface and solidified into a film. After the dichloromethane had completely evaporated, the solid particles were collected by centrifugation and repeatedly washed with anhydrous ethanol and deionized water to ensure no free catalyst residue remained on the wall material surface. Finally, the film was dried at 40°C to constant weight to obtain a capsule-shaped catalyst. The droplet size was determined by observing the liquid under an optical microscope.

[0063] Capsule-type catalysts for paraffin wall materials were prepared using the same preparation method as capsule-type plasticizers.

[0064] The following detailed description is provided in conjunction with specific embodiments and comparative examples.

[0065] Example 1 A one-component addition-cure silicone rubber, the formulation of which is shown in Table 1, is prepared by the following steps: S1. Mix vinyl polysiloxane and fumed silica in a vacuum kneader, heat and stir at 150°C for 2 hours to prepare a base material; S2. Cool the base material from step S1 to room temperature (25°C); S3. Transfer the cooled base material from step S2 to a planetary mixer, add hydrogen-containing polysiloxane, inhibitor and encapsulated plasticizer, and stir at 300 rpm for 20 minutes, controlling the material temperature to <40℃; S4. Continue adding the capsule-type platinum catalyst and disperse it at 100 rpm for 10 minutes, controlling the material temperature to be <40℃.

[0066] S5. Vacuum degassing for 5 minutes (temperature below 40℃), discharge and fill to obtain single-component addition-cure silicone rubber.

[0067] Examples 2-3 A one-component addition-curing silicone rubber, the formulation of which is shown in Table 1, and the preparation method is the same as in Example 1.

[0068] Comparative Examples 1-4 A one-component addition-curing silicone rubber, the formulation of which is shown in Table 1, and the preparation method is the same as in Example 1.

[0069] Table 1 Formulation table (parts by weight) of one-component addition-cure silicone rubbers for examples and comparative examples

[0070] Performance testing The performance of the one-component addition-cure silicone rubbers obtained in the above embodiments and comparative examples was tested using the following methods: Storage stability: The initial viscosity of the sample was measured at 25°C using a rotational viscometer (such as Brookfield DV-II). After being placed in a sealed container at 25°C for 1 month and 6 months, the viscosity change was measured again. The greater the viscosity change, the worse the storage stability.

[0071] Curing time: Measured using a rotorless vulcanizer (MDR) at 80℃, 100℃, and 120℃. The time required for the torque to reach 90% of its maximum value (t90) was recorded as the complete curing time at that temperature.

[0072] Hardness: After the sample is cured and molded, the hardness of the cured material is measured using a Shore A hardness tester in accordance with ISO 868-2003 standard.

[0073] Tensile strength: The sample was cured at 100℃ into a standard film with a thickness of 2 mm, and then punched into dumbbell-shaped specimens. The tensile strength was measured at room temperature using a universal testing machine at a tensile rate of 500 mm / min, in accordance with GB / T 528-2009 standard.

[0074] The test results are shown in Table 2 below.

[0075]

[0076] Comparative Examples 2 and 3 were mainly used to compare storage stability; curing time, hardness, and tensile strength were not specifically tested.

[0077] The results in Table 2 are analyzed as follows: Regarding low-temperature curing performance, the test results of the comparative examples and comparative examples show that Examples 1-3 can be completely cured within 25 minutes at 80℃. Examples 1 and 2 are completely cured within 12 minutes and 8 minutes respectively at 80℃, while Comparative Example 1 requires more than 60 minutes to fully cure, and Comparative Example 4 takes more than 60 minutes without curing. This demonstrates that even if the melting point of the capsule catalyst wall material is not reached, rapid low-temperature curing at 80℃ can be achieved by releasing DBP in the examples of this application. Comparative Example 1 cannot cure at 80℃, and even curing is slow at 100℃, requiring 120℃ (close to the softening flow temperature of the wall material) for effective curing. This illustrates the effectiveness of the dual-capsule synergistic system of this invention in reducing the curing temperature. Furthermore, in Example 3, the amount of capsule plasticizer is relatively small, and the curing time at 80℃ is extended to 25 minutes, indicating that the amount of capsule plasticizer in this invention directly affects the cell wall breaking efficiency, and the curing time can be controlled by adjusting the amount.

[0078] Regarding storage stability, Examples 1-3 showed minimal viscosity increase after 6 months at room temperature, indicating excellent isolation performance of the dual-capsule system. Comparative Example 2 directly added liquid DBP. Although theoretically DBP does not participate in the reaction, as a good solvent, it can slowly swell / permeate the PS wall material of the capsule catalyst at room temperature, leading to catalyst leakage and release, and gelation within one month. In Comparative Example 3, paraffin wax was directly used as the wall material for the platinum catalyst, and free plasticizer DBP was added to the system. The results showed that the system gelled in less than one month at room temperature. This is mainly because paraffin wax has a low softening point, allowing the catalyst to slowly permeate from the paraffin wall material. A small amount of catalyst can lead to the hydrosilylation reaction, resulting in gelation. This demonstrates that using a high-melting-point resin to encapsulate the catalyst and a low-melting-point material to independently encapsulate the plasticizer are necessary conditions for achieving long-term stability of the single-component addition-type silicone rubber system of this invention.

[0079] In Comparative Example 4, the amount of encapsulated plasticizer was reduced to 1 part. At this point, the proportion of DBP released at high temperature was too low compared to the high-melting-point wall material of the encapsulated catalyst. At 80°C, a small amount of DBP could only cause the polystyrene wall material to swell, forming a high-viscosity polymer gel layer wrapped around the catalyst, but it could not cause the wall material to completely collapse. Therefore, Comparative Example 4 did not cure for more than 60 minutes at 80°C, and even at 100°C, the curing time was significantly prolonged, and the surface became sticky after curing. This shows that the core role of the encapsulated plasticizer is not only "contact," but also requires reaching the "critical dissolution concentration" in the local environment. By adjusting the ratio range of the encapsulated plasticizer and the encapsulated catalyst, the effective operation of this dissolution and wall-breaking mechanism can be ensured.

[0080] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A one-component addition-curing silicone rubber, characterized in that, It includes vinyl polysiloxane, hydrogen-containing polysiloxane, encapsulated plasticizer and encapsulated catalyst; wherein, the melting point or softening point of the wall material of the encapsulated plasticizer is T1, the melting point or softening point of the wall material of the encapsulated catalyst is T2, 50℃≤T1≤100℃, and T2≥T1+t, where t is 10~40℃; The content of the capsule-type plasticizer is greater than the content of the capsule-type catalyst; the plasticizer in the capsule-type plasticizer is a plasticizer that can dissolve or swell the wall material of the capsule-type catalyst.

2. The one-component addition-cure silicone rubber according to claim 1, characterized in that, The mass ratio of the capsule-type plasticizer to the capsule-type catalyst is (2~12):

1.

3. The one-component addition-cure silicone rubber according to claim 1, characterized in that, The single-component addition-type silicone rubber also includes fillers and / or inhibitors.

4. The one-component addition-cure silicone rubber according to claim 3, characterized in that, By weight, it includes the following components: 100 parts vinyl polysiloxane, 1-15 parts hydrogen-containing polysiloxane, 10-60 parts filler, 2-15 parts encapsulated plasticizer, 0.2-5 parts encapsulated catalyst, and 0-1 parts inhibitor.

5. The one-component addition-cure silicone rubber according to any one of claims 1 to 4, characterized in that, The wall material of the capsule-type plasticizer includes at least one of paraffin wax, microcrystalline wax, and polyethylene wax; And / or, the wall material of the capsule-type catalyst includes at least one of polycarbonate, polymethyl methacrylate, polystyrene, and styrene-acrylonitrile copolymer.

6. The one-component addition-cure silicone rubber according to any one of claims 1 to 4, characterized in that, The plasticizer in the capsule-type plasticizer includes at least one of dibutyl phthalate, dioctyl phthalate, dioctyl adipate, tricresyl phosphate, and polyether.

7. The one-component addition-cure silicone rubber according to any one of claims 1 to 4, characterized in that, The preparation method of the capsule-type plasticizer includes the following steps: mixing and emulsifying the molten or melted wall material with the plasticizer to obtain the capsule-type plasticizer.

8. The one-component addition-cure silicone rubber according to claim 3, characterized in that, The filler includes fumed silica and / or precipitated silica.

9. A method for preparing a one-component addition-cure silicone rubber according to any one of claims 1 to 8, characterized in that, Includes the following steps: Vinyl polysiloxane and hydrogen-containing polysiloxane are mixed, and fillers, encapsulated plasticizers and encapsulated catalysts are added and mixed at a temperature below 40°C to obtain the single-component addition-type silicone rubber.

10. The application of the single-component addition-curing silicone rubber according to any one of claims 1 to 8 in the encapsulation, bonding or protection of electronic components.

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