Super-soft fip material with hole structure and preparation method and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-09
- Publication Date
- 2026-08-07
AI Technical Summary
①选用更低硬度的液体硅橡胶或者采用硅油替代一部分硅橡胶，即降低基胶的硬度来达到降低产品硬度的目的，这种方式虽然可以降低硬度，但降幅有限，因为为了保证体系的交联强度，基胶就会有一个最低硬度的限制，通过这种方式最低只能做出ShoreA45~50硬度的产品
传统FIP材料通过点胶工艺成型为0.6mm×0.75mm D型胶条，在保证屏蔽效能≥100dB（0.3~40GHz）的情况下测试压缩应力为0.45N/mm（@20%）和1.5N/mm（@40%）；本发明通过加入热膨胀微球来调整产品内部结构，在产品内部形成孔洞结构，从而达到降低应力的目的，超软FIP材料的压缩应力为0.2N/mm（@20%）和1.0N/mm（@40%），降幅为55%（@20%）和33%（@40%），可以满足低压缩应力的要求，同时屏蔽效能仍可满足≥100dB（0.3~40GHz）。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of FIP material structure control technology, and in particular to an ultrasoft FIP material with a porous structure, its preparation method and application. Background Technology
[0002] With the rapid development of various industries, electronic products are gradually becoming thinner and lighter, forcing the materials used in these products for shielding to also become thinner and lighter. For FIP materials, increasingly lower hardness and compressive stress have become the mainstream trend.
[0003] Existing technologies typically employ two methods to reduce compressive stress: ① Using a lower-hardness liquid silicone rubber or replacing a portion of the silicone rubber with silicone oil, thus reducing the hardness of the base rubber to lower the product's hardness. While this method can reduce hardness, the reduction is limited because the base rubber has a minimum hardness requirement to maintain the system's crosslinking strength. This method can only produce products with a minimum hardness of Shore A 45-50. ② Pre-treating the powder in the system to improve powder properties and increase the interfacial bonding between the rubber and powder. This method can reduce the amount of powder added to the system, thereby reducing hardness. However, to ensure the product's shielding effectiveness and conductivity, there is a lower limit to the amount of powder added, limiting this method to producing products with a Shore A of around 50. Both methods can reduce the hardness and compressive stress of FIP products to some extent, but they cannot meet the current market demand for products with even lower hardness and lower compressive stress.
[0004] Therefore, it is of great significance to provide an ultra-soft FIP material with a porous structure that has low hardness and low compressive stress. Summary of the Invention
[0005] The purpose of this invention is to provide an ultra-soft FIP material with a porous structure, its preparation method, and its application. The Shore A35 FIP material is prepared through structured control while ensuring its conductivity and shielding performance. This ultra-low hardness FIP material is used to meet the requirements of lightweight electronic materials and avoid problems such as excessive pressure or torque during assembly.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an ultra-soft FIP material with a porous structure. The raw materials for preparing the ultra-soft FIP material include vinyl silicone oil, conductive filler, thermally expandable microspheres, and hydrogen-containing silicone oil. The conductive filler has a mass fraction of ≥50% in the ultra-soft FIP material, and the thermally expandable microspheres have a mass fraction of 0.3~0.8% in the ultra-soft FIP material.
[0007] Preferably, the raw materials for preparing the ultrasoft FIP material include component A and component B, with a mass ratio of component A to component B of 0.8~1.2:1; component A includes vinyl silicone oil, platinum catalyst, conductive filler, and thermally expandable microspheres; component B includes vinyl silicone oil, hydrogen-containing silicone oil, and conductive filler.
[0008] Preferably, the vinyl silicone oil has a molecular weight of 100,000 to 150,000, a molecular weight distribution of 1.2 to 2.2, and a vinyl content of 0.1 to 0.2% by mass; the conductive filler is Ag / Ni powder, which is spherical in shape and has a D50 of 15 to 25 μm.
[0009] Preferably, the mass of the thermally expandable microspheres is 0.3~0.8% of the total mass of components A and B; the mass fraction of the conductive filler in component A is ≥60%; the mass fraction of the conductive filler in component B is ≥60%; the molar ratio of vinyl groups in vinyl silicone oil to silanol groups in hydrogen-containing silicone oil in component B is 1:1.8~2.2; and the molar ratio of the sum of vinyl groups in vinyl silicone oil in components A and B to the silanol groups in hydrogen-containing silicone oil in component B is 0.8~1.2:0.8~1.2.
[0010] Preferably, in component A, the mass of Pt in the platinum catalyst is 1000~5000 ppm of the mass of vinyl silicone oil; component A also contains a diluent and / or a reinforcing agent, and component B also contains one or more of a diluent, a reinforcing agent, and an inhibitor.
[0011] Preferably, the diluent comprises an alkane diluent, and the reinforcing agent comprises silica; the inhibitor comprises one or more of 1-ethynyl-1-cyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol, diallyl maleate, and propyl methacrylate; the mass of the diluent is 8-12% of the mass of the vinyl silicone oil, the mass of the reinforcing agent is 0.8-1.2% of the mass of the vinyl silicone oil, and the mass of the inhibitor is 0.1-0.5% of the mass of the vinyl silicone oil.
[0012] Preferably, the thermally expandable microspheres have a core-shell structure, with the shell being an acrylate copolymer and the core being a volatile alkane gas. The particle size of the thermally expandable microspheres is 15~35μm, and the particle size of the expanded microspheres is 60~120μm.
[0013] The present invention also provides a method for preparing the aforementioned ultrasoft FIP material with porous structure, comprising the following steps: 1) Mix vinyl silicone oil and platinum catalyst to obtain component A base adhesive; Vinyl silicone oil and hydrogen-containing silicone oil are stirred and mixed to obtain component B base adhesive; 2) The conductive filler, thermally expandable microspheres, and component A base adhesive are fed in multiple stages and then kneaded and homogenized to obtain component A; The conductive filler and component B base adhesive are fed in multiple stages and then kneaded and homogenized to obtain component B.
[0014] Preferably, the linear velocity of stirring and mixing in step 1) is 30~60m / s, the number of stages of multi-stage feeding in step 2) is 4~6 stages, and the kneading and homogenization are carried out under vacuum with a vacuum degree of -1.05~-0.9kPa.
[0015] The present invention also provides the application of the ultra-soft FIP material with the porous structure in electronic components. The ultra-soft FIP material with the porous structure is applied to the surface of the electronic component and then thermosetting. The thermosetting temperature is 0~160℃ and the heating time is 40~60min.
[0016] The beneficial effects of this invention are: Traditional FIP materials are formed into 0.6mm×0.75mm D-shaped adhesive strips using an adhesive dispensing process. While maintaining a shielding effectiveness ≥100dB (0.3~40GHz), the compressive stress tested is 0.45N / mm (@20%) and 1.5N / mm (@40%). This invention, by incorporating thermally expanding microspheres to adjust the internal structure of the product and create a porous structure, achieves stress reduction. The compressive stress of the ultra-soft FIP material is 0.2N / mm (@20%) and 1.0N / mm (@40%), representing a reduction of 55% (@20%) and 33% (@40%), respectively. This meets the requirement of low compressive stress while still maintaining a shielding effectiveness ≥100dB (0.3~40GHz).
[0017] This invention creates a porous structure by adding thermally expandable microspheres, thereby reducing compressive stress while ensuring the electrical and shielding properties of the material, without affecting the dispensing process. Detailed Implementation
[0018] This invention provides an ultra-soft FIP material with a porous structure. The raw materials for preparing the ultra-soft FIP material include vinyl silicone oil, conductive filler, thermally expandable microspheres, and hydrogen-containing silicone oil. The conductive filler has a mass fraction of ≥50% in the ultra-soft FIP material, and the thermally expandable microspheres have a mass fraction of 0.3~0.8% in the ultra-soft FIP material.
[0019] In this invention, the mass fraction of conductive filler in the ultra-soft FIP material is preferably ≥60%, more preferably ≥80%, and even more preferably ≥85%; the mass fraction of thermally expandable microspheres in the ultra-soft FIP material is preferably 0.3~0.8%, more preferably 0.4~0.7%, and even more preferably 0.5~0.6%.
[0020] In this invention, vinyl silicone oil is used as the substrate, conductive fillers are dispersed in the substrate, and thermally expanded microspheres are used to create pores.
[0021] In this invention, the raw materials for preparing the ultrasoft FIP material include component A and component B. The mass ratio of component A to component B is preferably 0.8~1.2:1, more preferably 0.9~1.1:1, and even more preferably 1:1. Component A preferably includes vinyl silicone oil, platinum catalyst, conductive filler, and thermally expandable microspheres. Component B preferably includes vinyl silicone oil, hydrogen-containing silicone oil, and conductive filler.
[0022] In this invention, the vinyl silicone oil preferably has a molecular weight of 100,000 to 150,000, more preferably 110,000 to 140,000, and even more preferably 120,000 to 130,000; its molecular weight distribution is preferably 12,000 to 22,000, more preferably 14,000 to 20,000, and even more preferably 16,000 to 18,000; its vinyl content is preferably 0.1% to 0.2%, more preferably 0.12% to 0.18%, and even more preferably 0.15% to 0.16%; the conductive filler is preferably Ag / Ni powder, in a near-spherical shape, with a D50 preferably 15% to 25% μm, more preferably 17% to 23% μm, and even more preferably 20% μm.
[0023] In this invention, the mass of the thermally expandable microspheres is preferably 0.3-0.8% of the total mass of components A and B, more preferably 0.4-0.7%, and even more preferably 0.5-0.6%. The mass fraction of the conductive filler in component A is preferably ≥60%, more preferably ≥80%, and even more preferably ≥85%. The mass fraction of the conductive filler in component B is preferably ≥60%, more preferably ≥80%, and even more preferably ≥85%. The molar ratio of vinyl groups in vinyl silicone oil to silanol groups in hydrogen-containing silicone oil in component B is preferably 1:1.8-2.2, more preferably 1:1.9-2.1, and even more preferably 1:2. The molar ratio of the sum of vinyl groups in vinyl silicone oil in components A and B to the silanol groups in hydrogen-containing silicone oil in component B is preferably 0.8-1.2:0.8-1.2, more preferably 0.9-1.1:0.9-1.1, and even more preferably 1:1. The mass of the inhibitor is preferably 0.1-0.5% of the mass of vinyl silicone oil, more preferably 0.2-0.4%, and even more preferably 0.3%.
[0024] In component A of the present invention, the mass of Pt in the platinum catalyst is preferably 1000-5000 ppm of the mass of vinyl silicone oil, more preferably 2000-4000 ppm, and even more preferably 3000 ppm; component A preferably also contains a diluent and / or a reinforcing agent, and component B preferably also contains one or more of a diluent, a reinforcing agent, and an inhibitor.
[0025] In this invention, the diluent preferably comprises an alkane-based diluent, and the reinforcing agent preferably comprises silica; the inhibitor preferably comprises one or more of 1-ethynyl-1-cyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol, diallyl maleate, and propyl methacrylate; the mass of the diluent is preferably 8-12% of the mass of the vinyl silicone oil, more preferably 9-11%, and even more preferably 10%; the mass of the reinforcing agent is preferably 0.8-1.2% of the mass of the vinyl silicone oil, more preferably 0.9-1.1%, and even more preferably 1%.
[0026] In this invention, the thermally expandable microspheres are preferably core-shell structures, the shell layer is preferably an acrylate copolymer, the core layer is preferably a volatile alkane gas, the particle size of the thermally expandable microspheres is preferably 15~35μm, more preferably 20~30μm, more preferably 25μm, and the particle size of the expanded microspheres is preferably 60~120μm, more preferably 70~110μm, more preferably 80~100μm.
[0027] The present invention also provides a method for preparing the aforementioned ultrasoft FIP material with porous structure, comprising the following steps: 1) Mix vinyl silicone oil and platinum catalyst to obtain component A base adhesive; Vinyl silicone oil and hydrogen-containing silicone oil are stirred and mixed to obtain component B base adhesive; 2) The conductive filler, thermally expandable microspheres, and component A base adhesive are fed in multiple stages and then kneaded and homogenized to obtain component A; The conductive filler and component B base adhesive are fed in multiple stages and then kneaded and homogenized to obtain component B.
[0028] In this invention, the linear velocity of stirring and mixing in step 1) is preferably 30~60m / s, more preferably 40~50m / s, and even more preferably 45m / s. The number of stages for multi-stage feeding in step 2) is preferably 4~6 stages, more preferably 5 stages. Kneading and homogenization are carried out under vacuum, with a vacuum degree preferably -1.05~-0.9kPa, more preferably -1.02~-0.95kPa, and even more preferably -0.99~-0.98kPa.
[0029] The present invention also provides the application of the ultra-soft FIP material with the porous structure in electronic components. The ultra-soft FIP material with the porous structure is applied to the surface of the electronic component and then thermosetting. The thermosetting temperature is 0~160℃ and the heating time is 40~60min.
[0030] In this invention, the thermosetting temperature is preferably 30~120℃, more preferably 50~100℃, and the heating time is preferably 45~55min, more preferably 50min. The heating rate is adjusted according to the particle size and type of the thermally expandable microspheres to control the final particle size and pore size of the microspheres, thereby reducing stress and ensuring the electrical properties and shielding effectiveness of the system.
[0031] The ultra-soft FIP material with a porous structure of the present invention is used in the interface gap between two contact materials in the conductive path of electronic components, and the minimum gap distance is preferably 0.5 mm.
[0032] This invention controls the size of the microspheres after expansion by controlling the heating temperature and time of the microspheres, and controls the internal microsphere structure by combining microspheres of different sizes, thereby forming the desired porous structure inside the system to reduce compressive stress.
[0033] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0034] In the examples and comparative examples, the vinyl silicone oil had a molecular weight of 120,000 to 130,000, a molecular weight distribution of 14,000 to 18,000, and a vinyl mass content of 0.12% to 0.16%.
[0035] Example 1
[0036] The ultra-soft FIP material consists of component A and component B in a 1:1 mass ratio. Component A contains vinyl silicone oil, platinum catalyst, silica, conductive filler, thermally expandable microspheres, and isododecane diluent. The thermally expandable microspheres have a core-shell structure, with the shell being an acrylic acid-vinylidene chloride copolymer and the core being filled with isobutane. The microspheres have a particle size of 20 μm and an initiation temperature of 90~100℃. The platinum catalyst contains 1000 ppm platinum by mass of vinyl silicone oil, silica by mass of 1% by mass of vinyl silicone oil, and isododecane diluent by mass of 10% by mass of vinyl silicone oil. The conductive filler accounts for 85% of the mass of component A, and the thermally expandable microspheres account for 0.5% of the total mass of components A and B. Component B includes vinyl silicone oil, hydrogen-containing silicone oil, conductive filler, silica, and isododecane diluent. The molar ratio of vinyl groups in the vinyl silicone oil to hydroxyl groups in the hydrogen-containing silicone oil is 1:2. The mass of silica is 1% of the mass of vinyl silicone oil, and the mass of isododecane diluent is 10% of the mass of vinyl silicone oil. The mass fraction of conductive filler in component B is 85%. The molar ratio of the sum of vinyl groups in vinyl silicone oil to hydroxyl groups in hydrogen-containing silicone oil in components A and B is 1:1. The conductive filler in components A and B is Ag / Ni powder, with a near-spherical shape and a D50 of 20 μm.
[0037] First, the vinyl silicone oil of component A is stirred and homogenized with a platinum catalyst at a stirring speed of 40 m / s to obtain the base adhesive of component A. Then, conductive filler, thermally expandable microspheres, silica, isododecane diluent, and the base adhesive of component A are added in equal amounts in five stages and kneaded and homogenized under a vacuum of -0.99 kPa to obtain component A. Next, the vinyl silicone oil of component B is stirred and homogenized with a hydrogen-containing silicone oil at a stirring speed of 40 m / s to obtain the base adhesive of component B. Then, conductive filler, silica, isododecane diluent, and the base adhesive of component B are added in equal amounts in five stages and kneaded and homogenized under a vacuum of -0.99 kPa to obtain component B. Components A and B are then respectively packaged into adhesive tubes A and B.
[0038] Example 2
[0039] The ultra-soft FIP material consists of component A and component B in a 1:1 mass ratio. Component A contains vinyl silicone oil, platinum catalyst, silica, conductive filler, thermally expandable microspheres, and isododecane diluent. The thermally expandable microspheres have a core-shell structure, with the shell being an acrylic acid-vinylidene chloride copolymer and the core being filled with isobutane. The microspheres have a particle size of 30 μm and an initiation temperature of 90~100℃. The platinum catalyst contains 1000 ppm platinum by mass of vinyl silicone oil, silica by mass of 0.9% by mass of vinyl silicone oil, and isododecane diluent by mass of 9% by mass of vinyl silicone oil. The conductive filler accounts for 75% of the mass of component A, and the thermally expandable microspheres account for 0.4% of the total mass of components A and B. Component B includes vinyl silicone oil, hydrogen-containing silicone oil, conductive filler, silica, and isododecane diluent. The molar ratio of vinyl groups in the vinyl silicone oil to hydroxyl groups in the hydrogen-containing silicone oil is 1:1.9. The mass of silica is 0.9% of the mass of vinyl silicone oil, and the mass of isododecane diluent is 9% of the mass of vinyl silicone oil. The mass fraction of conductive filler in component B is 75%. The molar ratio of the sum of vinyl groups in vinyl silicone oil to hydroxyl groups in hydrogen-containing silicone oil in components A and B is 1:1. The conductive filler in components A and B is Ag / Ni powder, with a near-spherical shape and a D50 of 25 μm.
[0040] First, the vinyl silicone oil of component A and the platinum catalyst were stirred and homogenized at a stirring speed of 35 m / s to obtain the base adhesive of component A. Conductive filler, thermally expandable microspheres, silica, isododecane diluent, and the base adhesive of component A were added in equal amounts in five stages and kneaded and homogenized under a vacuum of -0.97 kPa to obtain component A. Then, the vinyl silicone oil of component B and the hydrogen-containing silicone oil were stirred and homogenized at a stirring speed of 35 m / s to obtain the base adhesive of component B. Conductive filler, silica, isododecane diluent, and the base adhesive of component B were added in equal amounts in five stages and kneaded and homogenized under a vacuum of -0.97 kPa to obtain component B. Components A and B were then respectively packaged into adhesive tubes A and B.
[0041] Example 3
[0042] The ultra-soft FIP material consists of component A and component B in a 1:1 mass ratio. Component A contains vinyl silicone oil, platinum catalyst, silica, conductive filler, thermally expandable microspheres, and isododecane diluent. The thermally expandable microspheres have a core-shell structure, with the shell being an acrylic acid-vinylidene chloride copolymer and the core being filled with isobutane. The microspheres have a particle size of 25 μm and an initiation temperature of 90~100℃. The platinum catalyst contains 1000 ppm platinum by mass of vinyl silicone oil, silica by mass of 1.1% by mass of vinyl silicone oil, isododecane diluent by mass of 11% by mass of vinyl silicone oil, conductive filler by mass of 70% by mass, and thermally expandable microspheres by mass of 0.8% of the total mass of components A and B. Component B includes vinyl silicone oil, hydrogen-containing silicone oil, conductive filler, silica, isododecane diluent, and 1-ethynyl-1-cyclohexanol. The molar ratio of vinyl groups in the vinyl silicone oil to hydroxyl groups in the hydrogen-containing silicone oil is 1:2.1. The mass of silica is 1.1% of the mass of vinyl silicone oil, the mass of isododecane diluent is 11% of the mass of vinyl silicone oil, and the mass of 1-ethynyl-1-cyclohexanol is 0.3% of the mass of vinyl silicone oil. The mass fraction of conductive filler in component B is 70%. The molar ratio of the sum of vinyl groups in vinyl silicone oil to hydroxyl groups in hydrogen-containing silicone oil in components A and B is 1:1. The conductive filler in components A and B is Ag / Ni powder, with a near-spherical shape and a D50 of 15 μm.
[0043] First, the vinyl silicone oil of component A and the platinum catalyst were stirred and homogenized at a stirring speed of 50 m / s to obtain the base adhesive of component A. Conductive filler, thermally expandable microspheres, silica, isododecane diluent, and the base adhesive of component A were added in equal amounts in five stages and kneaded and homogenized under a vacuum of -1.02 kPa to obtain component A. Then, the vinyl silicone oil of component B and the hydrogen-containing silicone oil were stirred and homogenized at a stirring speed of 50 m / s to obtain the base adhesive of component B. Conductive filler, silica, isododecane diluent, and the base adhesive of component B were added in equal amounts in five stages and kneaded and homogenized under a vacuum of -1.02 kPa to obtain component B. Components A and B were then respectively packaged into adhesive tubes A and B.
[0044] Comparative Example 1
[0045] The only difference between this comparative example and Example 1 is that the mass of the thermally expanded microspheres is 1% of the total mass of components A and B.
[0046] Comparative Example 2
[0047] The only difference between this comparative example and Example 1 is that the mass of the thermally expanded microspheres is 0.1% of the total mass of components A and B.
[0048] Comparative Example 3
[0049] The only difference between this comparative example and Example 1 is that the particle size of the thermally expandable microspheres is 10 μm.
[0050] Comparative Example 4
[0051] The only difference between this comparative example and Example 1 is that the particle size of the thermally expandable microspheres is 40 μm.
[0052] The performance of the ultrasoft FIP materials of Examples 1-3 and Comparative Examples 1-4 was investigated: 1) Dispensing process performance evaluation: Components A and B from the example were dispensed from tube A and tube B respectively, thoroughly mixed, and then poured into 30mL tubes. Under 90psi pressure, the dispensing speed of the G21 needle was >0.6g / 100s. After 4 hours of continuous dispensing, the flow rate decreased by <5%. After 7 days of refrigerated storage, the extrusion speed decreased by <5%. The unmixed components A and B had a shelf life of 6 months, and the extrusion speed decreased by <5% after mixing.
[0053] 2) Molding process: The FIP material of the embodiment is placed on the surface of the lower interface material (nickel-plated metal plate) by dispensing process. The shape is D-shaped, with a width and height of 0.75mm and 0.6mm respectively. It is heated by infrared lamp, and the temperature is raised from 0℃ to 160℃ by non-linear heating (heating time is 45min), and then cured and shaped.
[0054] 3) Shielding effect: The shielding effectiveness of the cured FIP materials of Example 1 and Comparative Examples 1 to 4 was tested using the cavity-to-cavity test method; the results are shown in Table 1 and Table 2.
[0055] 4) Compression stress test: The compression stress of the cured FIP materials of Example 1 and Comparative Examples 1-4 was tested. The compression stress test method was as follows: An electronic universal testing machine was used. The adhesive strip to be tested was placed on the compression test platform. A 25mm×25mm metal block was placed on the adhesive strip to be tested and centered. After the pressure head of the testing machine descended to contact the metal block, the position stroke was zeroed. Then, the machine descended at a rate of 1mm / min to compress until the strip height was 60%. The compression force curve of the descending compression was recorded, and the compression stress corresponding to 20% and 40% was taken from the curve. The results are shown in Table 1 and Table 2.
[0056] 5) Surface resistance test: The surface resistance of the cured FIP materials of Example 1 and Comparative Examples 1 to 4 was tested using MIL-DTL-83528C. The results are shown in Table 1 and Table 2.
[0057] The effects of the amount of thermally expanded microspheres added in Examples 1 and Comparative Examples 1-2 on the structure and properties of the ultrasoft FIP material are shown in Table 1.
[0058] Table 1. Effect of the amount of thermally expanded microspheres added on the ultrasoft FIP material
[0059] As shown in Table 1, adding different amounts of thermally expandable microspheres has a significant impact on the structure and performance of the system. When the amount added is too small, the volume ratio of the microspheres is too low, and they cannot reduce stress after expansion. However, when the amount of microspheres added is too large, the internal pores of the system will change from a closed-cell structure to a local open-cell structure, which will destroy the conductive network structure of the system and significantly reduce the electrical performance and shielding effectiveness. Only by reasonably controlling the amount of microspheres added to create a suitable internal pore structure can the electrical performance and shielding effectiveness of the product be guaranteed while reducing compressive stress.
[0060] The effects of the particle size of the thermally expanded microspheres in Examples 1 and Comparative Examples 3-4 on the structure and properties of the ultrasoft FIP materials are shown in Table 2.
[0061] Table 2. Effect of the particle size of thermally expanded microspheres on ultrasoft FIP materials
[0062] As shown in Table 2, when small-diameter thermally expandable microspheres are added, the pores formed inside are too small, resulting in insufficient stress reduction. When the added microspheres are too large, some microspheres will expand and connect to form a large open structure, causing discontinuity in the conductive network, which affects the electrical performance and shielding effectiveness.
[0063] The compressive stress of the ultrasoft FIP material in Example 2 was 0.2 N / mm (@20%) and 1.0 N / mm (@40%), and the compressive stress of the FIP material in Example 3 was 0.22 N / mm (@20%) and 1.03 N / mm (@40%).
[0064] This invention focuses on the structural control of materials, adjusting the internal structure of FIP materials. By adding thermally expandable microspheres to the traditional organosilicon-based FIP material system, the microspheres begin to expand during the product curing process. Simultaneously, prolonged high temperatures cause the microspheres to soften and crack, releasing the gas inside. At this point, the material itself has completed curing and shaping, forming pores within the material system. This pore structure significantly reduces the stress of the material, achieving the goal of stress reduction. At the same time, this closed-cell structure does not affect the conductive mesh structure of the FIP material itself.
[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. An ultrasoft FIP material with a porous structure, characterized in that, The raw materials for preparing the ultra-soft FIP material include vinyl silicone oil, conductive filler, thermally expandable microspheres, and hydrogen-containing silicone oil; the mass fraction of the conductive filler in the ultra-soft FIP material is ≥50%, and the mass fraction of the thermally expandable microspheres in the ultra-soft FIP material is 0.3~0.8%.
2. The ultrasoft FIP material with a porous structure according to claim 1, characterized in that, The raw materials for preparing the ultra-soft FIP material include component A and component B, with a mass ratio of component A to component B of 0.8~1.2:1; component A includes vinyl silicone oil, platinum catalyst, conductive filler, and thermally expandable microspheres; component B includes vinyl silicone oil, hydrogen-containing silicone oil, and conductive filler.
3. The ultrasoft FIP material with a porous structure according to claim 1 or 2, characterized in that, The vinyl silicone oil has a molecular weight of 100,000 to 150,000, a molecular weight distribution of 1.2 to 2.2, and a vinyl mass content of 0.1 to 0.2%. The conductive filler is Ag / Ni powder, which is spherical in shape and has a D50 of 15 to 25 μm.
4. The ultrasoft FIP material with a porous structure according to claim 3, characterized in that, The mass of the thermally expandable microspheres is 0.3~0.8% of the total mass of components A and B. The mass fraction of the conductive filler in component A is ≥60%; the mass fraction of the conductive filler in component B is ≥60%; the molar ratio of vinyl groups in vinyl silicone oil to silanol groups in hydrogen-containing silicone oil in component B is 1:1.8~2.2; the molar ratio of the sum of vinyl groups in vinyl silicone oil in components A and B to the silanol groups in hydrogen-containing silicone oil in component B is 0.8~1.2:0.8~1.
2.
5. The ultrasoft FIP material with a porous structure according to claim 4, characterized in that, In component A, the mass of Pt in the platinum catalyst is 1000~5000 ppm of the mass of vinyl silicone oil; component A also contains a diluent and / or a reinforcing agent, and component B also contains one or more of a diluent, a reinforcing agent and an inhibitor.
6. The ultrasoft FIP material with a porous structure according to claim 5, characterized in that, The diluent comprises an alkane diluent, and the reinforcing agent comprises silica; the inhibitor comprises one or more of 1-ethynyl-1-cyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol, diallyl maleate, and propyl methacrylate; the mass of the diluent is 8-12% of the mass of the vinyl silicone oil, the mass of the reinforcing agent is 0.8-1.2% of the mass of the vinyl silicone oil, and the mass of the inhibitor is 0.1-0.5% of the mass of the vinyl silicone oil.
7. The ultrasoft FIP material with a porous structure according to claim 5, characterized in that, The thermally expandable microspheres have a core-shell structure, with the shell being an acrylate copolymer and the core being a volatile alkane gas. The particle size of the thermally expandable microspheres is 15~35μm, and the particle size of the expanded microspheres is 60~120μm.
8. A method for preparing the ultrasoft FIP material with a porous structure according to any one of claims 1 to 7, characterized in that, It includes the following steps: 1) Mix vinyl silicone oil and platinum catalyst to obtain component A base adhesive; Vinyl silicone oil and hydrogen-containing silicone oil are stirred and mixed to obtain component B base adhesive; 2) The conductive filler, thermally expandable microspheres, and component A base adhesive are fed in multiple stages and then kneaded and homogenized to obtain component A; The conductive filler and component B base adhesive are fed in multiple stages and then kneaded and homogenized to obtain component B.
9. The preparation method according to claim 8, characterized in that, The linear velocity of stirring and mixing in step 1) is 30~60m / s. The number of stages of multi-stage feeding in step 2) is 4~6 stages. Kneading and homogenization are carried out under vacuum with a vacuum degree of -1.05~-0.9kPa.
10. The application of the ultra-soft FIP material with a porous structure as described in any one of claims 1 to 7 in electronic components, characterized in that, The ultra-soft FIP material with a porous structure is applied to the surface of electronic components and then thermo-cured. The thermo-curing temperature is 0~160℃ and the heating time is 40~60min.