Modification method of silicon dioxide filler, modified silicon dioxide filler and application

Abstract

The invention provides a silicon dioxide filler modification method, a modified silicon dioxide filler and application. The modification method comprises the following steps: carrying out dispersion treatment on silicon dioxide to be modified under the action of three-dimensional mechanical force to obtain primarily dispersed silicon dioxide; and in a protective atmosphere, carrying out dry modification treatment on the primarily dispersed silicon dioxide and a silane coupling agent under the action of three-dimensional mechanical force to obtain the modified silicon dioxide filler. According to the modification method provided by the invention, under the synergistic cooperation of the three-dimensional mechanical force effect and the protective atmosphere, the submicron silicon dioxide is fully dispersed, the grafting of the surface of the submicron silicon dioxide powder and the coupling agent is more uniform, the modification effect is excellent, the submicron silicon dioxide powder is used as a filler to be filled in an epoxy resin system, the thermal expansion coefficient of an epoxy material is reduced, and the service life of the epoxy material is prolonged. The impact resistance is improved, and the formed composition is more suitable for the field of semiconductor packaging.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic packaging materials and relates to a modification method of a silicon dioxide filler, a modified silicon dioxide filler and an application thereof. Background Art

[0002] Epoxy resin (EP) has the advantages of easy operation, small curing shrinkage, good adhesion, good heat resistance, good electrical insulation, and excellent mechanical properties. It has been widely used in the electronics field, including conductive adhesives, conformal coatings, printed circuit boards, and flip-chip packaging. Among them, in the field of chip packaging, EP can protect the chip from physical damage, moisture, and dust. At the same time, EP also helps to dissipate the energy generated by the chip. However, the brittleness and low impact strength of EP limit its application in modern industry. In recent years, polymer-based nanocomposites have received increasing attention due to their excellent properties. Modifying the properties of EP by adding inorganic fillers to epoxy resin has become a new means of developing chip packaging materials.

[0003] Silica fillers are widely used in epoxy resin systems for electronic packaging materials due to their low coefficient of thermal expansion and excellent thermal and chemical stability. Furthermore, as the integration of electronic devices increases, chip packaging sizes are further miniaturized and micro-miniaturized, and integrated circuits are becoming lighter, thinner, and smaller. Consequently, the particle size of fillers added to electronic packaging materials, such as semiconductor encapsulants or semiconductor mounting adhesives, represented by epoxy resin compositions, is gradually trending toward submicron sizes. Compared to traditional micron-sized silica fillers, submicron-sized silica has a high surface energy and a high number of hydroxyl groups, making the powder prone to agglomeration and highly hygroscopic. Adding silica to epoxy resin systems can easily lead to increased system viscosity, poor dispersibility, and weak bonding between the filler and the resin. Therefore, surface modification techniques are often used to introduce functional groups onto the surface of silica fillers using silane coupling agents to address these issues.

[0004] Currently, the main filler modification method used in industry is wet modification. This involves mixing powders into a slurry according to a specific ratio, then adding surface modifiers and additives, and performing the modification under specific stirring rates and temperature conditions. This method offers the advantage of achieving sufficient filler surface modification and good results. However, due to its high energy consumption and the cumbersome operation required for solid-liquid separation and drying, its industrial application is limited.

[0005] Although there are technical solutions for dry modification of silica fillers in the existing technology, there are still many problems that need to be solved in the conventional dry modification technical solutions: (1) Due to the presence of a large number of hydroxyl groups on the surface of submicron silica and nano-silica, the powder is very easy to agglomerate. The high-speed mixer used in the traditional dry modification process can usually only provide two-dimensional force for dispersion, which makes it difficult to fully disperse the submicron silica and nano-silica, resulting in uneven surface modification and poor dispersion. (2) Submicron silica and nano-silica usually have high surface energy and high surface reactivity. The level of moisture in the environment during the modification process directly affects the powder modification effect. The currently commonly used surface modification equipment and space do not have the ability to control the environmental conditions during the modification process.

[0006] Therefore, how to improve the dispersibility of silica filler, enhance its modification effect, and improve the compatibility of filler in epoxy resin is a technical problem that needs to be solved urgently. Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention aims to provide a method for modifying a silica filler, a modified silica filler, and its applications. The modification method provided by the present invention, through the synergistic effect of three-dimensional mechanical force and a protective atmosphere, fully disperses submicron silica, more uniformly grafts the coupling agent onto the surface of the submicron silica powder, and achieves excellent modification results. When used as a filler in an epoxy resin system, the thermal expansion coefficient of the epoxy material is reduced, impact resistance is improved, and the resulting composition is more suitable for use in semiconductor packaging.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for modifying a silica filler, the modification method comprising the following steps:

[0010] The silicon dioxide to be modified is dispersed under the action of three-dimensional mechanical force to obtain preliminarily dispersed silicon dioxide;

[0011] In a protective atmosphere, the preliminarily dispersed silicon dioxide and silane coupling agent are subjected to dry modification treatment under the action of three-dimensional mechanical force to obtain a modified silicon dioxide filler.

[0012] It should be noted that the so-called three-dimensional mechanical force in the present invention refers to the action of mechanical forces in three mutually perpendicular directions within the same space; further, the present invention does not specifically limit the specific equipment for realizing the three-dimensional mechanical force action. The present invention is applicable to all types of equipment that can realize the above-mentioned mechanical force action, such as a three-dimensional mixer, which can realize the action of shear force in three mutually perpendicular dimensions.

[0013] In addition, conventional high-speed mixers, ball mills, etc. in the prior art all act on two-dimensional mechanical forces.

[0014] The modification method provided by the present invention performs dispersion treatment under the action of three-dimensional mechanical force to achieve monodisperse treatment of silica powder. Then, under a protective atmosphere, dry modification of the coupling agent is performed under the action of three-dimensional mechanical force, so that the surface of the silica powder is more evenly grafted with the coupling agent, the modification effect is more excellent, and the dispersion effect is good, agglomeration is less, and the influence of environmental factors on the modified stability of the highly surface active silica is shielded. The modified silica is filled in the epoxy resin system, has a high bonding strength with the epoxy resin, and reduces the thermal expansion coefficient and impact resistance of the epoxy resin material. The formed composition can be used in fields such as semiconductor sealants or semiconductor mounting adhesives in electronic packaging materials, and has a wide range of applications. In addition, the modification method provided by the present invention is simple to operate, does not require a complicated processing process, and is suitable for large-scale production.

[0015] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0016] Preferably, the rotation speed of the dispersion treatment under the action of the three-dimensional mechanical force is 600rpm~1000rpm, for example, 600rpm, 650rpm, 700rpm, 750rpm, 800rpm, 850rpm, 900rpm, 950rpm or 1000rpm, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0017] Preferably, the time for the dispersion treatment under the action of the three-dimensional mechanical force is 1 to 10 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0018] Preferably, the silicon dioxide to be modified includes submicron silicon dioxide and / or nanometer silicon dioxide.

[0019] It should be noted that the submicron level in the present invention is defined as a median particle size D50 of 100 nm to 1 μm (excluding 1 μm), while the nanometer level is defined as a median particle size D50 of 1 nm to 100 nm (excluding 100 nm).

[0020] The modification method provided by the present invention can better solve the problems of submicron-sized silica and nano-sized silica, thereby achieving a better modification effect and further improving the bonding strength with epoxy resin.

[0021] Preferably, the median particle size D50 of the submicron silica is 100 to 800 nm, excluding 100 nm, for example, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm or 800 nm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the median particle size D50 of the nano-scale silica is 1 to 100 nm and does not include 100 nm, for example, 1nn, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 99nm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the protective atmosphere includes a nitrogen atmosphere and / or an inert gas atmosphere.

[0024] In the present invention, the inert gas includes but is not limited to argon or helium, etc., and under the above protective atmosphere, the modification process is protected and the influence of environmental factors on the modification effect is reduced.

[0025] Preferably, the amount of the silane coupling agent is 0.01% to 5% of the mass of the preliminarily dispersed submicron silica, for example, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] In the present invention, the amount of the silane coupling agent is controlled to be 0.01% to 5% of the mass of the preliminarily dispersed submicron-sized silica, which is more conducive to the surface grafting of silica and reduces agglomeration.

[0027] Preferably, the silane coupling agent is added in the form of spraying to perform dry modification treatment on the preliminarily dispersed submicron silicon dioxide.

[0028] In the present invention, the silane coupling agent is added in the form of spraying for modification, which can better improve the uniformity of silica modification.

[0029] Preferably, the silane coupling agent includes an epoxy silane coupling agent.

[0030] In the present invention, it is preferred that the epoxy silane coupling agent is used to modify the silica, so that it can better combine with the epoxy resin based on the principle of similar solubility. Furthermore, when the silica filler is used for other packaging materials, the type of silane coupling agent can be adaptively adjusted to facilitate better combination with the corresponding packaging materials.

[0031] It should also be noted that the present invention does not specifically limit the specific material type and specific model of the epoxy silane coupling agent. The present invention is applicable to the specific material types and models that can be known within a reasonable range by those skilled in the art. For example, the epoxy silane coupling agent can be KBM403 (Shin-Etsu Chemical).

[0032] Preferably, the dry modification treatment under the action of the three-dimensional mechanical force includes sequentially performing a first dry modification treatment and a second dry modification treatment.

[0033] Preferably, the rotation speed of the first dry modification process is lower than the rotation speed of the second dry modification process.

[0034] In the present invention, the first dry modification treatment at a relatively low rotation speed is performed first, and then the second dry modification treatment at a relatively high rotation speed is performed, so that the silane coupling agent and the silicon dioxide can be better mixed uniformly.

[0035] Preferably, the rotation speed of the first dry modification treatment is 600-800 rpm, for example, 600 rpm, 625 rpm, 650 rpm, 675 rpm, 700 rpm, 725 rpm, 750 rpm or 800 rpm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the time of the first dry modification treatment is 1 to 10 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the rotation speed of the second dry modification treatment is 1000-2000 rpm, for example, 1000 rpm, 1050 rpm, 1100 rpm, 1150 rpm, 1200 rpm, 1250 rpm, 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, 1750 rpm, 1800 rpm, 1850 rpm, 1900 rpm, 1950 rpm or 2000 rpm, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] In the present invention, by adjusting the rotation speed of the first dry modification treatment to 600-800 rpm and / or the rotation speed of the second dry modification treatment to 1000-2000 rpm, the problem of uneven dispersion of the silane coupling agent in silica is better solved.

[0039] Preferably, the time of the second dry modification treatment is 1 to 10 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes or 10 minutes, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the modified material is subjected to heat treatment to obtain a modified silica filler.

[0041] Preferably, the temperature of the heat treatment is 30-150°C, for example, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0042] Preferably, the heat treatment time is 1 to 10 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] As a preferred technical solution, the modification method comprises the following steps:

[0044] The modified submicron silica having a median particle size D50 of 100 to 800 nm is subjected to a dispersion treatment at a rotation speed of 600 rpm to 1000 pm under a three-dimensional mechanical force to obtain preliminarily dispersed submicron silica;

[0045] In a protective atmosphere, the preliminarily dispersed submicron silica and silane coupling agent are subjected to a first dry modification treatment at a rotation speed of 600 to 800 rpm under the action of a three-dimensional mechanical force, and then subjected to a second dry modification treatment at a rotation speed of 1000 to 2000 rpm;

[0046] The material after the second dry modification treatment is subjected to a heat treatment at 30 to 150° C. to obtain a modified silica filler.

[0047] In a second aspect, the present invention provides a modified silica filler, wherein the modified silica filler is obtained by the modification method described in the first aspect.

[0048] In a third aspect, the present invention provides an epoxy resin composition, wherein the raw materials of the epoxy resin composition include an epoxy resin, a curing agent and the modified silica filler as described in the second aspect.

[0049] The epoxy resin composition provided by the present invention has high bonding strength with epoxy resin, reduces the thermal expansion coefficient of epoxy material, improves impact resistance, and can be better used in the field of electronic packaging.

[0050] Preferably, the mass of the curing agent is 20% to 50% of the mass of the epoxy resin, for example, 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0051] Preferably, the mass of the modified silica filler is 20% to 60% of the total mass of the epoxy resin composition, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%, but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0052] It should be noted that the specific types of epoxy resin and curing agent in the present invention are all conventional technical solutions, and the specific preparation method of the epoxy resin composition is also a conventional technical solution. Those skilled in the art can make adaptive selections and adjustments based on actual needs.

[0053] Preferably, the epoxy resin includes but is not limited to at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin and naphthalene ring-containing epoxy resin.

[0054] Preferably, the curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, and 2-methylpentamethylenediamine.

[0055] Preferably, the preparation method of the epoxy resin composition comprises:

[0056] The epoxy resin and the curing agent are mixed first, then the modified silica filler provided by the application is added, and mixing, curing are carried out under vacuum conditions to obtain the epoxy resin composition.

[0057] In a fourth aspect, the application provides an application of the epoxy resin composition as described in the third aspect in semiconductor packaging.

[0058] Compared with the prior art, the application has the following beneficial effects:

[0059] The modification method provided by the application realizes the monodisperse treatment of the silica powder under the action of three-dimensional mechanical force, then the dry modification of the coupling agent is carried out under the protective atmosphere according to the action of the three-dimensional mechanical force, so that the silica powder surface is more uniformly grafted with the coupling agent, the modification effect is more excellent, the dispersion effect is good, the agglomeration phenomenon is less, and the influence of environmental factors on the modification stability of the high-surface-activity silica is shielded. The modified silica is filled in the epoxy resin system, has high bonding force with the epoxy resin, is not easy to fall off, reduces the thermal expansion coefficient and impact resistance of the epoxy resin material, and the formed composition can be used in the fields of semiconductor sealants or semiconductor mounting adhesives in electronic packaging materials, and has a wide application range. In addition, the modification method provided by the application is simple to operate, does not need a complex treatment process, and is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 The particle size distribution diagram of the modified silica filler provided for Example 1.

[0061] Figure 2 The SEM diagram of the modified silica filler provided for Example 1.

[0062] Figure 3 The particle size distribution diagram of the modified silica filler provided for Example 2.

[0063] Figure 4 The SEM diagram of the modified silica filler provided for Example 2.

[0064] Figure 5 The particle size distribution diagram of the modified silica filler provided for Example 3.

[0065] Figure 6 The SEM diagram of the modified silica filler provided for Example 3.

[0066] Figure 7 The particle size distribution diagram of the modified silica filler provided for Example 4.

[0067] Figure 8 SEM image of the modified silica filler provided for Example 4.

[0068] Figure 9 SEM image of the epoxy resin composition provided for Application Example 4.

[0069] Figure 10 SEM image of the epoxy resin composition provided for Comparative Application Example 4. DETAILED DESCRIPTION

[0070] The technical solutions of the present application will be further illustrated below by means of specific embodiments. It should be understood by those skilled in the art that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations to the present application.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the description and the drawings of the specification and the appended claims should be considered as included in the scope of the present application; the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion.

[0072] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0073] Example 1

[0074] The present embodiment provides a modification method of a silica filler, which is as follows:

[0075] 100g of spherical silica (D50=100nm) was placed in the mixing bin of a three-dimensional mixer, and shearing dispersion was carried out at 1000rpm for 1min to obtain a preliminarily dispersed submicron silica;

[0076] Then open the vacuum pump valve and the outlet valve to exhaust the air in the chamber. After the air is exhausted, close the exhaust valve, open the air inlet valve to introduce nitrogen, repeat the above steps three times to replace the air in the reaction chamber, so that the mixing chamber is filled with nitrogen, and use the spray head in the chamber to spray 3g of epoxy silane coupling agent KBM403 into the chamber with nitrogen. The first dry modification treatment is carried out at a speed of 600rpm for 2min, and then the speed is increased to 1800rpm for a second dry modification treatment for 1min to obtain a preliminary modified sample. The preliminary sample is then heat treated at 120°C for 1h to obtain the modified silica filler.

[0077] Example 2

[0078] This embodiment provides a method for modifying a silica filler, and the modification method is as follows:

[0079] 100 g of spherical silica (D50 = 300 nm) was placed in the mixing bin of a three-dimensional mixer and sheared and dispersed at 900 rpm for 1 min to obtain preliminarily dispersed submicron silica.

[0080] Then open the vacuum pump valve and the outlet valve to discharge the air in the chamber. After the air is exhausted, close the exhaust valve, open the air inlet valve to introduce nitrogen, repeat the above steps three times to replace the air in the reaction chamber, so that the mixing chamber is filled with nitrogen, and use the spray head in the chamber to spray 5g of epoxy silane coupling agent KBM403 into the chamber with nitrogen. The first dry modification treatment is carried out at a speed of 700rpm for 1min, and then the speed is increased to 1600rpm for a second dry modification treatment for 2min to obtain a preliminary modified sample. The preliminary sample is then heat treated at 120°C for 1h to obtain the modified silica filler.

[0081] Example 3

[0082] This embodiment provides a method for modifying a silica filler, and the modification method is as follows:

[0083] 100 g of spherical silica (D50 = 500 nm) was placed in the mixing bin of a three-dimensional mixer and sheared and dispersed at 600 rpm for 3 min to obtain preliminarily dispersed submicron silica.

[0084] Then open the vacuum pump valve and the outlet valve to discharge the air in the chamber. After the air is exhausted, close the exhaust valve, open the air inlet valve to introduce nitrogen, repeat the above steps three times to replace the air in the reaction chamber, so that the mixing chamber is filled with nitrogen, and use the spray head in the chamber to spray 2g of epoxy silane coupling agent KBM403 into the chamber with nitrogen. The first dry modification treatment is carried out at a speed of 800rpm for 1min, and then the speed is increased to 1400rpm for the second dry modification treatment for 5min to obtain a preliminary modified sample. The preliminary sample is then heat treated at 60°C for 3h to obtain the modified silica filler.

[0085] Example 4

[0086] This embodiment provides a method for modifying a silica filler, and the modification method is as follows:

[0087] 100 g of spherical silica (D50 = 800 nm) was placed in the mixing bin of a three-dimensional mixer and sheared and dispersed at 600 rpm for 1 min to obtain preliminarily dispersed submicron silica.

[0088] Then open the vacuum pump valve and the air outlet valve to discharge the air in the chamber. After the air is exhausted, close the exhaust valve, open the air inlet valve to introduce nitrogen, repeat the above steps three times to replace the air in the reaction chamber, so that the mixing chamber is filled with nitrogen, and use the spray head in the chamber to spray 0.75g of epoxy silane coupling agent KBM403 into the chamber with nitrogen. The first dry modification treatment is carried out at a speed of 600rpm for 2min, and then the speed is increased to 1200rpm for a second dry modification treatment for 2min to obtain a preliminary modified sample. The preliminary sample is then heat treated at 150°C for 1h to obtain the modified silica filler.

[0089] Example 5

[0090] The difference between this embodiment and embodiment 1 is that the D50 of the silicon dioxide to be modified in this embodiment is 50 nm.

[0091] The remaining modification methods and parameters remained the same as in Example 1.

[0092] Example 6

[0093] The difference between this embodiment and embodiment 1 is that in this embodiment, the epoxy silane coupling agent KBM403 is directly poured into the mixing bin, and the coupling agent is not added by spraying.

[0094] The remaining modification methods and parameters remained the same as in Example 1.

[0095] Example 7

[0096] The difference between this embodiment and embodiment 1 is that the first dry modification treatment is not performed in this embodiment.

[0097] The remaining modification methods and parameters remained the same as in Example 1.

[0098] Example 8

[0099] The difference between this embodiment and embodiment 1 is that the second dry modification treatment is not performed in this embodiment.

[0100] The remaining modification methods and parameters remained the same as in Example 1.

[0101] Example 9

[0102] The difference between this embodiment and embodiment 1 is that the rotation speed of the first dry modification treatment in this embodiment is 1800 rpm, and the rotation speed of the second dry modification treatment is 600 rpm.

[0103] The remaining modification methods and parameters remained the same as in Example 1.

[0104] Example 10

[0105] The difference between this embodiment and embodiment 1 is that the rotation speed of the first dry modification treatment in this embodiment is 500 rpm.

[0106] The remaining modification methods and parameters remained the same as in Example 1.

[0107] Example 11

[0108] The difference between this embodiment and embodiment 1 is that the rotation speed of the second dry modification treatment in this embodiment is 900 rpm.

[0109] The remaining modification methods and parameters remained the same as in Example 1.

[0110] Example 12

[0111] The difference between this embodiment and embodiment 1 is that the rotation speed of the second dry modification treatment in this embodiment is 2100 rpm.

[0112] The remaining modification methods and parameters remained the same as in Example 1.

[0113] Comparative Example 1

[0114] The difference between this comparative example and Example 1 is that this comparative example does not undergo any modification treatment, and directly uses spherical silica (D50=100 nm) as the silica filler.

[0115] Comparative Example 2

[0116] The difference between this comparative example and Example 2 is that this comparative example does not undergo any modification treatment, and directly uses spherical silica (D50=300 nm) as the silica filler.

[0117] Comparative Example 3

[0118] The difference between this comparative example and Example 3 is that this comparative example does not undergo any modification treatment, and directly uses spherical silica (D50=500 nm) as the silica filler.

[0119] Comparative Example 4

[0120] The difference between this comparative example and Example 4 is that this comparative example does not undergo any modification treatment, and directly uses spherical silica (D50=800 nm) as the silica filler.

[0121] Comparative Example 5

[0122] The difference between this comparative example and Example 1 is that this comparative example does not undergo the shear dispersion treatment process, but directly undergoes the modification treatment process.

[0123] The remaining modification methods and parameters remained the same as in Example 1.

[0124] Comparative Example 6

[0125] The difference between this comparative example and Example 1 is that the modification process in this comparative example is not carried out in a three-dimensional mixer, but is directly carried out in a high-speed mixer under the action of a two-dimensional shear force.

[0126] The remaining modification methods and parameters remained the same as in Example 1.

[0127] Comparative Example 7

[0128] The difference between this comparative example and Example 1 is that, after the shear dispersion, the modification process is directly carried out in an air atmosphere.

[0129] The remaining modification methods and parameters remained the same as in Example 1.

[0130] Figure 1 The particle size distribution of the modified silica filler provided for Example 1 is shown.

[0131] Figure 2 The SEM image of the modified silica filler provided in Example 1 is shown.

[0132] Figure 3 The particle size distribution diagram of the modified silica filler provided in Example 2 is shown.

[0133] Figure 4 The SEM image of the modified silica filler provided in Example 2 is shown.

[0134] Figure 5 The particle size distribution diagram of the modified silica filler provided in Example 3 is shown.

[0135] Figure 6 The SEM image of the modified silica filler provided in Example 3 is shown.

[0136] Figure 7 The particle size distribution diagram of the modified silica filler provided in Example 4 is shown.

[0137] Figure 8 The SEM image of the modified silica filler provided in Example 4 is shown.

[0138] from Figures 1 to 8 It can be seen that the modified silica filler obtained by the modification method provided by the present invention, especially the submicron silica filler, has good monodispersity, uniform morphology, and no agglomeration.

[0139] The silica fillers provided in Examples 1-12 and Comparative Examples 1-7 were used in the resin composition, as follows.

[0140] Application Example 1

[0141] This application example provides an epoxy resin composition, and the preparation method of the epoxy resin composition is as follows:

[0142] 45 g of bisphenol A epoxy resin and 15 g of m-xylene diamine curing agent were mixed evenly, 40 g of modified silica provided in Example 1 was added, and vacuum degassing was performed in a vacuum degassing machine at a speed of 1500 r / min for 2 minutes, and then vacuum degassing was continued at a speed of 2000 r / min for 2 minutes. The mixture was mixed evenly and degassed to obtain an epoxy resin composition, which was then cured at 165° C. for 2 hours to obtain the epoxy resin composition.

[0143] Application Example 2

[0144] This application example provides an epoxy resin composition, and the preparation method of the epoxy resin composition is as follows:

[0145] 30 g of bisphenol A epoxy resin and 10 g of m-xylene diamine curing agent were uniformly stirred, 60 g of modified silica provided in Example 2 were added, and vacuum degassing was performed in a vacuum degassing machine at a speed of 1500 r / min for 2 minutes, and then vacuum degassing was continued at a speed of 2000 r / min for 2 minutes. The mixture was mixed evenly and degassed to obtain an epoxy resin composition, which was then cured at 165° C. for 2 hours to obtain the epoxy resin composition.

[0146] Application Example 3-12

[0147] The difference between application example 3-12 and application example 1 is that the hole-filling silica provided in application example 3-12 is used respectively.

[0148] The rest of the preparation method and parameters are consistent with application example 1.

[0149] Comparative application example 1 and comparative application example 3-7

[0150] The difference between comparative application example 1-7 and application example 1 is that the hole-filling silica provided in comparative example 1-7 is used respectively.

[0151] The rest of the preparation method and parameters are consistent with application example 1.

[0152] Comparative application example 2

[0153] The difference between comparative application example 2 and application example 2 is that the hole-filling silica provided in comparative example 2 is used respectively.

[0154] The rest of the preparation method and parameters are consistent with application example 2.

[0155] Figure 9 The SEM image of the epoxy resin composition provided in application example 4 is shown.

[0156] Figure 10 The SEM image of the epoxy resin composition provided in comparative application example 4 is shown.

[0157] From Figure 9 and Figure 10 From the comparison of the SEM images at the cross section, it can be seen that in the epoxy resin composition, the silica filler modified by the modification method provided by the present application is well combined with the epoxy resin, and there is no filler shedding, while the silica filler without modification has poor bonding force with the resin, and the agglomeration phenomenon is very serious.

[0158] The epoxy resin compositions provided in application examples 1-12 and comparative examples 1-7 are tested for filler shedding, thermal expansion coefficient and impact resistance.

[0159] (1) Filler shedding: by observing the brittle resin interface SEM image, when the filler shedding is less than or equal to 5%, it is determined that there is no obvious shedding; when the filler shedding is between 5% and 15%, it is determined that a small part of the filler is shed; when the filler shedding is between 15% and 85%, it is determined that most of the filler is shed, and when the shedding is greater than 85%, it is determined that the filler cannot be wrapped.

[0160] (2) Thermal expansion coefficient: tested according to the method specified in IPC-TM-650 2.4.24.

[0161] (3) Impact strength: Tested according to the method specified in 17.76 (GB / T 2567-2008).

[0162] The test results of the above tests are shown in Tables 1 to 4.

[0163] Table 1

[0164]

[0165]

[0166] Table 2

[0167] Filler falling off Coefficient of thermal expansion Impact strength Application Example 2 No obvious shedding 18 14 Comparative Application Example 2 Unable to encapsulate fillers 63 8

[0168] Table 3

[0169] Filler falling off Coefficient of thermal expansion Impact strength Application Example 3 No obvious shedding 25 14 Comparative Application Example 3 Unable to encapsulate fillers 62 7

[0170] Table 4

[0171] Filler falling off Coefficient of thermal expansion Impact strength Application Example 4 No obvious shedding 23 13 Comparative Application Example 4 Unable to encapsulate fillers 63 8

[0172] In summary, the modification method provided by the present invention performs dispersion treatment under the action of three-dimensional mechanical force to achieve monodisperse treatment of silica powder, and then, under a protective atmosphere, the coupling agent is dry-modified under the action of three-dimensional mechanical force, so that the surface of the silica powder is more evenly grafted with the coupling agent, the modification effect is more excellent, and the dispersion effect is good, the agglomeration phenomenon is less, and the influence of environmental factors on the modified stability of highly surface active silica is also shielded. The modified silica is filled in the epoxy resin system, has a high bonding force with the epoxy resin, is not easy to fall off, and reduces the thermal expansion coefficient and impact resistance of the epoxy resin material. The formed composition can be used in fields such as semiconductor sealants or semiconductor mounting adhesives in electronic packaging materials, and has a wide range of applications. In addition, the modification method provided by the present invention is simple to operate, does not require a complicated processing process, and is suitable for large-scale production.

[0173] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for modifying a silica filler, characterized in that: The modification method comprises the following steps: The silicon dioxide to be modified is dispersed under the action of three-dimensional mechanical force to obtain preliminarily dispersed silicon dioxide; In a protective atmosphere, the preliminarily dispersed silicon dioxide and silane coupling agent are subjected to dry modification treatment under the action of three-dimensional mechanical force to obtain a modified silicon dioxide filler.

2. The modification method according to claim 1, characterized in that The rotation speed of the dispersion treatment under the action of the three-dimensional mechanical force is 600 to 1000 rpm, and the time of the dispersion treatment under the action of the three-dimensional mechanical force is 1 to 10 minutes; Preferably, the silicon dioxide to be modified comprises submicron silicon dioxide and / or nanometer silicon dioxide; Preferably, the median particle size D50 of the submicron silica is 100-800 nm.

3. The modification method according to claim 1 or 2, characterized in that The protective atmosphere includes nitrogen atmosphere and / or inert gas atmosphere; Preferably, the amount of the silane coupling agent is 0.01% to 5% of the mass of the preliminarily dispersed submicron silica; Preferably, the silane coupling agent is added in the form of spraying to perform dry modification treatment on the preliminarily dispersed submicron silicon dioxide; Preferably, the silane coupling agent includes an epoxy silane coupling agent.

4. The modification method according to any one of claims 1 to 3, characterized in that: The dry modification treatment under the action of the three-dimensional mechanical force includes sequentially performing a first dry modification treatment and a second dry modification treatment; Preferably, the rotation speed of the first dry modification treatment is lower than the rotation speed of the second dry modification treatment; Preferably, the rotation speed of the first dry modification treatment is 600-800 rpm, and the time of the first dry modification treatment is 1-10 min; Preferably, the rotation speed of the second dry modification treatment is 1000-2000 rpm, and the time of the second dry modification treatment is 1-10 minutes.

5. The modification method according to any one of claims 1 to 4, characterized in that: heat-treating the modified material to obtain a modified silica filler; Preferably, the heat treatment temperature is 30-150° C., and the heat treatment time is 1-10 h.

6. The modification method according to any one of claims 1 to 5, characterized in that: The modification method comprises the following steps: The modified submicron-sized silica having a median particle size D50 of 100 to 800 nm is subjected to a dispersion treatment at a rotation speed of 600 to 1000 rpm under a three-dimensional mechanical force to obtain preliminarily dispersed submicron-sized silica; In a protective atmosphere, the preliminarily dispersed submicron silica and silane coupling agent are subjected to a first dry modification treatment at a rotation speed of 600 to 800 rpm under the action of a three-dimensional mechanical force, and then subjected to a second dry modification treatment at a rotation speed of 1000 to 2000 rpm; The material after the second dry modification treatment is subjected to a heat treatment at 30 to 150° C. to obtain a modified silica filler.

7. A modified silica filler, characterized in that: The modified silica filler is obtained by modification according to any one of claims 1 to 6.

8. An epoxy resin composition, characterized in that The raw materials of the epoxy resin composition include epoxy resin, curing agent and the modified silica filler as claimed in claim 7.

9. The epoxy resin composition according to claim 8, characterized in that The mass of the curing agent is 20% to 50% of the mass of the epoxy resin; Preferably, the mass of the modified silica filler is 20% to 60% of the total mass of the epoxy resin composition.

10. Use of the epoxy resin composition according to claim 8 or 9 in electronic packaging.

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