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CN-122011989-A - Low-dielectric adhesive and preparation method thereof

CN122011989ACN 122011989 ACN122011989 ACN 122011989ACN-122011989-A

Abstract

The invention discloses a low dielectric adhesive and a preparation method thereof, and relates to the field of adhesive, wherein the preparation method comprises the following steps of chemically modifying the surface of a silica filler a to obtain a silica filler b with an organic molecular layer on the surface; the preparation method comprises the steps of mixing a resin matrix, a curing agent and the silica filler b at high temperature to obtain slurry, adding a functional auxiliary agent into the slurry to perform low-temperature mixing to obtain a glue solution, and performing stage curing on the glue solution to obtain the low-dielectric adhesive with the gradient interface structure. According to the invention, the gradient interface structure is used as a stress buffering and transferring layer, so that stress can be effectively absorbed and dispersed through a transition region with modulus continuously changed under the action of external force, crack propagation is inhibited, the fracture toughness, impact resistance and delamination resistance of the material are improved, and finally, the cooperative enhancement of the toughness and reliability of the adhesive layer is realized on the premise of keeping excellent low dielectric property.

Inventors

  • LIU QINGMIN
  • LIN YUAN
  • ZENG WENTAO

Assignees

  • 迈高精细高新材料(宜昌)有限公司
  • 迈高精细高新材料（深圳）有限公司

Dates

Publication Date
20260512
Application Date
20260302

Claims (10)

  1. 1. A method for preparing a low dielectric adhesive, which is characterized by comprising the following steps: S1, chemically modifying the surface of a silica filler a to obtain a silica filler b with an organic molecular layer on the surface, wherein the surface of the silica filler b is hydrophobic and has amino functional groups; S2, mixing the resin matrix, the curing agent and the silica filler b at high temperature to obtain slurry, and adding the functional auxiliary agent into the slurry to perform low-temperature mixing to obtain a glue solution; and step S3, performing stage curing on the glue solution to obtain the low-dielectric adhesive with the gradient interface structure.
  2. 2. The method for preparing a low dielectric adhesive according to claim 1, wherein, The step S1 specifically comprises the following steps: Step S11, firstly, performing controllable hydrolysis on a silane coupling agent in a mixed system of absolute ethyl alcohol and deionized water to generate hydrolysate rich in silicon hydroxyl; And step S12, fully mixing the hydrolysate with the silica filler a, performing condensation reaction under the heating condition to obtain a mixture, and performing vacuum heat treatment on the mixture to obtain the silica filler b after the treatment is finished.
  3. 3. The method for preparing a low dielectric adhesive according to claim 2, wherein, In the step S11, the silane coupling agent is gamma-aminopropyl triethoxysilane, the mass ratio of the silane coupling agent to absolute ethyl alcohol is 1 (8-10), the mass of deionized water in the mixed system is 4-6% of the mass of the silane coupling agent, and the stirring time in the hydrolysis process is 25-35min; In the step S12, the silicon dioxide filler a is spherical fused silicon dioxide filler, the average grain diameter is 1-2 mu m, the heating condition is 65-75 ℃, the stirring time is 1.5-2.5h, the stirring rotating speed is 150-250rpm, and the vacuum heat treatment temperature is 110-125 ℃ and the time is 3.5-4.5h.
  4. 4. The method for preparing a low dielectric adhesive according to claim 1, wherein, The slurry is obtained according to the following steps: Adding the resin matrix, the curing agent and the silica filler b into a planetary stirring tank, stirring and mixing under the first temperature condition, and obtaining slurry after the stirring and mixing are finished.
  5. 5. The method for preparing a low dielectric adhesive according to claim 4, wherein, The resin matrix is hydrogenated bisphenol A epoxy resin, the curing agent is methyl hexahydrophthalic anhydride, the weight ratio of the resin matrix to the curing agent to the silicon dioxide filler b is 100 (66-70) (30-50), the temperature under the first temperature condition is 48-52 ℃, the vacuum degree is less than or equal to-0.095 MPa, the stirring time is 50-70min, and the stirring rotating speed is 500-1000 rpm.
  6. 6. The method for preparing a low dielectric adhesive according to claim 5, wherein, The glue solution is obtained according to the following steps: And (3) controlling the slurry to be stirred and mixed under the second temperature condition, and then sequentially adding the functional auxiliary agent a, the functional auxiliary agent b and the functional auxiliary agent c into the slurry to obtain the glue solution after the mixing and stirring are finished.
  7. 7. The method for preparing a low dielectric adhesive according to claim 6, wherein, The temperature under the second temperature condition is 28-32 ℃, the weight ratio of the resin matrix to the functional auxiliary agent a to the functional auxiliary agent b to the functional auxiliary agent C is 100 (5-12): (2-10): (0.5-1.5), the functional auxiliary agent a is an epoxy-polydimethylsiloxane-epoxy triblock copolymer, the stirring speed of the functional auxiliary agent a during addition is 180-220 rpm, the stirring time is 18-25min, the functional auxiliary agent b is core-shell elastomer particles, the stirring speed of the functional auxiliary agent b during addition is 130-170 rpm, the stirring time is 12-18min, the functional auxiliary agent C is microencapsulated imidazole, and the stirring speed of the functional auxiliary agent C during addition is 80-120 rpm, and the stirring time is 5-10min.
  8. 8. The method for preparing a low dielectric adhesive according to claim 1, wherein, The step S3 specifically comprises the following steps: Step S31, performing primary heat treatment after coating or dispensing the glue solution to obtain gel; and S32, performing heat treatment on the gel again to obtain the low-dielectric adhesive.
  9. 9. The method for preparing a low dielectric adhesive according to claim 8, wherein, In the step S31, the heating rate of the primary heat treatment is 2-3 ℃ per minute, the temperature is 105-115 ℃ and the time is 80-100min; In the step S32, the temperature rising rate of the reheating treatment is 2-3 ℃ per minute, the temperature is 138-142 ℃ and the time is 170-190min.
  10. 10. A low dielectric adhesive tape prepared by the preparation method according to any one of claims 1 to 9.

Description

Low-dielectric adhesive and preparation method thereof Technical Field The invention relates to the field of adhesive, in particular to low-dielectric adhesive and a preparation method thereof. Background With the rapid development of advanced electronic technologies such as 5G communication and high performance computing, stringent requirements are put forward on the dielectric properties of packaging materials, low dielectric constant (Dk) and low dielectric loss (Df) have become key indexes, and in order to reduce the dielectric constant, technical routes for introducing porous or hollow inorganic fillers into an organic resin matrix are generally adopted in the industry, and the reduction of the overall dielectric constant is realized by utilizing the low dielectric properties of air. In the traditional method for reducing the low dielectric property of the adhesive, while excellent dielectric property can be obtained, a large number of structural defects and fragile interfaces are inevitably introduced, so that the brittleness of the cured adhesive layer is extremely high, the impact resistance and bending resistance are remarkably deteriorated, for example, in the practical application of chip packaging, the packaging body is continuously subjected to temperature circulation and unavoidable mechanical stress impact, and the internal brittleness enables microcracks to be more easily initiated and spread in the adhesive layer or at the interface, and finally catastrophic cracking and delamination failure are initiated, thereby seriously threatening the long-term reliability of electronic devices. Therefore, a low dielectric adhesive and a preparation method thereof are provided for solving the problems of high brittleness of the cured adhesive layer and poor impact resistance and bending resistance. Disclosure of Invention The invention aims to provide a low-dielectric adhesive and a preparation method thereof, which solve the problems of high brittleness and poor impact resistance and bending resistance of a cured adhesive layer. To achieve the purpose, the invention adopts the following technical scheme: A method for preparing a low dielectric adhesive, the method comprising the steps of: S1, chemically modifying the surface of a silica filler a to obtain a silica filler b with an organic molecular layer on the surface, wherein the surface of the silica filler b is hydrophobic and has amino functional groups; S2, mixing the resin matrix, the curing agent and the silica filler b at high temperature to obtain slurry, and adding the functional auxiliary agent into the slurry to perform low-temperature mixing to obtain a glue solution; and step S3, performing stage curing on the glue solution to obtain the low-dielectric adhesive with the gradient interface structure. The step S1 specifically comprises the following steps: Step S11, firstly, performing controllable hydrolysis on a silane coupling agent in a mixed system of absolute ethyl alcohol and deionized water to generate hydrolysate rich in silicon hydroxyl; And step S12, fully mixing the hydrolysate with the silica filler a, performing condensation reaction under the heating condition to obtain a mixture, and performing vacuum heat treatment on the mixture to obtain the silica filler b after the treatment is finished. In the step S11, the silane coupling agent is gamma-aminopropyl triethoxysilane, the mass ratio of the silane coupling agent to absolute ethyl alcohol is 1 (8-10), the mass of deionized water in the mixed system is 4-6% of the mass of the silane coupling agent, and the stirring time in the hydrolysis process is 25-35min; In the step S12, the silicon dioxide filler a is spherical fused silicon dioxide filler, the average grain diameter is 1-2 mu m, the heating condition is 65-75 ℃, the stirring time is 1.5-2.5h, the stirring rotating speed is 150-250rpm, and the vacuum heat treatment temperature is 110-125 ℃ and the time is 3.5-4.5h. The slurry is obtained according to the following steps: Adding the resin matrix, the curing agent and the silica filler b into a planetary stirring tank, stirring and mixing under the first temperature condition, and obtaining slurry after the stirring and mixing are finished. The resin matrix is hydrogenated bisphenol A epoxy resin, the curing agent is methyl hexahydrophthalic anhydride, the weight ratio of the resin matrix to the curing agent to the silicon dioxide filler b is 100 (66-70) (30-50), the temperature under the first temperature condition is 48-52 ℃, the vacuum degree is less than or equal to-0.095 MPa, the stirring time is 50-70min, and the stirring rotating speed is 500-1000 rpm. The glue solution is obtained according to the following steps: And (3) controlling the slurry to be stirred and mixed under the second temperature condition, and then sequentially adding the functional auxiliary agent a, the functional auxiliary agent b and the functional auxiliary agent c into the slurry to obta