Search

CN-121975327-A - High thixotropic silica gel and preparation method and application thereof

CN121975327ACN 121975327 ACN121975327 ACN 121975327ACN-121975327-A

Abstract

The invention relates to the technical field of high polymer materials, in particular to a high thixotropic silica gel and a preparation method and application thereof. The high thixotropic silica gel comprises, by weight, 100 parts of silicone resin, 0.1-0.8 part of a catalyst, 0.2-1 part of a reaction stabilizer, 5-10 parts of a cross-linking agent, 4-15 parts of a diluent, 0.5-2 parts of a thickener and 5-10 parts of fumed silica, wherein the fumed silica is selected from polymethyl dichlorosilane modified HDK amorphous silica and/or polymethyl disiloxane modified amorphous silica. The Gao Chubian silica gel realizes stable printing of a 15 mu m inner diameter ceramic needle, and meanwhile, the height-width ratio of a printed single-layer material can reach more than 0.7, so that the ceramic needle is suitable for electronic packaging, coating and 3D printing, screen printing, and forming a 60 mu m thickness coating after solidification, the transmittance is kept at more than 93%, and the material has excellent room temperature storage stability in a single-component state.

Inventors

  • Request for anonymity
  • Request for anonymity
  • Request for anonymity
  • Request for anonymity
  • Request for anonymity
  • Request for anonymity
  • Request for anonymity

Assignees

  • 芯体素(杭州)科技发展有限公司

Dates

Publication Date
20260505
Application Date
20260205

Claims (10)

  1. 1. The high thixotropic silica gel is characterized by comprising, by weight, 100 parts of silicone resin, 0.1-0.8 part of catalyst, 0.2-1 part of reaction stabilizer, 5-10 parts of cross-linking agent, 4-15 parts of diluent, 0.5-2 parts of thickener and 5-10 parts of fumed silica, wherein the fumed silica is selected from polymethyl dichlorosilane modified HDK amorphous silica and/or polymethyl disiloxane modified amorphous silica.
  2. 2. The high thixotropic silicone gel of claim 1, wherein the silicone is selected from one or more of a vinyl MQ silicone, a vinyl MT silicone, a vinyl MDQ silicone, a methyl vinyl MQ silicone, or a methyl phenyl vinyl silicone.
  3. 3. The high thixotropic silicone gel according to claim 2, wherein the silicone resin has a weight average molecular weight of 2000 to 15000 g/mol, a viscosity of 2500~22000 mPa.s@25 ℃ and a vinyl content of 0.3 to 1.6%.
  4. 4. The high thixotropic silicone gel of claim 1, wherein the thickener is selected from one or more of polyurea-based, polyurethane-based, or ester-based thickeners.
  5. 5. The high thixotropic silica gel of claim 1, wherein the catalyst is selected from one or more of a Speier catalyst, a Karstedt catalyst.
  6. 6. The high thixotropic silica gel of claim 1, wherein the reaction stabilizer is selected from one or more of alkynols, amides, maleates.
  7. 7. The high thixotropic silicone gum according to claim 1, wherein the cross-linking agent is selected from solvent-free hydrogen-containing polysiloxanes containing reactive hydrosilylation groups.
  8. 8. The high thixotropic silicone gel of claim 1, wherein the diluent is selected from one or more of hexamethyldisiloxane, hexamethyldisilazane, octamethyl cyclotetrasiloxane, decamethyl cyclopentasiloxane.
  9. 9. A method for preparing the Gao Chubian silica gel according to any one of claims 1to 8, comprising the steps of: mixing and stirring silicone resin and a catalyst to obtain a mixture A; adding a reaction stabilizer into the mixture A, mixing and stirring to obtain a mixture B; Mixing and stirring a cross-linking agent and a diluent to obtain a mixture C; adding the mixture C into the mixture B, mixing and stirring to obtain a mixture D; Adding a thickener into the mixture D, mixing and stirring to obtain a mixture E; Adding fumed silica into the mixture E, mixing and stirring to obtain a mixture F; grinding the mixture F to finally obtain the high thixotropic silica gel.
  10. 10. Use of a highly thixotropic gel according to any one of claims 1 to 8 or a highly thixotropic gel prepared by a preparation method according to claim 9 for electronic packaging and coating, direct-write 3D printing and/or screen printing.

Description

High thixotropic silica gel and preparation method and application thereof Technical Field The invention relates to the technical field of high polymer materials, in particular to a high thixotropic silica gel and a preparation method and application thereof. Background Silicone resin plays a key role in a plurality of technical fields by virtue of its excellent applicability and wide development prospect as an important branch in the field of high-performance materials. The material takes siloxane bond (R-Si-O) as a basic skeleton, and side chain alkane is designed through substitution, grafting, copolymerization and other processes, so that the material has the characteristics of high temperature resistance, weather resistance, excellent chemical stability and the like, and is widely applied to the fields of medical treatment, food daily chemicals, electronic industry, aerospace and the like. In the electronics industry, highly thixotropic silicone has a particular and important role, for example for chip dam filling, encapsulation and the like. On a part of precise PCB substrate, the traditional transfer printing and silk screen printing process is difficult to realize the precision requirement below 15 mu m, so that the 3D printing technology is generated, and a new possibility is provided for the application of the high thixotropic silica gel in a fine scene. However, this technology still faces the following problems: Firstly, most of the existing touch enhancers in the high thixotropic silica gel are made of particle materials such as bentonite, solid polyamide wax or kaolin, and the like, so that the touch enhancers have poor dispersibility and are not suitable for a fine dispensing process. On part of the PCB substrate, the 3D printing mode is adopted to perform fine printing more properly, but the printing material needs to meet the condition that the ceramic needle with the inner diameter of 15 mu m can stably discharge, and the high thixotropic silica gel added with bentonite, solid polyamide wax or kaolin has larger particles or uneven dispersion, so that the condition that the needle is blocked by a printing needle or the flow is greatly reduced when the printing is continuously performed for a period of time, and the printing stability is affected. Moreover, the sagging prevention performance of Gao Chubian silica gel is generally insufficient, the single-layer material height-width ratio is not more than 0.5, collapse easily occurs after 10 minutes of line printing, the scenes with high requirements on the height-width ratio such as stacking and laminating printing cannot be met, and an effective surrounding dam structure is difficult to form. In addition, the high thixotropic silica gel generally exhibits a cloudy state before and after vulcanization, and generally has a transmittance of less than 90% at a film thickness of 60. Mu.m. For printing of partial LED lamp bead dams, insufficient transmittance of dam materials can cause insufficient brightness of the lamp beads, overall light efficiency is reduced, and heating is caused. Finally, the existing high thixotropic material single-component storage stability is insufficient, double-component preparation is mostly adopted, temporary preparation is needed on site, operation procedures are increased, use is inconvenient, a valve body needs to be cleaned in time after printing, otherwise, needle blocking is caused, and continuous operation is affected. Therefore, there is a need to provide a high thixotropic silica gel suitable for laminating and printing high aspect ratio materials, with higher transmittance and better stability, so as to meet the increasingly refined electronic additive manufacturing requirements. Disclosure of Invention The invention mainly aims to provide a high thixotropic silica gel which is suitable for laminating printing of materials with large aspect ratio, higher transmittance and better stability, and a preparation method and application thereof. In a first aspect, the invention provides a high thixotropic silica gel, which comprises, by weight, 100 parts of a silicone resin, 0.1-0.8 part of a catalyst, 0.2-1 part of a reaction stabilizer, 5-10 parts of a cross-linking agent, 4-15 parts of a diluent, 0.5-2 parts of a thickener and 5-10 parts of fumed silica, wherein the fumed silica is selected from polymethyl dichlorosilane modified HDK amorphous silica and/or polymethyl disiloxane modified amorphous silica. Further, the silicone is selected from one or more of vinyl MQ silicone, vinyl MT silicone, vinyl MDQ silicone, methyl vinyl MQ silicone, or methyl phenyl vinyl silicone. Further, the weight average molecular weight of the silicone resin is 2000-15000 g/mol, the viscosity is 2500~22000 mPa.s@25 ℃, and the vinyl content is 0.3-1.6%. Further, the thickener is selected from one or more of polyurea-based, polyurethane-based or ester-based thickeners. Further, the catalyst is selected from one or more of a Speie