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CN-121975350-A - Narrow-distribution high-activation calcium carbonate for organic silicon pouring sealant and preparation method thereof

CN121975350ACN 121975350 ACN121975350 ACN 121975350ACN-121975350-A

Abstract

The invention discloses narrow-distribution high-activation calcium carbonate for organic silicon pouring sealant and a preparation method thereof, and belongs to the technical field of calcium carbonate preparation and organic silicon materials. The preparation method of the invention comprises the steps of taking superfine heavy calcium carbonate with the granularity distribution width less than or equal to 2.5 and the D50 of 5.5+/-0.5 mu m as a raw material, removing water at high temperature until the water content is less than 0.2%, and reacting the compound modifier subjected to constant-temperature air atomization at 55-85 ℃ with the raw material for 3-10 seconds under the negative pressure environment of 85-115 ℃ and minus 150-750 Pa, thereby preparing the product with the activation rate more than 95% and the oil absorption value less than or equal to 16.0g/100 g. The calcium carbonate provided by the invention is used as reinforcing and/or heat conducting filler for the organic silicon pouring sealant, has strong process controllability and high efficiency, can improve the compatibility and the comprehensive performance of the pouring sealant, and has remarkable industrial application value.

Inventors

  • XIE YUN
  • CHEN SHIYUAN
  • LI CHANGHUA
  • Guan Chenfei
  • LI YONGYAN
  • LIANG XIAOYIN
  • LIN YAN

Assignees

  • 广西贺州市科隆粉体有限公司

Dates

Publication Date
20260505
Application Date
20260127

Claims (10)

  1. 1. The preparation method of the narrow-distribution high-activation calcium carbonate for the organic silicon pouring sealant is characterized by comprising the following steps of: (1) Providing superfine heavy calcium carbonate powder with the particle size distribution width less than or equal to 2.5 as a raw material; (2) Carrying out contact coating reaction on the raw material powder in a modification system at the temperature of 85-115 ℃ and a compound modifier added in an atomization mode, wherein the residence time of the reaction is 3-10 seconds, so as to obtain modified powder; (3) Collecting the modified powder to obtain a calcium carbonate product with an activation rate of more than 95% and an oil absorption value of less than or equal to 16.0g/100 g; wherein the silane coupling agent, the coupling lubricating dispersant and the stearic acid are sequentially or simultaneously but independently controllably added to the modifying system.
  2. 2. The method for preparing the narrow-distribution high-activation calcium carbonate for the organosilicon pouring sealant according to claim 1, wherein in the step (1), the particle size parameter of the superfine heavy calcium carbonate powder is satisfied that the median particle diameter D50 is 5.5+/-0.5 μm, and the 97% particle diameter D97 is 15.0+/-1.5 μm.
  3. 3. The preparation method of the narrow-distribution high-activation calcium carbonate for the organosilicon pouring sealant according to claim 1, wherein in the step (2), the silane coupling agent, the coupling lubricating dispersing agent and the stearic acid are sequentially added for coating according to the sequence of the silane coupling agent, the coupling lubricating dispersing agent and the stearic acid.
  4. 4. The method for preparing the narrow-distribution high-activation calcium carbonate for the organic silicon pouring sealant according to claim 1, wherein in the step (2), the total dosage of the compound modifier is 1.0-2.3% of the mass of the raw material powder.
  5. 5. The preparation method of the narrow-distribution high-activation calcium carbonate for the organosilicon pouring sealant according to claim 1, wherein in the step (2), the mass ratio of the silane coupling agent to the coupling lubricating dispersant to the stearic acid is (0.5-1.5): 0.2-0.8): 0.1-0.5.
  6. 6. The method for preparing the narrow-distribution high-activation calcium carbonate for the organic silicon pouring sealant according to claim 1, wherein in the step (2), the modification system is provided with a negative pressure self-stabilizing subsystem so as to maintain a stable negative pressure environment of a reaction area from-150 Pa to-750 Pa.
  7. 7. The method for preparing the narrow-distribution high-activation calcium carbonate for the organic silicon pouring sealant according to claim 1, wherein in the step (2), the silane coupling agent, the coupling lubricating dispersant and the stearic acid are atomized by independent atomizing devices adopting constant-temperature compressed air, and the temperature of the constant-temperature compressed air is 55-85 ℃.
  8. 8. The method for preparing the narrow-distribution high-activation calcium carbonate for the organic silicon pouring sealant according to claim 1, wherein the method further comprises a pretreatment step of carrying out high-temperature water removal on the raw material powder before the step (2) so as to enable the water content of the powder to be less than 0.2%.
  9. 9. The narrow-distribution high-activation calcium carbonate for the organosilicon pouring sealant is characterized in that the width of particle size distribution is less than or equal to 2.5, the activation rate is more than 95%, and the oil absorption value is less than or equal to 16.0g/100g.
  10. 10. A silicone potting adhesive comprising the narrow distribution high activation calcium carbonate of claim 9.

Description

Narrow-distribution high-activation calcium carbonate for organic silicon pouring sealant and preparation method thereof Technical Field The invention relates to the technical field of calcium carbonate preparation and organic silicon materials, in particular to narrow-distribution high-activation calcium carbonate for organic silicon pouring sealant and a preparation method thereof. Background The organic silicon pouring sealant is widely applied to the fields of electronic appliances, new energy sources, aerospace and the like by virtue of excellent high and low temperature resistance, insulativity, sealing property and chemical stability, is used for packaging and protecting electronic components, prevents water vapor, dust, impact and the like in the external environment from influencing the performance of the components, and ensures long-term stable operation of equipment. The filler is used as one of core components of the organic silicon pouring sealant, so that the production cost of the pouring sealant can be reduced, and key indexes such as mechanical property, heat conduction property and dimensional stability of the pouring sealant can be optimized, wherein calcium carbonate is one of the most widely applied inorganic fillers in the organic silicon pouring sealant due to the advantages of wide sources, low price, strong chemical inertness and the like. Along with the iteration of electronic components to high precision and high density, the organosilicon pouring sealant brings out the cooperative requirements of narrow particle size distribution, high activation rate and low oil absorption value for the calcium carbonate filler. The narrow distribution can avoid powder agglomeration, promote dispersion uniformity, strengthen interface binding force by high activation rate, exert reinforcing effect, optimize system viscosity by low oil absorption value, and give consideration to processability and solidification performance, which are core requirements of high-end pouring sealant. The prior preparation technology has obvious bottleneck, and is difficult to simultaneously meet the requirements. In the aspect of particle size control, the Span value of the product of the traditional crushing process is more than 2.5, the product is wide in distribution and contains large-particle impurities, so that the internal defects of pouring sealant are increased, the performance is attenuated, and the grading screening can optimize the particle size but restrict the industrialized application at the cost of raw material loss and efficiency reduction. The modification treatment is a core short plate, and the existing technology mostly adopts a single or simple compound modifier, the addition mode is extensive, and the problems of uneven coating and insufficient contact are easy to occur. The single silane coupling agent cannot achieve both dispersibility and hydrophobicity, the interface binding force is insufficient when stearic acid is modified, and the temperature and humidity and residence time controllability is poor under normal pressure environment. Part of the optimization schemes still have the limitations that the high-temperature modification is easy to volatilize the modifier, the mixed atomization is added to trigger mutual interference of the modifier, an ordered coating structure cannot be formed, the water content of the raw materials is not controlled enough, and the coating stability can be damaged due to the hydrolysis of the water and the silane coupling agent. Meanwhile, the existing product has single function, is difficult to have both reinforcing and heat conducting properties, and cannot be matched with high-end scene requirements of new energy automobiles, photovoltaic inverters and the like. In conclusion, the short plates in the prior art are used for precisely controlling granularity, optimizing modification process and cooperatively improving performance, so that the expansion of the organosilicon pouring sealant to the high-end field is restricted. The research and development of the calcium carbonate preparation technology with simple process and strong controllability can synchronously realize narrow distribution, high activation, low oil absorption and multifunctional synergy, and has important practical significance for promoting the technical upgrade of the industry. Disclosure of Invention Aiming at the defects, the invention provides the narrow-distribution high-activation calcium carbonate for the organic silicon pouring sealant and the preparation method thereof, which solve the problems of wide granularity, poor coating and substandard performance in the prior art by independently controllable atomization compound modifier and stable negative pressure temperature control process. In order to achieve the technical purpose, the invention adopts the following technical scheme: the preparation method of the narrow-distribution high-activation calcium carbonate for the orga