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CN-121992686-A - Preparation method of all-inorganic alumina fiber/aerogel composite thermal insulation paper

CN121992686ACN 121992686 ACN121992686 ACN 121992686ACN-121992686-A

Abstract

The invention discloses a preparation method of an all-inorganic alumina fiber/aerogel composite heat insulation paper, which comprises the following steps that an alumina fiber net tire is subjected to inorganic glue and anilox roller reinforcement pretreatment to obtain alumina fiber base paper; preparing silica sol and alkali catalytic liquid, mixing the silica sol and the alkali catalytic liquid, compounding with alumina fiber base paper, performing solvent replacement and aging treatment on the obtained alumina fiber base/wet gel paper, and drying the aged alumina fiber base/wet gel paper to obtain the alumina fiber base/wet gel paper. The alumina fiber/aerogel composite thermal insulation paper prepared by the method has the advantages of good mechanical strength, adjustable hardness, excellent thermal insulation performance, high temperature resistance of over 900 ℃ and low firing reduction rate, and meets the application scene requirements of thermal insulation material cladding, ring punching and the like in a high-temperature closed environment.

Inventors

  • YAO HUA
  • ZHAO TIANJUN
  • LI HAIYANG
  • SHEN HUIYING
  • SUN QIZHONG
  • HU XIAODONG

Assignees

  • 浙江鹏辰新材料科技有限公司
  • 浙江鹏辰造纸研究所有限公司

Dates

Publication Date
20260508
Application Date
20260410

Claims (9)

  1. 1. The preparation method of the all-inorganic alumina fiber/aerogel composite thermal insulation paper is characterized by comprising the following steps of: s1, fully soaking an alumina fiber net tire with alumina gel, extruding by an anilox roller, discharging excessive alumina gel, physically reinforcing the net tire, and drying to obtain alumina inorganic gel and anilox roller reinforced alumina fiber base paper; s2, dispersing a silicon source in a solvent, adding water and an acid catalyst, uniformly stirring, and heating for hydrolysis reaction to obtain silica sol; S3, mixing the silica sol with the alkali catalytic liquid, spraying the mixed liquid onto the alumina fiber base paper obtained in the step S1, fully penetrating the mixed liquid into the alumina fiber base paper, heating the sprayed alumina fiber base paper, and obtaining the alumina fiber base/wet gel paper after the silica sol is gelled; s4, soaking the alumina fiber-based/wet gel paper with ethanol solution, heating, performing solvent replacement to obtain aged alumina fiber-based/wet gel paper, and finally performing supercritical drying to obtain the full inorganic alumina fiber/aerogel composite thermal insulation paper.
  2. 2. The method for preparing the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S1, an alumina fiber net tire is prepared by combining blowing and electrostatic spinning, the gram weight is 30-400 g/m 2 , the alumina gel concentration is 3-20 wt%, the mesh number of an anilox roller is 10-300 meshes, the extrusion pressure is 0.1-0.5 MPa, and the extrusion line speed is 1-20 m/min.
  3. 3. The preparation method of the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S2, the silicon source comprises any one or more than two of methyl orthosilicate, ethyl orthosilicate, tetraethyl orthosilicate, phenyl trimethoxy silane, dimethyl dimethoxy silane, dimethyl diethoxy silane and water-soluble silica gel, the solvent comprises any one or more than two of methanol, ethanol, acetone, tetrahydrofuran, dimethylformamide, pyrrolidone and dimethyl sulfoxide, and the mass ratio of the silicon source to the solvent is 1:0.5-5.
  4. 4. The preparation method of the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S2, the acid catalyst is any one or more than two of sulfuric acid, hydrochloric acid, nitric acid, 85% phosphoric acid, boric acid and acetic acid, the mass ratio of a silicon source to the acid catalyst is 1:0.0005-0.05, and the mass ratio of the silicon source to water is 1:0.05-2 in the process of preparing the silica sol in the step S2; The alkali catalyst is any one or the combination of more than two of sodium bicarbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, calcium hydroxide and ammonia water, and the concentration of the alkali catalyst solution is 0.01-1wt%.
  5. 5. The method for preparing the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S2, the temperature of the heating hydrolysis reaction is 40-60 ℃, and the hydrolysis reaction time is 2-3 h.
  6. 6. The preparation method of the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S3, the mixing volume ratio of the silica sol to the alkali catalytic liquid is 1:0.1-10, the spraying flow of the mixed liquid is 1-200L/h, and the sprayed base paper is heated for 1-30min at 40-60 ℃.
  7. 7. The method for preparing the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S4, the alumina fiber/wet gel paper is subjected to repeated soaking and heating by the ethanol solution to perform solvent replacement, the number of times of solvent replacement is 3-6 times, the concentration of the ethanol solution at the later time is greater than or equal to the concentration of the ethanol solution at the previous time, the concentration of the ethanol solution at the first time is 50-95wt%, the concentration of the ethanol solution at each time in the middle is 80-99wt%, and the concentration of the ethanol solution at the last time is 98-100wt%.
  8. 8. The method for preparing the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein in the step S4, the solvent replacement temperature is 40-60 ℃ and the time is 6-12 h.
  9. 9. The method for preparing the all-inorganic alumina fiber/aerogel composite thermal insulation paper according to claim 1, wherein the supercritical drying temperature is 250-300 ℃, the pressure is 7-10 MPa, and the heat preservation and pressure maintaining time is 1-10h.

Description

Preparation method of all-inorganic alumina fiber/aerogel composite thermal insulation paper Technical Field The invention belongs to the technical field of nanometer heat insulation materials, and particularly relates to a preparation method of an all-inorganic alumina fiber/aerogel composite heat insulation paper. Background The aerogel material is a new material with high specific surface area, nanoscale holes, low density and other special microstructures, and based on the special microstructures, the aerogel material has excellent heat insulation performance, in addition, the special microstructures also cause poor mechanical strength, so that the aerogel material is usually compounded with various fiber substrates for realizing practical application, and the mechanical strength of the aerogel is increased while the excellent heat insulation performance of the aerogel is maintained. The thermal battery is a high-efficiency stable reserve chemical power supply used on spaceflight vehicles and missiles, has the advantages of high energy density, high stability, sensitive reaction, small volume, light weight and the like, and the working principle is that the thermal battery is activated by heat at one time, inorganic molten salt is used as electrolyte, electrochemical reaction is carried out for a certain period of time to continuously provide electric energy, in the discharging process, the solidification of the electrolyte means the end of the service life of the thermal battery, and the heat insulation material can effectively slow down the temperature drop of the electrolyte, prolong the time of the molten state of the thermal battery and avoid the influence of the external temperature on the thermal battery. Therefore, the performance of the heat insulation material directly determines the discharge performance and the service life of the thermal battery, and is a key composition material of the thermal battery. The prior aerogel heat insulation and preservation material such as ZL200910154313.1 used in the thermal battery discloses a preparation method of a silica aerogel composite heat insulation sleeve taking glass fiber as a base material, the aerogel takes the glass fiber as the base material, the highest use temperature is 600 ℃, and along with the service life extension of a novel thermal battery, the high temperature resistance of the traditional silica aerogel composite heat insulation material taking the glass fiber as the base material can not meet the requirements. The existing fiber base materials resistant to the high temperature of more than 900 ℃ such as quartz glass fibers, alumina fibers, mullite fibers and carbon fibers can be used only by reinforcing the fiber base materials with organic glue. The thermal battery is internally of a closed structure, and the heat insulation material cannot generate gas at high temperature, and the burning reduction rate is required to be less than 3.5%, so that no fiber base material capable of being directly used at the high temperature of over 900 ℃ exists on the market at present. On the other hand, the heat insulating material used in the thermal battery is limited by the volume of the battery, the thickness is generally less than 1mm, a punching ring is sometimes required, and winding and coating are sometimes required, so that the heat insulating material is required to have good mechanical strength and adjustable hardness. Disclosure of Invention The invention aims to provide a preparation method of an all-inorganic alumina fiber/aerogel composite heat insulation paper, and the heat insulation material which has good mechanical strength, adjustable softness and hardness, excellent heat insulation performance, high temperature resistance of more than 900 ℃ and low burning reduction rate is prepared by the method, so as to meet the requirements of application scenes such as winding, coating, ring punching and the like of novel thermal batteries and other heat insulation materials in high-temperature closed environments. The technical scheme adopted by the invention for achieving the purpose is as follows: the preparation method of the all-inorganic alumina fiber/aerogel composite thermal insulation paper comprises the following steps: (1) And (3) carrying out inorganic glue/anilox roller reinforcement pretreatment on the alumina fiber net tyre, namely soaking the alumina fiber net tyre in alumina glue with a certain concentration, extruding the alumina fiber net tyre through an anilox roller, discharging excessive alumina glue and physically reinforcing the alumina fiber net tyre, and then putting the alumina fiber net tyre into an oven for drying and removing excessive moisture to obtain the alumina fiber base paper reinforced by the alumina inorganic glue and the anilox roller. (2) The preparation of silica sol and alkali catalyst liquid includes dispersing silicon source in certain amount of solvent, adding water and acid catalyst, stirrin