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CN-122006675-A - Sheet-shaped drying agent and preparation method thereof

CN122006675ACN 122006675 ACN122006675 ACN 122006675ACN-122006675-A

Abstract

The application belongs to the technical field of drying agents, and discloses a flaky drying agent and a preparation method thereof, wherein the preparation method comprises the following steps of mixing anhydrous magnesium chloride, a gel compound and a tabletting auxiliary agent to obtain a surface material; the preparation method comprises the steps of mixing anhydrous magnesium chloride, metal oxide and a disintegrating agent to obtain an inner material, dividing the surface material into a lower surface material and an upper surface material, adding the lower surface material, the middle inner material and the upper surface material into a die in sequence, and tabletting to obtain the sheet-shaped drying agent. The flaky drying agent prepared by the method can effectively avoid the problem of over-fast surface saturation under the high-humidity condition, and improves the moisture absorption rate.

Inventors

  • ZHAO YONG
  • WANG JIANPING
  • WANG HONGYI
  • LIU JING
  • ZENG JIAO

Assignees

  • 深圳市春旺新材料股份有限公司
  • 广东春旺新材料有限公司

Dates

Publication Date
20260512
Application Date
20260407

Claims (8)

  1. 1. A method of preparing a sheet desiccant, the method comprising the steps of: S1, mixing anhydrous magnesium chloride, a gel compound and a tabletting auxiliary agent to obtain a surface material; S2, mixing anhydrous magnesium chloride, metal oxide and a disintegrating agent to obtain an inner material; S3, dividing the surface material into a lower surface material and an upper surface material, then adding the lower surface material, the middle inner material and the upper surface material into a die in sequence, and tabletting to obtain the sheet-shaped drying agent.
  2. 2. The method of claim 1, wherein step S1 comprises: S1.1, adding anhydrous magnesium chloride into anhydrous lower alcohol in an inert atmosphere, adding the anhydrous magnesium chloride into the anhydrous lower alcohol at 60-70 ℃, stirring and reacting for 2-3 hours, and cooling to 20-30 ℃ to obtain an alcoholic magnesium chloride suspension, wherein the mass ratio of the anhydrous magnesium chloride to the anhydrous lower alcohol is (6-10); S1.2, adding a gel compound and an ammonia compound into an alcoholate magnesium chloride suspension, and stirring and reacting for 1-2 hours at a temperature of 30-40 ℃ to obtain mixed slurry, wherein the mass ratio of anhydrous magnesium chloride to gel compound to ammonia compound is (20-45): (10-30): (5-15), and the particle size D90 of the ammonia compound is less than or equal to 10 mu m; S1.3, performing reduced pressure distillation on the mixed slurry at-0.05 to-0.02 MPa and at 30-40 ℃ until the anhydrous lower alcohol content reaches 85-90% of the initial content to obtain a pretreated paste, and then drying the pretreated paste to constant weight under the vacuum condition of 30-40 ℃ and 0.01-0.03 MPa, and crushing to obtain composite powder; S1.4, adding the composite powder, the tabletting auxiliary agent and the release agent into a stirrer, and mixing for 40-50 min at 20-30 rpm to obtain a surface material, wherein the mass ratio of anhydrous magnesium chloride to the tabletting auxiliary agent to the release agent is (20-45): (10-35): (0-2.5).
  3. 3. The method for preparing a sheet-like desiccant according to claim 2, wherein the anhydrous lower alcohol comprises at least one of methanol, ethanol, propanol, and isopropanol, the gel compound comprises at least one of carboxyethyl cellulose, sodium carboxymethyl cellulose, and guar gum, the ammonia compound is ammonium bicarbonate and/or ammonium carbonate, the tabletting auxiliary comprises at least one of nano silica, microcrystalline cellulose, and mannitol, and the release agent comprises at least one of sodium stearate, magnesium stearate, and polyethylene glycol.
  4. 4. The method of claim 1, wherein step S2 comprises: S2.1, adding anhydrous magnesium chloride, metal oxide and a disintegrating agent into a stirrer, and mixing for 15-25min at 20-30 rpm to obtain a mixed material, wherein the mass ratio of the anhydrous magnesium chloride to the metal oxide to the disintegrating agent is (10-30) (0-10); S2.2, adding an ammonia reactant and a release agent into the pre-mixed material, and continuously mixing for 5-15 min to obtain an inner material, wherein the mass ratio of anhydrous magnesium chloride to the ammonia reactant to the release agent is (10-30): 3-10): 0-2.5.
  5. 5. The method for preparing a sheet-like desiccant according to any one of claims 1 or 4, wherein the metal oxide comprises at least one of light burned magnesium oxide, activated zinc oxide, and activated calcium oxide, the disintegrant is magnesium aluminum silicate and/or povidone K30, the ammonia reactant comprises at least one of polyacrylic acid, aluminum sulfate, and calcium chloride, and the release agent comprises at least one of sodium stearate, magnesium stearate, and polyethylene glycol.
  6. 6. The method of claim 1, wherein step S3 comprises: S3.1, dividing the surface material into a lower surface material and an upper surface material, then adding the lower surface material, a middle inner material and the upper surface material into a mold in sequence, and heating at 80-90 ℃ for 1-3 hours to obtain a heat treated material, wherein the mass ratio of anhydrous magnesium chloride in the surface material to anhydrous magnesium chloride in the inner material is (20-45): (10-30), and the mass of the lower surface material is the same as that of the upper surface material; S3.2, tabletting the heat-treated material, wherein the tabletting pressure is 5-15 kN/cm 2 , and the flaky drying agent is obtained.
  7. 7. A sheet-shaped desiccant, characterized in that the sheet-shaped desiccant is produced by a method for producing a sheet-shaped desiccant according to any one of claims 1 to 6; The tablet drying comprises, by mass, 30-75 parts of anhydrous magnesium chloride, 10-30 parts of metal oxide, 10-30 parts of gel compound, 1-10 parts of disintegrating agent, 10-35 parts of tabletting auxiliary agent and 1-5 parts of release agent.
  8. 8. The sheet desiccant of claim 7, further comprising 3-10 parts of an ammonia reactant.

Description

Sheet-shaped drying agent and preparation method thereof Technical Field The application relates to the technical field of drying agents, in particular to a flaky drying agent and a preparation method thereof. Background The magnesium chloride desiccant is a high-efficiency dampproof product based on the chemical moisture absorption principle, the anhydrous magnesium chloride as a core component absorbs moisture to form a surface solution through deliquescence, and further generates irreversible hydration reaction with water to generate a crystalline compound, and the process not only endows the magnesium chloride with extremely strong moisture absorption capability (especially in a low-temperature high-humidity environment), but also causes the magnesium chloride to gradually change from particles into solution and finally harden and agglomerate, thus visually displaying the moisture absorption saturation state. The desiccant is widely used in a plurality of fields because of the easy availability of raw materials, low cost, large moisture absorption capacity and good safety. The traditional powder or granule magnesium chloride desiccant has the core advantages of high moisture absorption starting speed, high moisture absorption efficiency and large moisture absorption capacity per unit weight because of the extremely large specific surface area and the capability of fully contacting with air. The characteristic makes the material especially suitable for the industrial situations of storage packaging of precise electronic components, mildew prevention of optical instruments, rust prevention among metal product procedures, damp prevention in shipping containers and the like, which have strict requirements on humidity control. In these places, the powder can quickly reduce the humidity inside the package and maintain the dry state for a long time, thereby effectively protecting the product quality. However, in some specific small, closed or precise spaces, such as small packages of medicines, inside small electronic products (such as sensor modules), high-grade camera lens barrels, precise instrument pods, etc., the powder form has the problems of easy dust emission, inconvenient filling, possible leakage and pollution of sensitive elements, etc. In order to meet the strict requirements of the scenes on the convenience, the cleanliness and the quantitative delivery of the magnesium chloride desiccant, the magnesium chloride desiccant is prepared into a tablet form in the industry. The tablet is easy to take and fix, and can better meet the miniaturized and integrated packaging requirement. However, the tablet form also brings about significant performance drawbacks, wherein the most prominent is the crusting phenomenon, namely that the surface magnesium chloride is saturated too fast in the moisture absorption process of the tablet, especially in a high-humidity environment, so that the surface is subjected to moisture absorption, and the phenomenon of internal drying occurs, so that the overall moisture absorption rate of the drying agent is greatly reduced, and the effective protection period of the drying agent is shortened. Disclosure of Invention The invention aims to solve the technical problem that the moisture absorption rate of a flaky magnesium chloride drying agent is reduced due to over-high surface saturation in a high-humidity environment. In order to solve the technical problems, the invention provides a preparation method of a sheet-shaped drying agent, which comprises the following steps: S1, mixing anhydrous magnesium chloride, a gel compound and a tabletting auxiliary agent to obtain a surface material; S2, mixing anhydrous magnesium chloride, metal oxide and a disintegrating agent to obtain an inner material; S3, dividing the surface material into a lower surface material and an upper surface material, then adding the lower surface material, the middle inner material and the upper surface material into a die in sequence, and tabletting to obtain the sheet-shaped drying agent. In some embodiments, step S1 comprises: S1.1, adding anhydrous magnesium chloride into anhydrous lower alcohol in an inert atmosphere, adding the anhydrous magnesium chloride into the anhydrous lower alcohol at 60-70 ℃, stirring and reacting for 2-3 hours, and cooling to 20-30 ℃ to obtain an alcoholic magnesium chloride suspension, wherein the mass ratio of the anhydrous magnesium chloride to the anhydrous lower alcohol is (6-10); S1.2, adding a gel compound and an ammonia compound into an alcoholate magnesium chloride suspension, and stirring and reacting for 1-2 hours at a temperature of 30-40 ℃ to obtain mixed slurry, wherein the mass ratio of anhydrous magnesium chloride to gel compound to ammonia compound is (20-45): (10-30): (5-15), and the particle size D90 of the ammonia compound is less than or equal to 10 mu m; S1.3, performing reduced pressure distillation on the mixed slurry at-0.05 to-0.02 MPa and at 30-