Anti-hardening reversible drying agent as well as preparation method and application thereof

Abstract

The invention provides an anti-hardening reversible drying agent as well as a preparation method and application thereof. The reversible desiccant comprises an inorganic desiccant A, an inorganic desiccant B, an organic desiccant, an anti-hardening agent and the like which are uniformly mixed. Wherein the inorganic drying agent A comprises alkali metal salt and / or alkaline earth metal salt, and the inorganic drying agent B comprises alkali metal oxide and / or alkaline earth metal oxide. The water absorption rate of the reversible drying agent in a 40 DEG C / 90% RH environment within 72 h exceeds 180%, the moisture liberation rate of the reversible drying agent in a 40 DEG C / 60% RH environment within 72 h exceeds 80%, the performance of the reversible drying agent cannot be remarkably reduced after multiple times of moisture absorption and liberation circulation, and therefore the reversible drying agent can be repeatedly used for a long time.

Description

Technical Field

[0001] The present application relates to a desiccant, and in particular to an anti-caking reversible desiccant and a preparation method and application thereof. Background Art

[0002] Desiccant can absorb moisture in the air and reduce the humidity of the environment. Therefore, it is widely used in the fields of automobiles, electronic equipment, food storage, etc. In the automotive field, desiccant is usually used to prevent the fogging of car lights.

[0003] The fogging of headlights is a natural physical phenomenon. The reason is that after the headlights are turned on, the internal temperature will gradually rise. If the humidity inside the lamp is relatively high at this time, the water inside the lamp will be evaporated by the high temperature to form water vapor. During the natural convection process, water vapor will condense and adhere to the inner surface of the lampshade when it encounters areas such as the corners of the lampshade where the temperature inside the headlight is relatively low, forming a large number of small water droplets visible to the naked eye, thereby causing the headlights to fog. The three important factors that cause the headlights to fog include: temperature field, flow field, and humidity field. Placing a desiccant in the headlights is one of the measures commonly taken. The moisture absorption rate of desiccant is generally high, and it can absorb the water vapor in the headlights and keep the headlights dry. However, conventional desiccant is easy to harden, form free water, has poor reversibility, and has a short timeliness. Summary of the invention

[0004] The main purpose of the present application is to provide a reversible desiccant with anti-caking properties and a preparation method and application thereof, so as to overcome the deficiencies in the prior art.

[0005] In order to achieve the above-mentioned invention objectives, this application adopts the following technical solutions.

[0006] The first aspect of the present application provides a reversible desiccant for resisting caking, which comprises the following components calculated in parts by mass: 100 parts of inorganic desiccant A, 10 to 60 parts of inorganic desiccant B, 10 to 20 parts of organic desiccant and 1 to 5 parts of anti-caking agent; the inorganic desiccant A comprises an alkali metal salt and / or an alkaline earth metal salt, and the inorganic desiccant B comprises an alkali metal oxide and / or an alkaline earth metal oxide.

[0007] In one embodiment, the reversible desiccant is formed by uniformly mixing an inorganic desiccant A, an inorganic desiccant B, an organic desiccant and an anti-caking agent.

[0008] In one embodiment, under the conditions of an ambient temperature of 25°C and an ambient humidity of 90%RH, the moisture absorption rate of the inorganic desiccant A is 5 to 20 times that of the organic desiccant, and the moisture absorption rate of the inorganic desiccant B is 2 to 4 times that of the organic desiccant. By using inorganic desiccant A, inorganic desiccant B and organic desiccant with the above-mentioned difference in moisture absorption rate, the reversible desiccant can better balance the moisture absorption and release rate and capacity.

[0009] In one embodiment, the inorganic desiccant A, inorganic desiccant B, organic desiccant and anti-caking agent are all powders, and the particle size of the inorganic desiccant A and inorganic desiccant B is 5 to 50 times the particle size of the anti-caking agent. It should be noted that the inorganic desiccant A and inorganic desiccant B in the reversible desiccant are both ground and processed.

[0010] In one embodiment, the anti-caking agent has a particle size of 0.5 μm to 5 μm.

[0011] In one embodiment, the powder particles of at least one of the inorganic desiccant A and the inorganic desiccant B are combined with powder particles of an anti-caking agent on their surface.

[0012] Preferably, the powder particles of the inorganic desiccant A and the inorganic desiccant B are uniformly bonded with powder particles of the anti-caking agent.

[0013] In some cases, the organic desiccant is also uniformly combined with the anti-caking agent.

[0014] In one embodiment, the particle size of the organic desiccant is 50-500 μm.

[0015] In one embodiment, the inorganic desiccant A includes one or more of sodium sulfate, sodium carbonate, sodium silicate, magnesium chloride, magnesium sulfate, magnesium carbonate, calcium chloride, calcium sulfate or calcium silicate, and is not limited thereto.

[0016] Preferably, the inorganic desiccant A contains at least one alkali metal salt and at least one alkaline earth metal salt. By utilizing the compounding effect of the alkali metal salt and the alkaline earth metal salt, the moisture absorption capacity of the desiccant A can be increased while keeping the usage amount unchanged.

[0017] In one embodiment, the inorganic desiccant B includes one or more of lithium oxide, potassium oxide, sodium oxide, magnesium oxide or calcium oxide, but is not limited thereto.

[0018] Preferably, the inorganic desiccant B contains at least one alkali metal oxide and at least one alkaline earth metal oxide. The moisture absorption rate of the desiccant B can be effectively improved by utilizing the compounding effect of these two types of metal oxides.

[0019] Surprisingly, when the inorganic desiccant A contains both alkali metal salts and alkaline earth metal salts, and the inorganic desiccant B contains both alkali metal oxides and alkaline earth metal oxides, the reversible desiccant not only has a significant improvement in moisture absorption capacity and moisture absorption rate, but also has a significantly improved surface hardening condition after long-term use.

[0020] In one embodiment, the organic desiccant includes one or more of polyethylene glycol with a Mw of 1000 to 10000, polyvinyl alcohol with a Mw of 20000 to 220000, polyvinyl pyrrolidone with a Mw of 8000 to 100000, sodium polyacrylate with a Mw of 1000000 to 5000000, or polyacrylamide with a Mw of 1000000 to 5000000, and is not limited thereto.

[0021] In one embodiment, the anti-caking agent includes a combination of one or more of potassium ferrocyanide, ammonium ferric citrate or silicon dioxide, but is not limited thereto.

[0022] In a more preferred embodiment, the reversible desiccant simultaneously comprises alkali metal salts, alkaline earth metal salts, alkali metal oxides, alkaline earth metal oxides, organic desiccant and anti-caking agent, which has better moisture release performance and cyclic regeneration performance.

[0023] The reversible desiccant of the present application adopts an inorganic desiccant as the main hygroscopic component, wherein the alkali (alkaline earth) metal oxide has the characteristic of rapid hygroscopicity, and the alkali (alkaline earth) metal salt has the characteristic of large hygroscopicity. The two can synergistically improve the migration of water vapor inside the desiccant, while improving the hygroscopicity speed and hygroscopicity, thereby achieving rapid hygroscopicity. At the same time, by adding an organic desiccant, the hygroscopicity rate of the desiccant can be adjusted, and the free water inside can be absorbed, thereby preventing the supersaturated hygroscopicity phenomenon caused by the excessively fast water absorption rate of the inorganic desiccant, and eliminating the bulging problem caused by the retention of a large amount of free water in the desiccant package. The added anti-caking agent, especially the ultra-fine anti-caking agent powder, can adhere to the surface of the desiccant due to its strong adsorption capacity, and can effectively reduce the contact area between the inorganic desiccant particles. At the same time, its surface carries charge distribution, which can increase the repulsive force between the desiccant particles and prevent the desiccant particles from agglomerating, thereby forming a physical barrier between the desiccant particles, keeping the desiccant surface loose, and enhancing the fluidity of water vapor in the desiccant. It can also increase the desiccant loading per unit volume, ensure a reasonable gap, promote the absorption and discharge of water vapor, and significantly increase the moisture absorption and desorption of the desiccant. In addition, it can also disrupt the crystal structure growth of the desiccant after moisture absorption and inhibit the formation of large-particle crystals, thereby more effectively preventing the desiccant surface from caking and improving the overall moisture absorption and desorption effect of the desiccant and its cycle life.

[0024] The second aspect of the present application provides a method for preparing an anti-caking reversible desiccant, comprising:

[0025] Prepare raw materials according to the composition of the anti-caking reversible desiccant;

[0026] Evenly mix inorganic desiccant A, inorganic desiccant B, organic desiccant and anti-caking agent, and then dry at 80-100°C for 1-3 hours.

[0027] Preferably, the inorganic desiccant A, inorganic desiccant B, organic desiccant and anti-caking agent can be uniformly mixed, ground to 100-300 meshes, and then dried at 80-100° C. for 1-3 hours.

[0028] The third aspect of the present application provides a dry bag structure, which includes:

[0029] The packaging cavity formed by the waterproof and breathable composite membrane:

[0030] And, the anti-caking reversible desiccant is filled in the packaging cavity.

[0031] In one embodiment, the air permeability of the waterproof breathable composite membrane is 200-1200 mL / cm 2 / min.

[0032] In one embodiment, the waterproof breathable composite membrane comprises a breathable inner layer and a packaging outer layer which are sequentially arranged in a direction away from the packaging cavity.

[0033] Furthermore, the packaging outer layer includes an expanded polytetrafluoroethylene (ePTFE) film, but is not limited thereto.

[0034] Further, the breathable inner layer includes one or more combinations of polyethylene (PE) porous breathable film, polyurethane (PU) breathable film, polyolefin (PO) breathable film or non-woven fabric, but is not limited thereto.

[0035] In one embodiment, the breathable inner layer is heat-pressed and laminated with the packaging outer layer.

[0036] In the present application, the desiccant bag structure formed by the aforementioned waterproof and breathable composite film and the reversible desiccant can not only achieve excellent waterproof and breathable effects, but also have good sealing performance, which can effectively prevent the bag from breaking and ensure the reliability of the desiccant bag.

[0037] The fourth aspect of the present application provides a method for preparing the desiccant package structure, which comprises: filling a reversible desiccant with anti-caking properties into a packaging cavity formed by enclosing a waterproof and breathable composite film and heat-sealing the cavity, wherein the heat-sealing temperature is 150 to 250°C.

[0038] Compared with the prior art, this application has at least the following beneficial effects:

[0039] (1) The reversible desiccant provided by the above-mentioned formula design can effectively inhibit or eliminate the compaction and free water retention phenomena of the existing desiccant during the moisture absorption and desorption process, and the moisture absorption and desorption efficiency is significantly improved. The water absorption rate within 72 hours under a 40°C / 90%RH environment exceeds 180%, and the moisture release rate within 72 hours under a 40°C / 60%RH environment exceeds 80%. It can effectively reduce the occurrence of fog in the environment and accelerate the dissipation of fog in the environment. Moreover, the performance does not decrease significantly after repeated moisture absorption and desorption cycles, and can be reused for a long time.

[0040] (2) The preparation method of the reversible desiccant provided is simple, the raw material source is wide, the cost is low, and it is suitable for large-scale production and application.

[0041] (3) The provided desiccant bag structure is easy to manufacture and has high reliability, which can reduce or even eliminate the problem of desiccant powder leakage and can give full play to the moisture absorption and desorption performance of the reversible desiccant. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 This is a physical photo of the drying package product containing the anti-caking reversible desiccant prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0044] The technical solution of the present application is described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solution of the present application. The specific functional details disclosed herein should not be interpreted as being restrictive, but only as the basis for the claims and as a representative basis for teaching those skilled in the art to adopt the present application in different ways in any appropriate detailed embodiment.

[0045] Unless otherwise specified, the raw materials and reagents used in the specific implementation methods of this application are all commercially available.

[0046] Embodiment 1 A method for preparing a reversible desiccant with anti-caking properties comprises the following steps:

[0047] S1. Weigh 100 parts by mass of magnesium chloride (average particle size of about 1 mm), 50 parts by mass of magnesium oxide (average particle size of about 1 mm) and 5 parts by mass of potassium ferrocyanide (particle size of about 5 μm) and put them into a ball grinder, and grind them to a particle size of 250 mesh.

[0048] S2. Add 20 parts by mass of polyacrylamide (Mw of about 2,500,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 1 hour to obtain a reversible desiccant.

[0049] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 500 mL / cm 2 / min ePTFE / PE composite film is placed in a packaging bag (size: 5 cm×5 cm) and heat-sealed at 200°C. The resulting dry package product is as follows Figure 1 shown.

[0050] Comparative Example 1 The preparation method of a desiccant provided in this comparative example is basically the same as that of Example 1, except that potassium ferrocyanide is not added.

[0051] Comparative Example 2 The preparation method of a desiccant provided in this comparative example is basically the same as that of Example 1, except that magnesium oxide is not added.

[0052] Comparative Example 3 The preparation method of a desiccant provided in this comparative example is basically the same as that of Example 1, except that no magnesium chloride is added.

[0053] Comparative Example 4 The preparation method of a desiccant provided in this comparative example is basically the same as that of Example 1, except that no polyacrylamide is added.

[0054] Comparative Example 5 The preparation method of a desiccant provided in this comparative example is basically the same as that in Example 1, except that the particle size of the potassium ferrocyanide powder used therein is about 0.5 mm.

[0055] Embodiment 2 A method for preparing a reversible desiccant with anti-caking properties comprises the following steps:

[0056] S1. Weigh 100 parts by mass of calcium chloride (average particle size of about 0.5 mm), 60 parts by mass of calcium oxide (average particle size of about 2 mm) and 3 parts by mass of ammonium ferric citrate (average particle size of about 1 μm) and put them into a ball grinder, and grind them to a particle size of 100 mesh.

[0057] S2. Add 20 parts by mass of polyvinyl alcohol (Mw of about 50,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 2 hours to obtain a reversible desiccant.

[0058] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 1200 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 150°C.

[0059] Embodiment 3 A method for preparing a reversible desiccant with anti-caking properties comprises the following steps:

[0060] S1. Weigh 100 parts by mass of sodium silicate (average particle size of about 1.5 mm), 10 parts by mass of sodium oxide (average particle size of about 1.5 mm) and 5 parts by mass of silicon dioxide powder (average particle size of about 5 μm) and put them into a ball grinder, and grind them to a particle size of 100 mesh.

[0061] S2. Add 20 parts by mass of sodium polyacrylate (Mw of about 3,000,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 3 hours to obtain a reversible desiccant.

[0062] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 200 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 250°C.

[0063] Embodiment 4 A method for preparing a reversible desiccant with anti-caking properties comprises the following steps:

[0064] S1. Weigh 100 parts by mass of calcium sulfate (average particle size of about 0.5 mm), 20 parts by mass of lithium oxide (average particle size of about 1 mm) and 1 part by mass of potassium ferrocyanide (particle size of about 5 μm) and put them into a ball grinder, and grind them to a particle size of 300 mesh.

[0065] S2. Add 10 parts by mass of polyethylene glycol (Mw of about 8,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 100° C. for 1 hour to obtain a reversible desiccant.

[0066] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 800 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 200℃.

[0067] Example 5 A method for preparing an anti-caking reversible desiccant comprises the following steps:

[0068] S1. Weigh 100 parts by mass of magnesium carbonate (average particle size of about 2 mm), 30 parts by mass of calcium oxide (average particle size of about 2 mm) and 2 parts by mass of potassium ferrocyanide (particle size of about 5 μm) and put them into a ball grinder, and grind them to a particle size of 250 mesh.

[0069] S2. Add 15 parts by mass of polyvinyl pyrrolidone (Mw of about 100,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 2 hours to obtain a reversible desiccant.

[0070] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 500 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 150°C.

[0071] Example 6 A method for preparing an anti-caking reversible desiccant comprises the following steps:

[0072] S1, weigh 50 parts by mass of magnesium carbonate (average particle size of about 2 mm), 50 parts by mass of sodium carbonate (average particle size of about 1 mm), 30 parts by mass of calcium oxide (average particle size of about 2 mm) and 2 parts by mass of potassium ferrocyanide (average particle size of about 5 μ m), put them into a ball mill, and grind them to a particle size of 250 mesh.

[0073] S2. Add 15 parts by mass of polyvinyl pyrrolidone (Mw of about 100,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 2 hours to obtain a reversible desiccant.

[0074] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 500 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 150°C.

[0075] Example 7 A method for preparing an anti-caking reversible desiccant comprises the following steps:

[0076] S1, weigh 100 parts by mass of magnesium carbonate (average particle size of about 2 mm), 15 parts by mass of calcium oxide (average particle size of about 2 mm), 15 parts by mass of sodium oxide (average particle size of about 1.5 mm) and 2 parts by mass of potassium ferrocyanide (average particle size of about 5 μ m) and put them into a ball mill, and grind them to a particle size of 250 mesh.

[0077] S2. Add 15 parts by mass of polyvinyl pyrrolidone (Mw of about 100,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 2 hours to obtain a reversible desiccant.

[0078] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 500 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 150°C.

[0079] Example 8 A method for preparing an anti-caking reversible desiccant comprises the following steps:

[0080] S1. Weigh 50 parts by mass of magnesium carbonate (average particle size of about 2 mm), 50 parts by mass of sodium carbonate (average particle size of about 1 mm), 15 parts by mass of calcium oxide (average particle size of about 2 mm), 15 parts by mass of sodium oxide (average particle size of about 1.5 mm), and 2 parts by mass of potassium ferrocyanide (average particle size of about 5 μm), put them into a ball grinder, and grind them to a particle size of 250 mesh.

[0081] S2. Add 15 parts by mass of polyvinyl pyrrolidone (Mw of about 100,000) to the mixed powder obtained in step S1, disperse it evenly at high speed, and then treat it in an oven at 80° C. for 2 hours to obtain a reversible desiccant.

[0082] Furthermore, 10 g of the reversible desiccant can be weighed and placed in a container having an air permeability of 500 mL / cm 2 / min in a packaging bag (size 5cm×5cm) formed by an ePTFE / PE composite film and heat-sealed at 150°C.

[0083] Then, the following methods were used to test the various properties of the desiccant products obtained in Examples 1 to 8 and Comparative Examples 1 to 5. The test results are shown in Table 1.

[0084] Balanced moisture absorption and release performance: Place the samples of Examples 1 to 8 and Comparative Examples 1 to 5 in a constant temperature and humidity chamber at 40°C / 90%RH for 72 hours, and weigh and calculate the moisture absorption rate; Place the samples that have reached the saturated moisture absorption state in a constant humidity chamber at 40°C / 60%RH for 72 hours, and weigh and calculate the moisture release rate.

[0085] Short-term moisture absorption and desorption performance: The samples of Examples 1 to 8 and Comparative Examples 1 to 5 were placed in a constant temperature and humidity chamber at 40°C / 90%RH for 12 hours, and the moisture absorption rate was calculated by weighing; the samples that reached saturated moisture absorption were placed in a constant humidity chamber at 40°C / 60%RH for 12 hours, and the moisture release rate was calculated by weighing.

[0086] Cyclic moisture absorption and desorption performance: The samples of Examples 1 to 8 and Comparative Examples 1 to 5 were placed alternately in a 40°C / 90% RH moisture absorption environment and a 40°C / 60% RH desorption environment for 72 hours, and the cycle was repeated 10 times, each time for 72 hours. After that, the last moisture absorption and desorption ratio was calculated by weighing.

[0087] Hardening and free water inspection: Place the samples of Examples 1 to 8 and Comparative Examples 1 to 5 in a constant temperature and humidity chamber at 40°C / 90%RH for 72 hours, unpack them, and observe the hardening and free water formation.

[0088] Table 1 Test results of relevant properties of desiccants prepared in Examples 1 to 8 and Comparative Examples 1 to 5

[0089]

[0090]

[0091] Note: The units of moisture absorption rate and moisture release rate in Table 1 are %.

[0092] It should be noted that the data in the above table are the average values ​​of multiple test results of multiple batches of products.

[0093] As can be seen from the above table, the reversible desiccants of Examples 1 to 8 of the present invention do not form a hardening state, do not produce free water retention, and have a good moisture absorption and desorption effect. However, the desiccants of Comparative Examples 1 to 5 cannot simultaneously take into account the moisture absorption and desorption performance and the anti-hardening performance, and it is also difficult to prevent the generation of free water.

[0094] In addition, the applicant also referred to the above embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0095] In summary, the reversible desiccant of the present application can quickly absorb water vapor in a high humidity environment, reduce the internal humidity of the environment, and prevent the occurrence of condensation. At the same time, the reversible desiccant can release moisture to the external environment and has a long cycle life.

[0096] Although the present application has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made and that substantial equivalents may be substituted for the materials of the described embodiments without departing from the spirit and scope of the present application. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the present application without departing from the scope of the present application. Therefore, it is not intended herein to limit the present application to the disclosed specific embodiments for carrying out the present application, but rather it is intended that the present application will include all embodiments within the scope of the appended claims.

Claims

1. A reversible desiccant for resisting hardening, characterized in that: The invention comprises the following components calculated in parts by mass: 100 parts of inorganic desiccant A, 10 to 60 parts of inorganic desiccant B, 10 to 20 parts of organic desiccant and 1 to 5 parts of anti-caking agent; the inorganic desiccant A comprises alkali metal salt and / or alkaline earth metal salt, and the inorganic desiccant B comprises alkali metal oxide and / or alkaline earth metal oxide.

2. The anti-hardening reversible desiccant according to claim 1, characterized in that: The inorganic desiccant A, inorganic desiccant B, organic desiccant and anti-caking agent are all powders, and the particle size of the inorganic desiccant A and inorganic desiccant B is 5 to 50 times that of the anti-caking agent.

3. The anti-hardening reversible desiccant according to claim 2, characterized in that: The powder particles of at least one of the inorganic desiccant A and the inorganic desiccant B are combined with powder particles of an anti-caking agent on their surfaces.

4. The anti-hardening reversible desiccant according to claim 2, characterized in that: The particle size of the anti-caking agent is 0.5 μm to 5 μm.

5. The anti-caking reversible desiccant according to any one of claims 1 to 4, characterized in that: The inorganic desiccant A comprises a combination of one or more of sodium sulfate, sodium carbonate, sodium silicate, magnesium chloride, magnesium sulfate, magnesium carbonate, calcium chloride, calcium sulfate or calcium silicate; And / or, the inorganic desiccant B comprises a combination of one or more of lithium oxide, potassium oxide, sodium oxide, magnesium oxide or calcium oxide; And / or, the organic desiccant comprises a combination of one or more of polyethylene glycol with a Mw of 1000 to 10000, polyvinyl alcohol with a Mw of 20000 to 220000, polyvinyl pyrrolidone with a Mw of 8000 to 100000, sodium polyacrylate with a Mw of 1000000 to 5000000, or polyacrylamide with a Mw of 1000000 to 5000000; And / or, the anti-caking agent includes a combination of one or more of potassium ferrocyanide, ammonium ferric citrate or silicon dioxide.

6. A method for preparing an anti-caking reversible desiccant, characterized in that: include: The raw materials are prepared according to the composition of the anti-hardening reversible desiccant according to any one of claims 1 to 5; The inorganic desiccant A, inorganic desiccant B, organic desiccant and anti-caking agent are uniformly mixed, then ground to 100-300 mesh, and then dried at 80-100°C for 1-3 hours.

7. A drying bag structure, characterized in that: include: A packaging cavity formed by enclosing a waterproof and breathable composite membrane; And, the anti-caking reversible desiccant according to any one of claims 1 to 5, wherein the reversible desiccant is filled in the packaging cavity.

8. The drying bag structure according to claim 7, characterized in that: The air permeability of the waterproof and breathable composite membrane is 200-1200 mL / cm 2 / min; and / or, the waterproof breathable composite membrane comprises a breathable inner layer and a packaging outer layer arranged in sequence along a direction away from the packaging cavity, the packaging outer layer comprises an expanded polytetrafluoroethylene membrane, and the breathable inner layer comprises a polyethylene porous breathable membrane, a polyurethane breathable membrane, a polyolefin breathable membrane or a combination of one or more of non-woven fabrics.

9. The drying bag structure according to claim 8, characterized in that: The air-permeable inner layer and the packaging outer layer are composited by heat pressing.

10. A method for preparing the drying bag structure according to any one of claims 7 to 9, characterized in that: include: The anti-caking reversible desiccant is filled in a packaging cavity formed by enclosing a waterproof and breathable composite film and heat-sealed at a heat-sealing temperature of 150-250°C.

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