CN112958044A

CN112958044A - Preparation method of drying agent and drying agent

Info

Publication number: CN112958044A
Application number: CN202110147324.8A
Authority: CN
Inventors: 张欣; 张红军
Original assignee: Hangzhou Jiashuang Packaging Materials Co ltd
Current assignee: Hangzhou Jiashuang Packaging Materials Co ltd
Priority date: 2021-02-03
Filing date: 2021-02-03
Publication date: 2021-06-15

Abstract

The invention discloses a preparation method of a drying agent and the drying agent, which is mainly composed of super absorbent resin, magnesium chloride and/or a stabilizing agent, and the components are as follows: 10-90 parts of super absorbent resin, 5-90 parts of anhydrous magnesium chloride containing high content of magnesium chloride and/or magnesium chloride containing N crystal water and/or calcium chloride, and/or 0.1-5.0 parts of stabilizer, which are obtained by stirring and mixing; the prepared drying agent has excellent moisture absorption capacity, is a colloid which is not easy to flow after absorbing moisture, has small volume increase change, is environment-friendly and nontoxic, has good stability and is convenient to prepare; the drying agent is very good in universality, and is particularly suitable for the security industry which is limited in space and needs high moisture absorption capacity and prevents the fogging of the camera lens.

Description

Preparation method of drying agent and drying agent

Technical Field

The invention relates to a preparation method of a drying agent and the drying agent.

Background

The desiccant is produced in order to avoid the occurrence of defective products due to excessive moisture. The types of the desiccant are classified into physical adsorption desiccant and chemical adsorption desiccant according to their drying principle. The physical adsorption drying agent comprises silica gel, alumina, molecular sieve, charcoal, mineral drying agent, activated clay and the like, and the drying principle is that water molecules are adsorbed in the self structure through a physical mode. The desiccant is used for adsorbing moisture in the bagged articles, the articles are kept relatively dry for a long time, and the moisture conditions of microbial survival, chemical reaction, photolysis reaction and enzymatic reaction are regulated and controlled, so that the aims of preventing moisture, mildew, insect and rust, resisting oxidation and prolonging the product retention period are fulfilled, and the effective measure is generally applied to scientific research, production and daily life; the chemisorption drying agent is exemplified by calcium oxide (also called quicklime), and the water absorption capacity of the chemisorption drying agent is realized by combining with water to generate stable calcium hydroxide, and the water absorption of the chemisorption drying agent is irreversible. The moisture absorption capacity can be kept better regardless of the humidity of the external environment.

Most of the traditional desiccants are made of a single raw material, and are mainly made of silica gel, quicklime, calcium chloride and the like. The moisture absorption rate of the silica gel is low; the quicklime desiccant is pulverized after moisture absorption and has corrosiveness on oropharynx and esophagus; the anhydrous calcium chloride desiccant has high moisture absorption rate, but is easy to cause liquid seepage and the like. The use of a single raw material to make a desiccant is therefore limited.

Researchers have studied many new composite drying agents in recent years, but basically adopt a mixture of super absorbent resin, starch, plant polysaccharides, quicklime, silica gel and calcium chloride as main materials, for example, chinese patent application No. CN 109248664 a discloses a powder drying agent which is prepared by using super absorbent resin, easily-soluble salt plant polysaccharides and inorganic thickening agent as raw materials in a certain weight ratio. The desiccant is not easy to absorb moisture and liquefy, and is suitable for various humidity environments. The defect of the patent is that the desiccant used in the technology adopts the principle of physical adsorption to absorb water, so that the water absorption capacity is limited, and the absorbed water can be released when the environmental humidity is low, thereby affecting the drying effect. Meanwhile, the Chinese patent application No. CN 108927115A discloses a military mildew-proof oxidation-resistant high moisture absorption type drying agent and a preparation method thereof, wherein the drying agent comprises the following components in parts by weight: 20-30 parts of montmorillonite; 20-30 parts of attapulgite; 5-10 parts of microsphere silica gel; 3-5 parts of lemon peel powder; 0.5-1 part of chitosan; 5-8 parts of shaddock peel powder; 10-15 parts of calcium chloride; 5-8 parts of sodium carboxymethylcellulose; the desiccant of the invention has the defects that although microspherical silica gel, montmorillonite, attapulgite, chitosan and sodium carboxymethylcellulose are used as physical adsorption raw materials and calcium chloride is used as chemical adsorption raw materials in a mixing way, the water absorption capacity is not very strong due to the combination of the calcium chloride and two crystal waters, and the preparation process is complex and is not suitable for large-scale production and popularization.

Disclosure of Invention

The invention aims to solve the technical problem of providing a high-moisture-absorption colloid which has excellent moisture absorption capacity, is a colloid which is not easy to flow after moisture absorption, has small volume increase and change, is environment-friendly and nontoxic, has good stability and is convenient to manufacture; is particularly suitable for the security industry with limited space for placing a desiccant and requiring a desiccant with high moisture absorption capacity to prevent the fogging of the camera lens, is a very good universal desiccant,

the technical scheme provided by the invention is as follows:

the drying agent is prepared from the following raw materials in parts by weight: 10-90% of super absorbent resin, 5-90% of magnesium chloride and 0.1-5.0% of stabilizing agent.

Further, the super absorbent resin is cellulose ether.

Further, the super absorbent resin is preferably hydroxyethyl cellulose HEC.

Further, the super absorbent resin is preferably hydroxypropyl methylcellulose HPMC

Further, the super absorbent resin is sodium carboxymethyl cellulose CMC.

Further, the magnesium chloride is anhydrous magnesium chloride.

Further, the stabilizer is ascorbic acid.

Compared with the prior art, the method has the following advantages:

the cellulose ether preferably used in the present invention has improved hydrophilicity by destroying its strong hydrogen bond by introducing a substituent such as a single ether such as alkyl ether, hydroxyalkyl ether, carboxymethyl ether and the like or a mixed ether, increased water solubility; and the special bench conformation of the molecule thereof, the macromolecules are mutually wound and combined under the action of molecular forces such as hydrogen bond, Van der Waals force and the like to form a three-dimensional space network structure which can combine a large amount of water. In addition, in the process of water absorption, on one hand, the cellulose ether tends to penetrate into the high polymer to expand the volume of the high polymer, and on the other hand, the crosslinked polymer expands in volume, so that the molecular chains of the network stretch to three-dimensional space, and the molecular network is stressed to generate elastic contraction energy to contract the molecular network. Equilibrium is reached when these two opposite tendencies counterbalance each other. Therefore, the volume change of cellulose ether expansion due to water absorption is not large, the space for placing the drying agent is limited, and the security industry which needs the drying agent with high moisture absorption capacity to prevent the camera lens from fogging is particularly suitable. The cellulose ether adopted by the invention does not cause water discharge under the condition that the drying agent absorbs more water, but the drying agent gradually swells, becomes soft and viscous, and does not cause water leakage and liquid overflow all the time.

Compared with the commonly used drying agent taking calcium oxide and calcium chloride as raw materials in the market at present, the anhydrous magnesium chloride is adopted, the calcium oxide can be chemically combined with only one water molecule, the calcium chloride can only form stable crystal water with two water molecules, and the magnesium chloride can form stable crystal water with six water molecules, so that the moisture absorption capacity of the drying agent is greatly improved.

The invention adopts the ascorbic acid as the stabilizer, so that the drying agent has better mildew-proof function and oxidation resistance, cellulose ether is not degraded due to oxidation and bacteria, and the stability of the drying agent is greatly improved.

The drying agent can also be used in combination with chitosan, sodium alginate, carrageenan, gelatin, xanthan gum, etc.

Detailed Description

Example 1: preparation of drying agent

(1) Weighing 60 parts of hydroxyethyl cellulose (HEC), 39 parts of anhydrous magnesium chloride and 1.0 part of ascorbic acid as a stabilizer according to requirements;

(2) adding the weighed powder into a mixer and uniformly stirring to obtain a drying agent;

(3) or granulating to obtain a granular drying agent;

(4) the materials are packaged by a breathable packaging material to obtain the desiccant product.

Example 2: preparation of drying agent

The preparation is carried out according to the reference example 1, and 65 parts of hydroxypropyl methylcellulose HPMC, 34.5 parts of anhydrous magnesium chloride and 0.5 part of ascorbic acid are weighed according to requirements.

Example 3: preparation of drying agent

The preparation is carried out as in reference example 1, weighing 70 parts of sodium carboxymethylcellulose CMC, 30 parts of anhydrous magnesium chloride as required.

Example 4: preparation of drying agent

The preparation is carried out as in reference example 1, 75 parts of sodium carboxymethylcellulose CMC, 25 parts of anhydrous magnesium chloride being weighed as required.

Comparative example 1:

selected from the commercially available calcium chloride starch desiccants (calcium chloride desiccants for short).

Comparative example 2:

selected from commercially available magnesium chloride-magnesium oxide drying agents (magnesium chloride drying agents for short).

Comparative example 3:

selected from commercially available calcium oxide desiccants (abbreviated as quicklime desiccants)

Performance test:

3g of the desiccant materials of examples 1-4 and comparative examples 1 and 2 were weighed, respectively, and packaged into desiccant products with moisture permeable packaging materials, and the desiccant products were placed in an environment at a temperature and humidity of: 30 ℃, 70.0% RH in a constant temperature and humidity cabinet, after 10 days:

comparison of Experimental data

The experimental data show that: under the same environment, the desiccant of the invention has irreplaceable advantages in the aspects of moisture absorption performance, moisture absorption state, volume increment after moisture absorption and subsequent use risk of products compared with the commercially available calcium chloride desiccant, magnesium chloride desiccant and quicklime desiccant with better performance.

In sum, the drying agent prepared by the invention has extremely good moisture absorption capacity; after moisture absorption, the gel is in a colloid which is not easy to flow; and the volume of the device is not greatly increased and changed; also has the advantages of environmental protection, no toxicity, good stability and convenient manufacture. The desiccant is a very good universal desiccant, and is particularly suitable for security industry in which the space for placing the desiccant is limited and a desiccant with high moisture absorption capacity is needed to prevent fogging of a camera lens.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that are not thought of through the inventive work should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.

Claims

1. A preparation method of a drying agent is characterized by comprising the following steps: the drying agent is prepared by combining 5-90 parts of super absorbent resin, 10-90 parts of anhydrous magnesium chloride and/or calcium chloride with N crystal water and/or 0.1-5.0 parts of stabilizing agent by weight of raw materials, wherein the stabilizing agent is obtained by stirring and mixing or granulating to obtain the drying agent.

2. A desiccant as claimed in claim 1, wherein: the super absorbent resin is cellulose ether and/or starch ether, and comprises one or a mixture of more of methyl cellulose MC, hydroxypropyl methyl cellulose HPMC, hydroxypropyl cellulose HPC, hydroxyethyl cellulose HEC, hydroxyethyl methyl cellulose HEMC, sodium carboxymethyl cellulose CMC, ethyl cellulose EC, polyanionic cellulose PAC, sodium carboxymethyl starch CMS and hydroxypropyl starch ether HPS.

3. A desiccant as claimed in claim 2, wherein: the super absorbent resin is preferably a cellulose ether.

4. A desiccant as claimed in claim 3, wherein: the super absorbent resin is preferably hydroxyethyl cellulose HEC.

5. A desiccant as claimed in claim 3, wherein: the super absorbent resin is preferably hydroxypropyl methylcellulose HPMC.

6. A desiccant as claimed in claim 3, wherein: the super absorbent resin is preferably sodium carboxymethyl cellulose CMC.

7. A desiccant as claimed in claim 1, wherein: the anhydrous magnesium chloride or the magnesium chloride with N crystal water containing high magnesium chloride is preferably anhydrous magnesium chloride.

8. A desiccant as claimed in claim 1, wherein: the stabilizer is ascorbic acid.