Many customers will test the moisture absorption effect of the desiccant immediately when they receive the desiccant sample. However, it is found that the moisture absorption effect of the desiccant is far from our promise. Is it a problem with the moisture absorption effect of the desiccant, or is the customer's test method for the desiccant?
First
Many customers say that the desiccant is hygroscopic, just throw it in the water and see if he is full after a few hours.
The desiccant is to absorb the moisture (moisture) in the air to achieve the desiccant of the holding space. Usually the desiccant's role is that the water vapor is not liquid water, and the target object is selected incorrectly.
High-quality desiccant will use waterproof and breathable packaging materials (DuPont paper), because the desiccant absorbs water vapor in the air instead of liquid water. If you throw the desiccant directly into the water, under the action of liquid water, the water should be impervious to waterproof and breathable packaging materials, otherwise the water can enter and reverse osmosis (similar to sponge), thus losing the desiccant itself The effect of moisture absorption and anti-osmosis.
After the desiccant absorbs moisture, the moisture should be absorbed in the desiccant, and no moisture should appear on the surface. If you take out the desiccant soaked in water, it will definitely drip. This also shows that the test method of throwing the desiccant directly into the water and immersing it in the moisture absorption is wrong.
Second:
After the customer took out the sample, he poured a glass of water directly on it to see if the desiccant absorbed moisture quickly?
The desiccant absorbs the moisture in the air to achieve a relatively dry environment. The main ability is to absorb the moisture in the air instead of liquid water. It is not a sponge. The super absorbent resins (commonly used in baby diapers) are used to absorb liquid water, so it is a wrong practice to directly pour water on the desiccant to test the moisture absorption effect. (Note: Some desiccant manufacturers use this material as a desiccant, and post a video on the Internet to show how effective this type of desiccant is when it is poured into liquid water to absorb moisture. In fact, this is a behavior that deceives customers. The water adsorption performance is very good, but it cannot be used to adsorb water vapor in the air.)
Third:
When testing the effect of desiccant moisture absorption, some customers take apart the outer bag of desiccant and only take the desiccant raw materials (particles or powder) for testing, which is also wrong.
Confused the concept of desiccant raw materials and finished products. The desiccant raw material refers to the inner packaging of the desiccant, which is the content inside the desiccant. Any one of the desiccant content can be called the desiccant raw material. Some desiccant products are composed of a single desiccant raw material such as silica gel desiccant, mineral desiccant, and some desiccant is formed by mixing two or more chemicals (such as container desiccant, calcium chloride desiccant) Wait).
Ignoring the role of the desiccant outer packaging bag in the finished desiccant, the desiccant outer packaging bag is an integral part of the desiccant. Therefore, when testing, you can't just test the content of raw materials. In fact, to some extent, packaging materials are more important than raw materials. Especially in the packaging of food and medicine, it is the packaging material part of the desiccant that directly contacts the product. Moreover, the strength of the packaging material, air permeability and other properties directly determine the quality of the desiccant.
Forth:
Put the desiccant directly in the indoor environment for testing, but the effect of moisture absorption is not good.
The temperature and humidity of the desiccant test environment are unstable. The ambient temperature and humidity have a significant impact on the desiccant's ability to absorb moisture. The open test environment can only be used for qualitative comparison of different desiccant products. If quantitative analysis is required, it must be tested in a constant temperature and humidity environment, and professional equipment "constant temperature and humidity box" is required, and the data obtained by the test is of reference significance.
Then there is no professional "constant temperature and humidity box" equipment, you can also use a simple method to replace, the method is as follows:
(1) Preparation materials: 2 plastic cups, a piece of fiber paper with excellent air permeability and hardness, and a sample of unopened desiccant.
(2) Put a cup of hot water in a plastic cup, put it on a flat table, and put the white paper on the plastic cup (the plastic cup should not touch the water).
(3) Disassemble a pack of desiccant, take out a small sample, weigh it, and record the weight M1 of the desiccant before absorbing moisture.
(4) Put the desiccant on the fiber paper and quickly cover it with another plastic cup to maintain a sealed environment.
(5) Record the weight M2 of the desiccant at 12h, 24h, 36h, 48h, etc. (The water droplets on the surface of the desiccant should be regarded as accurate data)
(6) Use (M2-M1)/M1*100% to get the moisture absorption rate of the desiccant at different times.
(7) Continue to observe that until the weight of the desiccant no longer increases, the maximum moisture absorption rate of the desiccant is obtained.
If the sample of the desiccant is too large, you can use a plastic sealed box (a food preservation box), a small bowl, and a barbed wire that can withstand weight (plastic bowls, breathable white paper), to simulate the desiccant moisture absorption Closed environment. Note: If you need to measure the moisture absorption rate in a short time, you can replace the new hot boiling water after the water in the cup is cooled. The purpose of using hot boiling water is to evaporate the water vapor fast enough, so that the desiccant absorbs moisture and reaches saturation in a short time. status.
Note: If you need to measure the moisture absorption rate in a short time, you can replace the new hot boiling water after the water in the cup is cooled. The purpose of using hot boiling water is to evaporate the water vapor fast enough, so that the desiccant absorbs moisture and reaches saturation in a short time. status.