Moisture is one of the main factors causing deterioration of products, such as reducing the performance of products or even completely losing their use value. Moisture proof packaging is used to isolate the effect of moisture in the atmosphere on the packaged products and avoid deterioration, mildew, decay, moisture, rust, etc.
Moisture proof packaging is to use moisture-proof materials for packaging protection of products, isolate the influence of external moisture on products, and keep the air in the packaging dry to keep the products below the critical relative humidity, so as to achieve the purpose of moisture-proof. Therefore, moisture-proof packaging requires that the moisture in the sealed container be removed during packaging, and the amount of water vapor penetrating into the container due to the moisture permeability of packaging materials is limited. Here we need to pay attention to the following issues:
1. Moisture absorption environment of packaging products. The moisture absorption characteristics of each product are different, and the sensitivity to moisture is also different. During the circulation of packaging products, the moisture content of the air exposed to them is often changing, and the moisture-proof performance requirements of moisture-proof packaging are also different. In order to correctly select moisture-proof packaging process and materials, the moisture absorption characteristics and external conditions of packaging products should be fully considered.
2. Moisture absorption characteristics of packaging products. Almost all packaging products are hygroscopic. Before reaching the saturation state, the moisture absorption will increase with the increase of relative humidity in the exposed air. Because the packaged products are not * * * dry and contain a certain amount of water, and within some allowable relative humidity range, the moisture absorption and evaporation are equal, that is, to achieve the allowable equilibrium water content, the performance of the products can be guaranteed. Exceeding this humidity range will change the allowable equilibrium water content, cause deliquescence of the packaged products and cause losses.
3. Moisture proof packaging technology. All products requiring moisture-proof packaging are easy to absorb water or absorb water on the surface
Products that cause deliquescence, mildew and corrosion. In order to make the moisture-proof packaging achieve good moisture-proof effect /, when designing the moisture-proof packaging, we should fully understand the moisture absorption characteristics of the product, clearly put forward the moisture-proof purpose and grade requirements, and select appropriate moisture-proof materials and technologies.