One. Data isolation definition 1. The isolation of data […]
One. Data isolation definition
1. The isolation of data refers to the isolation function of a specific permeate from one side of the data to the other side (usually from the high-concentration side through the data and into the low-concentration side). Common permeates include inorganic gas and water. Vapor and organic matter. According to the different properties of the permeable material, the corresponding insulation is called air permeability (oxygen permeability, nitrogen permeability, carbon dioxide permeability, etc.), moisture permeability and organic permeability.
2. Generally speaking, when we say that the material has good isolation, it means that this material should have good gas isolation, water vapor isolation, and organic isolation. It is said that the isolation of a certain material should be for a specific permeate Good isolation. It is difficult to be satisfied that a single material has good insulation for all permeable materials. For example, materials with good gas insulation may not necessarily be good for water vapor and organic matter in practice, even if a certain material has good gas insulation It also refers to a good barrier for specific gases, such as good oxygen or nitrogen barrier; for example, the commonly used HDPE has better water barrier function than PA, but the gas barrier function is lower than PA; for example, EVOH is in When the environmental humidity is very low, it has a high gas insulation, but as the environmental humidity increases, after water is absorbed, its insulation to inorganic gases will be significantly reduced, and the corresponding water vapor isolation function will be worse. Therefore, in practice, the requirements for the isolation of cosmetic packaging are clearly specified to the requirements of the suppliers. According to the direction of soaking, there is a difference between isolation and seepage.
Two. Soaking mechanism
1. The high insulation of the data for a specific permeate indicates the low permeability of the data. For example, low oxygen permeability indicates high oxygen barrier, and low moisture permeability indicates high water barrier. Isolation function can be said to be barrier property. Understanding the process of permeation in the packaging materials can help us understand the factors affecting the barrier property.
2. The entire soaking process can be divided into four parts: adsorption, dissolution, dispersion, and desorption. Gas, water vapor or organic matter enters the data surface from the high concentration area, and after being dispersed in the data, it desorbs from another surface in the low concentration area. . Assuming that the sealed high-water content cosmetics are in a low-humidity environment, we use this model to simulate the process of water loss in the packaging container. As shown in Figure 2 below, water vapor will contact the inner wall of the packaging container and dissolve into the packaging layer. The data is dispersed along the concentration gradient, and finally desorbed and dispersed into the atmosphere. If the external temperature is added, it will speed up this infiltration process. This can also explain that even cosmetics with good sealing properties mentioned before will still thicken and thicken the product due to the seepage of water vapor, which will affect the customer's use.
3. The penetration of the small molecule permeate through the polymer is mainly completed through the amorphous area and the crystalline defect. The microcracks, pinholes, and defects of the material will all lead to the addition of permeability. From Figure 1, we can see significant data shortcomings under a high-power microscope.