The influence of processing technology on the sealing performance of plastic cosmetic bottles

In the production process of cosmetic bottles, the processing technology plays a very important role in ensuring the sealing of the bottle body and bottle cap. From injection molding to assembly, every step affects the fit between the bottle and cap, thereby affecting the effectiveness of the seal.
First of all, injection molding is the most common method for producing plastic cosmetic bottles. In this process, molten plastic is injected into a mold and cooled into the desired shape. The accuracy of the mold and the molding conditions are key factors that affect the size and shape tolerance of the bottle.
The accuracy of the mold directly affects the size and shape tolerances of the bottle. High-precision molds can produce bottles with smaller size and shape tolerances, thereby improving the fit and sealing of the bottle cap. In addition, molding conditions are also crucial. Parameters such as molding temperature, pressure and cooling time affect the crystallinity and orientation of the bottle, thereby affecting its mechanical properties and sealing properties.
Secondly, blow molding is also a commonly used production method. In this method, molten plastic is blown into a mold, creating a hollow bottle. The process parameters of blow molding will affect the thickness, surface finish and sealing of the bottle. Higher blow molding pressure will produce a thinner bottle, but may result in uneven surfaces or weak areas that affect sealing. Proper cooling time can ensure that the bottle is completely crystallized, thereby improving its rigidity and sealing.
In addition, the surface treatment of plastic cosmetic bottles will also affect the sealing performance. Electroplating and spraying are commonly used surface treatment methods. Electroplating can improve the surface finish of the bottle and reduce friction, thereby improving the performance of the seal. Spray coating can provide an extra layer of protection to the bottle, preventing scratches or scuffs to maintain a seal.
Finally, the assembly process is also an important link that affects the sealing performance of plastic cosmetic bottles. The fit of the bottle body and cap is critical and needs to be carefully controlled. The accuracy of the thread fit will affect the engagement between the bottle cap and the bottle body, thereby affecting the sealing performance. The strength and uniformity of the press fit will also affect the sealing of the cap and bottle body.