As a key packaging form for cosmetics, personal care products and other liquid products, the effectiveness of the spray pump design has an important impact on the product experience and market competitiveness. Among the many design factors, material selection is crucial to the leak-proof performance of the spray pump.

Chemical stability of materials
Spray pumps are often used to store and dispense a variety of liquids, including oily, acidic and alkaline cosmetics. Therefore, it is particularly important to select materials with good chemical stability to prevent reactions with the internal liquids, causing material aging, deformation or corrosion. Polypropylene (PP) and high-density polyethylene (HDPE) are widely used plastic materials. Their excellent chemical resistance can effectively resist the erosion of most cosmetic ingredients, thereby ensuring the sealing and leak-proof performance of the spray pump.

Physical properties of materials
The physical properties of materials, such as elasticity, strength and sealing performance, directly affect the design and function of the spray pump. Elastic materials (such as silicone or rubber) are often used to make seals and gaskets. These materials can quickly return to their original shape after being compressed to ensure a good seal between the pump body and the bottle mouth. If the elasticity of the sealing material is insufficient, it may lead to a poor seal and cause leakage.
The strength of the material is also crucial. Spray pumps may be subjected to external forces during use, such as squeezing or impact. If the material strength is insufficient, the pump body may crack or deform, which will affect the sealing performance. High-strength plastic or metal materials usually provide better protection and reduce the risk of leakage.

Material processability
The material processability directly affects the production process and final product quality of the spray pump. High-quality materials are not only easy to form and process, but also ensure good dimensional accuracy and surface smoothness during the production process. Injection molding is a common process in the production of spray pumps. Choosing materials suitable for injection molding can reduce the gaps in the finished product caused by poor processing, thereby improving the sealing effect.
In addition, the material processability also affects the connection between the pump body and the nozzle. The accuracy and smoothness of the connection part are directly related to the effectiveness of the sealing ring. If there are unevenness or gaps in the connection part, the sealing ring will not play its due role, resulting in leakage problems.

Material temperature resistance
The spray pump may be exposed to different temperature environments during use, especially in high temperatures in summer or low temperatures in winter. The material temperature resistance directly affects the performance of the spray pump. For example, some plastic materials may soften at high temperatures, causing the pump body to deform, thus affecting the sealing. On the contrary, in low temperature environments, some materials may become brittle, increasing the risk of rupture. Therefore, when designing spray pumps, materials with good temperature resistance should be selected, such as high-temperature resistant polyamide (PA) or low-temperature resistant polyurethane (PU), to ensure good leakage-proof performance under various temperature conditions.