Features and principles for selecting water-soluble films for powder packaging

Water-soluble film for powder packaging is an environmentally friendly packaging material produced by modifying polyvinyl alcohol. It is widely used for individual small‑batch packaging of water‑soluble fertilizers, disinfectant powders, detergents, and pesticide powders. It helps prevent dust contamination and direct human contact with corrosive substances from the very beginning, making it a leading green packaging solution in today’s powder‑processing industry.

I. Key Features

1. Significant contrast in properties between dry and wet states: When stored dry, the film exhibits high tensile strength, excellent moisture resistance, and does not soften or stick together under normal warehouse storage conditions. Upon immersion in room‑temperature water, it dissolves completely within one minute, leaving no residual fragments or adhesive residues, and does not clog irrigation equipment.
2. Excellent chemical stability: It exhibits high compatibility with a wide range of powders. Even after prolonged contact with powders containing salts, weak acids and bases, as well as oxidizing agents, the packaging remains intact, does not react with the powder, and reliably protects it from degradation over an extended period.
3. Safe and dust-free operation: The film features built-in antistatic properties, does not attract dust during machine packaging, and completely eliminates dust contamination and the risk of inhaling dust. Operators are spared direct contact with corrosive powders, making its use safer.
4. Green and readily biodegradable: Contains no harmful substances such as fluorescent whitening agents or heavy metals. Upon dissolution in water, it biodegrades naturally, leaves no plastic waste, and meets environmental sustainability standards.

II. Principles of Selection

1. Selection based on water temperature during use: For powders that are typically diluted with room-temperature water, choose a film that dissolves quickly in cold water. For industrial-grade powders that require dilution with hot water, select a moisture-resistant, long‑shelf‑life film that dissolves in warm water.
2. Selection based on the powder’s need for moisture protection: Water-soluble fertilizers and chlorine-containing disinfectant powders are highly hygroscopic. It is necessary to use a modified film with low hygroscopicity to prevent moisture absorption and clumping of the film bags during storage.
3. Selection based on the acid–alkaline composition of the powder: For alkaline and oxidizing disinfectant powders, do not use boron‑containing water‑soluble films to prevent yellowing and package rupture during long-term storage. For neutral detergents, a universal‑type formulation is sufficient.
4. Strict compliance with regulatory requirements: Products intended for the domestic market and for export must, respectively, meet China’s national standards and European/American environmental standards to ensure safe use.