Agricultural films (especially greenhouse films) are one of the most demanding battlefields for polymer additives. They not only have to withstand high-intensity solar radiation but also face complex chemical erosion.

1. The Dual Challenges for Agri-films: UV Rays and Pesticides

Pesticide and Sulfur Poisoning: Agricultural chemicals (especially those containing sulfur and chlorine) are "killers" of light stabilizers. Traditional alkaline HALS react with acidic pesticides, forming inactive salts, leading to the total failure of the protection system.In agricultural applications, the commonly used greenhouse films generally need to be used for more than 12 months, and some need to be used for more than 18 months. In recent years, higher requirements have been put forward for the sulfur resistance and pesticide resistance of agricultural films.

2. Formulation-Building a "Collaborative Defense" System

A single stabilizer cannot cope with complex environments; a "team effort" is essential.

Synergistic Blending with UV Absorbers

◦ Principle: UV absorbers (UVAs), such as benzotriazole types (e.g., Leadstab UV 326) or benzophenone types, serve as the first line of defense. They absorb UV radiation and convert it into harmless heat, thereby reducing the generation of free radicals and lessening the scavenging burden on HALS. Even if some HALS gets "poisoned," the UVAs continue to provide fundamental protection.

◦ Classic Combination: HALS + UVA is the most mainstream stabilizer combination scheme for agricultural films.

3. NOR-HALS Technology

To solve the "poisoning" problem, the new generation NOR-HALS technology was recommended. 

NOR Series products: Uses alkoxy modification, resulting in extremely low alkalinity. It does not react chemically with pesticides, maintaining high free-radical trapping activity even in environments with sulfur concentrations up to 1000ppm.