| abstract |
A composition and method for the controlled release of compounds from a plastic dispenser, usually a thermoplastic, generally in association with a porosigen in contact with water, for example, an aquatic environment or soil moisture. Thermoplastic dispensers are generally made from a water insoluble polymer such as polyethylene, polypropylene, ethylene vinyl acetate, polyamide, polystyrene, polyvinyl acetate, polyurethane, etc. Thermoset plastics, such as epoxy, are also used. The porosigen, depending upon the desired end use and release rate of a compound, can have a solubility of less than 0.1 or 0.001 grams per 100 grams of water, or up to 100 grams per 100 grams of water. The released compound, for example, a larvicide, a molluscicide, a nematicide, a trace nutrient, a plant regulant, etc., is contained in the thermoplastic dispenser. The combination of the plastic dispenser containing the porosigen and compound results in a slow release which can last for days, months, and even years, through dissolution of the porosigen and the formation of a porous network permitting water to contact the dispersed compound located in the interior portions of the dispenser. |