Chemically stable, insecticidally active phosphoromidothioate pellet compositions and methods for their manufacture

Chemically stable, low moisture content pellets comprising an insecticidally active compound and up to about 0.5% by weight water, said compound being of the formula:

• 4
• wherein R and R1 individually are an alkyl, alkenyl or alkynyl group containing up to 6 carbon atoms, R2 is hydrogen, an alkyl group containing 1 to 18 carbon atoms, a cycloalkyl group containing 3 to 8 carbon atoms, an alkenyl group containing 2 to 18 carbon atoms or an alkynyl group containing 3 to 18 carbon atoms, R 3 is hydrogen or an alkyl group containing 1 to 6 carbon atoms, and Y is oxygen or sulfur,
• said pellets having been made by a process comprising the steps of feeding a powder comprising at least about 95% by weight of said insecticidally active compound to an extruder,
• feeding water to the extruder during at least a portion of feeding of said powder, the water contacting the powder to form a mixture,
• extruding an extrusion product while controlling the temperature within the extruder and the rate and quantity of water fed to the extruder to minimize tackiness and clumping together of said extrusion product, and
• forming pellets having a moisture content of about 0.5% or less by weight from said extrusion product.

A process for producing low moisture content pellets comprising an insecticidally active compound of the formula:

• 6
• wherein R and R1 individually are an alkyl, alkenyl or alkynyl group containing up to 6 carbon atoms, R2 is hydrogen, an alkyl group containing 1 to 18 carbon atoms, a cycloalkyl group containing 3 to 8 carbon atoms, an alkenyl group containing 2 to 18 carbon atoms or an alkynyl group containing 3 to 18 carbon atoms, R3 is hydrogen or an alkyl group containing 1 to 6 carbon atoms, and Y is oxygen or sulfur, comprising the steps of
• providing a powder comprising at least about 95% by weight of the insecticidally active compound,
• contacting the powder with water to form a damp or wet mixture, and thereafter
• extruding an extrusion product of predetermined diameter from the damp or wet mixture,
• forming pellets from the extrusion product, and drying the pellets to a moisture content of less than about 0.5% by weight.

Chemically stable, low moisture content pellets comprising an insecticidally active compound and up to about 0.5% by weight water, said compound being of the formula:

• 7
• wherein R and R1 individually are an alkyl, alkenyl or alkynyl group containing up to 6 carbon atoms, R2 is hydrogen, an alkyl group containing 1 to 18 carbon atoms, a cycloalkyl group containing 3 to 8 carbon atoms, an alkenyl group containing 2 to 18 carbon atoms or an alkynyl group containing 3 to 18 carbon atoms, R3 is hydrogen or an alkyl group containing 1 to 6 carbon atoms, and Y is oxygen or sulfur,
• said pellets having been made by a process comprising the steps of
• providing a powder comprising at least about 95% by weight of the insecticidally active compound,
• contacting the powder with water to form a damp or wet mixture, and thereafter
• extruding an extrusion product of predetermined diameter from the damp or wet mixture,
• forming pellets from the extrusion product, and
• drying the pellets to a moisture content of less than about 0.5% by weight.