A crop protection sprayer at work in a field
From the moment the aqueous suspension concentrate enters the bead mill, the surfactant carries air into the slurry with it: the foam tops out, the grinding chamber builds back pressure, the filling machine's metering drifts, and the content uniformity of a whole batch is left without a guarantee.
Chemi Tech makes defoamers for agrochemical formulation systems such as pesticide aqueous suspension concentrates and emulsifiable concentrates, drawn from the defoamer KM-302 series. How a grade is matched depends on the pH of the formulation, the grinding temperature and the surfactant level in the system. KM-302 is a milky white silicone grade made for agrochemicals: it disperses well and resists alkali, so systems from pH 3 to 12 and below 98 °C hold up, and suppression is steady through the high temperature stage. Chemi Tech customises against the formulation pH and the high temperature process and recommends a defoamer that fits.
Advantages of Chemi Tech Defoamers
Chemi Tech defoamer KM-302 series disperses well: a milky white liquid added to a high viscosity suspension concentrate spreads by itself, without having to be forced in by high shear. It resists alkali as well, so it does not precipitate or float out in an alkaline formulation, and the liquor does not separate on standing. Suppression holds too, so foam is pressed back as soon as it gathers in the grinding chamber and grinding efficiency is not dragged down. It does not demulsify through the high temperature stage either, so the effect is stable in systems below 98 °C and a warm grinding chamber in summer is no concern. And it is made for the agrochemical direction, with high compatibility with the wetting and dispersing auxiliaries in a suspension concentrate, so the uniformity of the active ingredient is not dragged in.
Industry Pain Points and Solutions
When an aqueous suspension concentrate foams, the first thing to go wrong is the grinding stage topping out. Surfactant grinding carries air into the slurry, foam piles up at the machine inlet, the grinding chamber builds back pressure, and the only option is to stop and clear the foam, so capacity drops a grade outright. Chemi Tech's approach is to place the defoamer dosing point at the feed end of the bead mill, so the defoamer enters the chamber in step with the slurry and disperses before the foam gathers.
The problem that follows is foam being carried to the filling machine. If the microfoam in the slurry is not knocked down, the filling machine's metering runs high and low, the bottle mouth foams over, and even the labelling will not hold. Chemi Tech verifies the grinding and the filling stages together: knock the foam down in the grinding stage, suppress it in the let-down stage, and foam entering the filling machine is ruled out.
The last point is the wide acid-alkali span, where an ordinary defoamer cannot hold steady. Pesticide formulations run from pH 3 to 12, and the system changes as the chemistry is switched: a defoamer that worked at room temperature and neutral pH will precipitate the moment it meets a strongly alkaline system. Chemi Tech works from the pH and grinding temperature data of the pesticide formulation and runs the fit comparison across a coverage of below 98 °C and pH 3 to 12, which makes the test result more precise.
Typical Conditions and Verification
Customer: an agrochemical enterprise in Shandong, applying it to the grinding and filling stages of an aqueous suspension concentrate.
The aqueous suspension concentrate from this plant topped out with foam during grinding, the line had to stop two or three times a shift to clear it, the filling machine's metering swung high and low, and content sampling was unsteady. The solution offered by Chemi Tech defoamer was: against the formulation pH and the grinding temperature, KM-308 — a grade that resists high temperature, acid and alkali and grinding — was selected from the KM-302 series, the dosing point was set at the feed end of the bead mill, and a trace of KM-308 was dripped into the let-down tank before filling. After that the bead mill stopped topping out, a whole shift ran through without a stop, filling metering came back into the qualified range, and content sampling held.
Frequently Asked Questions
Will the defoamer added to a pesticide formulation pull the stability of the active ingredient off course?
There are cases where it does: some chemistry holds the foam down while the liquor starts separating and precipitating. The KM-302 Chemi Tech supplies to agrochemical enterprises has been compared for compatibility against the formulation system, and at normal addition levels content uniformity is not affected. Chemi Tech will recommend the product that fits on the basis of the formulation pH and the surfactant system.