Technical note
Load rate is not release rate: what a supplier can and cannot control
Two numbers get used interchangeably in blend sheets and they should not be. Load rate is how much active is in the formulation. Release rate is how much leaves it per unit time. The first is a decision, the second is a result, and only one of them belongs in a purchase specification.
Why a load rate does not transfer
A rubber septum, an EVA matrix and a liquid formulation each hold and release the same compound differently. Rubber takes up a lipophilic active readily and gives it back slowly; a liquid formulation releases quickly but loses its volatile fraction early; a polymer matrix sits between the two depending on loading and on the surface area exposed. Copy a load rate from one to another and you have copied a number, not a behaviour.
The variables that decide release
- Vapour pressure of the active — the compound’s own property, and the reason short-chain acetates behave differently from long-chain ones.
- Matrix polarity and cross-link density — how tightly the matrix holds a lipophilic molecule.
- Surface area and geometry — a thin septum and a thick one release at different rates from the same load.
- Temperature and air movement — field conditions, not factory conditions.
What a supplier can hold constant
Composition, including the isomeric ratio, reported per lot. Packing that limits headspace so the material arriving at the blending house is the material that was released. Lot identity, so a change in the field can be traced to a change in input instead of being argued about.
What a supplier cannot hold constant is the release curve, because it is created downstream. Any supplier offering a release rate without knowing your dispenser is quoting a number from a different experiment.
Diagnosing a fall-off in catch
Late-season drop-off is usually the dispenser ageing, not the active degrading. The order to check things in is: dispenser age and storage conditions of the finished lure, then the blend record from the batch that was filled, then the certificates for the actives. Starting at the third step is how perfectly good material gets rejected.
What to send with an enquiry
Dispenser type, intended season length, the load you are working to and the climate the lure will sit in. Those four turn a generic answer into a specific one. The load and release page sets out how that conversation runs.
Need the specification behind this?
Send a CAS number and the quantity, and the answer comes back in writing with the isomeric form and packing attached.