A dropper tip fitment is an orifice reducer that is pushed into a bottle to turn it from an ordinary bottle into a dropper bottle. Which dropper tip fitment you choose depends on several things, including the properties of your product and the use application. Once you know the terminology used for dropper tips, making the right product choice is easy.
Controlled vs. Uncontrolled Dispensing
When choosing a dropper tip, the first thing to consider is whether you need a controlled or uncontrolled tip.
- Uncontrolled tips dispense product in a continuous stream. This can be useful for precisely transferring product from one location to another, such as rinsing contact lenses or refilling e-cigarette cartridges.
- Controlled tips dispense product in individual, uniform drop sizes. This is especially important in precise dosing applications, such as eye drops or medication.
The orifice size along with the viscosity of the product determines how easy or difficult it will be to dispense the product from the bottle. For controlled dropper tips, the orifice size also determines how quickly the drop is formed and released from the dropper tip. There are two ways that orifices are created during the production process.
- Molded droppers have orifices that are cast during the molding of the tip.
- Pierced droppers are molded without an orifice. Once the dropper tip is molded it is then punctured with a needle to form the orifice.
How Drop Size is Determined
Drop sizes are typically measured in microliters (μL). There are several factors that determine the drop size that will be formed when dispensing product.
- The external size and shape of the dropper tip. The bigger the tip, the larger the drop size that is formed during dispensing.
- The coefficient of friction of the product being dispensed. The coefficient of friction is “The amount of force necessary to move the product being dispensed against the tip.” This is a fancy way of saying how much the product “sticks” to the dropper tip. This will be different for various products, so to determine a standard drop size, often water is used.
- Flaws in the dropper tip such as chipping or cracking will also affect drop size and the dispensing of product.
It’s important to remember that dropper tips do not work alone. They need to be paired with a bottle (typically LDPE which is squeezable) and an overcap to cover and protect the dropper tip. At Freund, we’ve made it easy to choose the right dropper by pairing the bottles, dropper tip fitments and overcaps for you. Click here to shop our selection of plastic dropper bottles.