Person holding bulb of cosmetic pipette

In Depth: Cosmetic Dropper Pipettes (Part 3 of 3)

This blog, focussing on the bulb, is the last of three-part series; in Part 1 we looked at the Pipette Tube, and Part 2 discussed the Collar. The bulb is possibly the most critical part of the product, as it is essential to get the specification correct to ensure the correct dosage, compatibility with the product and to provide a leak-proof seal between the bottle and the cap.

The Pipette Bulb

Exploded Pipette Diagram.webp (33 KB)

So, what do we even mean when we talk about the bulb?

 

Put simply, the component known as the bulb, or the teat, is the squeezy part at the top of the pipette. It inserts into the top of the collar and fits tightly onto the top of the tube, holding all three components together.

 

 

Why is the pipette bulb so important for a cosmetic brand?

Like most cosmetic primary packaging, a pipette bulb is not so simple as it might first seem. Here are some of the key variables - we'll run through each of them in more detail below:

  • Size (or capacity)
  • Colour
  • Finish
  • Material

Read on, we'll dive into each of these in some more detail to help you specify your perfect pipette...

Products this case study features:

Metal-shelled Pipettes

One of the most popular finishes - the thin metal shell on these gives an ultimately smooth, high-quality finish for a cosmetic product.

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Child resistant and tamper evident pipettes

Tamper evidence and child resistance is now more commonly requested...now both functions are available in one pipette!

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Pipette Bulb Variables - A Deep Dive

Material

The material used in the manufacturing of the bulb is probably the single most important aspect to get right when choosing a pipette. The bulb must be flexible by definition - and remain so throughout its life. In the event of liquid coming into contact with the bulb, it is essential the liquid doesn't have a detrimental effect on the bulb, and vice versa. Pipette bulbs are made from a whole range of materials - and so far, there's no winner-takes-all solution on this front. Here are some of the most common options you'll find, with a brief explanation of why they're used:

 

Material Advantages Disadvantages
 TPE (Thermoplastic Elastomer)
  • More sustainable/recyclable than Thermoset polymers and rubbers
  • Commonly available
  • May be available in some standard or custom colours
  • Some compatibility limitations and loses flexibility with elevated temperatures
 Silicone
  • Provides a very smooth, glossy finish
  • Very good chemical resistance to most ingredients
  • Poor recyclability
 Natural rubber
  • Made from latex sap and then vulcanised
  • Good all-round compatibility
  • Very durable
  • Maintains flexibility over long periods and wide temperature ranges
  • Commonly available
  • Colour normally restricted to black
  • Natural product which may tend to discolour with time (white, powdery look)
  • Limited compatibility with solvents and oils
  • Poor recyclability
 Butyl rubber
  • Synthetic rubber product
  • Good chemical resistance to most liquids
  • May be affected by strong oils and solvents
  • Poor recyclability
 Nitrile rubber (NBR)
  • Synthetic rubber product
  • Generally available in black but may be possible to mould in off-white or limited colours
  • Very good chemical resistance to most ingredients, including many organic compounds
  • Very durable
  • Cannot be recycled
  • Hard to get smooth surface finish

 

Size

Size matters! - in some uses, more than others. Two of the most common sizes (capacities) for a pipette bulb in the skincare market are 0.7ml and 1ml. This means that, in a perfect world, you put the tip of the pipette into the liquid, squeeze the bulb, and it draws up exactly that amount of liquid. In reality, this may not be the case, it depends on the size of your fingers, if the bulb is completely squeezed and the liquid being dispensed (liquids may behave differently depending on how viscous they are).

This is particularly important when recommending that the consumer use a specific volume of product, such as '1ml dosage' rather than, '3 or 4 drops', as in this case, the bulb then needs to have the capacity to draw up the right amount of product into the stem and then evacuate (empty) the full stem with one further squeeze.

 

Colour

While every brand loves a colour-matched product, brand-owners may need to be ready to compromise when it comes to colour-matching the bulb. Some materials, particularly rubber materials are only available in black, while other materials such as TPE give more scope for coloration. Richmond is working on solutions that will allow a far greater degree of colour-matching, subject to production minimums, obviously.

 

Finish

Matt and textured or smooth and glossy? The option depends on the material choice - but since the bulb is a very tactile part of the user experience, it can become a consideration for brands. Silicone tends to be smooth and glossy, while TPE and rubber tend to provide a matt finish.

 

It's easier when you can chat to an expert - especially one who is happy to discuss your brand's packaging for hours! Get in touch