Black Plastic Cap & Dropper, 28/400

Plastic cap for bottle 28/400 is a simple screw closure made of rigid plastic that reliably seals a bottle or small bottle with a neck of this type. The contents do not spill, do not dry out, and are not unnecessarily exposed to air. The black colour looks neutral and pairs well with dark, matte, and clear glass, making it suitable for oils, tinctures, syrups, tonics, and cleansers that are dispensed by pouring.

The cap is suitable for contact with cosmetics and food. You can therefore use it not only for cosmetic products, but also for homemade herbal oils, syrups, or infusions stored in bottles with the same neck.

Where to use it

• Cosmetic preparations for pouring – body and massage oils, facial tonics, makeup-removing waters, or cleansing milks that are not dispensed with a pump or dropper.
• Storage and working bottles – carrier oils, hydrolats, or finished semi-finished products in a workshop where you need to open and close the packaging quickly.
• Home food products – flavoured oils, syrups, vinegars, and infusions, for which it matters that the cap has confirmed suitability for direct food contact.
• Replacement closure – if the original bottle cap has been damaged or lost and the neck has a 28/400 thread.

Use and choosing the right neck

The cap is placed on the neck and tightened by hand. For every screw closure, the rule is that tightening should be firm, not forceful. Too much force deforms the thread and the seal will deteriorate rather than improve. Before fitting, check that the bottle neck is dry and clean. Residues of oil or syrup on the thread reduce the seal.

The designation 28/400 refers to a neck with a diameter of 28 mm and a standard thread profile used on glass and plastic bottles of this size. Bottles with the same neck type, listed in the parameters, and ready-made bottle + cap combinations are available in the Handymade range. For a custom combination, we recommend verifying the seal, the behaviour of the packaging with a specific formulation, and any leakage when inverted.

Good to know

• Preparation before first use – wash the cap with warm water and a small amount of detergent, rinse, optionally wipe with isopropyl alcohol or ethanol and allow to dry completely. Moisture under the cap shortens the shelf life of water-based products.
• Repeated use – rigid plastic withstands repeated screwing and washing. Before each new fill, check that the thread is not cracked or deformed, and replace a damaged cap.
• Oil-based and alcohol-based contents – we recommend verifying compatibility with a specific formulation, especially with a higher proportion of essential oils, in the finished product.
• Labelling – the cap is not normally labelled. This leaves room for a tamper-evident seal or shrink band over the neck, if you use one at point of sale.
• Recycling – at end of life, it belongs in plastic waste according to the material code listed in the parameters.

Frequently asked questions