Common thread cap types

Threaded closures can be identified by the threads that wrap around the inside of a closure. The threads inside the cap grip onto the neck threads of a container with a twisting motion to create a strong seal. Threaded closures are most often found on bottles, jars, and tubes. Closure sizing is identified by the neck finish of the container the closure will match with. The following are some of the common types of threaded closures you'll find in the packaging industry.

Continuous Thread

The most common style cap is a continuous thread closure. Continuous thread lids and caps serve the basic function of sealing products in a container with a twisting motion. Common styles of plastic continuous thread closures are smooth, ribbed, and dome. Smooth continuous thread closures have a smooth finish, ribbed closures have vertical grooves on the outside edges to allow better grip, and dome closures have rounded edges for a smooth look. Metal continuous thread closures are limited in style and provide the basic function of sealing a container. Continuous thread closures can be used with both plastic and glass containers with a matching neck finish.

Lug Cap

Lug caps are best identified by the popping sound released when initially opening. Unlike continuous thread caps, the threads of lug caps are not continuous and are equally spaced around the container. Lug caps are made of metal and are only compatible with glass jars with a lug neck finish. Lug caps are a popular option for products that need to be airtight such as salsas, jams, and other food products.

Phenolic Cone Cap

Phenolic cone caps are composed of two pieces, the outer cap and an LDPE cone inside the cap. The cap is designed for oil-based products that may seep through a regular continuous thread closure. The cap is often used with glass bottles for products such as essential oils and chemicals.

Dispensing Closures

Dispensing closures are threaded closures designed with the additional function of dispensing products. A wide range of dispensing closures are available to accommodate a wide variety of products. Each dispensing closure is designed to dispense a certain amount of product based on the product's viscosity. Common types of dispensing closures include disc-tops, flip-tops, yorkers, polytops, droppers, pumps, and sprayers. Certain types of dispensing closures are better suited for certain types of products, for example, creams used in the personal care industry are often dispensed with pumps, disc tops, and flip-top caps. Dispensing closures allow a controlled amount of product to be dispensed which effectively reduces wasted product.

Child Resistant Cap

Child-resistant caps, also known as CRCs, are a type of continuous thread closure that has a mechanism that needs two motions in order to release from the container. The two most common motions needed to release a child-resistant cap are 'Push Down and Turn' or 'Squeeze Sides to Unlock'. Both are designed to be significantly more difficult for children under five to open in order to prevent them from ingesting products that may cause injury or fatality. Child-resistant caps are often found on consumer pharmaceutical or chemical products that may be within reach of small children.

Pail Screw-Top Covers

Screw-top covers are a closure option for plastic pails. A screw-top lid provides a stronger seal than a basic pail lid which relies on pressure to snap and seal. Threaded pails and covers are less commonly used compared to non-threaded pails and covers.