Ever wonder why some plastic bottle caps twist off easily, while others provide a more robust seal? The answer lies in their thread profiles. The thread profile is a crucial component of an effective closure solution. Thread profiles are based primarily on standardized specifications, to ensure compatibility and proper sealing between the cap and the bottle.
Popular thread profiles for the packaging industry
The two most popular thread designs used in plastics and packaging are standard thread profiles and buttress thread profiles. Standard thread profiles are the most commonly used design and typically come from a strip mold. Standard threads tend to have symmetrical “bell” shaped curves and are easier to manufacture. They are often used for general purpose applications, where high torque retention is not required.
Buttress thread profiles come from an unwinding core mold and have a sharper thread profile. This allows the cap to withstand higher pressure and have greater sealing strength. The buttress thread’s higher torque retention also reduces the cap’s ability to back off from its seal. Buttress threaded caps are better suited for applications that need to maintain a secure seal under stress, such as chemical, pharmaceutical, and industrial packaging. At Reliable Caps, we offer both standard and buttress thread profiles in our diverse selection of closures.
Advantages of the standard thread profile
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Budget friendly: Easier and less expensive to produce due to standardized tooling and processes.
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Easier to line: Liners are friction fit, so no glue is needed to line a standard thread profile closure.
Common applications of standard thread profile closures
The standard thread profile is a great choice for polyethylene terephthalate (PET) bottles, which are commonly used in the beverage, food, personal care, and household industries. Standard thread profiles are also ideal for glass bottles and bottles made from newer molds.
Reliable Caps closures with standard thread profiles
Advantages of the buttress thread profile
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Durability: Buttress thread closures have larger and sharper threading that will withstand repeated use and high stress.
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More secure fit: The buttress thread profile provides a secure and robust seal, and the high contact surface between the thread on the bottle and the thread on the cap helps prevent leaking and back-off.
Common applications of buttress thread profile closures
Since buttress thread profile caps are stronger, they are commonly used for large or heavy bottles such as 2.5-liter bottles, older bottle molds, or less-than-ideal bottle threads. Since they are more leak-resistant, they are also a popular choice for chemical bottles and certain pharmaceuticals.
Reliable Caps closures with buttress thread profiles
Pros and cons at a glance
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Standard thread |
Buttress thread |
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How do I select the right thread profile?
The benefits and disadvantages that we’ve outlined for each type of thread profile can get you started as you consider your specific closure needs. If you have any questions, or just want some extra help guiding you through the decision-making process, we are always here to offer personalized assistance with your closure orders. No matter how small or large your order, we promise that it will always get to you with the shortest possible lead time, without sacrificing quality. Contact us to discuss your cap needs.