Plastic Bottle Closures Child Resistant and Tamper Evident with Sealing Liners

A closure has to do three jobs at once: seal the container, open for the user, and tell the user whether the container has been opened before. We mould closures for pharmaceutical, household chemical, food and personal care packaging, and the liner is moulded and inserted in the same facility so the sealing interface is one controlled process.

Range

• Child-resistant push-and-turn caps to 16 CFR 1700.20 and ISO 8317
• Tamper-evident screw caps with moulded or applied bands
• Flip-top sports caps with tether and hinge retention
• Disc-top and pump closures for viscous products
• Loose liners: F217, silicone, EVA foam and induction foils

Child-resistant does not mean adult-difficult

The test for a child-resistant closure is that a panel of children cannot open it in five minutes, and a panel of adults can open it on the first try. Those two requirements pull in opposite directions, and the usual failure is not a cap that children open, it is a cap that adults defeat by prying with a tool. We tune the push-force and turn torque against both panels during development, and we run the child panel test through an external lab rather than in house.

Specification

The liner is a separate engineering problem

The closure shell is moulded to the neck finish; the seal is made by the liner, and the liner has to seal against the bottle's top surface, not against the thread. That means the liner is compression set over months of storage, and a liner that seals on day one can leak on day ninety if the compression set is too high. We run a three-month compression set test on new liner compounds and report the residual load, not just the initial seal.

Development path

Send the bottle drawing or a physical sample and the product type. We propose a closure, mould a prototype in aluminium, and run a seal integrity test with your actual fill, because a water-based product and an oil-based product behave differently against the same liner. Tooling follows prototype approval, typically 25 to 30 days for a steel tool.