Choosing a proper flip-top cap.
Visual and technical features to look at, even if there’s no testing equipment.
When considering any feature of the new product, always think of the client in the first place. If the cap looks and feels fine with container, is easy to open and seal, and let’s no water in between the cap’s lid and body – that’s a cap we’ve been looking for.
There are several technical features that distinguish high quality caps. First, the durability of the joint. Polypropylene (PP), of which most capes are made, is quite a wearproof material itself to sustain frequent openings and closings. But only under condition of using high quality raw materials and meeting all the technological requirements. Otherwise, the caps gets all the chances of falling apart ruining the entire user experience with the broken joint scratching fingers every time the customer takes the bottle in hand. That’s why opening/closing frequency test always comes prior when it comes to quality control. Luckily, such a test does not require special equipment – poor quality caps deform and get covered with a net of cracks in the joint area after several manual operations.
Second feature to look at is the opening/closing “click”. Ideally, a slight but clearly audible “click” should appear every time the peg blocks or pops out of the dosing orifice. In, general, a comparatively loud click is preferable. Though, there are cases when specific usage conditions (like for lubricants, for example) require a silent one. Anyways the signal must by distinct. If one accidentally leaves a tube shower gel cap loose – no disaster. But if that’s a tube of hand crème – a travel bag turns into a greasy swamp.
Feature number three – opening reluctance. Here, balance is everything. The cap must neither take too much, nor too little effort to open or close. If it’s not a case of toxic or volatile products, too tight sealing will only result in sore fingers (especially for kids with their sensitive skin). And reverse – if the flip-top opens up to any slight squishing or shaking, such cap provides more trouble than profit.
Another feature common for all closures – leak-tightness. Compatible (on paper) bottle neck and cap thread don’t yet guarantee a leek-proof set. Actually, it’s not even all about the nominal quality of the cap. Airtightness also depends on production error tolerance of both the cap and the container manufacturers, of the production technology itself. In some cases, it is the particular product or ingredient, that the cap can’t keep inside no matter how precisely it’s fitted to the bottle’s neck (most frequently this happens to oils or too tenuous liquids). For best assurance, tightness tests are advised for every new batch of packaging, even if the same sets had been previously ordered from the same manufacturer. At times there appear specific visual requirements, that are best to be tested before the actual order.
Some brands might require the cap’s “peak” to point at a specific direction once the cap is screwed on the bottle. For example, if there is a refined engraving on a side we’d like to highlight, or the printing pattern would otherwise get uneven. Generally, such feature is achievable, yet most often comes out way too expensive, so all that’s left is either changing the design pattern, or considering another kind of packaging set.