Why Plastic Can Needs Easy-Open Lid

Why Plastic Can Needs Easy-Open Lid

Plastic wide-mouth containers often create confusion — people frequently mix up plastic cans with cosmetic jars, and it’s understandable. At a glance, both share a similar look: a cylindrical form with a broad opening.
Look a little closer, though, and the differences become clear — and they’re anything but random. Each design choice reflects specific goals around performance, compliance, and usability, tailored to the demands of different sectors.
In this article, we’ll break down the reasoning behind these nuanced but important differences — from material choices and build methods to regulatory requirements — so you can tell them apart confidently and select the right option for your product.

Material Differences

Packaging that directly contacts food — such as plastic snack cans or can-shaped containers — has to comply with rigorous food-safety rules. The materials must be non-toxic, resist acids and alkalis, and prevent component migration so nothing leaches into the food. Polypropylene (PP) and polyethylene terephthalate (PET) are the go-to choices, both cleared by the FDA for direct contact. PET is prized for its glass-like clarity that showcases the contents, while PP stands out for heat tolerance and is the only food-grade plastic considered microwave-safe.

By contrast, wide-mouth jars for cosmetics emphasize formula compatibility and visual design. A wider range of plastics — like PETG, AS, and ABS — is used to balance transparency with cost. Premium versions often employ multi-layer or composite constructions to create layered effects and enhance shelf appeal.

Differences in Opening Structures

PET cans and plastic jars start with the same CTC thread design in their preforms, but they diverge where it matters: at the mouth. PET cans are built with a flared lip above the threads. That flare is intentional — it’s made to accept easy-open ends, like metal can ends or aluminum pull-tab lids, to create a tight, air-secure seal. If you try to cap this flared finish with a standard screw-on closure, the lid won’t seat correctly and the seal will be compromised.
By comparison, wide-mouth plastic jars have a straightforward, smooth-thread finish. Their sealing depends on screw caps, often paired with liners or discs — such as PE or PP sealing discs, foam liners, or pressure-sensitive liners — to achieve proper closure performance.

Sealing Method Differences

In contrast to wide-neck plastic cosmetic jars, plastic canisters with easy-open ends need a dedicated can seamer. The market largely offers two categories:
- Industrial high-speed seamers: Built for continuous, high-volume lines and suited to sealing standard plastic cans as well as soda/beverage cans.
- Compact benchtop seamers: Intended for short runs and on-demand use, ideal for ready-to-fill food and beverage cans with flexible, easy adjustments.

Keep in mind the purchase isn’t a single, fixed expense. Because food and beverage cans come with different neck diameters, you’ll need corresponding sealing heads for each size. Strategic, long-term packaging decisions are therefore crucial, as they directly influence both equipment and tooling/accessory costs.

Neck Size Differences

Plastic canisters designed for easy-open lids and cosmetic wide-mouth jars use very different standard neck dimensions. Because canisters span a broader volume range, they come in more neck sizes — commonly 68 mm, 75 mm, 85 mm, 100 mm, and 115 mm for food applications — whereas soda cans are typically fixed at 55 mm. These established measurements align with widely used easy-open ends and screw closures. PET canisters usually start around 150 ml; the most common sizes fall between 300 ml and 1,000 ml, with large food containers extending to about 3,000–6,000 ml.

Cosmetic wide-mouth jars, by comparison, have fewer neck options, most often 47 mm, 68 mm, or 78 mm. Their capacities are also smaller: standard formats run about 30–100 ml, and even the larger versions generally top out at 300–1,000 ml. In both categories, the neck size dictates which closures will fit, so specifying it correctly is essential for plastic canisters and cosmetic packs alike.

Differences in Base Groove Design

Aside from the neck, plastic food cans and cosmetic wide-mouth jars are set apart by how their bases are grooved. Containers for foods and drinks generally use much deeper base grooves than cosmetic jars, a choice driven by the different demands of each application.
Mechanically, a deeper groove in a plastic food can broadens the load-bearing footprint, which boosts stability. From a physical standpoint, it also raises resistance to internal and external pressure — crucial for hot-fill items, where cooling-induced shrinkage might otherwise warp the container. Carbonated drink packaging pushes this concept further with extra-deep grooves that spread liquid pressure more evenly and help avert ruptures when pressure swings occur in cold conditions.

Cosmetic wide-mouth jars, by comparison, usually have only shallow channels or even completely flat bases. The emphasis here is on visual appeal, and the structure is adequate for purpose since these products don’t encounter notable pressure differences or the heavy, high-density contents (such as honey or jam) that would require stronger reinforcement.