Jars, and Why the Lid Liner Decides the Seal

What Buyers Get Wrong

Skipping the Liner Decision

Oil-based creams swell EPE liners. Specify the liner with the jar, not after the first leak.

Double-Wall Thread Depth

The thread sits on the outer shell; a liner that fits a single-wall rim may not sit flat.

Frosting as a Colour

Frosting is a surface treatment, not a colour — it does not add a changeover, and it does not hide a yellowing resin.

Cosmetic Jars and Food Jars Are Different Products

A cosmetic jar is sold by fill weight (30 g, 50 g, 100 g) and judged by the weight in the hand and the sound of the lid. A food jar is sold by volume and judged by whether the seal holds and how fast it fills. They share a mould shop, not a specification.

Cosmetic jars are usually single-wall PET or double-wall PETG. Double wall costs more and feels expensive; it is also heavier to ship. Food jars are PET for cold fill and PP where the product goes in hot.

Sealing, and Where Jars Fail

For cosmetics, the thread and the liner decide whether the cream leaks into the cap. For food, an induction seal liner needs a flat land on the rim; not every jar design has one, and that is worth checking before you print the carton.

Hot fill above roughly 60 C distorts standard PET. For jam and sauces we quote PP, even though clear PET looks better on shelf.

MOQ and Colour

1,000 pcs per colour on existing moulds. Frosting is a surface treatment, not a colour, so it does not add a changeover; spray coat and metallising start at 3,000 pcs.

Single Wall, Double Wall, and What the Rim Does

A single-wall jar is one moulded piece: lighter, costs less, and is the standard for volume skincare. A double-wall jar has an outer shell and an inner cup, so the product never touches the decorated surface and the wall can feel thick without using more resin than necessary.

The rim is where both types fail. Cosmetic jars need a flat land for the liner; food jars need a land wide enough for an induction seal. A 63 mm food jar with a 2 mm land seals reliably; a decorative rim with a 1 mm land does not, and no amount of torque fixes it.

Sealing Methods Compared

Screw cap with a PE gasket: lowest unit cost, recloseable, fine for creams and dry food. Screw cap with an induction liner: a foil membrane seals to the rim, visible tamper evidence, needs a flat land, adds about USD 0.02-0.04 per jar. Pressure-sensitive liner: easier to apply, easier to reseal unnoticed, weaker tamper evidence.

For export food, induction is the safer conversation; for cosmetics, a gasket and a good thread are usually enough.

Decoration and Packing

Frosting is a surface treatment and starts at 1,000 pcs; spray coat, metallising and hot stamp start at 3,000. Jars stack well in cartons, which keeps freight lower than bottles of the same volume: a 250 ml jar ships about 300 per carton against 200 for a 250 ml bottle.

If the jar is double wall, the outer shell and inner cup are packed assembled; the carton quantity is based on the assembled height, not the shell alone.

Applications for This Range

• Distributors stocking three to five SKUs for the same market
• Brands launching a first range at 1,000–5,000 pcs per colour
• Contract fillers who need closures fitted and tested before the line
• Private-label programmes that change colour every season
• Export orders that need packing data before the freight quote

The Guides Behind These Decisions