GL18, White, Integrated Liner EPE

EPE stands for expanded polyethylene — a lightweight, chemically inert foam material. The EPE liner disc sits inside the closure cap and compresses against the glass bottle rim when tightened, creating a mechanical seal that prevents leakage and contamination. It provides no additional barrier enhancement beyond the primary seal, making it the entry-level liner option in the GL18 system — appropriate for cosmetic and personal care formulations that do not require oxygen, moisture, or chemical barrier protection.

Both the GL18W-ILE and the GL18W-SSC are standard screw caps with no tamper-evident ring, but they use different sealing mechanisms. The self-seal closure (GL18W-SSC) uses an integrated membrane that creates a hermetic seal on first application. The GL18W-ILE uses an EPE foam liner disc that compresses against the bottle rim on tightening — a mechanical seal that remains in place across repeated openings and closings. The self-seal is typically used for single-access or first-seal applications; the EPE liner is appropriate for products that will be opened and reclosed multiple times during use.

EPE is appropriate for formulations that are not sensitive to oxygen or moisture ingress and do not contain chemically aggressive ingredients. If your formulation is oxygen-sensitive — such as vitamin C serums or retinol preparations — a PET or aluminium lining is more appropriate. For essential oils, solvents, or high-concentration actives, a PTFE (Teflon) liner provides the highest chemical resistance. For pharmaceutical oral drops, butyl rubber is the standard specification. Contact BlueSky’s team to discuss liner selection for your specific formulation.

The GL18W-ILE fits all GL18 glass dropper bottles in the BlueSky range — 5ml, 10ml, 15ml, 20ml, 30ml, 50ml, and 100ml — in both amber and clear glass. As a standard screw cap, it does not include tamper-evident or child-resistant features. For applications requiring tamper evidence, BlueSky’s OVII or OVIII GL18 closures are available. For child-resistant applications, the GL18 CRC closure (ISO 8317) is the correct specification. All closures and accessories within the GL18 system are interchangeable across the full bottle range.