Moving the Foil to the Top A Container Seal You Can See Through Before You Break It

This application covers the peelable foil seal found under the cap of a jar or bottle, rebuilt so that the metal foil sits in the upper layer of the laminate instead of the lower one. The applicant is Selig, one of the larger suppliers of closure liners to the packaging industry. Moving the foil upward makes the part of the seal that stays against the container transparent, thinner and cheaper, and it is a deliberate inversion of how induction sealing has been done for decades.

The Problem

The inner seal across the mouth of a container has to do two contradictory things. It has to bond hard enough to the rim to survive shipping, shelf life and tampering, and it has to come off cleanly in the hand of a consumer who has just unscrewed the cap. The earliest versions were plain discs, sealed well, and were close to impossible to remove without picking at the edge with a fingernail.

The industry’s answer was the tab. A side tab extending past the rim gives something to grip, but it protrudes into the threads of the closure, where it gets crushed and wrinkled when the cap goes on, and if it is made large enough to grip properly it starts to interfere with the seal itself. Top tabs solved the gripping problem by folding a full extra layer over the top of the seal, bonded to only half of it, but that means paying for a whole additional layer of film and adhesive across the entire disc to get a tab covering part of it.

There is a deeper structural problem underneath both. In a conventional seal, the aluminium foil that absorbs the induction energy is placed in the lower laminate, right next to the heat seal layer, because that is where the heat is needed. Foil in that position has to be insulated and reinforced so it does not tear when the consumer pulls, and each reinforcing layer makes the lower laminate thicker and more expensive. Even then it can still tear.

The foil also makes the seal opaque. With metal in the lower laminate, nobody can see the contents of the container until the seal has been destroyed, which matters for retail inspection, for quality control and for the consumer deciding whether the product is what they expected. And when the seal is designed to tear along a line to leave a pour spout behind, the extra layers frequently tear unevenly or not at all, leaving a jagged remnant or no spout.

What This Invention Does

The claimed sealing member is a multi layer laminate with an upper laminate portion partially bonded to a lower laminate portion. Where they are bonded, they behave as one seal. Where they are not, the upper portion lifts free to form a gripping tab, and because it is defined by the bonding pattern rather than by an added strip, the tab can be made large without adding an entire extra layer of material.

The inversion is the key limitation. The induction heating layer sits in the upper laminate. The lower laminate, the part actually welded to the container rim, is claimed as free of metal foil, containing at least a heat seal layer and a support layer. Induction heat is generated further from the bond it is meant to create, and has to conduct down through the intervening layers rather than being produced right at the interface.

The trade goes the other way on almost everything else. Without foil in the lower laminate, that portion can be transparent or translucent, so the contents are visible through the intact seal. It no longer needs the insulating and reinforcing layers that were there to protect the foil from tearing, so it can be downgauged, which cuts both cost and total seal thickness. And because the foil is on the far side of the split, it leaves with the tab rather than fighting the peel.

A second family of claims addresses the peel itself. The heat seal layer can carry a plurality of adhesive portions with different bond strengths, so the seal releases progressively rather than all at once, a differential peel. That is also what makes a reliable pour spout possible: a defined region of the lower laminate is engineered to stay bonded to the container when the rest of the seal is removed, so the remnant forms the spout by design rather than by accident.

The application claims three things in parallel: the finished sealing member, the laminate stock from which it is cut, and the combination of container and seal as a system. Optional layers named in the specification include a polymer foam layer, a polymer film layer, a tab layer in either portion, a liner, and barrier films of SiOx, AlOx or EVOH.

Key Features

• Induction layer in the upper laminate. The heating layer is moved above the split, contrary to conventional tabbed seals where it sits next to the heat seal.
• Foil free lower laminate. The portion bonded to the container carries only a heat seal layer and a support layer, so it can be thinner, cheaper and less prone to tearing under peel.
• Transparent or translucent seal. With the metal removed from the lower portion, the contents of the container can be seen through the seal before it is opened.
• Tab formed by partial bonding. The gripping tab is created by bonding the upper laminate to only part of the lower laminate, and can be defined wholly within the perimeter of the seal rather than protruding into the closure threads.
• Differential peel adhesive. The heat seal layer can use adhesive regions of different bond strengths so the seal releases progressively instead of in a single jerk.
• Engineered pour spout. A defined portion of the lower laminate is designed to remain on the container after removal, forming a spout for liquids or powders instead of a jagged remnant.

Who Is Behind It

Selig Sealing Products traces back to a business founded in Chicago and is now part of the Selig Group, a supplier of closure liners, induction and conduction seals, lidding and container sealing systems to the food, beverage, pharmaceutical, personal care and industrial chemical markets, with manufacturing in the United States, Europe and Asia. Its Lift n Peel tabbed induction seal is one of the more widely used tabbed liners in the sector.

On ownership, the company is not part of a business called CC Wrappers. Selig Sealing Holdings was sold by Behrman Capital to CC Industries in August 2015, and CC Industries is the holding company for the privately held operating businesses of the Chicago based Crown family office, Henry Crown and Company. Under that ownership Selig has continued to consolidate the liner market, acquiring Performance Systematix and the French foam liner maker Manufacture Generale de Joints in 2021.

The sole named inventor is Robert William Thorstensen Woll, a prolific inventor on Selig’s sealing filings whose name appears across much of the company’s tabbed seal portfolio. The application is a divisional of Australian application 2020392113, the national phase of PCT/US2020/062231 filed on 25 November 2020, which claims the benefit of United States provisional application 62/941,912 filed on 29 November 2019.

Why It Matters

Closure liners are a high volume, low unit cost business where a fraction of a cent per seal, multiplied across billions of containers, decides who wins a contract. Removing an insulating layer and a reinforcing layer from the lower laminate and downgauging what remains is exactly the kind of change that shifts a tender. The visibility argument is a separate commercial lever: a seal you can see through allows a filler, a retailer and a consumer to inspect contents without breaking tamper evidence, which has value in both quality control and returns handling.

The technical trend running through this is the unbundling of functions that used to be carried by a single foil layer. Historically the foil was the induction susceptor, the oxygen and moisture barrier, and part of the structural strength of the seal all at once, which is why it had to sit where the heat was needed. Once thin film barriers such as SiOx, AlOx and EVOH can carry the barrier duty independently, the foil is free to be relocated to wherever it works best, and the design becomes a heat conduction problem rather than a materials constraint.

The filing pattern is a standard one for a mid sized industrial supplier with a defensible product line. A 2019 United States provisional taken through PCT to an Australian national phase and then divided in 2026 keeps the family alive for the full term while allowing the claim scope to be reshaped as competitors respond. Australia is a modest market for closure liners in its own right, but it is a jurisdiction where local converters supply a large dairy, wine and agricultural chemical packaging base, which makes it worth holding.

Related Concepts

• Induction sealing – the process this liner is designed for, and the convention it inverts.
• Aluminium foil – the induction heating layer whose position defines the invention.
• Eddy current – the mechanism by which the induction coil heats the foil without touching it.
• Lamination – the multi layer construction technique behind the sealing member.
• Ethylene vinyl alcohol – one of the barrier films that lets the foil be relocated.
• Closure (container)) – the cap over the seal, and the source of the tab crushing problem.

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AU 2026202083 was published in the Australian Official Journal of Patents on 9 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.