Category: Cap Lining Materials and Machinery

Cap Liners

Often found yet still rarely realized, inside of many high quality container caps is a material that was placed into the cap prior to the cap being applied on the container or jar.

Sometimes, the end user discover this material.They ask themselves what is the goal of that seal and just how was it put in place? To the astonishment of many, that security seal or freshness seal was put in place with the aid of the cap or lid itself.

Single Piece and two Piece Cap Liners

Individual Piece Cap Liners

Several bottled goods are smaller packs where their contents are required being consumed or used as soon as they are opened. The buyer is not

anticipated to reclose this product or keep product within the container and this kind of product packaging is referred to as one time use packaging. The expected purpose of the lining material or sealing material, in such cases, would be to provide tamper evidence as a protection up until it is opened up. Induction sealing is realized with the aid of single piece materials welded to the peak rim of the jar. Any time you open up a product like this you will observe the aluminium foil across the top of the bottle and when you look into the cap or lid there will not be any other material left from the cap.

2 Piece Cap Liners

Other bottled products and bigger packs usually are not likely to be totally consumed once they are opened. The end user of the product is quite likely going to reclose and store the bottle or container, and thus there is a requirement for a cap the reseals effectively.

As soon as the induction seal has been taken away, there really should still be a material that could result in “friction seal” after the package is closed again. Normally, this is achieved with compressible laminated foam that is around 1 to 2 mm thick.

The soft quality of the foam permit compression as the cap or lid is tightened on the bottle or container. This offers the sort of friction fit tightness which can be kept regardless if the cap or lid is not screwed to its highest possible pressure. Although it is not as effective as a heat induction welded foil, the foam cap inserts supply a resealable seal, permitting the cap or lid can be removed and then replaced and tightened to create a high integrity seal.

Larger sized juice bottles frequently have both a foil lining material and a independent foam lining material. Freshness assurance is justified by the foil while the foam liner provide the resealable capability. For the duration of heat sealing process, the foam element ensures even contact of the foil layer.

When the bottle caps turn loosened while transporting or expand and contract due to temperature or perhaps failed to properly apply, in any case the merchandise integrity and packaging is damaged. With the application of the foil seal on the top of the container, spillage and spoilage are a uncommon occurrence regardless if the caps become loose.

Tamper Evident Seal

When looking into whether to use a pressure sensitive tamper evident seal or an induction seal it is a good idea to understand the core reasons behind applying tamper evident seals and induction seals to bottles and jars. 

For induction sealing the key benefits from that type of seal include: 

1. A visual tamper proof barrier showing the client the contents of this product have not been compromised.
2. An oxygen and moisture barrier, preserving the integrity and shelf life of products.  For this reason alone induction seals are often referred to as freshness seals.
3. Eliminate leaks through caps.  Often plastic caps are well tightened after their bottle has been filled, however temperature changes resulting in slight cap expansion and contraction and the vibration of transport result in caps loosening and product leaking, Eg. Often compromising significant portions of product shipment that become very difficult to retail if not impossible.
4. To provide a professional finish to the product showing the manufacturer cares about the above three major benefits of good product sealing.

For pressure sensitive sealing – sometimes called PS22 Wadding the key benefits from that type of seal are reduced:

1. A visual tamper evident barrier showing the client the contents of this product have probably not been compromised
2. To provide a professional finish that resembles the level of care used by manufacturers using induction sealing.

Pressure sensitive wadding is susceptible to someone that can come along and carefully peel such a liner partially off the neck of a bottle and then simply tighten the cap again to apply pressure and re-seal the bottle; no equipment or tools is required. In this way bottle sealing with pressure sensitive cap sealing is more visual than practical. 

Pressure sensitive cap lining material usually has no foil barrier and therefore has little to no barrier properties to lengthen shelf life or preserve freshness.  Being glue based, many liquid contents are not suitable for pressure sensitive or PS22 cap sealing.

So why do companies choose pressure sensitive sealing materials over induction foil sealing?

In some cases it is ignorance of the induction sealing process and in other cases it is the “poor man’s” version of a tamper evident seal. 

Induction sealing tamper evidence requires induction sealing machinery.  Pressure sensitive sealing requires no machinery.

Safe bench top induction machinery can start at USD$3500.00.  Beware there are many hand held induction machines on offer for sub USD$1000 and manufacturers of that level of equipment refuse to provide safety certifications or advise that they do not “yet” have the certification.

An induction machine is not like a toaster or a kettle so beware of anyone offering toaster or kettle prices for induction sealing equipment.  An induction machine deals with high currents and produces high levels of magnetic and electrical fields. 

If you find a retail product on the shelf with a pressure sensitive seal be aware that while it looks like it is tamper proof it is at best only ‘tamper evident’.  The company producing that product is taking the cheapest path to providing you with a look that resembles but in no way performs like an induction seal or a tamper proof seal.