Cap wadding system: Importance of caps and liners

Cap wadding system

For the packaging industry, a perfectly sealed product is one of their priorities, since this characteristic also determines the safety with which the product can be transported by a cap wadding system.  

In the case of containers, it is very important to first consider the material with which they were manufactured.

PET, for example, is a material used mainly by the water and carbonated beverage industry, since the characteristics of bottles made of this material are ideal, since they are flexible, resistant to impact and gases, light, among other qualities; however, they are also used by the beauty or pharmaceutical industry. 

HDPE containers, on the other hand, are most requested for the chemical, agrochemical, cleaning products or corrosive industries.  

  • Lids

While choosing the ideal material according to the product to be packaged, the choice of the right lid and liner is fundamental, as these accessories will determine the safety of the container during storage and transportation. 

The first step to make a good choice is to make sure that the cap is made of a resistant material and has the necessary quality, there are caps of different sizes according to the container, drum or bottle. 

For example, our containers that are ideal for beverages such as Multimax and Boston use the 28 mm thread size, that is, these bottles are compatible with R-28 mm caps. Short neck with liner less and safety band, Push-Up R-28 mm. 

With liner less, R-28 mm. Flip Top with liner less and R-28 mm. Flip Top short neck with liner less. Each of the closures has very specific characteristics according to the use that will be made of the container of the cap wadding system

  • What are liners?

Liners are a kind of seals that are placed between the mouth of the bottle and the cap. They are made of different materials, the most common used for PET containers is the induction liner, but there is also the liner less and the foamed liner.

  • Inductive liner

The inductive liner is composed of 4 layers, a heat-sealing film that adheres to the contour of the container, the foil that gives it color, an adhesive film and a cardboard backing. What the inductive equipment does is to separate the heat-sealing layer and adhere to the contour of the container lip and separate it from the cardboard backing. 

Compatibility depends on the heat-sealing film on the foil; it has a different composition for PET and HDPE containers. The induction is an electromagnetic charge that will be exerted on the liner to make a perfect seal. The sealing equipment works with a constant voltage system.

  • Foamed liner

This type of liner is manufactured with a soft polymer, the sheet that composes it is covered by a very thin foam layer. Hermetic sealing with this type of accessory maintains freshness, prevents leakage of liquid products, and avoids the passage of air, bacteria or any other contaminating agent. 

It is recommended for alcohol, beverages, cosmetics, etc. It is very resistant to use, so the container can be closed and opened without fear of damaging the neck of the bottle or the liner itself. 

  • Valved Liner

This type of seals of a cap wadding system is used for products with gases such as carbonated beverages, chemicals or agrochemicals, it allows to balance the pressure generated inside the container and the outside, it helps the container not to deform, explode or leak due to the gases generated.