Board Lamination

The basic paperboard products are produced in a limited range of thicknesses because of the need for efficiency in paperboard manufacture. However, this thickness and stiffness range is extended considerably when two or more layers of paperboard are glue laminated together into equal-sided products with the same smooth and white printing surface on both sides. The many raw materials available provide numerous combinations so that many customer needs may be met.

Laminated paperboard offers good rigidity and smoothness which, when combined with excellent visual appeal, makes the package look more attractive to the consumer in the store. 

Laminated paperboard is smooth and flat with good cohesion and adhesion. The combination of stiff­ness and converting possibilities makes it suitable for the packaging of expensive and luxury products.

Packaging that will come in direct contact with foodstuffs must be designed for each specific end use.

Evaluation of paperboard lamination

Most of the evaluation is done off-line. The aim is to determine and document that:
• the glue covers the whole web
• the glue keeps the webs together after drying
• the sheets are flat and free from twist
• the pallets are flat
• there is no damage (e.g. indentations) to the surfaces
• there is no visible dust or loose particles that can disturb the converting operation.




7. Unwinding

The glue lamination machine has four unwind stands.

8. Drying

IR (infra-red) driers are used to control the shape of the sheets.

9. Gluing

Water-based adhesives are used to glue the board webs.

10. Press Nip

After gluing, the webs are pressed together.

11. Sheeting and Stacking

The glued board is sheeted and stacked on pallets in line.

Evaluation of extrusion coating and lamination

This process lends itself to control and continuous monitoring of the coat weight, coating profile, thickness and moisture profiles during production.

The following properties are measured off-line:
• adhesion
• surface smoothness (printing side, reverse side)
• surface tension (treated side)
• pinholes
• flatness of the sheet
• heat sealability (where applicable)
• odour and taint neutrality
• surface defects
• blistering (where applicable).

Conversion operations in practice

Slightly different settings and techniques are necessary with extrusion-coated and laminated products in printing, die-cutting, creasing, gluing, and sealing. They are well established and do not cause problems in practice.

Low odour printing inks and the programmed airing of pallets are important to prevent the absorption of taint into the plastic coating. Always use well-proven procedures as prescribed by the printing ink supplier.

Uniform coat weight is important for successful conversion.

When paperboard is glue laminated together to give a thicker and stiffer product, the following changes should be considered:


Conversion operation
  Considerations for extrusion coated and laminated products
  Printing on a plastic-coated surface requires corona treatment of the plastic to make it wettable. In addition, the basically non-absorbent nature of the surface requires the use of printing inks that do not require absorbency. Such inks are available and they can also be used on pigment coated surfaces.
Die-cutting and creasing
  Plastic-coated or laminated products with an extra tough layer like PET should preferably be die-cut from the plastic-coated side. In general, plastic surface layers improve creasability because they have very good elongation before breaking and tend to reduce the risk of surface cracking in the creases compared with plain paperboard.
  Corona treatment improves the sealing characteristics and permits the gluing of one-side PE-coated paperboard with emulsion adhesives.

The friction between the blanks should be considered, especially when they are made with a glossy PE on the outside. The glossy corona-treated surfaces may tend to stick together if not protected with printing ink or varnish plus spray powder.

Such sticking or blocking tendencies may also appear in some packing lines if the unprinted glossy PE has to slide past polished steel guides. The remedy is to use varnish and spray powder on the exposed areas of the paperboard.


Conversion operation
  Considerations for glue laminated products
  Stiffness may make flatbed printing necessary. Two-side pigment coating means that the reverse side is as smooth as the printing side. This can cause printing ink set-off.
Die-cutting and creasing
  Creasing must be carefully evaluated; the thicker products will need double creasing or scoring. Die-cutting and creasing will require higher pressure; this may affect the wear of the dies.
Gluing   Gluing is done pigment coating to pigment coating. This procedure will be slightly different compared to gluing the printing side to the normal reverse side. The higher stiffness and different creases will give much higher spring-back force, so glue seams must be well developed before pressure is released.


Iggesund Paperboard
825 80 Iggesund

+46 650 - 280 00

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