Liquid packaging board
Encyclopedia
Liquid packaging board is a multi-ply paperboard
with high stiffness, strong wet sizing
and a high barrier coating. Only virgin paper fibers
are used. The barrier coating must hold the liquid and prevent migration of air and flavors through the paperboard.
from bleached or unbleached chemical pulp, CTMP or broke (waste paper from a paper machine). CTMP gives more bulk and stiffness. The top ply (inside) is made of bleached chemical pulp. The barrier coating depend of the application and might be applied on both sides. The back side of the board is the printing side and might have an extra ply made from chemical pulp of quality that is suitable for the printing
applications. Liquid packages are normally heat sealed
.
Cartons filled with short shelf life diary products use board that are barrier coated on both sides with one layer of low density polyethylene
. For long shelf life products is is common to use aluminium foil
as barrier coating together with polyethylene. Commonly the plastic coating on the top side is 12 - 20 g/m2 and on the reverse side 15 - 60 g/m2.
Liquid packaging board are used for two package types: brick and gable top carton
s.
Paperboard
Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper. According to ISO standards, paperboard is a paper with a basis weight above 224 g/m2, but there are exceptions. Paperboard can be single...
with high stiffness, strong wet sizing
Wet strength
Wet strength of paper is a measure of how well the fibreweb is holding together upon a force of rupture. Wet strength is routinely expressed as the ratio of wet to dry tensile force at break.-Mechanism:...
and a high barrier coating. Only virgin paper fibers
Pulp (paper)
Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops or waste paper. Wood pulp is the most common raw material in papermaking.-History:...
are used. The barrier coating must hold the liquid and prevent migration of air and flavors through the paperboard.
Manufacture
A liquid packaging board might be up to five plies and is formed on a multi-ply paper machine with online coating. The most common is to use three plies with a basis weight of about 300 g/m2. The base or middle ply is normally made of pulpPulp (paper)
Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops or waste paper. Wood pulp is the most common raw material in papermaking.-History:...
from bleached or unbleached chemical pulp, CTMP or broke (waste paper from a paper machine). CTMP gives more bulk and stiffness. The top ply (inside) is made of bleached chemical pulp. The barrier coating depend of the application and might be applied on both sides. The back side of the board is the printing side and might have an extra ply made from chemical pulp of quality that is suitable for the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
applications. Liquid packages are normally heat sealed
Heat sealer
A heat sealer is a machine used to seal products, packaging, and other thermoplastic materials using heat. This can be with uniform thermoplastic monolayers or with materials having several layers, at least one being thermoplastic...
.
Cartons filled with short shelf life diary products use board that are barrier coated on both sides with one layer of low density polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
. For long shelf life products is is common to use aluminium foil
Aluminium foil
Aluminium foil is aluminium prepared in thin metal leaves, with a thickness less than , thinner gauges down to are also commonly used. In the USA, foils are commonly gauged in mils. Standard household foil is typically thick and heavy duty household foil is typically .The foil is pliable, and...
as barrier coating together with polyethylene. Commonly the plastic coating on the top side is 12 - 20 g/m2 and on the reverse side 15 - 60 g/m2.
Liquid packaging board are used for two package types: brick and gable top carton
Carton
Carton is the name of certain types of containers typically made from paperboard which is also sometimes known as cardboard. Many types of cartons are used in packaging. Sometimes a carton is also called a box.-Folding cartons:...
s.
Applications
- Packaging for beverages. The most common applications are milkMilkMilk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
and juiceboxJuicebox (container)A juice box, also called a carton or popper, is a small container used to conveniently carry and consume drinks . They are frequently made of paperboard with an aluminium foil lining, but variations exist...
packaging.