Liquid packaging board is a multi-ply

paperboard Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.30 mm, 0.012 in, or 12 Inch#Equivalents, points) than paper and has certain superior ...

with high stiffness, strong wet sizing and a high barrier

coating A coating is a covering that is applied to the surface of an object, or substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. powder coatings. Paints ...

, e.g.

plastic Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding ...

. Only virgin paper fibers 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 Grammage and basis weight, in the pulp and paper industry, are the area density of a paper product, that is, its mass per unit of area. Two ways of expressing the area density of a paper product are commonly used: * Expressed in grams (g) per ...

of about 300 g/m². The base or middle ply is normally made of pulp from bleached or unbleached chemical pulp, chemi-thermo-mechanical 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 depends on the application and might be applied on both sides. When induction welding is employed an aluminum foil layer is used for barrier protection and for heating. 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 is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ...

applications. Liquid packages are normally heat sealed. Cartons filled with short-shelf-life

dairy products Dairy products or milk products are food products made from (or containing) milk. The most common dairy animals are cow, water buffalo, goat, nanny goat, and Sheep, ewe. Dairy products include common grocery store food around the world such as y ...

use board that are barrier coated on both sides with one layer of low density

polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bott ...

. For long-shelf-life products it 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. Sanitary and

aseptic processing Aseptic processing is a processing technique wherein commercially thermally sterilized liquid products (typically food or pharmaceutical) are packaged into previously sterilized containers under sterile conditions to produce shelf-stable products ...

of food contact products are critical.

Uses

Liquid Packaging Board (LPB) is traditionally associated with beverage packaging, including for

milk Milk is a white liquid food produced by the mammary glands of lactating mammals. It is the primary source of nutrition for young mammals (including breastfeeding, breastfed human infants) before they are able to digestion, digest solid food. ...

, juiceboxes and other dairy products, but its applications extend beyond just liquids, encompassing a broad range of uses due to its strength, barrier properties, and versatility. Liquid packaging board is used for two package types: brick and gable top

carton A carton is a box or container usually made of liquid packaging board, paperboard and sometimes of corrugated fiberboard. Many types of cartons are used in packaging. Sometimes a carton is also called a box. Types of cartons Folding cartons ...

References

{{packaging Paperboard Packaging materials

Manufacture

Uses

See also

References