Product Properties

Many factors contribute to the production of high-quality liquid packaging board. At Weyerhaeuser, we measure product quality using these important properties:

Purity

All over the world, our products hold food and drink for human consumption. To help keep people safe and healthy, we ensure that our liquid packaging board is free of taints, odors, and microbiological and other contaminants by paying stringent attention to housekeeping and paper manufacturing methods. Our liquid packaging board is checked for imperfections using 100% low-angle camera inspection in multiple locations.

Appearance

Attractive packaging is not only essential for successful sales, but also for clear communication of product information. Appearance is influenced by board brightness, whiteness, and smoothness. Brightness is the percentage of light reflected from the board surface. Whiteness is also determined by a reflective test, but it measures the yellowness and blueness (known as b*) of the board. The necessary level of brightness and whiteness depends on the type of printing that will be used and other aesthetic goals.

Proper smoothness of the board surface, which is impacted by coating finish and properties of the paper fibers, is also a critical factor for achieving printing goals. Smoothness is determined by measuring short and longer wavelength toughness as well as surface topography.

Runnability

For efficient production with little waste, liquid packaging board must perform well during cutting, folding, and conversion into containers. No single measurement specifies good runnability; however, uniformity is critical. Key properties for optimum runnability include board flatness, creasing and folding properties, and moisture content.

Sealability

The polymer coating on liquid packaging board not only acts as a barrier, but also as a bonding agent. During filling, when cartons are formed on machines, the polymer coating is melted using heat in areas that are critical to creating the container's shape. The heated surfaces are then pressed together and held while the coating rehardens.

Durability

Liquid containers must withstand jostling, jolting, and dropping during transportation, and they should avoid leaking when resting on store shelves or in home refrigerators. This kind of durability is achieved by selecting the right coating and board strength for the application.

Grip Firmness and Bulge

The finished containers must have appropriate grip firmness so they do not feel soft when handled, while unwanted carton bulge can affect product appearance and detract from an image of quality. Grip firmness is influenced by board stiffness. Carton bulge can be minimized by balancing board stiffness and coating weight against the storage conditions. Bulge can also be reduced by keeping cartons in crates for as long as possible prior to their display in retail refrigerators, by minimizing the storage time, and by maintaining lower humidity during storage.