Folding Carton 101

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What is cartonboard? We are glad you asked!!!

What is cartonboard?
Cartonboard (AKA: chipboard) is the raw material used in paperboard carton production. Even though all cartonboard is manufactured from renewable resources there are 4 distinct grades: solid bleached sulfate board, solid unbleached sulfate board, clay coated newsback, folding box board and white lined chipboard.

All chipboard grades are manufactured using a multi ply construction and the differences in what is used to make each individual layer is what makes the differences between the four grades. Some use 100% pulp as the raw material and some use 100% recovered fiber and some use a combination of both.

Solid Bleached Sulfate Board (SBB/SBS/GZ): This grade is made from pure bleached chemical pulp

Solid Unbleached Sulfate Board (SUB/SUS):
This grade is made from pure unbleached chemical pulp

Clay Coated Newsback (CCNB): This grade is made from recycled paperstock.

Folding Boxboard (FBB/GC/UC): This grade is made from layers of mechanical pulp layered between chemical pulp

White Lined Chipboard (WLC/GD/GT/UD): This grade is made from recovered fibres.

Properties of Cartonboard:

  • Weight: The weight of the cartonboard in grams
  • Thickness: The distance between the two surfaces of the cartonboard sheet.
  • Density: How compact the cartonboard is (kg/m3)
  • Bulk: How bulky the cartonboard is (m3/kg)
  • Machine Direction: Pulp fibres are aligned parallel to the direction in which the cartonboard web is moving. This means the cartonboard is stiffer and stronger in that direction… therefore, the machine direction is at right angles to the width of the web.
  • Stiffness: Probably one of the most important properties of cartonboard. Throughout the entire life span of a package (shipping>store shelf>consumer) the demand for stiffness occurs. If a cartonboard does not provide the adequate stiffness it is not going to provide its primary function of protecting the contents of the package.
  • Compression Strength: Compression strength is how strong the bottom package is when stacking cartons on top of each other. To avoid the stacked cartons from collapsing good compression strength is needed.
  • Tear Strength: This is the amount of force needed to tear a cartonboard open along an existing incision.
  • Surface Strength: This is a cartonboards ability to tolerate forces on its surface.
  • Surface Smoothness: How smooth the cartonboards surface is.
  • Dimensional Stability: How resistant is the cartonboard due to dimensional changes in properties such as moisture content.
  • Flatness: The carton boards ability to remain flat
  • Whiteness: How white the cartonboard looks to the eye
  • Brightness: The “brightness” of cartonboard is used in two different contexts.
    1. How intense the colors (how light or dark an image is) are in image reproduction.
    2. The percentage of light that is reflected from the cartonboard surface at a wavelength of 457nm.
  • Gloss: The more light reflected by the cartonboard, the higher the gloss. You can manipulate gloss by using various varnishing methods.
  • Opacity: The measurement of the capacity of cartonboard to hide what lies behind it. A high percentage corresponds to a cartonboard sheet with low transparency (high opacity).

 

Printing Methods 

Offset:
This is the most common form of printing cartonboard.  In this method the cartonboard sheets are sheet-fed offset.  Offset is referred to as an “indirect” printing method.  The ink is not transferred to the cartonboard sheet from the printing plate.  The printing cylinder sets off the printing ink onto a rubber-covered blanket cylinder, which transfers the ink/printing image to the cartonboard sheet.