Pick Paperboard Like a Pro

A few weeks ago, we blogged about four common types of paperboard and how to use them. This time we’re sharing the most important properties of paperboard. These characteristics affect performance, printability, and so much more. By understanding these basic variables and how they can help or hinder customers’ design goals, converters can easily choose the right kind of board for every job. 

Basic Properties

Caliper: Thickness of the board measured as thousandths of an inch or points. Paperboard ranges in thickness from 10 to 40 points (thousandths). In Europe, board is measured in millimeters or micrometers. 

Basis Weight: The weight of the board per unit area—generally pounds per thousand square feet. European converters use grams per square meter.

Moisture Content: The amount of water in the board, expressed as a percentage. Excessively dry or wet board will gain or lose moisture, resulting in property changes that converters must take into account. 

Density: The relationship between basis weight and caliper. For example, when two sheets of paperboard have the same weight but different calipers, the sheet with the higher caliper will have a lower density.

Performance Properties

Stiffness:The durability or strength of a particular board. Often measured in “Taber Units,” stiffness varies significantly between grain and cross-grain directions and will also vary with moisture content.

Scoreability: Ability of paperboard to bend (or fold) cleanly through 180° without surface fracture or flaking.

Compression: Resistance to collapse under pressure.

Tear: The ability to resist tearing in a predictable or controlled manner.

Flatness: Resistance to curling or unwanted curvature of the sheet. Curling can cause problems like mis-registration during the printing process.

Surface Strength: The ability of a board’s front and back surfaces to maintain integrity (i.e., no flaking, shredding, or linting) through the converting process.

Surface Properties

Smoothness: The opposite, or the lack, of roughness. Smoothness may be measured through several different methods and often relates to printability.

Slip: The measure of how much paperboard will move or slide during the converting, packaging, and distribution processes. High-slip boards may be more difficult to keep stacked in place during shipping. 

Absorption: The measure of how paperboard either absorbs or resists water.

Gluability: The ability to make a secure (fiber tearing) bond between surfaces of paperboard.

Appearance: The (largely subjective) evaluation of the evenness and opacity of a paperboard’s surface(s).

Color/Shade: The appearance of a board’s outer surface under different light sources.

Gloss: How much light reflects off the surface of paperboard (typically the outer surface). High-gloss boards have a brilliant, shiny character. 

Brightness: How intensely white a paperboard appears, defined as the percent of surface reflectance measured using a standardized testing method such as TAPPI Standard T 452m.

There is a lot to remember here, but in time, every converter can master the variables and qualities of our industry’s versatile substrate. To learn more about paperboard, including how it’s made, designed into exciting packaging, and recycled for multiple uses, sign up for PPC’s upcoming Folding Carton Boot Camp.