Paperboard is a thick, paper-based material. It is stronger than regular paper but still light and easy to shape. Paperboard is used to create boxes, food containers, and packaging for many products.
Paperboard is important in the packaging industry. It helps protect items, show off designs, and reduce waste. Many companies use it because it is affordable, recyclable, and easy to print on.
Now, let’s explore the different types of paperboard and how it is made.
Types of Paperboard
There are many types of paperboard. Each one has its own properties. Let’s look at the four main types of paperboard used in packaging:
1. Solid Bleached Sulfate (SBS)
SBS paperboard is white on both sides. It is made from wood pulp that is bleached during production. This makes it very clean and smooth.
Key Features:
- Bright white surface
- Great for printing and colors
- Strong and smooth
- Used for cosmetics, medicine boxes, and luxury packaging
SBS is perfect when brands want a high-end look. It is also safe for food and is often used in frozen food boxes and milk cartons.
2. Coated Unbleached Kraft (CUK)
Coated unbleached Kraft (CUK) is brown on one side and white on the other. It is made from strong, unbleached natural brown wood fibers. The top layer is coated to make printing easier.
Key Features:
- Natural brown look
- Strong and tear-resistant
- Used for drinks, tools, and heavy items
CUK is strong and can handle moisture. It is common for strong retail packaging, like hardware and laundry detergent.
3. Chipboard
Chipboard is made from recycled paper. It is the most eco-friendly option. It is not as strong as other types, but it works well for many products.
Key Features:
- Made from recycled paper
- Less expensive
- Used in puzzles, notepads, and shirt boxes
Chipboard is best for dry items and indoor use.
4. Corrugated Paperboard
Corrugated paperboard is thick and strong. It has three layers, two flat sheets and one wavy layer in between. This makes it strong and perfect for shipping.
Key Features:
- Very strong and durable
- Great for shipping boxes
- Protects items during delivery
Corrugated paperboard comes in different thicknesses. Some have more layers (flutes) for extra protection.
How is Paperboard Produced?
Paperboard is made in several steps. Each step helps turn wood into strong and thick sheets of board. Let’s go through these steps one by one.
1. Raw Materials Used
The first step is collecting raw materials. Most paperboard is made from wood. Some use recycled paper, too.
Common materials:
- Softwood trees like pine (strong fibers)
- Hardwood trees like birch (smooth finish)
- Recycled paper or old boxes
Trees are cut into chips and sent to a mill where the real process begins.
2. Pulping Process
Next is pulping. This is when wood chips are turned into pulp. Pulp is a mix of water and wood fibers.
There are two ways to make pulp:
- Mechanical Pulping: Uses machines to grind the wood.
- Chemical Pulping: Uses chemicals to break down wood and remove lignin (a sticky material in wood).
Bleaching may be done to make the pulp white, especially for SBS boards.
3. Forming the Paperboard
Once pulp is ready, it is sprayed onto a moving screen. Water drains out, and fibers begin to form a sheet. This is done using a Fourdrinier or cylinder machine.
This sheet is still wet and soft. It goes through more steps to make it stronger.
4. Pressing and Drying
The wet sheet is pressed to remove more water. Then it goes through heated rollers to dry it completely.
This step makes the paperboard flat and strong. It also helps remove any extra moisture that could cause damage later.
5. Coating and Finishing
After drying, a coating may be added. Coatings help improve the look and feel of paperboard.
Common coatings:
- Clay coating: for better printing
- Polyethylene: add moisture resistance and protect the board from damage
- Gloss or matte finish: for style
Some paperboard is printed at this stage, while others are left plain for future printing.
6. Cutting and Packaging
The last step is cutting. The large rolls or sheets are cut into the right size for boxes or other packaging.
The paperboard is then packed and sent to companies that use it to make packages, cartons, or displays.
