Generally speaking, there is no strict differentiation between paper and paperboard. However, paperboard is generally thicker (usually 12pt or 0.012″ in thickness or more). Because it’s both lightweight and strong, it’s easily cut and formed—perfect to use in packaging products.
Paperboard packaging is available in several different grades, each with unique features suitable for different packaging needs. The most popular grades of paperboard packaging are:

  • • Solid Bleached Sulfate (SBS)
  • • Coated Unbleached Kraft (CUK Board)
  • • Coated Recycled Board (CRB)
  • • MET- PET Board

Also known as Corrugated

Corrugated material is available in different wall thicknesses, known as flutes sizes. Each flute size has a particularly useful function, from shipping strength to reducing storage space to improved printability.

Corrugated material is comprised of three fiberboard layers; two linerboards sandwich a middle sheet that is in a wave-shaped pattern of arches known as flutes. These flutes are anchored to the linerboard with an adhesive.

On end, flutes form rigid columns, capable of supporting a great deal of weight. From the side of the board, the space between the flutes acts as a cushion to protect the container's contents. Flutes also serve as an insulator, providing protection from sudden temperature changes. The linerboard provides additional strength and protects the flutes from damage.

At a Glance

  • • Corrugated material is available in different wall thicknesses, known as flutes sizes
  • • A-Flute is 1/4 inch thick, greatest cushioning for fragile products
  • • C-Flute 3/16 inch thick, commonly used for shipping cases
  • • B-Flute is 1/8 inch thick, flatter surface for higher quality printing and die cutting
  • • E-Flute is 1/16 inch thick, a strong alternative for paperboard folding carton

Solid Bleached Sulfate
Also known as bleached paperboard, this is a premium paperboard grade produced from a finish containing at least 80 percent virgin bleached wood pulp. Most bleached paperboard is coated with a thin layer of kaolin clay to improve its printing surface and may also be coated with polyethylene (PE) resin for wet strength food packaging. SBS is most popular in the United States.

Major markets that use SBS:

  • • Medical packaging
  • • Cosmetic and perfume packaging
  • • Candy boxes
  • • Stand up displays
  • • Other high-quality packaging

This grade of paperboard mainly comes in two variations.

Also known as Solid Unbleached Sulfate (SUS®), this is a superior strength paperboard grade produced from a furnish containing at least 80 percent virgin unbleached, natural wood pulp. Most unbleached or natural kraft paperboard is coated with a thin layer of kaolin clay to improve its printing surface and may be also coated with polyethylene (PE) resin for wet strength food packaging.

Major markets that use CUK:

  • · Heavy duty packaging
  • · Frozen food packaging
  • · Beverage carrying containers
  • · Pharmaceutical packaging

Mainly SBS paperboard with metalized polyester film mounted on top (Silver, Rainbow, Gold, Patterns, etc.).

Major markets that use MET-PET Board:

  • · Media packaging
  • · Medical packaging
  • · Pharmaceutical packaging
  • · Signage
  • · Display packaging

Coated Recycled Paperboard
Also known as Clay Coated Newsback (CCNB), this material is typically coated with a thin layer of kaolin clay to improve its printing surface. It is produced from 100 percent recycled paperboard including old containers, newspapers, box board clippings and selected whites.

Major markets that use CRB:

  • · Soap and laundry detergent packaging
  • · Paper goods packaging (facial tissue and napkins)
  • · Cereal cartons
  • · Light bulbs
  • · Dry food stuffs (FDA compliant)

Window patching is a technique that incorporates a window film on a carton or any other product packaging serving a dual purpose.

The window provides a glimpse of the product. It is often to tease a product, creating excitement within the customer, therefore naturally enhancing their unboxing experience. The decision to add a window film patch will naturally, depend on the nature of the product.

Other Films

  • · Polypropylene is the most common material to pack candy, snacks and baked goods.
  • · Polyethylene is for frozen food products.
  • · Foil lamination is ideal for light and air sensitive food products.
  • · poly(ethylene terephthalate) film (PET)
  • · Polyester, (Polyethylene Terephtalate). Tough, temperature resistant polymer. Biaxial oriented PET film is used in laminates for packaging, where it provides strength, stiffness and temperature resistance. It is usually combined with other films for heat sealability and improved barrier properties

The Window Patching Process

Depending on the type of machine being used for the window patching, typically, the plastic film will stick instantly to the packaging material without any drying time. It is ready to package instantly once it is released from the machine.
  • · Die-cut cartons are fed print side down through the window machine.
  • · A pattern of adhesive is applied to the carton blank
  • · The roll of window material is unwound and cut to length
  • · This “patch” is transferred to a vacuum cylinder
  • · At the precise moment, the vacuum is released, and the patch is compressed onto the carton as it passes below.

Yes, polyester is actually PET. When used for clothing it is called Polyester. Polyethylene terephthalate (PET) is the chemical name used for the clear material used in the packaging industry.

Polyethylene Terephthalate is a plastic they call PET for short. It has see through clarity. Window Boxes and clear boxes are made from PET. Another name for PET is A-

APET is PET and the A is for the word Amorphous. Amorphous means completely transparent (soda bottles and clear sheeting). This is the most common state referred to as PET (the A is not usually said or used).

PET-G is PET, but with Glycol added. The Glycol makes the material softer and easier to bend. This is a higher price point material usually reserved for thicker material greater than 0.03 points.

RPET is short form for Recycled Polyethylene Terephthalate. RPET uses a maximum of 20% recycled content.

TerraPET™ is PET that can be made up of up to 30% renewable plant based material, usually partly sugar cane. TerraPET™ has the same properties and appearance of APET while offering a more sustainable footprint.

Polyvinyl Chloride (PVC) is a firm plastic that takes print well and has high impact strength. Flexible PVC is often referred to as Vinyl.

Acetate film is a clear plastic that is thin, flexible and easily torn (low tear strength). It is available in clear and matte and accepts screen and offset printing. This works well for window patching

PUR hot melt adhesives are much stronger than traditional hot melt glues and are a much better choice for carton closing. They can provide a strong bond greater than 1,000 lbs. PUR adhesives are clear and glue lines are less noticeable.

A Hybrid box is a folding carton package that is made from a combination, or hybrid, of paper and plastic.
When our clients have a customer in need of a folding carton that has visibility to the product inside, we can supply a clear PET section and attach it to the paper or SBS carton blank. This type of folding carton is also known as a Duo-Carton. Multifold has pick and place equipment to produce window boxes and full hybrid boxes where the bottom half may be sbs and the top half is clear PET

A window box is a folding carton that may contain one to four sides of clear PET or Cello plastic to provide visibility to the product inside.

Cello plastic is a thin flexible material which is often used on bakery type boxes. PET offers a more high-end look and retains the structural integrity of the carton. Unlike a Cello window, PET can handle offset print, hot & cold foil stamping, and silk screen printing.

A window can be added to an SBS or corrugated cardboard box and is assembled using Multifolds Pick and Place equipment.

A cartoner or auto cartoning machine, is a machine that is designed to form the flat carton. The package may then be hand filled or automatically filled with the product and then the cartoner will close and seal the folding carton.

This automated machine will pick the flat carton, form, tuck, and close the package whether it is an auto lock, tuck or glued bottom. If desired, an automatic feed conveyance system will fill the carton directly before sealing. This automates the entire procedure. There is also the option to hand feed the product before the machine closes the box.