Carton Sealing Options

There are many carton sealing methods to choose from.  To help you decide which is the best sealing method for your application, below is information about the most common sealing and closing methods which includes paper water-activated tape (WAT), plastic pressure-sensitive tape (PST), glue and staples.

Paper Water-Activated Tape (WAT)

Water-activated tape is made primarily of white or natural color (Kraft) paper and starch-based adhesive. It’s usually available in various widths and thicknesses and when reinforced, contains multiple layers of fiberglass reinforcement. When the adhesive is activated with water, it penetrates the carton material and the tape forms a permanent bond with the carton.

Common Terms
WAT, water-activated tape, paper tape, reinforced tape, gum tape, gummed tape, reinforced gummed tape , non-asphaltic tape, Kraft (non-reinforced) tape, brown paper tape.

Advantages
• Provides tamper-evident seal
• Difficult to remove without leaving obvious signs of tampering
• One strip produces a sturdy seal
• Easy to print on
• Retains integrity if punctured
• Can be used in dusty or dirty environments
• Maintains seal in extremes of cold, heat, light, humidity
• Carton can be reused or recycled
• Made from paper and is a more sustainable option

Disadvantages
• Requires water to activate
• Requires dispensing machine for application

Best Uses
• Cartons containing heavy items
• Individual or different sized cartons
• Contents requiring protection from tampering or pilferage
• Automated or semi-automated case sealing

Plastic Pressure-Sensitive Tape (PST)

A surface mount form of tape with a dry adhesive applied to a film. Both film and adhesive are made primarily of petroleum.

Common Terms
Plastic tape, PST, poly tape, packing tape

Advantages
• Portable
• Transparent
• Does not require solvent, water or heat to activate

Disadvantages
• Not tamper-evident
• Made from non-renewable resources
• Repetitive motion injury risk from portable tape handgun
• Tape fails very rapidly when punctured or torn
• The tape often gets stuck and has to be re-threaded on the handheld tape gun.
• Noisy, “chatters” when unrolled
• Quickly deteriorates when exposed to UV light, cold, heat, humidity

Best Uses
• Lightweight cartons
• Low value products
• Cartons that will be palletized and shrink-wrapped
• Contents not requiring protection from tampering or pilferage
• High speed case sealing

Glues

Adhesives that use polypropylene, which is flexible, soft but not pressure sensitive.  Formulated to bond to a variety of substrates.

Common Terms
Hot, cold, and natural glues

Advantages
• Generally unaffected by cold, light or humidity extremes
• Adapts well to high-speed production packaging lines

Disadvantages
• Messy, high heat, fumes potentially harmful
• Leaking glue or high temperature may cause damage to product being packaged
• High cost of equipment purchase
• Significant equipment maintenance

Best Uses
• Heavy products on high-speed packaging lines where all cartons are of uniform size, such as canned goods or paint

Staples

Metal fasteners driven through the carton material by a device that also bends its two ends inward and flattens them so that they grip the material firmly.

Advantages
• Holds up under stress
• Tamper evident
• Strong, robust seal

Disadvantages
• Carton often destroyed when opened
• Difficult to open
• Potential injury to handlers
• Unacceptable for many shipping companies
• Requires additional corrugated liner or overlapped flaps
• Extra steps to process for recycling

Best Uses
• Very heavy items that will be shipped on pallet by truck or rail