How to Heat Seal the Plastic Film

Biaxially Oriented Polypropylene or BOPP as it is called is basically a plastic film made out of polypropylene. It is stretched in both the machine and cross directions during manufacturing. BOPP films have gained popularity in the world due to some of their special characteristics. They act as a good barrier against water vapor and are resistant to grease and oil. They do not shrink because of changes in the environment, and are also resistant to moisture. They are dimensionally stable and have a low electrostatic charge. In fact, the BOPP films are also recyclable.

Whenever you buy a new household device, it is always packed in a tightly sealed plastic wrap. Even small items like soaps and shampoo bottles come with a sealed plastic film around them. Have you ever wondered how this is done? This is all thanks to innovation in the plastic films industry. Many variations of the BOPP film are now produced in the market, one of which is the heat sealable BOPP film. Its excellent sealing characteristic is a result of the co-extrusion process during manufacturing. This film can be one or two-side heat sealable. In a one-side heat sealable BOPP film, the non-sealable side is generally used for printing and laminating. It used for general purpose packaging for food items, tea, toffees, tooth brushes and cassette tapes. The BOPP films have good heat sealing strength and a smooth surface, and are highly transparent. Heat sealing is usually done at a temperature of around 130 degrees Celsius. The BOPP structure is also sometimes modified in order to lower the Seal Initial Temperature (SIT). This improves the sealing performance and allows high speed packaging, especially useful for temperature sensitive products like snacks and ice-creams. 

There are different kinds of heat sealing devices available, the basic principle being to heat up two separate layers of plastic film together till the seal is made.