What Materials are Suitable for Heat Sealing?

Heat sealers are some of the most popular and versatile machines in the world, used for manufacturing, food, and medical purposes.

Heat Sealing
A wide variety of materials can be used with bag sealers, such as polyethylene, PVC, and aluminium foils, but certain plastics like acetate cannot be heat sealed.

In this article, we cover materials that can be heat sealed, including two of the most commonly used plastics for heat sealing: polyethylene (PE) and polyethylene terephthalate (PET).

What Plastics can be Heat Sealed?
The majority of plastics can be heat sealed, including polyethylene, polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). These are used in bags and pouches to be sealed by a heat-sealing machine, which fuses the plastic together to create an airtight seal.

Heat sealing poly bags is an ideal way to create a seal with a neat, finished edge. What’s more, they are a cost-effective way to package products as they require no extra poly material to close the bag opening, making them a time-saving solution for many production lines.

What are the Advantages of Using Heat Seal Poly Bags?
Some benefits of heat-sealing plastic poly bags include:

  • Watertight and airtight seal that keeps out debris and moisture (particularly important for packaging medical appliances).
  • Protects products during transit and handling.
  • Clean, finished edges are able to display contents in an attractive way.


Low-density polyethylene is the plastic from which most heat seal poly bags are made from as it melts at around 160 degrees, which is hot enough to melt together the two sides but cool enough to fuse together quickly when the heat and pressure from the heat sealer machine is removed.

Another added benefit of polyethylene is that when it cools, the poly material contracts and pulls the seal even tighter, resulting in a better seal.

What Is a Mylar Bag?
A mylar bag is a type of commonly used heat seal bag made from polyethylene terephthalate. PET is used for its high tensile strength, transparency, electrical insulation, and for its dimensional stability.

It is often used in food, medical, or electrical component packaging due to its airtight nature, making them ideal to store sensitive products and items in. In fact, mylar bags are widely considered as one of the most effective types of moisture barrier packaging.

Its ultra-low water vapour transmission rate ensures that the bag will protect the product through all the hazards that can be faced in transportation and storage.

What are the Advantages of Using Mylar Bags?
Some other benefits of using mylar bags include:

  • Very high tear resistance – ideal for products with sharp edges and to assure airtightness.
  • Low packaging cost, making it suitable for use of mass production.
  • It meets the MIL- PRF-131-K Class 1 and Def Stan 81-147 (formerly Def Stan 81-75) specifications, making it compatible for packaging sensitive goods.


What Materials are Suitable for Heat Sealing: Are Certain Materials Only Suitable for Certain Bag Sealers?
Most heat sealers can seal many different types of materials, but some are not appropriate for certain materials and thicknesses. A hand-held heat sealer can seal poly material that is up to 10mil in thickness, whereas double impulse sealers (both automatic and foot options) are able to seal poly bags up to 20mil in thickness.

What Are VCI Bags?
VCI Bags are another extremely popular choice of packaging for use with a heat sealer, as they are designed to protect sensitive metals against corrosion during transportation.

For Excellent Heat Sealer Machines, Browse Valdamark’s Diverse Range Today
Here at Valdamark, we offer a wide variety of market leading heat sealers, such as direct heat sealers and band sealers, that will seal the majority of flexible packaging materials and constructions.

For more information, do not hesitate to contact us! Our experienced team of heat sealing experts are here to offer advice and support for all your heat sealer and sealing material needs.

Go Back

Featured Products

  • Heros

    Learning From Brands Like Ben & Jerry’s, Newman...

    Marketing magic transforms brands into real-life superheroes. Whether they champion communities, empower diversity, or embrace eco-heroics, brands can inspire with captivating stories. Think underdog origins, brand-as-hero journeys, and authentic struggles...

    Learning From Brands Like Ben & Jerry’s, Newman...

    Marketing magic transforms brands into real-life superheroes. Whether they champion communities, empower diversity, or embrace eco-heroics, brands can inspire with captivating stories. Think underdog origins, brand-as-hero journeys, and authentic struggles...

  • Benefits of Sustainable Sourcing

    Benefits of Sustainable Sourcing will be Promot...

    PEFC, the Programme for the Endorsement of Forest Certification, will be a participant at the upcoming Packaging Innovations show in London on September 16th and 17th. The organization will showcase...

    Benefits of Sustainable Sourcing will be Promot...

    PEFC, the Programme for the Endorsement of Forest Certification, will be a participant at the upcoming Packaging Innovations show in London on September 16th and 17th. The organization will showcase...

  • Amcor Pouch Packaging Solution Addresses Drug Device Delivery Challenges

    Amcor Pouch Packaging Solution Addresses Drug D...

    In the demanding world of medical and healthcare, ensuring the sterility and shelf life of combination medical devices is paramount. This requires high-performance, sophisticated packaging materials that act as effective...

    Amcor Pouch Packaging Solution Addresses Drug D...

    In the demanding world of medical and healthcare, ensuring the sterility and shelf life of combination medical devices is paramount. This requires high-performance, sophisticated packaging materials that act as effective...

1 of 3