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Heat Sealing Application Spotlight

Application: The sealing together of two or more layers of packaging films, generally to close the package. It is necessary to provide a means of assuring the easy release of plastic packaging materials after heat-sealing. When making heat-seals on plastic materials the softened plastic will tend to adhere to the heat-seal band, heat-seal bar, or platen. This can damage the seal, contaminate the seal bar, and prevent the material from moving freely through the machine.

Solution: The best solution is a PTFE tape or fabric over the heat-seal band. Used in conjunction with precise time and temperature control, PTFE tape or fabric will achieve satisfactory release of the plastic material after heat-sealing. Time and temperature is a critical component. In spite of the best PTFE products if the heat-seal jaw is opened to early or too late, and the temperature is too low or too high sticking may occur.

  • DuraStick® 250-03S, 250-05S & 250-06S
  • DuraFab® 20-03, 20-05 & 20-06

Products:

  • PTFE Tape

Fluon tape is primarily used as a covering over heat seal bands to prevent the hot plastic material from sticking to the band as well as over the silicone elastomers on the opposing jaw. The proper selection of thickness and style is imperative if good consistent seals are to be obtained.

Tape thickness is an important consideration in selecting a PTFE tape for heat-sealing applications. Although the tapes are available in thickness of 3 to 14 mil the most popular thickness for heat-sealing is 3, 5 and 6 mil. Thin 3 mil has the advantage of permitting the heat to flow faster from the heat seal band through the tape and into the plastic material to be sealed thus reducing sealing time and permitting higher production rates. The use of thick tapes (10 & 14Mil) to cover the heat seal band is undesirable because it will require the temperature of the sealer to be increased as much as 35 ° C to compensate for the insulating effect of the tape. Thinner tapes must be replaced more frequently, but when thick tapes are used, the heat-seal wire must be replaced more often because they must be operated at higher temperatures for prolonged heating cycles to allow for the slower heat flow through the tape. Ideally either a 3 or 5 mil tapes is used over the heating element, and a 5 or 6 mil on the opposite side covering the elastomer jaw.

  • DuraStick® 250-03S, 250-05S & 250-06S
  • Tape Width

PTFE tape can be supplied in virtually any width.

  • Tape Grade

For heat-sealing applications, Industrial grade is commonly used; however, Premium grade is available in most thicknesses. Premium grade is made with a heavier coating of PTFE, which results in smoother surface and better release characteristics at the expense of slightly slower heat transfer. 3 and 5 Mil industrial is the best selection for covering heat-seal wires.

  • DuraStick® 250-03S, 250-05S & 250-06S
  • Types of Tapes:
    • PSA Tape

    Provide with about 1.0 – 1.5 mils of adhesive on the back these tapes are used for covering the heating element or opposing unheated jaw and for various general purposes such as covering the machine surfaces and web formers to reduce friction or to cover silicone elastomers for anti stick purposes. 3 to 6 Mil industrial grade tapes are ideal in these applications. This is the most popular and standard product in the industry.

    • DuraStick® 250-03S, 250-05S & 250-06S
    • Zone Tape

    Zone tapes utilize industrial grade fabrics and have an adhesive on the edges. The absence of adhesive in the center zone allows for faster heat transfer through the tape, and makes the tape excellent choice for specific types of sealing applications allowing for free movement when the sealer is expanding and contracting.

    • DuraStick® 260-03S & 260-05S
  • PTFE Cloth

    PTFE cloth is most commonly used to cover special profile bands and platens or irregular shapes where a self adhesive tape cannot be used because of adhesive contact with the heat seal band.

    • DuraFab® 20-03, 20-05 & 20-06

Types of Sealers:

  • Impulse Sealers
  • Drop Sealers
  • Form and Fill Sealers
  • L Bar Sealers
  • Side Sealers
  • Tray Sealers
  • Blister Packs

Products that are commonly heat sealed into plastic bags include:

  • Candy
  • Magazines
  • Snack Foods
  • Flour tortillas
  • Pre-made salads
  • Sterilized hospital instruments
  • Fresh vegetables
  • Frozen food
  • Microwavable food
  • Balloons
  • Lawn and Garden supplies
  • Office supplies
  • Toiletries
Products that are blister packed include:
  • Small toys
  • Batteries
  • Hardware supplies
  • Cosmetics
  • Pharmaceuticals
  • Toiletries