1. Slit Seals Blown Film
2. Slit Seals Blown Film Machine
3. Slit Seals Blown Film Air
4. Slit Seals Blown Film Video

• Our units for LLDPE an LDPE film offers smooth and precise slit seal film from.0005' to.005' Gauge and consist of high quality stainless steel block holder and brackets which accommodates the highest grade of stainless steel blades with carbide tips.
• The area where ink extends into the slit area to provide a clean edge on a finished impression. Blown films Plastic films produced from synthetic resins (such as polyethylene) using a process where molten resin is extruded through a circular die into a tube.

Primary films for tapes can be produced via a blown, cast or water quenched film process. They are then continuously or discontinuously cut into strips then heated by means of hot air or a hot plate and stretched into the final tape size.

Blown film extrusion is the process by which most commodity and specialized plastic films are made for the packaging industry. The film blowing process basically consists of a extruding a tube of molten thermoplastic and continuously inflating it to several times initial diameter, to form a thin tubular product that can be used directly, or slit to form a flat film.

Slit Seals Blown Film

The Process

Plastic melt is extruded through an annular slit die, usually vertically, to form a thin walled tube. Air is introduced via a hole in the centre of the die to blow up the tube like a balloon. Mounted on top of the die, a high-speed air ring blows onto the hot film to cool it. The tube of film then continues upwards, continually cooling, until it passes through nip rolls where the tube is flattened to create what is known as a ‘ lay-flat’ tube of film. This lay-flat or collapsed tube is then taken back down the extrusion ‘ tower’ via more rollers. On higher output lines, the air inside the bubble is also exchanged. This is known as IBS (Internal Bubble Cooling).

The lay-flat film is then either kept as such or the edges of the lay-flat are slit off to produce two flat film sheets and wound up onto reels. If kept as lay-flat, the tube of film is made into bags by sealing across the width of film and cutting or perforating to make each bag. This is done either in line with the blown film process or at a later stage.

Typically, the expansion ratio between die and blown tube of film would be 1.5 to 4 times the die diameter. The drawdown between the melt wall thickness and the cooled film thickness occurs in both radial and longitudinal directions and is easily controlled by changing the volume of air inside the bubble and by altering the haul off speed. This gives blown film a better balance of properties than traditional cast or extruded film which is drawn down along the extrusion direction only.

materials:
Polyethylenes (HDPE, LDPE and LLDPE) are the most common resins in use, but a wide variety of other materials can be used as blends with these resins or as single layers in a multi-layer film structure. these include pp, pa, evoh. In some cases, these materials do not gel together, so a multi-layer film would delaminate. To overcome this, small layers of special adhesive resins are used in between. These are known as “tie layers”.

advantages:

Slit Seals Blown Film Machine

• Produce tubing (both flat and gussetted) in a single operation
• Regulation of film width and thichness by control of the volume of air in the bubble, the output of the extruder and the speed of the haul-off
• Eliminate end effects such as edge bead trim and non uniform temperature that can result from flat die film extrusion
• capability of biaxial orientation (allowing uniformity of mechanical properties)
• Very high productivity
• Permits the combination of a number of different materials and properties

applications:
Blown film can be used either in tube form (e.g. for plastic bags and sacks) or the tube can be slit to form a sheet.
Typical applications include Industry packaging (e.g. shrink film, stretch film, bag film or container liners), Consumer packaging (e.g. packaging film for frozen products, shrink film for transport packaging, food wrap film, packaging bags, or form, fill and seal packaging film), Laminating film (e.g. laminating of aluminium or paper used for packaging for example milk or coffee), Barrier film (e.g. film made of raw materials such as polyamides and EVOH acting as an aroma or oxygen barrier used for packaging food, e. g. cold meats and cheese), films for the packaging of medical products, Agricultural film (e.g. greenhouse film, crop forcing film, silage film, silage stretch film).

Replace the Traditional Slit Seal Systems with High Quality Machine Direction Seals from
D R Joseph, Inc.

Slit Seals Blown Film Air

The high-speed Seal-Cut sealing system for plastic film offers an original, innovative solution that replaces traditional slit seal (hot knife) systems for machine direction sealing. The Seal-Cut is capable of producing high quality, sealed edges in a wide variety of film applications. The stand-alone design allows it to be free standing or easily attached to winders, bag-making machines and rewinders

Versatility

The Seal-Cut is versatile. Not only thin gauges, but even heavy gauge jumbo or master rolls are easily converted into narrower tubes. Conversely slit seal systems cannot handle much more than 2 mil (50 um). Even multi-layer films can be sealed with the Seal-Cut. A machine like this saves production and equipment costs because you can run several webs of material from one larger line rather than needing several smaller lines to run the same number of webs.

Safe

The seal-cut uses a non-sharp sealing element and has no driven parts. All high temperature and pinch points are clearly labeled.

The Seal-Cut operates below the ignition point of nearly all polymers, therefore eliminating the risk of fire should the line / web stop while the unit heat is ON… a common occurrence when using a traditional slit seal system.

Slit Seals Blown Film Video

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