Tags: blown film, blown film extrusion, silicone release liner, multi-layer film

Tags: silicone coatings, custom coating converting, blown film extrusion, silicone release liner, Earth Day

Blown Film Extrusion

 

One of the most common methods of film manufacture is Blown Film (also referred to as the Tubular Film) Extrusion. The process involves extrusion of a plastic through a circular die, followed by "bubble-like" expansion. The principal advantages of manufacturing film by this process include the ability to: 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) Blown Film Extrusion can be used for the manufacture of co-extruded, multi-layer films for high barrier applications such as food packaging.

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. 

3 layer die head with air ring and internal bubble cooling	Film bubble going into a collapsing frame
Control panel graphic from an automated blown film line	Taking an edge trim from film web
The layflat tube is separated into 2 single sheets	Blown Film Line In Action

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”.

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Tags: RELEASE FILMS, blown film, plastic film, Polyethylene, blown film extrusion, Polypropylene, converting, multi-layer film

Tags: RELEASE PAPERS, blown film, base films, release liner, plastic film, Polyolefins, Polyethylene, blown film extrusion, silicone release liner, Polypropylene, TPO, converting, rewinding services

Making Plastics

To make plastics, chemists and chemical engineers must do the following on an industrial scale:

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Tags: anti skid, RELEASE PAPERS, RELEASE FILMS, FILMS - Coextrusion, FILMS - Polyethylene, FILMS - Polypropylene, blown film, base films, custom coating converting, Polyolefins, blown film extrusion, Film slitting, How plastics work

MTi Polyexe Corporation would like to thank every one for taking the time to visit our site. from mtipolyexe on Vimeo.

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Tags: anti skid, RELEASE PAPERS, RELEASE FILMS, FILMS - Coextrusion, HDPE, LDPE, LLDPE, blown film, base films, release liner, plastic film, silicone coatings, custom coating converting, Polyethylene, blown film extrusion

Tags: anti skid, RELEASE PAPERS, RELEASE FILMS, FILMS - Coextrusion, FILMS - Ethyl Vinyl Acetate, FILMS - Polyethylene, LDPE, FILMS - Polypropylene, blown film, base films, release liner, plastic film, silicone coatings, custom coating converting, Polyolefins, Polyethylene, blown film extrusion

Tags: anti skid, RELEASE PAPERS, base films, release liner, silicone coatings, custom coating converting, Polyethylene, blown film extrusion, silicone release liner, Polypropylene

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Tags: anti skid, blown film, base films, release liner, plastic film, silicone coatings, custom coating converting, Polyolefins, blown film extrusion, silicone release liner

MTI Polyexe Corporation wants to thank each and every one of you for taking the time to visit our blog. If you are new to our company here is a list of things we manufacture or provide. Film slitting, cutting, converting, and rewinding services. For a range of different materials such as blown film, base films, release liner, plastic film, silicone coatings, silicone release liner, custom coating converting, plastics films, Polyolefins, Polyethylene, Polypropylene, LDPP, LLPP, LLPE, LDPE, anti skid, blown film extrusion and TPO. At MTI Polyexe Corporation we do our best to accommodate any request. Give us a call; we can surely help with any of your blown film and silicone coating requirements.

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Tags: anti skid, blown film, base films, release liner, plastic film, silicone coatings, custom coating converting, Polyolefins, Polyethylene, blown film extrusion, silicone release liner, Polypropylene, TPO