Characteristics of cast film

The performance of all thermoplastic films is not only closely related to the use of plastic raw material particles, but also related to the production process and process parameters of the film. The same plastic products, such as film can be used the same production process to produce, that is, the use of the same material, the same production process, due to the production of temperature, pressure, blowing ratio and other process parameters, the performance of the film is also different. Cast film is called cast film, with C as the prefix, such as cast polypropylene film CPP film. There are two kinds of casting film solvent casting film and extruded casting film.

Solvent casting film: the film produced by solvent casting method has the advantage of thinner mesh thickness uniformity, 1~3um ultra-thin film is only used in some high-tech materials, generally not used in packaging materials, because the equipment investment is large, the solvent toxicity is large, and the purpose needs to use a large number of solvents, solvent recovery equipment and operation costs are large, only like cellophane and other very few films that can not or difficult to be produced by extrusion method can use the solvent method

Production.

Solvent method of production of flow film process is: the thermoplastic solution or the use of thermosetting plastic prepolymer sol coated on the carrier can be stripped, after a dry heating slow, and then molten plastic into a film layer cooling down, from the carrier off the surface of the peel roll and film. The carrier can be a steel strip, silicone coated release paper or paint cylinder. Some of the need for ultra thin and thickness flatness of the film is particularly good

The sol stream is spread over a heated mercury tank, and the film is formed by volatilizing the solvent, and the film is picked up from the mercury surface and rolled.

Solvent casting film has the following characteristics.

1）The thickness of the film can be very small, generally in 5~8um, the use of mercury as a carrier of the film, called molecular film, its thickness can be as low as 3um thick

2) High transparency of the film, small internal stress, most used in the case of high optical performance requirements, such as: film, safety glass sandwiching film.