BOPET film, as known as biaxially oriented polyethylene terephthalate, is a polyester film made by stretching polyethylene terephthalate (PET) in its two primary directions to make a versatile engineered film.
It was developed by the British ICI company in the 1950s.
It has many benefits high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties, and electrical insulation.
After years of development, the product has evolved from the original single insulating film to the current capacitor film, packaging film, a photosensitive insulating film, etc.
Its thickness can be from 4.5um to 350 μm.
Its production process has also developed from simple kettle batch production to multiple stretching and simultaneous bidirectional stretching.
Its product form has also evolved from flat film to multilayer coextruded film, reinforced film, and coated film.
Polyester film has become one of the fast-growing film varieties in the market.
Dehui FIlm is one of bopet film suppliers in China. Currently, We mainly produce them by a two-step two-way stretching process. With the expansion of its application volume, the quality requirements of polyester films are getting higher and higher. Forcing us to improve the quality and enlarge the output.
BOPET film production process
Now, let’s introduce the bopet film production process. The general process is as follows:
PET resin drying → extrusion casting → longitudinal stretching of thick sheets → transverse stretching → winding → slitting and packaging → deep processing.
PET melt-extruded cast sheet
After melt-extruded and plasticized the dried PET resin, and then mixed by coarse and fine filters and static mixer,It is transported to the machine head by the metering pump. Then cooled by the quenching roller Into thick slices for use.
Extrusion of biaxially stretched
PET thick film Biaxial (direction) stretching is to stretch the film or sheet extruded from the extruder at a certain temperature. In the longitudinal and transverse directions to make the molecular chain.
The crystal face to be determined is oriented, and then heat-setting treatment is carried out in the case of stretching.
The biaxially stretched film, due to the orientation of the molecular segments, improves the crystallinity.
So it can significantly increase the tensile strength, tensile elastic modulus, impact strength, tear strength, improve cold resistance, transparency, airtightness, Electrical insulation, and gloss.
Most of the flat film adopts the plane-type successive biaxial stretching process.
Post time: May-26-2023