Promyde® BF840

• High transparency
• Lower melt temperature (155-160ºC): suitable for coextruded films with temperature sensible polymers such as EVOH
• Low crystallization speed, low curling

Drying

Material is supplied pre dried and ready to process. Bags should be stored in a dry place at room temperature. Storage time should not exceed twelve months. Material from open or damaged bags should be dried in a dry-air dryer at 70ºC, the drying time required will depend on the moisture content. Drying temperatures of above 70ºC should be avoided because of possible oxidation.

Extrusion Processing

Promyde® BF840 may be processed on standard single-flighted, three-section screws. Better results can be obtained by using high-performance screws equipped with shearing and mixing sections. The screw length should be at least 24D, and preferably 28-33D to guarantee optimum plasticizing and conveying with the high through-put rates of film extrusion (D: screw diameter). A three-section screw should have a compression ratio (ratio of flight depth in the feed section to flight depth in the metering section) of 3:1 to 4:1.

It is recommended the length of screw sections as follows (L: overall length of screw):

• Feed section: 0.25 to 0.30 x L
• Compression section: 0.15 to 0.25 x L
• Metering section: 0.4 to 0.55 x L

Excellent processing and film properties can be obtained by using following temperatures at the extruder:

• Hopper: 40-50ºC
• Extruder: 200ºC
• Adapter&Die: 200ºC

Conditioning

Films made of Promyde® BF840 will achieve their final dimensions and properties after equilibrium moisture absorption.

Promyde® BF840 is supplied in 25Kg moisture-proof packaging.