Standard for biaxially oriented polypropylene films

　　The standards for biaxially oriented polypropylene films are as follows:

　　The quality of biaxial tensile polypropylene film should meet the requirements of GB / T 10003-2008. This standard is suitable for general purpose films with polypropylene resin as the main raw material, which are formed by biaxially drawing the color flat film method or tube film method.

　　1) The film can be divided into ordinary type (a) and heat sealing type (type b) according to whether there is heat sealing layer on the surface.

　　2) When the width of the film is 1000 mm, the width deviation is - 1.0 · + 2.0 mm; when the width is 1000.1600 mm, the width deviation is + - 2.0 mm;

　　3) When the thickness of the film is within 12.60um, the average deviation and thickness limit deviation should meet certain requirements.

　　4) The hygienic standard index of PP biaxial tensile film used for food packaging should comply with the provisions of GB 9688-1988.

　　Production process:

　　Polypropylene resin and auxiliary materials are mixed evenly after metering according to the formula requirements - raw materials are mixed and plasticized into molten state by single screw extruder - extruding through porous plate and filter screen - forming membrane by forming die - cooling and setting on roller surface - thickness measurement by thickness gauge - longitudinal stretching - transverse stretching - heat setting - trimming - thickness measurement - corona treatment - - rewinding