Resources Contact Us Home
Method for the manufacture of biaxially stretched polyolefin film

Image Number 4 for United States Patent #4261944.

A method is disclosed for the manufacture of a biaxially stretched polyolefin film, particularly a polypropylene film, having improved properties, in which the material is first partially prestretched in a longitudinal direction and, thereafter, simultaneously biaxially (longitudinally and laterally) stretched, the apparatus comprising stretching rollers for effecting partial longitudinal stretching of the film, the rollers being arranged upstream of an assembly for effecting simultaneous biaxial stretching of the film. The speed of the stretching rollers is infinitely variable so as to influence the total degree of film-stretching only by changing the speed of the rollers. The rollers used for longitudinal prestretching are arranged at the inlet section of the biaxial stretching assembly. A system is provided to maintain the film exactly at the temperature required by the film characteristics for stretching, and biaxial stretching is done such that any given point on the film in the region the film is being biaxially stretched undergoes simultaneous biaxial stretching both in the longitudinal and transverse directions of the film.

  Recently Added Patents
Cancer vaccines containing epitopes of oncofetal antigen
N-phenyl-(homo)piperazinyl-benzenesulfonyl or benzenesulfonamide compounds suitable for treating disorders that respond to the modulation of the serotonin 5-HT.sub.6 receptor
Method and apparatus for transmitting and receiving extension information of component carrier in wireless communication system
Fire detector
Inductive signal transfer system for computing devices
Flood protection apparatus and container data center including the same
Tools and methods for yield-aware semiconductor manufacturing process target generation
  Randomly Featured Patents
Compact disc case
Radiation-curable composition with simultaneous color formation during cure
Guidewire and collapsable filter system
Tumor marker
Hollow fiber membrane air drier
VoIP anomaly traffic detection method with flow-level data
Method and apparatus for adaptively shifting a powershift transmission
Controlled entertainment spending account
Energy damping flow device for printing system
Hand-operated tool for bending pipes