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
Circuit board and display panel assembly having the same
Optoelectronic semiconductor chip and method for manufacturing a contact structure for such a chip
Method and apparatus for efficiently inserting fills in an integrated circuit layout
Metal halide lamps with fast run-up and methods of operating the same
Mobile communication apparatus
Memory device and semiconductor device
Process for manufacturing a self-sealing composition
  Randomly Featured Patents
Microprocessor apparatus and method for optimizing block cipher cryptographic functions
Image forming device regulating sheet conveying timings
Method, system, and apparatus for RF switching amplifier
Semiconductor intra-field dose correction
Process for treating a hydrocarbon substrate with a bisoxazolidine hydrogen sulfide scavenger
Sample preparation apparatus and method
Baby bowl
Cover for an engine
Frame for shelves
System and method for model-based control of a building fluid distribution system