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
Modified binding proteins inhibiting the VEGF-A receptor interaction
Dry-cooling unit with gravity-assisted coolant flow
Removable storage device and method for identifying drive letter of the removable storage device
Semiconductor device
Digital processing method and system for determination of optical flow
Purine compounds used as CB2 agonists
Circuit board having semiconductor chip embedded therein
  Randomly Featured Patents
Method of vector magnetic resonance measurement and imaging and associated apparatus
Media depository
Method for evaluating three-dimensional rendering systems
Mixing apparatus
Video signal quantizing apparatus and method thereof
Presser foot for concealed slide fasteners
Automated location-intelligent traffic notification service systems and methods
Apparatus for driving stitches of textile articles
Treatment of uncooked pasta products to reduce cooking loss
Spear-type tractor-attached hay bale pickup device