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
System and method for improving cache efficiency
Fan guide
Image forming apparatus and method of translating virtual memory address into physical memory address
Over the counter medicinal container with surface ornamentation
Optical article comprising a temporary anti-fogging coating with improved durability
MOS resistor apparatus and methods
Optical imaging device and imaging method for microscopy
  Randomly Featured Patents
Window component extrusion
Ultrasonic methods and apparatus for separating materials in a fluid mixture
Automatic feeder for pets
High resolution cryosurgical method and apparatus
Apparatuses, systems and processes for surface cleaning
Timepiece and chronometer with overlapping, separately driven analog and digital displays
Plastic molding steel having improved resistance to corrosion by halogen gas
Print pattern recognition apparatus, recognition method, and information storage medium
Cell phone housing
Machine readable label system with offline capture and processing