Patent · US Expired

Process for producing insulating paper where the paper is frictionally calendered

US3957573A · kind A · utility

22Cited by
14References
29Claims
0Family size

Assignees

Inventors

Key dates

Filing dateNov 8, 1972
Grant dateMay 18, 1976
Priority date
Expiry dateNov 8, 1992

Classification

  • Technology area (CPC D)Textiles; Paper
  • CPC primaryD21H5/202
  • WIPO fieldTextile and paper machines
  • WIPO sectorMechanical engineering

Abstract

Polyolefin fibers containing at least 70% by weight of polypropylene fibers having a denier of at least 0.5 and a birefringence of at least 2.5 .times. 10.sup.-.sup.2 are formed into a sheet. The sheet is then frictionally calendered in the dry state at a frictional ratio of at least 15% and at a temperature in the range from 90.degree.C to 160.degree.C whereby an insulating paper having excellent air-impermeability and oil-resistance is obtained.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.