Hard paper

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Electric circuit board made of phenolic resin hard paper in the typical brown color
Strelow-Hartpapier AG shares from July 1923 - this company a. Furniture made from hard paper

Hard paper is a fiber composite material made from paper and a phenol - formaldehyde synthetic resin ( phenoplast ). Hard paper is used in electrical engineering and electronics as an insulating material and insulating carrier material for electronic components and printed circuits, mainly in the form of printed circuit boards .

The density of hard paper is about 1.35-1.36 g / cm 3 .

Printed circuit boards made of hard paper evaporate small amounts of phenol and formaldehyde . This becomes noticeable when heated (e.g. by soldering) or machining in a characteristic, pungent odor. Phenol and formaldehyde are harmful if they get into the human body. Therefore, it should be ensured during mechanical processing that no large quantities of dust and outgassing are inhaled.

Markings of circuit board base materials based on phenolic resin, FR stands for English flame retardant (German: flame retardant ) .:

  • FR1 = phenolic resin + paper (cheap type)
  • FR2 = phenolic resin + paper (standard quality)

Other PCB base materials based on hard paper:

  • FR3 = core made of epoxy resin + paper (improved electrical properties)
  • FR4 = epoxy resin + fiberglass fabric
  • FR5 = epoxy resin + glass fiber fabric (more heat resistant)
  • CEM1 = core made of phenolic resin or epoxy resin + paper, covered with two outer layers of FR-4 (excellent thermal stability, less expensive than FR-4, electrical properties better than FR-3 and slightly worse than FR-4)

Hard paper is available under different brand names . Examples are Pertinax , Turbonit , Carta , Wahnerit , Repelit , Haefelyt or Preßzell .

The particularly well-known brand Pertinax was founded in 2014 by Dr. Dietrich Müller GmbH, Ahlhorn took over as material processor.

Individual evidence

  1. [1]
  2. [2]
  3. Pertinax (material) chemie-schule.de, accessed September 11, 2019.
  4. [3]
  5. [4]
  6. [5]
  7. [6]
  8. [7]
  9. PDF on www.nonstopsystems.com
  10. Pertinax® - a traditional material with a new future mueller-ahlhorn.com, January 6, 2014, accessed September 11, 2019. - Notes on shapes and applications.

Web links