Pertinax

Pertinax is the trade name for a thermoset material made of paper laminate and phenolic resin or formaldehyde resin. It is a robust, insulating and versatile material that is widely used in electrical engineering, mechanical engineering and model making. Thanks to its good mechanical and thermal properties, Pertinax (laminated paper, also known as phenolic paper or FR-2) is a proven material wherever electrical insulation and dimensional stability are required.

Applications

• Electrical industry: printed circuit boards, insulating panels, switch contacts, spacers
• Mechanical engineering: components with electrical insulation, spacers, mounting plates, plain bearings
• Vehicle construction: insulating parts in electrical control units
• Household appliances: switch housings, insulation in electric motors
• Model making: lightweight, stable components and prototypes

How is Pertinax made?

Pertinax is produced by pressing paper webs with phenolic resin under heat and pressure:

1. Impregnation: the paper layers are soaked with phenolic resin.
2. Layering: several paper webs are stacked on top of each other.
3. Pressing: the layers cure under high pressure at around 150 to 170 °C.
4. Finishing: the finished laminate is cut to size or processed further.

Machining Pertinax

Pertinax is easy to machine, but its layered structure calls for the right technique:

• Water jet cutting: at SIEGEL we cut Pertinax by water jet, precisely and without heat input. This is how we make Pertinax washers, insulating plates and contoured parts to drawing.
• Milling, drilling and grinding: for holes, chamfers and individual adjustments after cutting.
• Laser cutting: possible for fine contours, but limited by discolouration at the cut edge.

Machining produces fine dust, which should be extracted at the machine.

Temperature range and resistance

Pertinax withstands continuous temperatures up to around +120 °C. Above that the laminated paper loses strength; epoxy or glass fibre laminates are better suited for higher temperatures. Moisture is the main limitation: in humid conditions Pertinax can swell and lose insulating capacity. In a dry environment it remains dimensionally stable and electrically reliable.

Pertinax compared with other insulating materials

Property	Pertinax	Epoxy resin	Glass fibre laminate
Electrical insulation	very good	very good	excellent
Mechanical strength	good	very good	excellent
Machinability	very easy	medium	more difficult
Cost	low	medium	high
Thermal resistance	up to 120 °C	up to 180 °C	up to 200 °C

Advantages of Pertinax: more cost-effective than many high-performance insulators, lightweight, easy to machine and a good insulator. Thanks to its paper content it is also more environmentally friendly than many purely plastic alternatives.

Limitations: Pertinax is sensitive to moisture, not suitable for continuous temperatures above 120 °C, and brittle. It can break under heavy mechanical load.

Frequently asked questions about Pertinax

How does SIEGEL machine Pertinax? We cut Pertinax by water jet and can then drill, mill and grind it, for example into Pertinax washers or insulating plates to your drawing.

Is Pertinax environmentally friendly? Pertinax is paper-based and therefore more environmentally friendly than many other plastics. The phenolic resin, however, is not biodegradable.

Can Pertinax be recycled? Hardly. As a thermoset, Pertinax cannot be melted down again.

What are the alternatives to Pertinax? Epoxy and glass fibre laminates offer higher thermal and mechanical values, but are more expensive and harder to machine.

Do you need Pertinax in custom cuts or special formats? We manufacture to your drawing, from prototype to series production.