Machining PP-H

PP-H belongs to the polyolefins – thermoplastics with a pure hydrocarbon chain. As a homopolymer it is stiffer, harder and more temperature-resistant than PE-HD and than the tougher PP copolymer (PP-C), but more brittle and impact-sensitive at low temperatures. With a density around 0.90 g/cm³, PP-H is one of the lightest engineering plastics and floats on water. It absorbs virtually no moisture and is chemically resistant across a very wide range.

PP-H machines easily and cleanly – turning, milling, drilling and sawing are effortless. Because of the high thermal expansion, we use adapted cutting parameters and ensure good cooling. Its strength is weldability: on request we build complete welded tanks and apparatus from PP-H plates. This is how we reliably produce components and assemblies for chemical and water technology – from single pieces to series production.

PP-H is worthwhile whenever chemical resistance, weldability and temperature resistance up to 100 °C are required at low cost – for example:

• Welded tanks, containers and pipework in chemical plant engineering
• Electroplating and pickling baths, scrubbers and exhaust air purification plants
• Components for drinking water, wastewater and process water technology
• Cleanroom and ventilation systems as well as aquafarming installations
• Corrosion-free constructions in contact with aggressive media

PP-H is one of the most economical engineering plastics and is priced at the level of PE-HD, considerably below POM, PET, PA and high-performance plastics. As a rough guide, semi-finished stock prices are in the range of about 3–8 €/kg. The component price is determined mainly by the semi-finished shape and dimension, material utilisation (offcut), machining or welding effort and lot size. We are happy to quote binding prices on request based on your drawing.

Equally important are the limits of the material:

• Applications below 0 °C or with impact/shock loading – PP-H is brittle in the cold; use PP-C (copolymer) or PE-HD
• Precision parts with tight tolerances – high thermal expansion, creep tendency; use PET or POM
• High mechanical load or stiffness requirements – moderate modulus and strength
• Components with fire-safety requirements – PP-H only reaches UL 94 HB
• Permanent outdoor use with natural-coloured stock – not UV-resistant without stabilisation

An honest assessment – and how the disadvantages can be mitigated in practice: Advantages:

Disadvantages:

Practical tip: PP-H plays to its strengths wherever chemical resistance, weldability and temperatures up to 100 °C matter – for example in chemical tank and apparatus construction. Where cold or impact loading is expected, we recommend the tougher PP-C (copolymer) or PE-HD; for high stiffness and dimensional stability PET or POM.

• Very broad chemical and corrosion resistance
• Excellently weldable – ideal for tank and apparatus construction
• Higher strength, stiffness and temperature than PE-HD (up to 100 °C)
• Very low density and moisture absorption
• Physiologically inert, suitable for food contact
• Brittle and impact-sensitive in the cold (service from about 0 °C)
• High thermal expansion and creep tendency – limited dimensional stability
• Moderate mechanical strength and stiffness
• Only UL 94 HB, and natural grade not UV-resistant