RHL to present new range of Nomex calender rolls at Techtextil

24 Jan '09

3 min read

A new range of calender rolls offering highest-ever levels of temperature resistance is being launched at Techtextil North America (Las Vegas, April 21-23). The rolls are filled with Nomex, DuPont's high-performance meta-aramid fibre and are targeted specifically at high-temperature calendering for technical textiles applications.

Richard Hough Ltd. (RHL), of Bolton, UK, will present the Nomex calender rolls at the Las Vegas event (Booth 421), promoting their outstanding temperature resistance, excellent resistance to surface damage and resistance to high nip loads, ensuring minimum maintenance and a very long service life.

Says RHL's Anthony Ashton: “This is by far the highest temperature-resistant calender roll on the market and ideal for new technical textile applications.”

RHL produces complete new Nomex rolls or can refill existing filled rolls with Nomex material. Nomex can be resurfaced using standard equipment such as diamond tool, abrasive belt or stone grinding.

Key applications for the Nomex rolls include:-

- High-temperature 'supercalenders' (e.g. for glassine papers, candy-wrap papers, release papers, condenser papers).

- High-temperature textile calenders (e.g. glazing calenders, friction calenders, thermobonding calenders for nonwovens).

- High-temperature / high-speed embossing calenders

RHL's expertise in producing the Nomex rolls is officially approved by DuPont, which certifies that it considers the company “fully technically capable to manufacture filled rolls with Nomex. We therefore recommend this company as an excellent source for long lasting Nomex calender rolls”.

Construction

Nomex is a man-made fibre based material with a rigid and regular (meta-aramid) molecular structure. Because of the strong structural linkages, Nomex fibres are both chemically and thermally very stable and will not flow or melt even above 350°C. For this reason Nomex is suited to high-temperature calendering, where alternative roll cover materials would quickly break down.

This unique construction also gives Nomex excellent marking resistance. Marking resistance and recovery are closely related to Modulus of Elasticity (the ability of the material to rebound to its original shape after being dented). The Nomex structure has a high modulus of elasticity, which is maintained at elevated temperatures (Figure 2).

Operational benefits

- Outstanding temperature resistance, enabling the heated steel rolls to be run at up to 360°C.
- Excellent mark resistance due to its high Modulus of Elasticity.
- Outstanding service life. Typically a Nomex roll will last five to ten times longer than a normal elastic-filled roll, leading to lower operating costs.
- Nomex can withstand high nip loads up to 450kN/m.
- Nomex can be filled on the same roll shafts used for conventional cotton fibre cover materials
- Lower risk in case of accidental surface damage (compared to polymer rolls) due to cover thickness. Nomex rolls have a regrind depth of typically 60-70mm compared to typically 6mm for polymer rolls

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