Frequently Asked Questions


  1. Blue Denim Paper

    Why is there a cover material known as Blue Denim Paper?

    • Blue Denim Paper is a paper based cover material produced from 100% cotton. The cotton fibres used are derived from off-cuts of Blue Denim fabric or from original blue denim threads. The blue dye in the Blue Denim gives the rolls their distinctive dark blue colour.
  2. Bowls

    What is a 'bowl'?

    • 'Bowl' or 'calender bowl' is a widely used term for a pressed fibre covered calender roll. The word bowl derives from the word 'bole' meaning trunk of a tree. Historically bowls were made using wooden tree trunks and the terminology has continued into modern use.
  3. Cover Material Specification

    Can RHL assist with cover material specification?

    • Yes, RHL have extensive experience of calendering applications and can assist with cover material specification. RHL are happy to review your application to advise the optimum cover material.  
  4. Grinding Services

     Do RHL offer roll grinding services?

    • Yes, RHL offer roll grinding service for many roll types including fibre covered rolls, rubber rolls, PU rolls and steel rolls. RHL can accurately grind cambered profiles.
  5. New Fibre Covered Rolls

    Do RHL produce complete new fibre covered rolls?

    • Yes, RHL regularly manufacture complete new fibre covered rolls for both end users and many of the world's leading calender manufacturers.
  6. Nomex

    Is Nomex still available as a calender roll cover material?

    • Yes, RHL are actively involved in the supply of Nomex rolls for specialist calendering applications.
  7. Polymer Rolls

    Do RHL supply Polymer/Composite rolls for Supercalendering?

    • Yes, RHL have recently introduced Diamantal Composite rolls to its range. Diamantal is suitable for Supercalender and Soft Calender applications.
  8. Roberto

    How does Roberto achieve improved expression compared to rubber and PU?

    • Roberto utilises both the liquid dam effect of compact rolls (eg Rubber and PU), however in addition its micro-porous structure absorbs liquid from the fabric enabling increased squeezing performance of 20-50% compared to rubber or PU.
  9. Rubber & PU Rolls

    Do RHL supply Rubber and PU rolls?

    • Yes, as well as MaxExtractor™ and MaxResistor™ (RHL's high performance textile squeezing rubber roll cover compounds), RHL offer a full range of standard rubber and PU roll coverings.
  10. Syncast Polyamide Rolls

    Can Syncast polyamide sleeves be fitted over existing fibre covered rolls?

    • Yes, for many textile calendering applications and embossing applications, RHL's Syncast sleeves can be fitted over the existing fibre covering avoiding the high cost of new roll shafts.  
  11. Woollen Paper

    What is the difference between Woollen Paper and Blue Denim Paper?

    • Woollen Paper is a variation of Blue Denim Paper with a proportion of wool fibres added to the Blue Denim cotton fibres. The Wool fibres give the rolls extra resilience and slightly different performance properties compared to Blue Denim Paper.