First-rate resistance to microbes and hydrolysis

  

First-rate resistance to microbes and hydrolysis

Synthetic materials in long-term contact with soils and similar substances or heavy contamination under conditions favourable to microbes can be destroyed by enzymes from the organisms, which attack the chemical bonds. Under particularly unfavourable conditions, the first signs of damage can become apparent after two to six months.

Moreover, in tropical climates many plastics in contact with warm water or water vapour undergo irreversible degradation of the molecular chains (hydrolysis) at about 60°C or above. Materials with little stabilization can suffer a loss of more than 95% of their tensile strength after just three weeks of exposure to hydrolytic conditions at 80°C.

For many hoses, NORRES uses a special, high quality ether-polyurethane instead of the ester-polyurethane frequently used for commercial applications. Our ether-polyurethane hoses have the following characteristics:

• Resistant to microbes
  (The chemical structure of ether-polyurethanes gives the materials permanent resistance to microbial attack. We believe this is clearly a better solution than ester-polyurethanes that are often stabilized with for health not completely harmless additives for this purpose. With these ester-polyurethanes there is a risk that the additive will leach out, causing the level to fall below that required for protection as the additive migrates to the surface of the hose and comes in contact with the user and the material transported.)
• Resistant to hydrolysis.
  (This is critical for wet applications at higher temperatures and for use in tropical climates.)
• Better chemical stability than comparable ester-polyurethanes.
• Better flexibility at low temperatures than comparable ester-polyurethanes.

These characteristics are particularly important in public utility vehicles. NORRES manufactures a comprehensive range of products that are specially designed for the diverse operating conditions prevailing in this sector. The following pages contain useful information about hose qualities for use on street cleaning machines of all sizes, including crush-proof hedge suction hoses for public utility machines and gardening or landscaping applications.

All information provided by NORRES in the drawings on these pages is merely intended as a guide to help you identify and recommend the most suitable hose qualities in quotations to customers.

Engineering modifications subject to change.