Elastomers for Automotive Air Conditioning Hoses 900575
Discussion centers on elastomeric material used for liners in automotive air conditioning systems. The following facts must be taken into consideration:
the ambient temperatures may reach greater than 120 C
there will be a move towards R 134a or R 22 as substitutes for the refrigerants now in use.
The three materials that are discussed are NBR, HNBR and CM (an example of heat-resistant elastomers containing chlorine, CM).
HNBR is a heat-resistant alternative to NBR and withstands both R 12 and R 134a.
HNBR has good low-temperature bending behavior. It, therefore, has the widest, most useful temperature range of all the elastomers tested.
Where NBR is in use at present, the introduction of R 134a does not necessitate the use of a different elastomer. However, CM is a more suitable elastomer for R 22.
