Polyvinyl chloride test tubes, e.g. for dialysis - which are coated internally with a transparent, plasticiser-free layer of thermoplastic (NL 22.11.77)

摘要

Multi-layered plastics tube consists of a support tube (A) and a light-transmitting inner layer (B). (A) is of transparent plasticised PVC and (B) is of an elastic thermoplastic contg. no plasticiser. Ratio of thicknesses of (A): (B) is 20-2:1 esp. 10-4:1. Tubes are e.g. used in heart-lung machines, dialysis and infusion appts. No plasticiser is extracted into the blood, ((B) is (almost) completely resistant to migration of plasticiser from (A) and the tube is sufficiently transparent for visual examination of fluid flow and of the internal condition of the tube.