Removing Cured Polyvinylpyrrolidone (PVP) From Nitinol Rods

[fortycoats]

Hello all. Hope you can help

I have come accross a problem where I am dip coating catheters in Polyvinylpyrrolidone (PVP), which is a water-soluble polymer used to lubricate catheters before use. The catheter is dipped into a solution containing methanol and PVP and then cured for 12mins. The catheter has two eyes in the bottom to allow waste from the body to drain from the bladder. The catheter is mounted on a nitinol rod to help support it during the coating process. I have found that over time deposits of PVP are being left behind on the rods and then transferred onto the inside of the catheter. Becasue of this visual defect the catheters are rejected. After each Cycle the rods are washed in an ultrasonic bath containing boiling water. This is not able to remove all the PVP.

My question is - does anybody know of a process / chemical that can removed dried on PVP

 

[GregoireMC]

Hi,

It seems that PVP solvents are Polar ones(like water,Ethanol, Methanol, IPA...).
Did you tried another of these solvents (in ultrasonic bath too)?

http://en.wikipedia.org/wiki/Solvent#Solvent_classifications>solvent

classification>Polar solvent