Isoplast question...

[pjhall]

We run quite a bit of Isoplast 2530 and 2531. Currently our operation is only 2 shifts and we shut down from midnight until about 5 am when the early morning fella comes in. The problem we run into with Isoplast PU are yellow spots. I've tried a few things like banking the heats, purging with PC, purging with Purge compound...I've asked Dow what they recommend any they say to purge with PC for the down period. The PC seems to work the best, but some days we still pull out orange chunks for a good couple of hours and other days there is no problem. Purge compound can be tough to get completely out causing "milky" parts. As you can imagine it gets worse the longer the run is.

Just curious if any of you have had to deal with this head ache!!!

[Suhas]

Hi PJ, I do not have experience with Isoplast. But the question I have is: Are the yellow 'spots' or 'tear drops' or sometime 'streaks'?

[rickbatey]

I've never ran that resin, but I too wonder what exactly is the cause of the yellow. Could it be from the press being up to heat and sitting too long before starting? I know when we were banking the heats on clear PC, if we waited too long after the press was ready we would get defects.
Rick.