White ink yellowing on black Badger jerseys

[Binkspot]

We do a run of 700-2000 reversible black/white Basketball jerseys four times a year, we just finished our tenth run last week. This is a contract job so I have little control on what is sent. Usually 75% of the jerseys are Badger and the rest are Augusta. The Augusta run perfect every time but some of the Badger's, maybe 3-4 per 100 the white imprint will yellow a little. I am using the same poly ink we run for everything else, but only the Badgers yellow. Once we start running we wont stop until the job is done. The process is the same for all the shirts, flash settings the same and dryer the same. I run the job print 2 strokes, flash, print one stroke then off, the image comes out crisp and clean. The Augusta's are mixed in with the Badgers as well.

Most of the time they come off the press, go through the dryer perfect then notice the yellowing when stacking later in the day. There doesn't seem to be any pattern to the issue. I went as far as to mark every tenth shirt so I could see if it was the first shirts, middle of run or maybe the end of the run with no real results. It just seems to be random. I know the heat from the flash, dryer and heat press will cause the yellowing but if that was the case why would 20 come out perfect, 2 yellow then the next 100 run perfect. I have spoken to some other shops about this who claim they also have the same issue.

The customer has never complained and I have always disclosed that there was a few yellowed but I'm still not happy with the end product. Is there something I'm missing here? Any comments would be greatly appreciated.

[squeegee]

I'd say try Wilflex performance UB grey followed by Performance white, cure at 290.

[Evo]

Honestly I don't think you're missing anything. I've tried sampling a couple Badger baseball jerseys  for band shirts and I thought the quality was terrible. Bad dye and really screwy fit.

[jsheridan]

maybe 3-4 per 100 the white imprint will yellow a little.

Yellow is part of black dye and you're just seeing the excess gas off. If you have the bases covered and this is as random as it sounds, just keep doing what you're doing and keep tracking the occurrences as evidence that it's random if the customer starts to have a problem.

[pwalsh]

Brian:  The folks at Badger are going to be just as baffled as you are regards the randomness of this issue, and I expect that they will also struggle with how you can have a few garments that yellow, and then a run of them that are perfect.  I haven’t seen Badgers production process but I assume that they mass produce their garments under consistent conditions, and as such they’ll claim that all garments are consistent without any difference in between specific garments to cause the issue that you’re seeing. 

So where do you go from here?  I think that John Sheridan has nailed it by saying that the yellow that you’re seeing is some bleeding or sublimation from the black dye, which suggests that you might be getting excessive heat in the garments either through flashing (possible) or when they run through the dryer (more likely)  The fact is that most of the dryers that we use in this industry aren’t all that consistent for temperature, and/or they can be subject to some pretty wide swings in temperature dependent on the load of garments in the chamber at the time.

 In normal production when the press is running at a good rate and the dryer belt is totally full of garments, the burner or IR panels will be running at near max capacity to maintain the temperature at the set value.  Then you stop the press for 30 – 45 seconds to add/scrape the ink, or to remove some lint etc. which will result in an empty spot on the belt.  The first garments that go back into the dryer chamber are going to be exposed to a higher temperature than when the belt was fully loaded. This phenomenon occurs every day with almost every dryer, and when printing cotton or other bleed resistant garments the temperature variations don’t cause the color shift that you have experienced on synthetic performance wear garments.

The biggest issue that you are facing is the narrow processing window between hitting the correct temperature to fully cure the ink vs. the max temperature that the garments can take before they bleed.   You didn’t mention what type of ink that you’re using, but the suggestion to look at an ink like the Wilflex Epic Performance Series, or another ink system that cures at a lower temperature is a good one as it will help you build in a safety margin between achieving effective cure while avoiding heat induced bleeding / sublimation.

[Binkspot]

Thanks, I appreciate the help. Makes me feel a little better.

Peter, we are using the Wilflex Epic Performance.

It is interesting you mention the pause in production causing "gaps" in the dryer. About every 80-100 shirts we pull all the shirts off and scrape the pallets. I keep the press spinning when we do this, turn the two print heads off and leave the flash on to keep everything on the press side consistent, it usually takes two cycles to accomplish this. Then start printing again. We are running 250 overs later this week and this is something I will definitively look at.   

[pwalsh]

Brian:  Your original post stated that you were using the regular PolyWhite which is why I provided the caution on cure temperature.  The Tech Data Sheet for the PolyWhite shows that this ink requires 320F through the entire ink film to achieve full cure, while the Epic Performance White has a cure temp of just 290F. 

I know that it doesn't sound like a lot but the 30 degree lower temp provides a much wider window between full cure and bleeding garments than traditional plastisol ink systems.  I hope that the info on the dryer is of some help and that you can put these yellowing issues quickly behind you.