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screen printing => Ink and Chemicals => Topic started by: balloonguy on May 01, 2012, 03:36:29 PM

Title: Poly white on cotton
Post by: balloonguy on May 01, 2012, 03:36:29 PM

I remember hearing or seeing somewhere that you should not use a low bleed poly white on 100% cotton. Does anyone know if/why that is true?
Thanks,
matt

Title: Re: Poly white on cotton
Post by: ScreenFoo on May 01, 2012, 03:40:47 PM

A combination of heat, pressure, and humidity can cause the ink to 'ghost' when stacking a bunch of shirts at the end of the dryer--we're in a semi-arid region, and use LB white for many 100% cotton garments, and have never had problems--but that's at an average RH of 15%.

Could definitely be an issue if it's humid where you print.

Title: Re: Poly white on cotton
Post by: Frog on May 01, 2012, 03:45:26 PM

It also depends on which ink and which fabric.
Inks with bleaching agents in them are more prone to ghosting as well as are some shirts.

You can test before running. http://www.iccink.com/screenprint/howto_fabricdiscoloration.htm (http://www.iccink.com/screenprint/howto_fabricdiscoloration.htm)

Also, a strictly-for-Poly White (rather than a typical low-bleed) usually sacrifices some printability for it's bleed resistance.

Title: Re: Poly white on cotton
Post by: Colin on May 01, 2012, 03:53:37 PM

The chemical used is peroxide.

As the peroxide gasses out, it bleaches the dyes used to color the garment.  If allllll the peroxide has finished gassing out by the end of the dryer, then you should not have any problems.  But that does not always happen :)

Now there are a number of low bleed whites on the market that do not use any peroxides.  They fight bleed by using better chemistry ;)  The resin and plasticisers fight/block the bleed instead of destroying the color.

Title: Re: Poly white on cotton
Post by: RICK STEFANICK on May 01, 2012, 05:00:15 PM

It happens but is very very unlikely. In 30 years ghosting has happened to me once.

Title: Re: Poly white on cotton
Post by: balloonguy on May 01, 2012, 05:04:02 PM

I am using rutland super poly white. I will check to see if there is any peroxide. I am not sure. This stuff prints so nicely I would seriously consider making it the 1 and only white I use. I have a very short dryer. The tunnel is only 36" long so I am skeptical about the inks being completely gassed out by the time they reach the end of the heat chamber. We are in FL so the humidity is alway high. Yes, it is more expensive than our normal whites but the time saved on easy, beautiful prints will be worth the trade off to me.
I will contact rutland.
Thanks,
matt

Title: Re: Poly white on cotton
Post by: RICK STEFANICK on May 01, 2012, 07:11:00 PM

GO WITH RUTLAND STREETFIGHTER LB..

Title: Re: Poly white on cotton
Post by: Get Shirts on May 01, 2012, 07:27:38 PM

I second that, SF White!