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screen printing => General Screen Printing => Topic started by: Parker 1 on April 04, 2013, 05:37:01 PM
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I need to print an order of Polypropylene Bags Tomorrow.
I need a ink that will cure at very low Temps (under 270).
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There is a catalyst for plastisol inks that will help you out. But be careful and test first. I am sure all of the ink companies make the same thing. Sorry, at home with a root canal. Ugh...
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we added the catalyst, and still had our belt speed super high
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I need to print an order of Polypropylene Bags Tomorrow.
I need a ink that will cure at very low Temps (under 270).
add nylonbond and run them just enough to be flashed. NB will make them solidify on their own over few days. You might get away with 250 or so this way.
pierre
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Some companies have a low-temp plastisol that works fine out of the bucket, but it can be pricey. Failing that, nylon additive as some have mentioned.
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Got lucky last week--did 600, catalyzed ink as mentioned, turned down the heat till the chamber was around 320, and ran them through rather slow.
I'd be rather interested in hearing from anyone who reps the companies that make these. There are several types of PP manufactured, and the melting points range from 266-340F. I've gotten bags that started balling up well under 300F.
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Wilflex performance. Cures at 280. That is what I use. Spendy but so is replacing F'd up bags.
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We run regular plastisol one nice stroke and off to the dryer, I speed the belt up just enough the bags are hot and the ink is cured...I look at these bags as a one time thing no washing just grab an go, we print them for a doctors office every other month.
Darryl
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Got lucky last week--did 600, catalyzed ink as mentioned, turned down the heat till the chamber was around 320, and ran them through rather slow.
I'd be rather interested in hearing from anyone who reps the companies that make these. There are several types of PP manufactured, and the melting points range from 266-340F. I've gotten bags that started balling up well under 300F.
the bags I've done go through at about 260-280 for about 1 minute dwell. 320 would shrivel them down to almost nothing.
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For synthetic printing, we use Sericol Nylobag.
To speed up the drying, we just flash at low temp.
Just be careful when stacking because the ink can still be wet in the inside.
http://www.fujifilmsericol.co.uk/ff/pi_sheets/PIforWEB23_5_00/Nylobag%20NB.pdf (http://www.fujifilmsericol.co.uk/ff/pi_sheets/PIforWEB23_5_00/Nylobag%20NB.pdf)
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We always keep a LCA (low cure additive) for this. Reduce dryer temp by 100 degrees. Does'nt have a pot life
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tony, who's low cure additive do you use? I am not sure I've seen it at my regular ink supplier.
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Excalibur LCA PF (Phthalate Free) from the Lancer group. Tell my friend Brannon to stock it. Its a well kept secret for some reason.
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Got lucky last week--did 600, catalyzed ink as mentioned, turned down the heat till the chamber was around 320, and ran them through rather slow.
I'd be rather interested in hearing from anyone who reps the companies that make these. There are several types of PP manufactured, and the melting points range from 266-340F. I've gotten bags that started balling up well under 300F.
the bags I've done go through at about 260-280 for about 1 minute dwell. 320 would shrivel them down to almost nothing.
Chambers at 320--bags got right around 300--had to hit 320 before they puckered around the print. Good bags, got lucky.
Had an order last year I could not do anything with. Even at 250 they started to pucker. The quality of the polypropylene, and how it's manufactured directly affects it's melting point, I can tell you that much.
Anthony: Great tip, that nylobag looks like the ticket from the spec sheet.
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I think most ASI suppliers print these bags with air dry inks......Maybe the Nazdar folks can chime in on this subject...
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I think the majority of these bags are printed in China as flat fabric before being sewn. Probably with melamine based
inks or any other industrial waste they can sell back to us. Eco friendly grocery totes made of petro based plastics
printed with god knows what used once and thrown away.
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I wish I could be everyone here a cold adult beverage.
Finished the job 1,200pcs total.
Had to reduce tunel temp to 300 and the suface temp. stayed btw 270 and 290.
Again a HUGE THANK YOU to everyone for the help!
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I think most ASI suppliers print these bags with air dry inks......Maybe the Nazdar folks can chime in on this subject...
If I recall correctly polypropylene/polyethylene products are print receptive for as short time after being molded/extruded/spun etc. In this short period of time they can be printed with many solvent and UV inks successfully. After a while they cure completely and most inks no longer stick to them. If that isn't the case with non-woven poly bags, then they most likely use corona-discharge priming to make the fabric print receptive just prior to printing. This type of priming, along with propane-flame priming also only last for a few days before the product reverts to something that almost no ink will adhere to properly.
Glad it went well for you Parker, once you dial it in they print pretty nicely!
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In case anyone is wondering, Screen And Digital supply carries a low cure additive...
http://www.screenanddigitalsupply.com/store/3804-low-temp-cure-additive.html (http://www.screenanddigitalsupply.com/store/3804-low-temp-cure-additive.html)
They are in NJ, so about 2 days shipping to me.
Thanks for the tip tony.
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We do them, very rarely, without any real heat. We have a primer we spray on them, send them down the dryer, then use air-dry multi-purpose inks. A few extra steps, but absolutely no curling up. We send them through the dryer quickly at 250 or so, gas only, IR panels off. This gives us the best results, and we charge what we need to. If they want cheap, cheap, cheap, then we'll send it to an ASI distributor.
Steve
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I am more worried about other things like these stupid 50/50 neons from American Apparel, these suckers are bleeders. If I can cut the heat, I would be VERY happy.