Author Topic: Emulsion Expiration  (Read 1077 times)

Offline Pangea

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Emulsion Expiration
« on: November 06, 2018, 01:50:24 PM »
Will old emulsion cause premature screen breakdowns? I have some Cryocoat that's about 13 months old and think it may be the culprit.


Offline Frog

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Re: Emulsion Expiration
« Reply #1 on: November 06, 2018, 03:29:02 PM »
Well, though your particular storage conditions can affect it, Photopolymer emulsions are the most tolerant of time. Specs are usually conservative and have some wiggle room.
Yours has a shelf life described thusly(wrong word and all, LOL): Shelf live: Unopened, 24 months. Opened, 6-8 months.
"It's crackers to slip a rozzer the dropsy in snide"

Offline Pangea

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Re: Emulsion Expiration
« Reply #2 on: November 06, 2018, 03:36:26 PM »
This gallon went through a move and a summer with little to no A/C so I think to be safe it's time to toss it.

Offline Frog

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Re: Emulsion Expiration
« Reply #3 on: November 06, 2018, 03:44:46 PM »
Photopolymers are pretty tolerant of temps up to 100.
In my experience, emulsion that has gone bad starts displaying negative characteristics way before the middle of a run.
I've had it curdle and coat poorly, (as well as stink)
I've seen it not develop as usual, either hard to rinse out or entire areas fall apart.
"It's crackers to slip a rozzer the dropsy in snide"

Offline screenprintdirect

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Re: Emulsion Expiration
« Reply #4 on: January 10, 2019, 02:26:08 PM »
Generally most emulsions will have the same life span but it varies on which one you're using
Ready to use emulsion 10-12 month life span
Diazo mixed into the emulsion for waterbased printing 2-3 weeks

Tips to make your emulsion last longer
store in 59-77F or for best results keep it in your fridge and reseal it

After 13 months I would toss it and get a new batch
Also I would write the day you open your emulsion on the container just to keep easier track



Offline Prince Art

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Re: Emulsion Expiration
« Reply #5 on: January 10, 2019, 11:24:29 PM »
Also I would write the day you open your emulsion on the container just to keep easier track

Seconding this. We write the day received, then the day opened. Helpful if you don't go through it quickly.
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Offline Sundaybest

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Re: Emulsion Expiration
« Reply #6 on: July 10, 2019, 02:33:20 AM »
From my experience expired emulsion will not expose perfectly and will leave rough edges in the stencil.

Online RICK STEFANICK

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Re: Emulsion Expiration
« Reply #7 on: July 10, 2019, 12:14:52 PM »
Generally most emulsions will have the same life span but it varies on which one you're using
Ready to use emulsion 10-12 month life span
Diazo mixed into the emulsion for waterbased printing 2-3 weeks

Tips to make your emulsion last longer
store in 59-77F or for best results keep it in your fridge and reseal it

After 13 months I would toss it and get a new batch
Also I would write the day you open your emulsion on the container just to keep easier track

I did not know that the fridge trick still was still in use with todays formulations. thanks

Online ABuffington

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Re: Emulsion Expiration
« Reply #8 on: July 10, 2019, 01:27:50 PM »
Refrigeration has some negative side effects on emulsion.  While it can keep it at a low temperature, diazo emulsion only needs to be kept below 80 and as mentioned SBQ can be stored to 100 degrees.  The issue is every time you put the emulsion into the refrigerator it is warm.  This causes moisture to condense on the inside of the bucket.  As the emulsion get used up, this condensation is added to the emulsion every time it is put back in the fridge.  This dilutes the emulsion and if not stirred in may show coating issues the next day.  The act of stirring the condensation into the emulsion creates bubbles which create pinholes. 

The second drawback is cold emulsion has much higher viscosity than room temp emulsion.  So it should be allowed to warm up to room temperature.  Most shops don't have that kind of time to wait for screens to be coated, so EOM varies as the emulsion warms up, which affects exposure quality.

It is far better to store in an air conditioned room.  Converting the entire screen room to an HVAC system standardizes temps and with a dehumidifier and in some cases in cold dry climates, a humidifier, keeping the room year round at <80 and 35% humidity provides year round consistency.  CTS ink jet machines may need their own room due to higher humidity needs.
Alan Buffington
Murakami Screen USA  - Technical Support and Sales
www.murakamiscreen.com