Attention Ink Folk - What's up with plastisol cure temps?

[Frog]

This is a question dear to my heart, and has once again popped up in another thread. I'd like it addressed by those truly in the know.
My post in a current low cure thread discussing low temp inks was something like this:

...most major ink manufacturers have a low cure additive to help with heat sensitive materials.

For me, since the chemistry is obviously there, it has always begged the point; why not lower the cure temp on all plastisols in the first place?
The energy savings would be a boon as well.

[Rob Coleman]

Two primary reasons as I see it.

1.  Cost.  No everybody wants to pay for something they do not need.
2.  Long term viscosity stability.  Lower the cure temperature, and most times the gelation temperature lowers as well.  So heat during transport/storage will decrease the shelf life.  Potential major issues for the big players that ship globally.

Great question though!!

[Colin]

Yep, Rob has it.

The lower the cure temp - the lower the flash/gel temp.

It is possible to go low enough that it will gel at room temperature.

[Frog]

Most of our rooms rarely getting very much over 100° kind of precludes that as an issue though, eh?


Sent from my iPhone using Tapatalk

[Colin]

It also thickens up during storage more so than standard plastisol inks.... this can render it unprintable.

[Frog]

It also thickens up during storage more so than standard plastisol inks.... this can render it unprintable.

But would knocking cure temp down to 270 or so really complicate storage and shipping enough to negate the positive aspects of shorter flash and less dye migration issues?

As pointed out, energy savings would be another bonus

[Colin]

During the summer months... yea.

Standard "Fast Flashing" plastisol has "potential" issues being transported during the hot times of the year...

I know the major payers have this happen at least a couple times a year.  At QCM we had a shipment go all the way to New Zealand that was essentially unusable when it arrived.  Not cheap to fix.  I have heard of some shipments going out in refrigerated trucks...

I do not know what Wilflex has done to fix/alleviate this potential issue with their Top Score inks.  Maybe Rob can show us some insight into that if he is allowed.

There is always new chemistry coming out every year.  Some of that may render a 320 cure temp a thing of the past.  But with my current knowledge of how everything interacts, it becomes very difficult to support an ink the lower the cure temp gets.

[brandon]

Thanks for posting on this thread guys. All good info for everyone to know. And I would hate to know how much that shipment cost. I assume shipping / freight insurance covers some of the damage? Or am I crazy?

[jvanick]

if the ink was in a shipping container that ended up at the 'top' of one of those ships, I could definitely see how the ink could be rendered unusable...

we had a tradeshow exhibit that was shipped in a truck that sat in the arizona sun, and the formica on some of the tops delaminated due to the heat... can't even imagine how hot it was inside the truck.

[Maxie]

Sounds logical, our plastisols are all shipped in metal shipping containers that must get extremely hot in the summer.
Why can't we buy an additive that lowers the curing temperature, we don't need it all the time but now and again it would be great.

[Frog]

Sounds logical, our plastisols are all shipped in metal shipping containers that must get extremely hot in the summer.
Why can't we buy an additive that lowers the curing temperature, we don't need it all the time but now and again it would be great.

You can. I use one from International Coatings, and some of the other manufacturers make one as well.

[mimosatexas]

Yea, low cure additive is very common/easy to get.  I think basically every manufacturer sells one.

[ebscreen]

It does lower the viscosity of an ink quite a bit though, in my experience. Not usually a bad thing,
but sometimes.

[Rob Coleman]

Colin is spot-on as well.  As far as overseas transport -- years back when I was at Wilflex (even pre-PolyOne days), we had an entire container that was a brick when it arrived in Australia.  This is standard cure/gel plastisol.  After that, specified below deck. 

A couple of years ago in Texas during a huge summer heat wave, EVERYONE had issues shipping and ink thickening way up in the back of the little brown trucks.

It does not take much heat guys and the process is IRREVERSIBLE once the resins start swelling and absorbing plasticizers.  Reducer does little good - you cannot reduce the particle size.

A did a study a number of years ago.  Put one gallon of white in my trunk in Atlanta at 8am in the morning.  At noon the air temp outside was 95F.  The air in the enclosed trunk was 130f.  Hitting the bucket with a non-contact thermometer showed bucket temp of >150f.  Boat anchor I had.....

[Frog]

In that same vein, I've had folks not want to send me pint or quart samples because of the added risk smaller quantities being more easily affected and me getting product which wouldn't present itself at its best.