Delamination of ink on acrylic

[Susan Stewart]

Good morning all.
We have a product that we cut on our CNC router and then print it on our Mimaki JFX200-2513. The substrate is 1/8" clear acrylic. We have been producing this product since August 2020 with no issues. We have produced over 2,000 parts. We sell them to 6 different plants. We have 1 plant that started having issues with delamination a couple months ago. We do not believe this problem is being caused by anything that we are doing. We produce them the same way every time. We are cleaning them before printing them with a 50/50 mixture of distilled water and isopropyl alcohol. We believe it is something they are doing seeing as how the other 5 plants that we sell to are not having any issues. We are using LH-100 inks except our primer which is PR-200. I have attached pictures of one of the worst pieces to show you what they look like.

We tried putting different liquids on the printed acrylic to try to figure out what is causing this problem, but we were unable to recreate this. We tried water, isopropyl alcohol (90%), hand sanitizer, simple green, glass cleaner, and brake kleen.

We pulled off the ink on one of these raised spots, and the primer was still on the acrylic.

Does anyone know what would cause this?

 

[White Haus]

Wow is that ever strange.

If it's only happening in one location my guess would be something environmental at that plant is causing it.

Rapid temperature fluctuations? Rapid rise/drop in humidity? Something has to different in the environment for that location.

Does it just suddenly appear one day like that or slowly start getting worse? How long after being installed?

Longer/different shipping times to that one location?

If your process hasn't changed, and the other 5 locations aren't affected............

 

[signheremd]

Not familiar with Mimaki ink chemistry, but for our UV flatbed printer Denatured Alcohol would do this to the ink - in fact, we can spray/flood a printed piece and let it soak in denatured for about 10-15 mintues and it peels up completely. I would guess some overspray is hitting these or fumes in the air. I could duplicate this exact look by misting some denatured alcohol on a piece we print, let it stand and dry. Speaking of ink chemistry, on our old CET 100% Isopropyl Alcohol would do this and yet the inks would resist Denatured...

Have you considered laminating your printed pieces?

 

[Susan Stewart]

Wow is that ever strange.

If it's only happening in one location my guess would be something environmental at that plant is causing it.

Rapid temperature fluctuations? Rapid rise/drop in humidity? Something has to different in the environment for that location.

Does it just suddenly appear one day like that or slowly start getting worse? How long after being installed?

Longer/different shipping times to that one location?

If your process hasn't changed, and the other 5 locations aren't affected............

It is very strange. We had a member of our sales staff go to that plant to see if maybe they were sitting outside or in an area where there was a big change in humidity. He said that he didn't see anything out of the ordinary.

They said that they are coming straight out of the box this way before they get a chance to install them.

The plant we're shipping these to are only a few blocks away from our shop.

We are having a member of our sales staff deliver their next order and look through the parts with our customer.

 

[Susan Stewart]

Not familiar with Mimaki ink chemistry, but for our UV flatbed printer Denatured Alcohol would do this to the ink - in fact, we can spray/flood a printed piece and let it soak in denatured for about 10-15 mintues and it peels up completely. I would guess some overspray is hitting these or fumes in the air. I could duplicate this exact look by misting some denatured alcohol on a piece we print, let it stand and dry. Speaking of ink chemistry, on our old CET 100% Isopropyl Alcohol would do this and yet the inks would resist Denatured...

Have you considered laminating your printed pieces?

We have cleaned everything we have printed (besides paper products and canvas) for the last 6 years with the 50/50 mixture of the 90% isopropyl alcohol and distilled water so I don't believe this is the issue.

Laminating is not an option for these parts.

 

[Gino]

A year or so ago, we had delivered about 30 pieces of acrylic, which we had flatbed printed and then used a light spray clear coat to give it a satiny finish. They loved them. About 2 weeks after they were delivered, they complained that some of them had almost the same identical look your pictures are showing. I couldn't figure it out, but one thing seemed odd, they mentioned that the maintenance crew had cleaned them a day or two earlier and they only cleaned the signs in the stairwells and non-sitting areas of this complex. Only the ones they cleaned were affected. I asked, why are perfectly good clean signs being washed so soon ?? Also, what are they using ?? They told me just water and hand wiping. No chemicals or nothing. I went in and talked to the maintenance people and it turns out they were experimenting and cleaning these signs with high pressure washers and some kinda detergent I never heard of, but they said it's totally safe, if you get it on your skin. I asked if the signs doing this crackling thing were the only ones they were having a problem with ?? Yep. I said, the sheet I gave to the purchasing person, says not to use any harsh cleaning agents on these signs. It doesn't say anything about power washers, but c'mon, use your frickin' head. You're blasting these at close range. That power washer will take the paint off just about anything, let alone a flatbed printed piece of plastic. I ended up doing about 8 more and charged them for the new material, but not the printing portion.

I would see if anything happened to fall on this stuff. I highly doubt they came outta the box like that. Someone is not telling the complete story. Somebody goofed and is covering their posterior.

 

[Susan Stewart]

A year or so ago, we had delivered about 30 pieces of acrylic, which we had flatbed printed and then used a light spray clear coat to give it a satiny finish. They loved them. About 2 weeks after they were delivered, they complained that some of them had almost the same identical look your pictures are showing. I couldn't figure it out, but one thing seemed odd, they mentioned that the maintenance crew had cleaned them a day or two earlier and they only cleaned the signs in the stairwells and non-sitting areas of this complex. Only the ones they cleaned were affected. I asked, why are perfectly good clean signs being washed so soon ?? Also, what are they using ?? They told me just water and hand wiping. No chemicals or nothing. I went in and talked to the maintenance people and it turns out they were experimenting and cleaning these signs with high pressure washers and some kinda detergent I never heard of, but they said it's totally safe, if you get it on your skin. I asked if the signs doing this crackling thing were the only ones they were having a problem with ?? Yep. I said, the sheet I gave to the purchasing person, says not to use any harsh cleaning agents on these signs. It doesn't say anything about power washers, but c'mon, use your frickin' head. You're blasting these at close range. That power washer will take the paint off just about anything, let alone a flatbed printed piece of plastic. I ended up doing about 8 more and charged them for the new material, but not the printing portion.

I would see if anything happened to fall on this stuff. I highly doubt they came outta the box like that. Someone is not telling the complete story. Somebody goofed and is covering their posterior.

Wow! How awful.

I agree with you. They say that they aren't wiping them with anything, but no one else is having issues. We're going to have a member of our sales staff deliver the next couple orders and go through the parts with them upon delivery.

 

[signheremd]

We have cleaned everything we have printed (besides paper products and canvas) for the last 6 years with the 50/50 mixture of the 90% isopropyl alcohol and distilled water so I don't believe this is the issue.

Laminating is not an option for these parts.

I was not referring to your cleaning procedure, but the chemistry that caused the adhesion failure of the printing. In other words, certain cleaners when sprayed onto the printed pieces can cause a similar effect. But it depends on the ink chemistry as to which ones will. On our printer Denatured Alcohol will cause the ink to let go of the acrylic, while our old printer Denatured did not impact the inks but 100% Isopropyl did. I am suggesting overspray at the factory of some chemical is the most likely issue.

 

[Gino]

I was not referring to your cleaning procedure, but the chemistry that caused the adhesion failure of the printing. In other words, certain cleaners when sprayed onto the printed pieces can cause a similar effect. But it depends on the ink chemistry as to which ones will. On our printer Denatured Alcohol will cause the ink to let go of the acrylic, while our old printer Denatured did not impact the inks but 100% Isopropyl did. I am suggesting overspray at the factory of some chemical is the most likely issue.

Are you suggesting from the factory it was contaminated before any printing was done...... or after the printing was done at/by the customer on the finished product ??

Are these signs for the various plants all done at the same time under all the same conditions or do you do one plant at a time and only order enough substrate for that particular plant ?? Seems odd that when we order materials, we always add extras in. Therefore, if it was from the factory, other pieces would be contaminated as well.

 

[unmateria]

Hi thats a very common... "orange skin" we call it here. Usually just too much ink, or unleveled bed. You need to limit the ink % with a densitometer, level the bed, and having the acrylic and inks at the same temperature before printing.

And for god shake, never use isopyl on acrylics or polycarbonate. Just look for some basic chemistry on google about acrylics and you will see why is not a good idea even when it USUALLY doesnt happen anything (until it happens)

Sorry for my english!!

 

[Browner]

Using alcohol on acrylic is bad.

 

[chinaski]

I use "Iris glass primer" and I get perfect results on both glass and acrylic. I don't need to pre-clean the sheet with alcohol, which as others have suggested is not very good for the acrylic.

If you're already hand-cleaning the acrylic, you might as well just hand-apply a different primer and skip the in-line jetting of primer.

 

[Susan Stewart]

I was not referring to your cleaning procedure, but the chemistry that caused the adhesion failure of the printing. In other words, certain cleaners when sprayed onto the printed pieces can cause a similar effect. But it depends on the ink chemistry as to which ones will. On our printer Denatured Alcohol will cause the ink to let go of the acrylic, while our old printer Denatured did not impact the inks but 100% Isopropyl did. I am suggesting overspray at the factory of some chemical is the most likely issue.

Gotcha. I will definitely have our sales guy be on the look out for this when he goes there. Thanks!

 

[Susan Stewart]

Are you suggesting from the factory it was contaminated before any printing was done...... or after the printing was done at/by the customer on the finished product ??

Are these signs for the various plants all done at the same time under all the same conditions or do you do one plant at a time and only order enough substrate for that particular plant ?? Seems odd that when we order materials, we always add extras in. Therefore, if it was from the factory, other pieces would be contaminated as well.

We bring in 4" x 8" sheets of the acrylic. We keep stock sheets on hand. We only cut and print the acrylic when we get an order. When we get low on acrylic sheets, we order more.

These are all done in the same conditions in a controlled environment.

I do believe this is something that is happening at the customer's facility because the other 5 plants that we ship to have never complained.

 

[unmateria]

If it never happen in your facilities... I would bet for a lacquer or varnish, an organic solvent or a kh7, ammonia or similar cleaner

 

[signheremd]

Are you suggesting from the factory it was contaminated before any printing was done...... or after the printing was done at/by the customer on the finished product ??

Are these signs for the various plants all done at the same time under all the same conditions or do you do one plant at a time and only order enough substrate for that particular plant ?? Seems odd that when we order materials, we always add extras in. Therefore, if it was from the factory, other pieces would be contaminated as well.

I was saying printed pieces exposed to some chemicals will lift like this - the case of denatured alcohol sprayed lightly onto printed pieces from our machine (Fluid Color UV flatbed) would cause this, or flooded onto the pieces would cause all the ink to peel off. So after printing. I am not sure which chemicals would do this to Mimaki ink as I have never used a Mimaki, but there will be one with the right chemistry.

As far as material prep, Since this is a new and isolated issue it does not sound like material prep is the issue. But 50/50 water/alcohol does sound like a weak prep spray - but as I said, I am not familiar with Mimaki's inks, so it may be more than strong enough.

I am of the opinion that spray or fumes at the specific plant are causing the failure.