Adhesive for Signs

Our prior adhesive supplier dropped the adhesive we had successfully used for more than two decades. They recommended a place or two I could contact for a replacement. In order or organize my own thoughts, I will lay out how it all breaks down.

I contacted 3M as recommended by the supplier who quit making our adhesive.  I started with a chat conversation. I described our need for something similar: 0.5 mil pet acrylic 60# SCK, information I found from the last invoice we got. Later I saw a spec sheet with this info:

Product consists of a thin polyester film coated on both sides with a high performance acrylic based pressure sensitive adhesive. The product is supplied self-wound on 60# semi-bleached, densified-kraft liner.

Product is typically used for industrial bonding applications where outstanding adhesion, high shear and good solvent resistance are required. The acrylic adhesive offers good clarity and has excellent resistance to U.V. light exposure. The polyester carrier provides excellent dimensional stability and die cutting properties.

I used Chat to discuss our needs, opening with this:

Looking to replace product that has been discontinued. It's roll adhesive, which is .5 mil pet acrylic 60# SCK. We use this to attach half-inch magnetic strips to vinyl (vinyl as is used on a three-ring binder). Signs are attached to vehicles and fully exposed to environment during use. We have to be careful about plasticizer issues.

Plasticizers are a chemical that is added to vinyl to keep it soft and flexible. Plasticizers are attracted by adhesives, so they tend to migrate out of the vinyl and into the adhesive, making the adhesive bond soft and gummy. At room temperature, it can take a couple of months to affect the adhesive. With heat, it happens much faster. 5 days at 150 degrees F will show if the vinyl and adhesive will react.

To test your vinyl with a tape, you can make some sample bonds and put them under a high intensity light for 5-7 days. That will give a good idea of whether or not the two will react. 

A sign on a black door will take a little longer, as it would only be in full sun for part of the day. It would help, though. Laying a sign out on the driveway would be even better. Assuming sun for 12 hours a day, you would probably want to leave it for a couple of weeks.

If the adhesive is starting to get soft, gooey, and loses strength, that's how the signs would eventually get.

We have 9465PC, which is a 5 mil thick transfer tape that is designed for bonding to plasticized vinyls. 

Just so you know, while most plasticizers are a problem, there are a few that aren't, so 9485PC may be a viable option. 

After the chat, 3M sent us two products.

9465
    designed for bonding to plasticized vinyls (see spec sheet notes below)
    same thickness as prior adhesive but has no polyester layer

We didn’t even test it because it was so messy to apply to the substrate.

9485
    for products where plasticizers are not a problem
    only for comparison to 9465

We tested the 3M 9485, and it seems to be working all right. But the Chat description says it is not for applications where plasticizers are a problem. Things got a little confused when the 9465 was a sticky mess to apply, and the 9485, which was sent only for comparison, seemed to hold up well. I got quotes from three suppliers recommended by 3M.

Our current price is for 81,000 feet, which comes on 750 ft rolls:  .038 per foot
$3003.48, plus $100 for slitting the roll to half-inch width.
This comes to $28.74 per roll, including slitting.

Miami/Famis
I think this guy told me $29 per roll. I e-mailed to get a quote in writing, and I have not received a response.

Tampa/Hughes
For 81,000 ft, sold on 60 yd rolls (450):  .118

Miami/Gard
$23.75 per roll
For 81,000 ft, sold on 60 yd rolls (450 rolls):  .132 per ft

This one is now offering two more options, one that is in a price range I might be able to consider. But we are now in a time crunch and would not have time for testing and then sufficient lead time for ordering, shipment, and delivery. I’m pretty sure they don’t know our requirements.

New quotes are:

$13.79 per roll or .077 per ft, compares at $6237 for 81K ft
$8.41 per roll or .047 per ft, compares at $3807 for 81K ft

I have now downloaded the spec sheets, and I am trying to learn enough to understand the products and make a wise decision. I am confused about the specs v the Chat. I think Chat may have mixed up her information. The 9465 sheet says:

Note: The 9465PC does not resist the effects of these particular fillers and plasticizers and is not recommended for use in bonding these materials.

But it is a moot point on the 3M products, because the costs were way above out budget.

We also contacted a non-3M manufacturer. We tested this product, and I have the spec sheet. The rep said it compared well to our prior product, and the adhesive tested very well. But it’s quite scary to commit to the large order. But we are thankful that it seems to be a great product and at a lower cost!

Non-3M Product

For 81,000 feet, which comes on 750 ft rolls:  .028 per foot
$2283.75
This comes to $21.15 per roll, including slitting.

We also reached out to our prior adhesive supplier to see if they might now have a product that will work. I did not think they really would have something to offer. But it has been a year and half, and they did have an adhesive for us to try. After I agreed to try samples, I realized that the time crunch would be a problem here, too. I have the spec sheet for comparison, and they will provide a quote on Monday. This adhesive is a little thicker: 2.4 on each side of liner instead of 2.0.

And we contacted our magnet supplier to see what they had to offer, and they had two items to send us. But, again, now we are up against a time crunch. Spec sheets received.

457 adhesive: .038 per ft, compares at $3078 for 81K ft
FTA adhesive: .052 per ft, compares at $4212 for 81K ft

So I have now looked up some terminology: PET, SCK, and PCK.

Carrier: The piece between the two sections of adhesive. PET means it is a polyester film.

Liner: The paper liner.

60# SCK, the standard, the workhorse for double-coated adhesive products, manages most die-cutting requirements.

72# PCK, can be used for single liner (which I think means single coated), 6 mil

And now I have more homework to do on this tomorrow. I will need to compare several items for the thickness of the adhesive, the carrier, and the liner. Also storage life and other details I don’t really understand. I wonder where I can get help.