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Parson

Parson

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My buddy and I want to know two things from some smart chemical engineer on this forum:

1. Is "flexible" CA glue the same as Medium CA glue? They sure look and act the same. If they're different, we want to know what in particular has been included to the medium CA glue to raise the price on it to call it "flexible."

2. What is the active ingredient in CA accelerator?
 
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I can't say where the CA is concerned. But I once had the same sort of question about Elmers glue and Elmers wood glue. other than the color what is the difference? I actual found out a lot about what was different. But what it all amounted to was water resistance as well as the ability to expand and contract as the wood does without loosing it's bond. I do know that finding the exact make up of any CA is nearly impossible. it falls in the arena of proprietary.
 
I'm not a chemical engineer, but the active ingredient in some brands of accelerant is acetone. Sounds strange, I know, but it's true.
 
1. Flexible CA's are not the same as Medium CA. The "Medium" refers to the viscosity, which is controlled by having small amounts of polymer mixed in with the cyanoacrylate monomers. In the abstract, low, medium, and high viscosity CA's can be rigid/brittle or flexible or anywhere in between. For finishing, I'd not use flexible CA's (although it might be interesting to try -- I'd guess you'd get a rubbery feel to the finish, but getting it smooth would be tough. It would not sand well. If you want to try, if you get the flexible CA cold enough, like MN in January, you might be able to sand it smooth.)

Flexible CA's can be made in two ways. The first is by adding a plasticizer, usually a phthalate, to the CA. The second is by using monomers such as dodecyl methacrylate to the usual mix of ethyl methacrylate and ethyl methacrylate. The long side chain (dodecyl = 12 carbons) is what gives the resulting cured CA its flexibility.

2. CA's are catalyzed by bases, most commonly water. Water is basic enough to trigger the curing reaction. If you have extremely dry conditions (MN in January again) cure will be slower due to the lack of a base (water) to trigger the cure. Anything that is more basic than water can be used as an accelerator for CA cure. Acetone in and of itself is not an accelerator for CA's but instead is used as a carrier solvent for bases such as toluidine.

Too much information I suppose......




Parson said:
My buddy and I want to know two things from some smart chemical engineer on this forum:

1. Is "flexible" CA glue the same as Medium CA glue? They sure look and act the same. If they're different, we want to know what in particular has been included to the medium CA glue to raise the price on it to call it "flexible."

2. What is the active ingredient in CA accelerator?
Click to expand...
 
jamiller99 said:
The second is by using monomers such as dodecyl methacrylate to the usual mix of ethyl methacrylate and ethyl methacrylate.
Click to expand...


I agree that this is a great answer, but this part of it leaves me a little confused - did you mean to list two ingredients and list the same ingredient twice by mistake? Or are the words simply too long and I missed some subtle spelling different deep in the middle of the word?

I'm still in awe - I can't even remember what CA stands for let alone pronounce it or spell it.
 
jkeithrussell said:
I'm not a chemical engineer, but the active ingredient in some brands of accelerant is acetone. Sounds strange, I know, but it's true.
Click to expand...


Actually, acetone is not the active ingredient. It's just a matrix that is used to keep the active ingrediant in solution. The evaporation rate (7.7) and the fact that it's a solvent that tends to readily 'bleed' makes is a great carrier and dispersant for the active ingredient.

Generally speaking, the active ingredient in CA Accelorators tend to be in the Toluidine family. The most popular is N,N-Dialkytoluidine. Depending on the brand, the toluidine make up anywhwere from <1% to 20% of the product.

Rite-Lok by 3M is a CA Accelorator in Concentrated form, and it is 100% N,N-Dimethyl-P-Toluidine.
 
oops, I meant a mixture of ethyl (2 carbons in the side chain) cyanoacrylate and methyl (1 carbon side chain) cyanoacrylate. btw, dodecyl has 12 carbons in the side chain......


hilltopper46 said:
I agree that this is a great answer, but this part of it leaves me a little confused - did you mean to list two ingredients and list the same ingredient twice by mistake? Or are the words simply too long and I missed some subtle spelling different deep in the middle of the word?

I'm still in awe - I can't even remember what CA stands for let alone pronounce it or spell it.
Click to expand...
 
GS,

There are a variety of CA acclerators/primers in the 3M line. The "pure" accelerator is 3M Ritelok AC306 -- it's the dimethyl toluidine variant. Personally I'd never use the pure form -- too expensive and you really don't need much. The diluted versions work just fine.


Grim Spirit said:
Actually, acetone is not the active ingredient. It's just a matrix that is used to keep the active ingrediant in solution. The evaporation rate (7.7) and the fact that it's a solvent that tends to readily 'bleed' makes is a great carrier and dispersant for the active ingredient.

Generally speaking, the active ingredient in CA Accelorators tend to be in the Toluidine family. The most popular is N,N-Dialkytoluidine. Depending on the brand, the toluidine make up anywhwere from <1% to 20% of the product.

Rite-Lok by 3M is a CA Accelorator in Concentrated form, and it is 100% N,N-Dimethyl-P-Toluidine.
Click to expand...
 
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