Help with Hardener for Films and Frilling
To all of our chemists and emulsion makers out there, as you might have read in some of the other postings, I have been trying to develop a method to coat emulsions on PET. Mostly it seems to work but I am trying to solve a problem regarding frilling at cut edges. In other words, everything is great until I try to slit the film sheet. Then I get frilling while processing. Frilling is worse in XTOL than plain water, so I believe that pH has something to do with this.
I believe I need to add a hardener, which I have resisted because of problems I've had with hardener and coating. Normally adding a drop or two of 10% Chrome alum turns the 10-20 ml emulsion I'm working with into glop in just a few seconds. So, obviously too strong. Trying to add very minute quantities gives not much or any effect. Done many a search through these archives and am now more confused yet! So I will put my question out there as a tongue-in-cheek textbook style question. :p These drive my kids nuts cause I do it to them in the car all the time.
So, no looking at your neighbor's paper. Pick up your pencils - - - begin! :p
Jason is working on coating 100 ml of an emulsion made with 8% gelatin on a 5 mil support. 5ml of 50% ethanol (aka vodka) has been added to the gelatin as a surfactant. He is having problems with frilling at cut edges when processing exposed film in XTOL. Jason has decided to try adding a hardener. He has chrome alum (CA) available. To add CA hardener to 100 ml of emulsion to be coated at 32.5 C,
A) Jason should mix a CA solution of what percentage?
B) How much of this solution should be added to the emulsion before coating?
Thanks for your help, Jason
Glop Question Might be Answered
I think the "glopping" problem has to do with using "recycled" emulsion vs a "first melt." Some times when doing coating tests I have taken stripped off emulsion, added some DW, allowed it to swell and remelted. Well, tonight that gave instant glop. Melted some new emulsion and no problems. IDK why this happens but seems to be the answer.
BTW, remelted emulsion seems to be OK for coating but it loses sensitivity.
Erythritol may be helping out with the adhesion and cut edge problem. That's what I was testing when I made the glop.
More to come.