I' m currently making tensile test samples for Unidirectional (UD) Prepreg. Therefore, I need to fabricate a 1mm thick unidirectional sheet. I used two glass plates that sandwich five layers of UD Prepreg and are vacuum baged and cured in the Prepreg oven at 100°C (see attached pic). The two glass plates were treated with six layers of Easylease coated with a 20min. separation between each coating. However, I still have the problem that the Prepreg sticks to the glass. I cannot manage to take the Prepreg sheet off the glass without braking the glass or the prepreg sheet (see attached pic). I tired this several times already. Any Idea how to resolve this? What about trying to use PVA or wax as a release agent, instead of Easylease?Looking forward fot some helpKind regardsPier
+x Pier - 1/3/2018 2:50:45 PM+x Pier - 1/3/2018 2:27:59 PM+x oekmont - 1/3/2018 12:13:53 PMBut usually easylease should work very well. Have you cleaned the glass before applying the release agent? Maybe there is something on the glass, wich causes this issue.I really don't understand why it is not working? I cleaned the surface and even switched from tempered glass to special heat resitant glass but it does not work good enough to be called a repetitive process. The reason could be hidden in:- Glass Type- Epoxy System (in my case E320/E321/E322/E323 from SGL)- Heat Control (In my case according to Sigrapreg datasheet)- Application method - Application quantity- Panel stiffnessThis is what I did so far:- Varied glass type (from tempered to heat resistant glass)- Varied application method (Circular movments to linear movments)- Application method (more and less release agent)- I tried with a Mylar foil between the glass and the carbon and it worked- Changed stiffness of the panelWhat I noticed was, that it worked with stiffer panels like [0/90/+45/-45/+45/-45/90/0] or unidirectional 0° with a 2mm thickness. Therefore my question:- Could it be that the stiffness of the sheet influences the release of the sheet itself?Next I will try with the HP-HGR5 release agent...Hi Matt, thank you for commenting on this. Here are the answers to your questions:- I use the Sigrapreg C U200-0/NF-E322/40% Prepreg system from the SGL Group. - My cure cycle is considering the Sigrapreg Epoxy System Specification and is as follows: 40min ramp to 100°C/120min at 100°C/40min ramp down to 20°. My comments concerning your points:1) Could be. This is the reason for which I tried with another glass that unfortunately failed as well. I guess I have to talk to a glass specialist here...2) The release agent was always properly sealed but it is 2 years old. Are two years considered to as old?3) This can be excluded because I checked it4) I tried different procedures but no one worked to be considered a reliable repetitive process5) This is very unlikely since I know the fiber and matrix system and have it documented in the specificationsLooking forward to hear from you...
+x Pier - 1/3/2018 2:27:59 PM+x oekmont - 1/3/2018 12:13:53 PMBut usually easylease should work very well. Have you cleaned the glass before applying the release agent? Maybe there is something on the glass, wich causes this issue.I really don't understand why it is not working? I cleaned the surface and even switched from tempered glass to special heat resitant glass but it does not work good enough to be called a repetitive process. The reason could be hidden in:- Glass Type- Epoxy System (in my case E320/E321/E322/E323 from SGL)- Heat Control (In my case according to Sigrapreg datasheet)- Application method - Application quantity- Panel stiffnessThis is what I did so far:- Varied glass type (from tempered to heat resistant glass)- Varied application method (Circular movments to linear movments)- Application method (more and less release agent)- I tried with a Mylar foil between the glass and the carbon and it worked- Changed stiffness of the panelWhat I noticed was, that it worked with stiffer panels like [0/90/+45/-45/+45/-45/90/0] or unidirectional 0° with a 2mm thickness. Therefore my question:- Could it be that the stiffness of the sheet influences the release of the sheet itself?Next I will try with the HP-HGR5 release agent...
+x oekmont - 1/3/2018 12:13:53 PMBut usually easylease should work very well. Have you cleaned the glass before applying the release agent? Maybe there is something on the glass, wich causes this issue.