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Pier
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Group: Forum Members
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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 help
Kind regards
Pier 
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Pier
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Group: Forum Members
Posts: 11,
Visits: 22
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+xBut 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 stiffness This 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 panel What 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...
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Pier
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Group: Forum Members
Posts: 11,
Visits: 22
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+x+xBut 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 stiffness This 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 panel What 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 it 4) I tried different procedures but no one worked to be considered a reliable repetitive process 5) This is very unlikely since I know the fiber and matrix system and have it documented in the specifications Looking forward to hear from you...
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Matt (Staff)
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Group: Forum Members
Posts: 680,
Visits: 1.9K
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+x+x+xBut 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 stiffness This 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 panel What 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 it 4) I tried different procedures but no one worked to be considered a reliable repetitive process 5) This is very unlikely since I know the fiber and matrix system and have it documented in the specifications Looking forward to hear from you... I think the age of the Easy-Lease is the most likely (and a very likely) explanation. Easy-Lease has a shelf life of 12 months. It will continue to work after 12 months but 24 months should really be considered to be too old. A 12 month shelf-life is typical for chemical release agents (some of them are in the 6 months region) and most of them will not perform well once you start to exceed their shelf-life by too long. I very much expect you would get different results from fresh release agent. I did also notice that you mentioned the release was OK for a thicker laminate but not OK for a very thin laminate. This is not something that has been focused on much in this discussion but it is an interesting result worthy of some further consideration. For example, release problems are not uncommon if there is not proper resin flow on the surface of the laminate which can sometimes happens following a failed cure such as a burst bag or incorrect temperature settings. Is it possible that you thin laminate is too thin to allow proper resin flow and therefore this could cause release problems similar to those after a burst bag or incomplete cure? This seems quite possible to me; especially in conjunction with release agent which is twice past its shelf-life.
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Pier
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Group: Forum Members
Posts: 11,
Visits: 22
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+x+x+xBut 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 stiffness This 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 panel What 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 it 4) I tried different procedures but no one worked to be considered a reliable repetitive process 5) This is very unlikely since I know the fiber and matrix system and have it documented in the specifications Looking forward to hear from you... Thank you Matt, this gives me another lever to pull for another test round tomorrow. I will post the results... Concerning the thickness, I can see that the epoxy flowed nicely and gave me a good surface finish. Non the less, there are some dry fibers not covered by the epoxy. You can see this in the pictures. I also have to mention that the Prepreg is expired for a year now. So that might be another reason, although I still get good results and the Prepreg was stored at -25 °C.
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Matt (Staff)
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Group: Forum Members
Posts: 680,
Visits: 1.9K
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+x+x+x+xBut 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 stiffness This 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 panel What 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 it 4) I tried different procedures but no one worked to be considered a reliable repetitive process 5) This is very unlikely since I know the fiber and matrix system and have it documented in the specifications Looking forward to hear from you... Thank you Matt, this gives me another lever to pull for another test round tomorrow. I will post the results... Concerning the thickness, I can see that the epoxy flowed nicely and gave me a good surface finish. Non the less, there are some dry fibers not covered by the epoxy. You can see this in the pictures. I also have to mention that the Prepreg is expired for a year now. So that might be another reason, although I still get good results and the Prepreg was stored at -25 °C. No problem; if the resin has flowed properly then it's less likely to be the prepreg itself or the thickness but still a consideration. I look forward to hearing how you go.
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Pier
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Group: Forum Members
Posts: 11,
Visits: 22
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+x+x+x+x+xBut 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 stiffness This 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 panel What 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 it 4) I tried different procedures but no one worked to be considered a reliable repetitive process 5) This is very unlikely since I know the fiber and matrix system and have it documented in the specifications Looking forward to hear from you... Thank you Matt, this gives me another lever to pull for another test round tomorrow. I will post the results... Concerning the thickness, I can see that the epoxy flowed nicely and gave me a good surface finish. Non the less, there are some dry fibers not covered by the epoxy. You can see this in the pictures. I also have to mention that the Prepreg is expired for a year now. So that might be another reason, although I still get good results and the Prepreg was stored at -25 °C. No problem; if the resin has flowed properly then it's less likely to be the prepreg itself or the thickness but still a consideration. I look forward to hearing how you go. So I was able to repeat the test with the Easy-Lease release agent and I got a perfect release from the glass. The Easy-Lease I used here, was newer and has a label that says 2017. The one I used before has a label with the date 2015 and was at least 2 years old. I learned it the hard way. "Never use Easy-Lease that is older then a year", was a nice lesson for me. Thank you Matt, I was not aware that the exspiration date of the Easy-Lease has to be taken that serious. On other products the expiration date is kind of fuzzier but I will certainly respect that one from now on. Kind regards
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Matt (Staff)
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Group: Forum Members
Posts: 680,
Visits: 1.9K
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+x+x+x+x+x+xBut 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 stiffness This 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 panel What 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 it 4) I tried different procedures but no one worked to be considered a reliable repetitive process 5) This is very unlikely since I know the fiber and matrix system and have it documented in the specifications Looking forward to hear from you... Thank you Matt, this gives me another lever to pull for another test round tomorrow. I will post the results... Concerning the thickness, I can see that the epoxy flowed nicely and gave me a good surface finish. Non the less, there are some dry fibers not covered by the epoxy. You can see this in the pictures. I also have to mention that the Prepreg is expired for a year now. So that might be another reason, although I still get good results and the Prepreg was stored at -25 °C. No problem; if the resin has flowed properly then it's less likely to be the prepreg itself or the thickness but still a consideration. I look forward to hearing how you go. So I was able to repeat the test with the Easy-Lease release agent and I got a perfect release from the glass. The Easy-Lease I used here, was newer and has a label that says 2017. The one I used before has a label with the date 2015 and was at least 2 years old. I learned it the hard way. "Never use Easy-Lease that is older then a year", was a nice lesson for me. Thank you Matt, I was not aware that the exspiration date of the Easy-Lease has to be taken that serious. On other products the expiration date is kind of fuzzier but I will certainly respect that one from now on. Kind regards Hi Pier, thank you for the feedback. I'm glad we have got to the bottom of your problems. There is some 'fuzziness' around the expiry date of the release agent and, as you've found, what happens is that its performance deteriorates (rather than stopping working completely) which is why you got mixed results working with the expired product and perfect results with the fresh product. Nonetheless, it's certainly a product where respect should be paid to its shelf life.
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